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– Heavy shelling was reported today in Aleppo and Damascus, as government forces and rebels both gear up for a major showdown, reports Reuters. The Syrian military is sending convoys of tanks, troop carriers, and other hardware to the vital central cities, leaving rebels in control of much of the countryside. Activists claimed that rebels controlled about half of Aleppo, and, outgunned by the military, they doubt rebels can hold the city, reported the New York Times. Other developments: Rebels are rushing to stockpile munitions in Aleppo, reports the BBC, and setting up checkpoints and snipers even as thousands of residents flee the city. One resident in a Palestinian refugee camp in southern Damascus reported heavy shelling in the south of the city, beginning around 7am and continuing for three hours. As government forces pull out of the Kurdish parts of Syria to prepare for the large offensive against the rebels in Aleppo and Damascus, Kurds are using the withdrawal to fly the Kurdish flag, asserting their independence, reports the Guardian.

BEIRUT, Lebanon — The Syrian military shelled rebel targets in urban enclaves on Thursday as it readied assault troops and armored columns for a possible invasion of Aleppo, Syria ’s densely populated commercial capital, where insurgents have embedded themselves over the past week in preparation for a battle.

 Antigovernment activists reached by phone and Skype in Aleppo said that the city’s civilian population was gripped by foreboding as government forces massed on the southern outskirts, and that fierce street clashes had sporadically erupted. But Syrian military commanders appeared to be awaiting reinforcements before issuing invasion orders.

 Military experts have long speculated that President Bashar al-Assad’s army, which has been scrambling to crush rebel resistance in urban areas like Homs, Hama and more recently central and southern neighborhoods of Damascus during the uprising, lacked the military resources to take on an armed rebellion in all major cities at once. That seemed to explain the delay in Aleppo, where anticipation of an attack has been building for days.

 The United States expressed alarm about the possibility of mass civilian casualties in Aleppo, a Unesco World Heritage site and one of the Middle East’s most storied cities. Victoria Nuland, a State Department spokeswoman, told reporters in Washington that there was “concern that we will see a massacre in Aleppo, and that’s what the regime appears to be lining up for.”

 But Ms. Nuland also indicated that the United States was not reconsidering its stance against military intervention, saying, “We do not think pouring more fuel onto the fire is going to save lives.” And she drew a sharp distinction between Aleppo and the Libyan city of Benghazi, where fears of a slaughter by government troops led to a NATO bombing campaign that proved decisive in toppling Col. Muammar el-Qaddafi last year.

 “The kind of groundswell call for external support that we’ve seen elsewhere is not there,” Ms. Nuland said.

 A resident in the city named Ahmed, reached by Skype on Thursday afternoon, said Aleppo was convulsed with rumors that the army’s elite Fourth Division, commanded by Mr. Assad’s brother Maher, was mobilizing for an attack. “We are terrified,” he said.

 Antigovernment fighters — including foreign fighters — were arriving or were preparing to travel to Aleppo from surrounding areas, activists said. Although the insurgents claimed to have destroyed police stations in two of the city’s neighborhoods, they were repulsed when they tried to take over two others, said Majed Abdel Nour, a spokesman in the city for the Shaam News Network, an antigovernment activist group.

 The possibility of a major battle for Aleppo came as Turkey’s prime minister injected a new element of tension into the Syrian conflict, asserting that Syrian forces had abandoned territories close to the Turkish border that had since been occupied by Kurdish militants hostile to Turkey.

 In recent weeks, activists from Kurdish hamlets near the Turkish border have posted videos of celebrations there, including in Kobani, where residents were seen raising the Kurdish flag.

 The Turkish prime minister, Recep Tayyip Erdogan, told reporters in Turkey that his country’s armed forces would “take whatever steps are necessary against terrorism” in these areas, foreshadowing possible Turkish military incursions into Syria, similar to Turkey’s incursions into areas of northern Iraq where Kurdish militants have sought sanctuary.

 Mr. Erdogan’s warning came a day after Turkey placed new restrictions on Syrian-Turkish commercial trade along the 550-mile border, barring Turkish vehicles from entering Syria after clashes inside Syria in which many were damaged. The Turkish restrictions do not prohibit Syrian merchants from entering Turkey or place any limits on refugees.

 Most of the clashes that have paralyzed Aleppo in recent days have taken place in the poorer, eastern parts, where a host of informal neighborhoods have sprung up in recent years. Populated mainly by Sunni Muslims arriving from rural areas, residents are sympathetic to the fighters, offering them meals to break the Ramadan fast and other support. There have also been clashes near the city’s historic center.

 But with shelling during the night, residents took advantage of daylight to try to flee. Government helicopters continued to patrol Aleppo, firing occasionally, activists said.

 The official Syrian news agency reported Thursday that clashes between the army and armed groups had “resulted in the killing and wounding of many terrorists.”

 Mohamed, a resident from the eastern part of Aleppo, said the army was randomly shelling the city and beefing up its presence at checkpoints. Dozens of civilians had been killed in the past two days, he said.

 “This used to be a restless city,” he said. “Now it’s the opposite.” He added that there were no police officers on the streets, no fuel available and no bread.

 Abu Qusay, a field activist and fighter from nearby Idlib Province, said that he and dozens of other fighters, including Libyans, were preparing to travel on farm roads toward Aleppo. The fighters were bringing some light weapons, and counting on finding more in stockpiles seized by the rebels inside the city, he said.

 In Damascus, activists reported scores of deaths, including among civilians, during heavy fighting in southern suburbs, the scene of clashes over the last two weeks.

 There were also reports of deadly clashes between rebel fighters and the army in Tall Shihab, a town that hugs Syria’s border with Jordan and that sits along a route used by refugees trying to escape Syria.

 At a news conference in Damascus on Thursday, Hervé Ladsous, the United Nations under secretary general in charge of peacekeeping operations globally, elaborated on a decision announced Wednesday to send back roughly half of the 300 monitors whose work has been suspended in Syria since mid-June because of the violence.

 “We found ourselves with too many people with not enough to do,” Mr. Ladsous said.

 Nonetheless, Mr. Ladsous offered assurances that the monitoring mission was still functioning, even though its mandate, which expired last Friday, was only renewed for a further 30 days by the United Nations Security Council. “The U.N. is in no way packing and going,” he said.

 Neil MacFarquhar reported from Beirut, and Rick Gladstone from New York. Reporting was contributed by Kareem Fahim, Dalal Mawad and Hwaida Saad from Beirut, and Jeffrey Gettleman from Antakya, Turkey. ||||| Here's a roundup of the latest developments relating to Syria:

 • The government's counter-offensive against Aleppo is due to start on Friday or Saturday, AFP reports citing a security source. Thousands of troops and opposition forces had been dispatched to the city, as well as 100 tanks and a large number of other military vehicles (see 1.39pm).

 • US officials are reported to favour defected Brigadier General Manaf Tlass as a successor to President Assad; others doubt that he would be acceptable to Syrians (see 9.47am). Saudi Arabia appears to be wooing Tlass too (see 11.23am).

 • Rebel forces in Damascus have retreated to the southern district of Hajar Aswad where they have come under attack, an witness told the Guardian (see 12.11pm).

 • Activists from Yarmouk Palestinian refugee camp in Damascus say at least five civilians were killed and 25 injured after regime forces attacked the camp with tanks and helicopter gunships this morning (see 4.41pm).

 • Syrian opposition factions are meeting in Qatar to seek agreement on a transitional administration. Ian Black, the Guardian's Middle East editor, says some bitter internal debate is likely.

 A statement from the Avaaz organisation regarding the situation in Yarmouk:

 Activists from Yarmouk Palestinian refugee camp in Damascus reported that at least five civilians were killed and 25 injured after regime forces attacked the camp with tanks and helicopter gunships this morning. Activist Muhammad told Avaaz: "The regime forces shelled the neighbourhoods of Orouba and Thalathin, and stormed into the camp with tanks and military vehicles. Deir Yassine clinics were also hit in the shelling." Snipers were positioned rooftops and were taking pot-shots at "anyone moving in the street" according to another resident. Security forces stormed into the Palestinian ICRC hospital, dragging away at least 10 wounded civilians. Activists confirmed that FSA groups are in the neighbourhoods of Tadamon and Hajar al Aswad next to Yarmouk camp, but not inside the camp itself, due to an agreement to keep it as a safe area for displaced civilians. Palestinian families the camp are hosting around 20,000 displaced people – either in their houses or in makeshift shelters inside schools. They are mainly residents who fled the neighbourhoods of Midan and Tadamon and the city of Douma in Damascus suburbs.

 Time Magazine is claiming the first-ever interview with a member of Jabhat al-Nusra, the shadowy group that is alleged to have carried out suicide bombings in Syria (though some have disputed its existence).

 It took weeks of negotiations to secure an interview with a member of the movement, the first time anyone from the group has talked to the media. Higher-ups in the Jabhat declined to be interviewed but agreed to let Ibrahim, a 21-year-old Syrian, be interviewed. The Jabhat has a presence in at least half a dozen towns in Idlib province, as well as elsewhere across the country, including strong showings in the capital Damascus and in Hama, according to the Jabhat member and other Islamists who are in contact with senior members of the group. Bespectacled, with a wispy beard and thin moustache, Ibrahim said he joined the group eight months ago. He was recruited by his cousin Ammar, the military operations commander for their unit and a Syrian veteran of the Iraq war who fought alongside his Sunni co-religionists against the American invaders.

 Luke Harding, who is in a rural area near Aleppo, relays FSA claims about shelling in the Salaheddin area in the south of the city.

 Didn't manage to reach #Aleppo today. Spoke to commander inside. He confirms regime shelling of Salaheddin and other rebel districts... — Luke Harding (@lukeharding1968) July 26, 2012

 ...Also reports helicopter gunship above Free Syrian Army neighbourhoods. Seven families killed on Tuesday night in shelling, locals say — Luke Harding (@lukeharding1968) July 26, 2012

 Activists posted footage purporting to show damage caused by shelling in the Salaheddin area.

 A spent shell cannister is shown at the end of the clip.

 The Syrian Observatory for Human Rights said helicopters had attacked the Salaheddine and al-Jazmaty neighbourhoods today.

 It says 11 people were killed in various districts of the city.

 Rebels' claims that they control many of the neighbourhoods of Aleppo, for now at least, have been underlined by a video showing them cleaning the streets in a central district.

 Greece is closing its embassy in the Mezzeh district of Damascus from today, "due to the worsening security situation", Reuters reports. Consulates in Aleppo, Latakia and Tartus will remain open, the foreign ministry said.

 The closure of Brazil's embassy, also in the Mezzeh district, was

 reported yesterday, with the ambassador quoted as saying "you simply cannot step outside there is so much shooting going on".

 Diplomatic mischief making from Russia? Foreign minister Sergei Lavrov has offered to send 30 observers to the depleted UN monitoring mission in Syria.

 Lavrov: I hope the UNSC will extend its mission in Syria and restore or even increase its strength. In this case, we could send 30 observers — MFA Russia (@MFA_Russia) July 26, 2012

 Yesterday, UN peacekeeping chief Herve Lasdous, said around half the 300 UN monitors had left Syria amid speculation among diplomats that he was trying to dismantle the mission. The mission's current mandate is not expected to be renewed when it expires in 26 days.

 Here's a roundup of the latest developments relating to Syria:

 • The government's counter-offensive against Aleppo is due to start on Friday or Saturday, AFP reports citing a security source. Thousands of troops and opposition forces had been dispatched to the city, as well as 100 tanks and a large number of other military vehicles (see 1.39pm).

 • US officials are reported to favour defected Brigadier General Manaf Tlass as a successor to President Assad; others doubt that he would be acceptable to Syrians (see 9.47am). Saudi Arabia appears to be wooing Tlass too (see 11.23am).

 • Rebel forces in Damascus have retreated to the southern district of Hajar Aswad where they have come under attack, an witness told the Guardian (see 12.11pm).

 • Syrian opposition factions are meeting in Qatar to seek agreement on a transitional administration. Ian Black, the Guardian's Middle East editor, says some bitter internal debate is likely.

 • Arab states plan to go to the UN general assembly and seek approval of a resolution calling for a political transition in Syria following the security council's failure to address the escalating crisis, AP reports.

 • The head of the UN peacekeeping Herve Ladsous is trying to dismantle the now depleted monitoring mission in Syria, diplomats have told Inner City Press. One claimed that Ladsous was deliberately "misinterpreting" a resolution to extend the mission for 30 days.

 • Arms control campaigners claim a first draft of a UN global arms trade treaty is meaningless as it would not stop weapons shipments from Russia to Syria.

 • The rebel-held town of Azaz (or Izzaz) north of Aleppo is ruins about after weeks of fighting, Reuters reports.

 More bluster from the Turkish prime Recep Tayyip Erdogan, or does he know something we don't?

 AP quotes him saying that Bashar al-Assad and those close to him are about to leave power and preparations are underway for a "new era" in Syria.

 We're wondering what has happened to Sana, the Syrian government's news agency. Its website has been down for the last two days.

 Sana has gone offline several times recently, but never for such a long period. Possibly it has come under a cyber attack, but usually someone claims responsibility for such attacks – and we're not aware of any claims.

 In theory, a cyber attack should not prevent Sana from using Twitter but there have been no tweets from its English-language Twitter account (@SANA_English) since Tuesday morning – which is very unusual.

 Activists have smashed framed photographs of president Assad looted from a police station in Aleppo, according to new video footage.

 The police building is in the Karm al-Qaterji district of the city, east of the centre according to Twitter user @markito0171 who has been mapping the location of activists videos for months.

 The government's counter offensive against Aleppo is due to start on Friday or Saturday, AFP reports citing a security source.

 It said that thousands of troops and opposition forces had been dispatched to the city.

 It quoted Free Syrian Army colonel, Abdul Gabbar Kaida, as saying:

 The army's reinforcements have arrived in Aleppo. We expect a major offensive at any time, specifically on areas across the southern belt, from east to west.

 Kaida, who is directing the rebel forces in Aleppo, also claimed that 100 army tanks — as well as a large number of military vehicles — had arrived in Aleppo.

 Yesterday Kaida told the Guardian's Luke Harding that the rebels controlled half of Aleppo.

 The Syrian foreign ministry is playing down the defection of two of its diplomats – Abdulatif al-Dabbagh, the ambassador in the UAE, and his wife, Lamia Hariri, (both pictured) who was Syria's envoy in Cyprus.

 The website of Syria's state news has been mysteriously out of action for most of this week, so for now we have to turn to the Chinese Xinhua agency for the Syrian government's line.

 It reports:

 Syrian foreign ministry spokesman Jihad Makdissi told Xinhua that Dabbagh arrived in Syria on June 4 for consultation upon the request of the ministry, adding that the embassy in UAE " since then was run by charge d'affairs and now we notified the UAE that he is no longer an ambassador." The ministry, meanwhile, made clear that Hariri is not ambassador, but a diplomat that has been running the Syrian embassy in Cyprus till an ambassador is appointed.

 Earlier this month, following the defection of Nawaf al-Fares, the Syrian ambassador in Baghdad, the foreign ministry said he had been dismissed for leaving the embassy without official authorisation.

 Russia said its flotilla of 10 battleships currently in the eastern Mediterranean will not dock at Tartus, its naval port in Syria.

 RIA Novosti quotes naval chief vice admiral Viktor Chirkov as saying: "The joint fleet flotilla will not enter the port of Tartus. It is carrying out military drills in the Mediterranean."

 Other sources have confirmed Mahmoud Nassar's account of the attack on Hajar Aswad.

 The Syrian Observatory for Human Rights has this:

 The Hajar al-Aswad neighbourhood is being bombarded by regime forces, who have surrounded the neighbourhood from several entrances; helicopters are being used in the attack.

 Activists have posted video of smouldering cars and a building purporting to show the nearby Yarmouk Palestinian camp.

 Dania, a Damascus activist, tweeted:

 You can listen to audio of Hajar Mahmoud Nassar describing what he witnessed during the government's assault on Hajr Aswad today.

 Read the previous post for the full report. At the end of the clip Nasar says: "I don't know if this day will end normal and safe ... they shoot everything."

 Rebel forces in Damascus have retreated to the southern district of Hajar Aswad where they have been under attack for the last six hours, an witness told the Guardian.

 Mahmoud Nassar, a citizen journalist from the area, said it has been under tank and helicopter bombardment.

 "They [the Free Syrian Army] have withdrawn to Hajar Aswad and the areas around Hajar Aswad," he said.

 The government's attack against the area is part of a counter offensive to retake the city. The government has retaken the Midan district and the nearby al-Qadam district. But there continue to be clashes across the whole of south of the city, according to to Nassar.

 I saw them since six hours trying to go up a street - we are talking about 500m. They didn't succeed to bust those 500m because there's strong resistance from Hajar Aswad. So they are trying to go from the side of Hajar Aswad - from Yarmouk and al-Qadam.

 View Damascus in a larger map

 This Google map shows the areas he mentioned.Nassar said he saw a tank shell kill a man working on the tyres of a car. He also mentioned another man who was shot by a sniper while shopping for bread.

 Nassar claimed that government forces were using heavy machine guns to attack an area that included a Palestinian hospital. "I saw the civilians trying to escape," he said. The security forces occupy the territory around the hospital in the area, he said.

 Nassar saw helicopter firing machine guns and rockets at an area to the south of Hajar Aswad that includes a military base. "There are no aircraft just helicopters - two helicopters," he said.

 The Free Syrian Army withdrew its forces from Damascus after the government began using helicopters against civilian areas, he claimed. Rebels don't have "smart weapons" to combat helicopters, he said.

 I think it will be a long day in Yarmouk and Hajar Aswad. I'm about a 1km away and I can hear shots.

 The Free Syrian Army is trying to attack tanks right now" he said, but added they could not fire because of Palestinian civilians in the area.

 He suggested that the rebels were trying to create a safe haven in the Yarmouk camp. Most of the Palestinians in the camp supported the rebels, he claimed.

 Brigadier General Manaf Tlass, the cigar-chomping defector backed by US officials (see 9.47am) seems to have thrown his lot in with the Saudis rather than the Qataris – unlike many of the other Syrian defectors.

 He's featured today in an interview (in Arabic) with the Saudi-owned Asharq al-Awsat where he thanks King Abdullah "for giving me this opportunity to visit Saudi Arabia" and describes the kingdom as "a friendly country to Syria".

 He also confirms – as we suggested in the live blog yesterday – that he has been in Saudi Arabia performing the umrah pilgrimage. This helps to explain the period of silence following his defection.

 In extracts from the interview translated by Reuters, Tlass says:

 I am discussing with ... people outside Syria to reach a consensus with those inside. I left (Syria) ... to try to help the best I can to unite the honourable people inside and outside Syria to set out a road map to get Syria out of this crisis. I realise this is a difficult phase ... It's difficult for one person to bear the responsibility of such a phase. A group (including opposition) from inside and outside Syria should cooperate to accomplish this phase.

 He adds that he "did not leave Syria to lead the transitional period".

 Following the Qubair massacre last month, the Syrian government appointed its own commission to investigate, but it wasn't long before reports started circulating that the head of the commission, Talal Houshan, had defected.

 These reports now appear to be confirmed by a video posted on YouTube where Houshan, apparently reading a prepared statement, accuses the Syrian government and its shabiha supporters of killing women and children.

 In the statement, he refers to numerous "crimes" by the regime and cites eyewitnesses.

 Many Kurdish towns in the northeast of Syria are now flying the Kurdish flag as Syrian troops have withdrawn from the region to fight back the offensives in Syria's two largest cities, Syria-watcher Joshua Landis writes on his blog.

 Landis quotes a friend in Iraqi Kurdistan who says the Kurds' takeover of towns in Syria has "led to a crisis of relations between them and the FSA/rebels".

 Supposedly, some months back there had been a pledge of mutual support between the Kurds and the rebels, regarding resistance against the regime. Now however, the Kurds seem more interested in protecting their homeland than in participating in the nation-wide struggle against the regime. After taking control of Hasake (haven't verified this), a conflict emerged between them and the FSA that wanted to control the area due to its strategic importance.

 Landis also points to an article in The National by Aymenn al-Tamimi which begins:

 Developments in Syria and Iraq have led some to speculate that the birth of an independent Kurdish state might be at hand. A closer analysis shows that a united Kurdistan is still unlikely, although a separate semi-autonomous Kurdish community in Syria, with some parallels to the Kurdish Autonomous Region in Iraq, is a growing possibility.

 Blogger Brown Moses has highlighted another video of a warplane flying over Aleppo.

 The outline of the aircraft in the video – much clearer than in previous clips – shows that it is not a MiG fighter, contrary to what various news organisations are reporting.

 The Wall Street Journal – which seems to think it's America's job to choose a replacement for Bashar al-Assad – says US officials have latched on to the cigar-chomping Manaf Tlass as a likely prospect.

 Tlass, who defected recently, is "one of the few figures in opposition to the regime who could potentially help restore order in Damascus and secure Syria's vast chemical-weapons stockpile", Eric Linton writes citing unnamed officials.

 Tlass was a commander in Syria's elite Republican Guard before his July 6 defection, and his father served as defense minister under Assad's late father, President Hafez al-Assad, for 30 years. He is also, unlike the Assad clan, a Sunni Muslim, which western officials hope could make him acceptable as a transitional figure to the country's rebel fighters and opposition leaders, who are also largely from the Sunni sect of Islam.

 But the article doesn't find many others who agree. It acknowledges that "many in the opposition consider Tlass and his family too closely tied to the Assads' repression and corruption to be acceptable to Syrians".

 It quotes a US defence official as saying "It's too early to say if Tlass will stand the strain and pick up traction or just fade away", while exiled Syrian activist Ammar Abdulhamid says:

 Someone like Tlass is difficult to sell to the Syrian people. He certainly can't play any leading role in a transition.

 In an article posted on the Jadaliyya website, Bassam Haddad describes some scary meetings with Manaf Tlass while researching the development of capitalism in Syria (and the related corruption).

 On reform, he asserted the importance of gradualism, a Hafez al-Asad mantra, one that suits the reformers' timetable, not that of the purported beneficiaries. But he was also unabashed in asserting the need for top-down control, which to him transcended questions of right and wrong, or democracy and authoritarianism. The regime had to guide the reform process based on a holistic view, one that takes into account local and regional variables. I interjected that this approach is the norm for regimes like Syria's because reform is not the goal. He did not correct me, and reasserted the need for control.

 Almost unnoticed last week, as attention focused on battles in Damascus, Kurdish activists in north-eastern Syria started taking control of a few towns without encountering much resistance from the Assad regime's security forces.

 In an article for Comment is free, Fazel Hawramy (aka Kurdishblogger) says this is a significant development which could potentially tilt the balance of power against Assad. Kurdish relations with the opposition Syrian National Council (SNC) are still problematic, though:

 In April, the SNC issued a National Charter to "redress the injustice … the Kurdish people have faced for decades …" and work towards "the abolition of all discriminatory policies … and compensate those affected." While this is an important starting point, the Kurds – who have faced years of discrimination at the hands of successive "Arab" regimes in Syria – find it difficult to trust a guarantee by the SNC, which is dominated by Arab nationalists and members of Muslim Brotherhood movement. The Kurdish parties believe the charter falls short of full constitutional recognition. The insistence of SNC members to retain the word "Arab" in the official name of the country – the "Syrian Arab Republic" – has been one of the main stumbling blocks for the Kurds to trust the SNC as their legitimate voice in a post-Assad Syria.

 (all times BST) Welcome to Middle East Live.

 Here's a roundup of the latest developments and analysis on Syria:

 • All the signs indicate that a battle is looming in Aleppo, the New York Times reports.

 After withdrawing all visible security forces, for a day, Syrian Army troops brought in on trucks or buses suddenly deployed around the 13th-century citadel. Thousands more were en route, according to rebel fighters and activists. "People know there is going to be chaos, fighting, shelling, so people are frightened," said one activist reached via Skype. "They have stocked up on canned goods and are not venturing out."

 • "Victory is coming soon. Almost half of Aleppo is now with the FSA," Abdul Gabbar Kaidi the colonel in charge of the rebel battle for Aleppo told Luke Harding in northern Syria.

 In this dark, asymmetric struggle, there is a sense that the rebels are winning, not by great degrees, but slowly and inexorably: an unstoppable human tide. The regime may have succeeded in quelling the rebellion in Damascus, for the moment. But virtually the entire country is in the grip of a popular revolution. The battle for Syria's biggest city, Aleppo ... is desperately poised. The rebels are outgunned, fighting street by street, and up against a mostly invisible enemy that rains death from the skies.

 You can see video a interview with Harding in Syria here.

 • Arab nations plan to go to the UN general assembly and seek approval of a resolution calling for a political transition in Syria following the security council's failure to address the escalating crisis, AP reports. Saudi Arabia's Ambassador Abdallah al-Mouallimi and Qatari diplomat Abdulrahman Al-Hamadi announced plans to seek action by the 193-member world body, where there are no vetoes, during a Security Council debate on the Middle East.

 • The head of the UN peacekeeping Herve Ladsous is trying to dismantle the now depleted monitoring mission in Syria, diplomats have told Inner City Press. One claim that Ladsous was deliberately "misinterpreting" a resolution to extend the mission for 30 days.

 • The opposition Syrian National Council is poised to set up a base on Syrian soil like the Libyan rebels did in Benghazi, but the divisions appearing to be opening up, writes Ian Black.

 The group's leaders will meet in the Qatari capital, Doha, today where SNC sources say that Riyad Seif, a respected dissident, is a leading candidate to head a "consensus-based" civilian administration. But Brigadier General Manaf Tlass, the most important member of Assad's inner circle yet to defect, is also being mooted as the head of an Egyptian-style supreme military council that could keep the Syrian armed forces intact and loyal, according to SNC officials and foreign diplomats.

 • Syria's ambassadors to the United Arab Emirates and Cyprus - a married couple - have become the latest senior figures to defect from the regime, the White House has confirmed. Spokesman Jay Carney said: "This is another indication, we believe, that senior officials around the Assad inner circle are fleeing the government because of the heinous actions taken by Assad against his own people, and the recognition that Assad's days are numbered."

 • Arms control campaigners claim a first draft of a UN global arms trade treaty is meaningless as it would not stop weapons shipments from Russia to Syria. Anna Macdonald, Oxfam's head of arms control, said the draft would allow countries to honour existing contracts to states no matter how much circumstances changed. "This means Russia could continue to supply arms to Syria. That is a key test for us. Would the draft [treaty] stop Russia arming Syria? No it wouldn't," she said.

 • The rebel-held town of Azaz (or Izzaz) north of Aleppo is ruins about after weeks of fighting, Reuters reports.

 Some houses have collapsed in heaps of rubble, pounded by tank fire, while the remaining buildings stand scorched or pock-marked with bullet holes. Burnt-out tanks struck by rebels' rocket-propelled grenades sit motionless on the town's roads, while spent bullet casings lay strewn across the ground next to an old leather Russian tank helmet. A mosque in the town's centre that served as a base for Assad's army is now all but destroyed, scorched tanks and armoured vehicles immobilised in its courtyard. Sandbags stacked in the mosque's windows mark deserted army sniper positions.

 • The question is not how long Assad can cling to power, but will the authoritarian structure survive him? argues Fawaz Gerges director of the LSE's Middle East Centre. ||||| 1 of 12. A building burns after shelling at Juret al-Shayah in Homs city July 25, 2012. Picture taken July 25, 2012.

 AMMAN/BEIRUT (Reuters) - President Bashar al-Assad's forces renewed a ground and aerial bombardment of Aleppo on Friday, extending efforts to crush rebels in Syria's commercial capital in what the United States said it feared could become a massacre.

 Insurgents targeted army roadblocks and security installations, with both sides avoiding close-quarters warfare in the city of 2.5 million people, Syria's biggest urban center.

 The U.S. State Department said credible reports of tank columns moving on Aleppo, along with air strikes by helicopters and fixed-wing aircraft, represented a serious escalation of Assad's efforts to crush a rebellion that began 16 months ago.

 "This is the concern: that we will see a massacre in Aleppo, and that's what the regime appears to be lining up for," State Department spokeswoman Victoria Nuland said.

 Troops stationed on the outskirts of Aleppo unleashed barrages of heavy-caliber mortar rounds on the western neighborhoods of Saladin, al-Sukkari and al-Fardos, while Russian MI-25 helicopter gunships struck al-Sakhour in the east with rockets, several opposition activists in the city said.

 RISING CASUALTIES

 In the first reported casualty on Friday, a man of about 60 wearing a traditional white prayer outfit was killed near a park in Saladin. His body was placed in a mosque pending identification.

 Thirty-four people were killed in Aleppo and its environs on Thursday, according to opposition activists keeping a tally of casualties in the northern city.

 "The rebels have so far been nimble, and civilians have mostly been the victims of the bombardment," said activist Abu Mohammad al-Halabi, speaking by phone from the city.

 "There is lots of internal displacement, and schools have been turned to makeshift shelters that are packed. One shell hitting a school will result in a catastrophe," he said.

 "The regime is massing troops and tanks at the entrances of Aleppo, but it seems it is for now content with bombarding the city, with the rebels constantly on the move."

 Majed al-Nour, another activist, said rebels attacked a security outpost in the neighborhood of Bustan al-Joz, which is close to the Aleppo city center, on Thursday.

 "The rebels are present in the east and west of the city, and have a foothold in areas of the center. The regime forces control the entrances of Aleppo and the main thoroughfares and commercial streets and are bombarding the residential districts that fell into rebel hands," he said.

 Nour said tens of thousands of people had fled Aleppo to nearby northern rural regions close to Turkey from which the Syrian army has withdrawn in recent weeks to focus on urban areas where relatively lightly armed rebels have hunkered down.

 UNITING THE OPPOSITION

 The heavy fighting around Aleppo follows an audacious bomb attack that killed four of Assad's closest lieutenants in Damascus on July 18 and led some analysts to speculate that the government's grip was slipping.

 With U.N. Security Council resolutions for sanctions against Syria vetoed by Russia and China for a third time last week, the United States has said it is stepping up assistance to Syria's fractured opposition, although it remains limited to non-lethal supplies such as communications gear and medical equipment.

 One of the most senior figures to defect from Assad's inner circle, Brigadier General Manaf Tlas, put himself forward on Thursday as someone who could help unify the opposition inside and outside Syria on a plan for a transfer of power.

 Tlas, speaking in a newspaper interview in the Saudi city of Jeddah, also said he was looking for support from Saudi Arabia and other powers. "I am discussing with ... people outside Syria to reach a consensus with those inside," Tlas told Thursday's edition of the Saudi newspaper Asharq al-Awsat.

 Tlas went on to Turkey and met with Foreign Minister Ahmet Davutoglu. Turkey, a former ally of Assad and now one of his fiercest critics, has a heavy strategic stake in shaping any post-Assad leadership in neighboring Syria.

 Tlas appeared briefly with Davutoglu at an official guest house, but made no statement.

 Turkey closed its border posts with Syria on Wednesday to all traffic except Syrian refugees.

 Russia, one of the few remaining allies of the authoritarian Assad whose family has run Syria for 42 years, said calls for him to quit power were hindering efforts to end the conflict.

 Foreign Minister Sergei Lavrov said such calls, led by the United States, Turkey and other Western and Arab nations, were fanning violence. He reiterated Moscow's contention that support for Syrian rebel groups was tantamount to backing terrorism.

 Iran promised to stand by Syria, come what may.

 First Vice President Mohammad Reza Rahimi told Iran's Press TV on Thursday that the Islamic Republic's support for Syria, its main Arab ally, was "unchangeable", countering suggestions that Iran could soften its backing for Assad.

 (Writing by Will Waterman; Editing by Mark Heinrich) ||||| Media caption The BBC's Ian Pannell travels with cheering rebels in Aleppo. His report contains unverified graphic images of the victims of Syria's conflict

 Syrian rebels in Aleppo have begun stockpiling ammunition and medical supplies as government forces prepare outside the city for a major battle.

 Artillery and helicopter gunships have resumed attacking rebel targets and 14 people have been killed, activists say.

 Troops and tanks are said to be ringing the city and reinforcements are reportedly on their way to join them.

 In Damascus, activists said the army had pounded the capital's last rebel-held areas and 20 civilians had died.

 Five children and four women were killed, according to London-based pro-opposition group Syrian Observatory for Human Rights, when shells hit the Yalda area. Helicopters also attacked the nearby district of Hajar al-Aswad.

 The government has said its forces are trying to dislodge the "remnants of mercenary terrorist groups".

 At the scene It is almost inconceivable that President Assad could allow his government to lose control of the city, so it is reasonable to expect that they are going to throw everything they possibly can at the city. And that is what they are preparing for here. One of the neighbourhoods is appealing for more blood supplies. We are hearing reports of hundreds, possibly thousands of families leaving some districts. Everybody is bracing themselves for an intensive campaign. The way it has worked in other cities is that there is an intensive bombardment by artillery and mortars, and then when it starts to go calm, tanks begin to roll in. This is a very congested heavily populated area, so it will be bloody. Rebels surprise regime in Aleppo

 Checkpoints and snipers

 In Syria's commercial hub of Aleppo, rebels have set up checkpoints and sniper positions and claim to be in control of half of the city.

 A Syrian security source was quoted by AFP news agency as saying that special forces had begun arriving on the edges of Aleppo in readiness for a "generalised counter-offensive on Friday or Saturday".

 A similar account has emerged from the Syrian Observatory for Human Rights, which talks of reinforcements arriving from the main Damascus to Aleppo road to the south.

 Columns of troops and tanks are also thought to be travelling from the city of Hama, and from the border posts with Turkey in Idlib province.

 Aleppo is the country's commercial capital, and key to the battle to control the north of the country.

 Street battles have been reported throughout the city for days, as rebels try to hold on to neighbourhoods captured in an offensive that began at the weekend.

 Although it was relatively quiet on Thursday, activists said artillery fire could be heard in the Salah al-Din neighbourhood in the southwest of the city and clashes in Tariq al-Bab in the east had led to two rebels being killed.

 Foreign journalists operate under heavy restrictions in Syria so claims made by either side are difficult to verify.

 The BBC's Ian Pannell near the city says thousands of people are leaving as fears grow that an intense battle is looming.

 He says the rebels are reinforcing their ranks with more fighters, medical supplies, and ammunition such as Kalashnikov rifles.

 Talal al-Mayhani, an activist with connections in the rebel movement in Aleppo, said the battle for the city was likely to play out in a similar way to an earlier battle in the capital Damascus, when rebels took control of large parts of the city before being forced to withdraw in the face of a government offensive.

 Reporter Laurent Van der Stockt from French newspaper Le Monde told the BBC that Free Syrian Army (FSA) commanders in Aleppo were full of confidence but were lacking weapons.

 "A commander told me this morning they attacked a convoy and destroyed 10 armoured vehicles."

 Luke Harding of the Guardian newspaper, 50km (30mi) west of Aleppo, told the BBC that much of the rest of Aleppo province was in rebel hands but it was an exaggeration to say they were in control of half of the city.

 "It's true they're in the southern part of the city and the northeast. Tactically, they're doing guerrilla-style attacks and they can melt away quite quickly."

 In Damascus, where government forces have largely repelled a sustained assault by rebels, state TV reported more clashes in the southern district of Qadam.

 The report showed army troops firing intensively as they moved into heavily damaged streets.

 The violence also spread to the Yarmouk Palestinian refugee camp, where activists said street battles had taken place between rebels and soldiers.

 More than 16,000 people have been killed in Syria since the start of anti-regime protests in March 2011.

 Repeated diplomatic attempts to stop the violence have foundered, with the UN Security Council bitterly divided.

 Thousands of refugees have already sought shelter in Turkey, Lebanon, Jordan and Iraq.

 And conditions throughout the country have worsened as the fighting has spread and intensified in the two main cities in recent weeks. |||||


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Participants.

 For this prospective cohort study, first-time mothers participated in an MRI acquisition before and after their pregnancy, allowing us to use each woman's pre-pregnancy brain scan as her individual baseline. Data were collected over a total period of 5 years and 4 months. The participants were recruited via the fertility center Instituto Valenciano de Infertilidad (IVI, Barcelona), by flyers and by word of mouth. We sought nulliparous individuals who were planning to try to become pregnant in the near future but were not pregnant yet and nulliparous individuals without such plans. Participants were therefore not randomly assigned to groups. Recruitment and data collection for all groups was initiated at the same time. Although individuals were recruited separately for the pregnancy (PRG) groups (women and men becoming parents between the sessions, hereafter referred to as F PRG and M PRG , respectively) and the control (CTR) groups (women who did not become pregnant within this time frame and men whose partners did not become pregnant, from here on referred to as F CTR and M CTR ) on the basis of their intention to become parents in the near future, the final group allocation depended on the transition from nulliparity into primiparity in between sessions. Women trying to become pregnant were scanned in the early follicular phase of their menstrual cycle or before the insemination or transfer in the fertility-treated group. Only participants who had never experienced a previous pregnancy beyond the first trimester were included in the study. Sixty-five nulliparous women and 56 men without children were scanned for the first time point, including 43 women and 37 of their male partners who wanted to become parents for the first time, aiming for a minimum of 16 participants51 in each group based on fertility statistics52. Pre-established exclusion criteria comprised neurological or psychiatric conditions or a history of substance use disorders as assessed by means of the MINI International Neuropsychiatric Interview53 applied by a clinical psychologist. The main criterion for continuing in the study for participants in the PRG group was achieving pregnancy in the period following the first MRI session. Of the final sample of 25 women who underwent pregnancy between the sessions, the majority (20 women) had an estimated pregnancy onset within 6 months after the session. Five participants became pregnant between 6 and 12 months after their participation in the first MRI session. To ensure that this longer period between the session and conception did not have a significant impact on the results, we also repeated our analysis excluding these 5 women, which rendered very similar results (Supplementary Table 15). Thirty-two participants, comprising 17 women and 15 men, did not achieve pregnancy within this period and did not participate in the follow-up session. Two women and 2 men who were initially recruited for the F PRG and M PRG groups participated as control subjects in the F CTR and M CTR groups when conception was not achieved. In addition, 2 women and 2 men who participated in the first session as control participants were scanned as participants of the F PRG and M PRG groups in the second MRI session following an unexpected pregnancy. In addition, 1 participant became claustrophobic inside the scanner, 4 did not return for the Post session and 3 participants had to be excluded due to poor image quality or neuropathological conditions encountered in the MRI scan.

 Our final sample consisted of the following subject groups with complete Pre and Post data sets: 25 primiparous women, 20 nulliparous control women, 19 first-time fathers and 17 control men without children. Unless explicitly stated otherwise (in case of analyses including other measures only available for a subset of the participants), these represent the sample sizes used in the comparisons. There were no statistically significant differences in Pre-to-Post time interval, age or level of education between the PRG and CTR groups (mean ± s.d.: Pre–Post time interval: M PRG : 459.00 ± 117.46 d, M CTR : 419.17 ± 93.17 d; t = 1.12, P = 0.272. F PRG : 463.52 ± 108.33 d, F CTR : 413.05 ± 106.86 d. t = 1.56, P = 0.126. Age: M PRG : 35.21 ± 4.30 years, M CTR : 31.64 ± 6.41 years. t = 1.94, P = 0.063. F PRG : 33.36 ± 3.97 years, F CTR : 31.10 ± 5.63 years. t = 1.58, P = 0.123. Education: number of participants finishing secondary school/college/university or above: M PRG : 2/4/13, M CTR : 1/3/13, χ2 0.37, P = 0.833. F PRG : 2/4/19, F CTR : 2/3/15, χ2 = 0.06, P = 0.971), but as there was a trend for an age difference in the male groups, we also repeated our model including age as a covariate (Supplementary Tables 16 and 17), which had very little impact on the results. In addition, correlation analyses were performed to further examine potential associations of age and Pre-to-Post time interval with GM volume changes within the observed areas affected by pregnancy (using an explicit mask of the main contrast). These analyses rendered only a trend for stronger volume reductions in the right superior temporal sulcus cluster in the younger women (P = 0.095, FWE-corrected).

 The Post session took place on average at 73.56 ± 47.83 d (mean ± s.d.) after parturition. A model including the time interval between the birth and the Post scan as a covariate rendered results that were highly similar to the main results (Supplementary Table 14). In addition, to further examine the effects of the time between parturition and the Post scan on the GM changes within these regions, we performed correlation analyses with this time interval using the main contrast as an explicit mask. These analyses rendered no significant results (for either a linear, quadratic or cubic positive or negative correlation).

 Nine women achieved pregnancy by natural conception and 16 women by means of fertility treatment. The effect of a natural or assisted conception was further investigated by comparing these groups (Supplementary Table 4) and by separately examining the changes within these groups (Fig. 2, Supplementary Fig. 4 and Supplementary Table 5), revealing no significant impact of the natural versus assisted route to conception on the brain changes of pregnancy. Of the fertility-assisted group, 12 women underwent in vitro fertilization (IVF, 3 involving an egg donation and 5 involving intracytoplasmic sperm injection (ICSI), 4 without egg donation or ICSI), 3 intrauterine insemination (IUI), and 1 a frozen embryo transfer. Albeit negligible in comparison to the hormone surges of pregnancy itself, each of these procedures involves hormone treatment which took place after the Pre session (for IUI: gonadotropins (follicle-stimulating hormone, luteinizing hormone, chorionic gonadotropin, human menopausal gonadotropin) and progesterone; IVF and ICSI: the same plus a gonadotropin-releasing hormone analog; egg donation or embryo transfer: estrogens, progesterone, GnRH analog). To further examine the possible effects of treatment-related hormone therapy, we also repeated these analyses with a more homogeneous group of fertility-assisted women undergoing a procedure with the same approach in terms of hormone therapy (i.e., only women undergoing conventional IVF or IVF involving ICSI, 9 in total). Again, no significant differences were observed between this group and the women who were not exposed to fertility treatment-related hormones (the naturally conceiving group) and similar brain changes were observed in these subgroups (Supplementary Table 18). Future studies involving a larger sample of women undergoing fertility treatments are likely to uncover more subtle changes related to the hormone therapy associated with fertility treatments.

 Ten of the women carried a boy, and 11 a girl. The remaining 4 had twins (2 mixed twins, 1 male twins, 1 female twins). Considering the previously observed effects of fetal sex on cognitive changes in pregnant women54, we additionally compared the women carrying a boy to the women carrying a girl (excluding the four women having twins). No differences in GM volume changes were observed between these groups.

 One woman suffered from eclampsia during labor, 2 had premature deliveries and 2 women suffered from high-risk pregnancies with kidney complications or antiphospholipid syndrome. Leaving out the women with complications during pregnancy or delivery had very little effect on our results (Supplementary Table 19). Twenty of the experimental women gave birth to a singleton and four had twins. Eight of the women gave birth by cesarean section and 17 by vaginal birth. All women except 1 received epidural anesthesia during delivery. Sixteen women practiced exclusive breastfeeding (breast milk as their infant's sole source of nutrition), 2 practiced breastfeeding supplemented by formula feedings, 2 had started breastfeeding their infants but had stopped by the time of the Post scan, and 2 never started breastfeeding. Very similar results were obtained when including variables representing the type of conception, type of delivery, breastfeeding status and number of fetuses as covariates in the model (Supplementary Table 20), suggesting that these factors are not driving the observed neural changes. However, the current study was not designed to further investigate the possible impact of such factors, and future studies investigating these in more detail may reveal specific neural changes associated with these variables.

 In the Post session, the Edinburgh Postnatal Depression Scale55 was administered to the primiparous women to detect symptoms of postpartum depression. One of the mothers showed symptoms of postpartum depression and was being helped by a specialist. Excluding this participant from our analyses did not significantly affect our results (Supplementary Table 21).

 Blood samples were acquired at the sessions before and after pregnancy from a large portion of our participants. Unfortunately, for practical reasons, we could only obtain blood samples from 2 of the women during pregnancy itself. Therefore, we cannot use hormonal data to pinpoint the observed neural changes to specific endocrine changes of pregnancy.

 For the Post + 2 years session, we asked the 25 primiparous women to come back for another MRI acquisition. Of these 25 women, 11 had not yet experienced a (partial) second pregnancy since the last MRI session and were willing and able to participate in this follow-up session (mean time since birth: mean ± s.d.: 2.32 ± 0.50 years, age at Pre scan: 33.72 ± 3.32 years).

 The study was approved by the local ethics committee (Comitè Ètic d'Investigació Clinica de l'Institut Municipal d'Assistència Sanitària), and written informed consent was obtained from all subjects before their participation in the study.

 Data acquisition.

 MRI images were obtained in a Philips 3T scanner. High-resolution anatomical MRI brain scans were acquired using a T1-weighted gradient echo pulse sequence (TR = 8.2 ms, TE = 3.7 ms, NSA = 1, matrix = 256 × 256, FOV = 240 mm, 180 slices, thickness = 1 mm, no gap, FA 8°). Due to an unexpected technical problem, the radio frequency head coil was replaced for some time with another head coil, and 28 scans in total were acquired using the latter coil. There were no significant differences between the groups in the number of scan acquired with this head coil (χ2 = 4.21, P = 0.240). Nonetheless, to err on the side of caution, we also repeated the main analysis without these scans acquired with the temporary head coil, which rendered highly similar results (Supplementary Table 22). Furthermore, direct comparisons of the subjects acquired with the different head coils were performed, rendering no significant results. Finally, the head coil was introduced as a nuisance covariate in all neuroimaging analyses. In the Post + 2 years session, an MRI scan was acquired with both radio frequency head coils for those participants for whom a different coil was used in a previous acquisition, allowing us to match the comparisons on head coil type. Therefore, no covariate for the head coil was included for analyses involving the Post + 2 years session.

 The Post MRI session also included an fMRI paradigm (T2*-weighted gradient echo EPI sequence. TR = 3,000 ms, TE = 35 ms, matrix = 128 × 128, FOV = 230 mm, 30 slices, thickness = 4 mm, gap 0.5 mm, FA 90°) that examined the new mothers' neural responses to their babies. During this MRI session, pictures of the women's own and other unknown babies were shown to the participants using Presentation software (NeuroBehavioral Systems). The images were extracted using Adobe Photoshop CS5 from short movies that were shot by one of the experimenters, or in some cases by the father, at a home visit a few days before the Post session. For the women who had twins, movies were acquired from both babies. The pictures represented cut-out faces on a black background and were matched for size, resolution, brightness and facial expression. For each participant, 28 images of their own baby (14 of each infant in case of twins) and 28 images of other babies were presented in randomized order in an event-related fashion (trial duration 1,500 ms, randomized inter-trial interval 750–1,250 ms), with an average number of trials of (mean ± s.d.) 72.15 ± 6.64 and 72.40 ± 6.99 for the other baby and own baby conditions respectively. Pictures involving sad facial expressions (crying) and neutral facial expressions were acquired from each infant. Additional explorations of the data based on facial expression are provided in Supplementary Table 23. Five participants could not be included in the fMRI analyses due to head motion exceeding 3 mm (for translations) or 3° (for rotations) (1 woman), artifacts in the data (2 women), or incomplete data sets (2 women), rendering a sample of 20 primiparous women for this part of the study (age at Pre session: 32.85 ± 4.13).

 At the Pre and Post session, our participants were also asked to complete several supplementary cognitive tests and questionnaires (the Test de Aprendizaje Verbal España Complutense56, based on the California Verbal Learning test57, the Digits subtest of the Wechsler Adult Intelligence Scale III58, a two-back working memory test, the Interpersonal Reactivity Index59, and a simple reaction time task). Normality of these variables was assessed by Shapiro-Wilk tests, and nonparametric tests were applied as some did not follow a normal distribution. Homoscedasticity was confirmed using a nonparametric Levene's test. No significant changes across sessions were observed in any of these measures (Supplementary Table 10). For completeness, a correlation analysis was performed between the number of correct responses on the verbal word learning paradigm (Post-Pre scores) and the changes in GM volume in the women who underwent pregnancy between sessions. No suprathreshold voxels were observed, either with a whole-brain approach or with an explicit mask representing the areas of GM volume change across pregnancy.

 The women were also asked to retrospectively fill in the Maternal Postnatal Attachment Scale (MPAS)24 for the first 6 months of being a mother. One of the mothers did not complete this measure, and hence these data are available for 24 of the primiparous women (age (at Pre scan): 33.42 ± 4.05). From this scale, the three scores of the MPAS were extracted (mean ± s.d., quality of attachment: 37.11 ± 3.99; absence of hostility: 16.93 ± 4.10; pleasure in interaction: 20.88 ± 3.10).

 Longitudinal symmetric diffeomorphic modeling.

 The anatomical MRI images were processed in SPM12 (http://www.fil.ion.ucl.ac.uk/spm/), implemented in Matlab 7.8 (MathWorks), using the longitudinal symmetric diffeomorphic modeling pipeline60. The images of each participant were first processed using the longitudinal registration tool provided within this framework, which incorporates rigid-body registration, intensity inhomogeneity correction and nonlinear diffeomorphic registration in an interleaved fashion. Considering the bias associated with asymmetry in pairwise registration, this approach registers both time points to a within-subject average image. These midpoint average images were segmented into tissue classes using the unified segmentation algorithm61. The jacobian determinants resulting from the longitudinal registration were subsequently multiplied by each subject's GM segment, creating maps of volumetric change in GM tissue. To bring these images into MNI space, the product images were normalized using DARTEL tools62 and smoothed with a 12-mm full-width half-maximum smoothing kernel63, 64, 65. The individual smoothed GM volume difference maps were entered into general linear models.

 To quantify the overlap between our results and other functional maps such as the neural activity of the mothers in response to pictures of their infant (the 'own baby > baby' contrast in the fMRI task) and the theory-of-mind network as defined by the large-scale meta-analysis of Schurz et al.22, we computed the intersection between these maps and our map of GM volume changes across pregnancy. A further assessment of the localization of these GM changes of pregnancy with respect to functional networks was performed by quantifying the overlap between our map and the 12 functional networks of Yeo et al.23, who investigated the functional specialization of the cerebral cortex with a meta-analysis of 10,449 experimental contrasts and confirmed intrinsic network organization using a resting-state fMRI data set of 1,000 individuals. The overlap of our results with these functional maps was extracted by computing the intersections between each of these maps and the map of GM volume changes of pregnancy, and defining the fraction of the observed intersection relative to the expected volume of the intersection based on a random distribution across the gray matter of the brain (see Supplementary Table 6).

 For completeness, although these MRI images are not optimal for investigating white matter, we also multiplied the individual jacobian difference maps with the white matter segments of the midpoint average images to obtain an indication of the changes in white matter signal across pregnancy. These maps were further processed and analyzed in the same manner as the images obtained by multiplying the jacobian maps with the gray matter segments.

 A cross-sectional voxel-based morphometric approach was also applied to the baseline images to confirm the absence of pre-existing baseline differences between the PRG and CTR groups. This approach included a segmentation of the baseline images using the unified segmentation algorithm61, a DARTEL normalization of the GM segments62 and the application of a 12-mm full-width half-maximum smoothing kernel. A two-sample t-test was performed to test for the presence of baseline group differences. Plots depicting the signal values extracted from this approach are provided in Supplementary Figure 10.

 The Post + 2 years images were processed using the same longitudinal approach described above, rendering volume difference maps between the Post + 2 years images and the two other sessions. To examine whether GM volumes within the regions affected by pregnancy underwent further changes across the first 2 years postpartum relative to the Pre and early Post sessions, we performed one-sample t-tests on the Pre – Post + 2 years and the Post – Post + 2 years difference maps, using an explicit mask of the Pre – Post changes across pregnancy.

 Regarding the main comparisons, each of the primiparous groups was first compared to their nulliparous control group in the framework of the general linear model. Maps of GM volume change were compared using two-sample t-tests. If a significant group difference was found, we then proceeded to separately examine the increases and decreases in GM volume across time within the relevant groups by means of one-sample t-tests to determine which changes were driving this group difference.

 The statistical maps were constructed by applying a stringent voxel-level Gaussian random field theory–based threshold of P < 0.05, FWE-corrected across the whole brain. A minimum cluster size of 10 contiguous voxels was imposed to discard very small clusters and restrict table sizes.

 Multivariate analyses.

 In addition to the above-described mass-univariate analyses, we also performed multivariate pattern recognition analyses using the analysis pipeline provided by PRoNTo 2.0 (http://www.mlnl.cs.ucl.ac.uk/pronto/)66 implemented in Matlab. This pipeline can be used to automatically search for regularities in the data and train a classifier function that models the relation between spatial signal patterns and experimental factors on the basis of a training data set66. This classifier can then be used to predict the group a new image belongs to using the spatial distribution of the signal within the image and to compute the accuracy with which groups can be discriminated from one another on the basis of whole-brain spatial signal patterns.

 To examine the degree to which the experimental women could be discriminated from the control women on the basis of the distribution of GM volume changes across the brain, we applied a linear support vector machine classification to the Post – Pre difference maps. A sample-specific GM mask was created using the SPM Masking Toolbox (http://www0.cs.ucl.ac.uk/staff/g.ridgway/masking/) to serve as the mask image. To evaluate model performance, we applied a leave-one-out cross-validation scheme. Using this cross-validation strategy, the classifier's accuracy is computed by leaving one subject out at a time and predicting this subject's group label on the basis of a training set including all remaining subjects. This procedure is then repeated for each subject, and the accuracy of the discriminant function is computed using all these runs. Permutation testing was used to estimate the null distribution and examine the statistical significance of the classification accuracy (N permutations = 10,000; P < 0.05)67.

 In addition, to further examine the regional contribution to the decision function and determine the areas with greatest relative prediction power, we built multiple kernels based on the regions of the Automated Anatomical Labeling Atlas (http://www.gin.cnrs.fr/AAL-217), using an L1 Multiple Kernel Learning algorithm as implemented in PRoNTo68 with the same cross-validation scheme and significance testing.

 Furthermore, to investigate whether the GM volume changes across pregnancy could significantly predict measures of maternal attachment, we performed kernel ridge regression analyses using the three dimensions of the MPAS24. Kernel ridge regression represents a form of support vector regression using a squared-error loss function combined with l2 regularization (see ref. 69 for a description of this approach). Using kernel ridge regression, MPAS scores were predicted from the changes in GM volume, and the correlation between true and predicted MPAS values was subsequently examined. A leave-one-out cross-validation was applied; that is, in every fold a participant was left out for whom the MPAS score was predicted and examined in relation to the actual MPAS score. As in the classification models, we used a leave-one-out cross-validation scheme and permutation testing (N permutations = 10,000; P < 0.05).

 Since the current version of PRoNTo does not yet allow the inclusion of covariates and we could therefore not include the radio frequency coil covariate in the models, the residuals were written in SPM12 and the multivariate classification and regression analyses were repeated on these images, rendering very similar results (SVM classification on residuals: balanced accuracy = 100%, P < 0.0001; kernel ridge regression with MPAS scores on residuals: quality of attachment: R = 0.38, P = 0.043, normalized mean squared error (nMSE) = 0.90, p nMSE = 0.034; absence of hostility: R = 0.42, P = 0.031, nMSE = 0.87, p nMSE = 0.023).

 Additional measures based on previous related results: manual regions of interest of the pituitary gland and total tissue volumes.

 As a supplementary analysis, we wanted to further explore our data on the basis of previous findings related to structural brain changes in human pregnancy. Therefore, we also examined total tissue volumes and pituitary gland volume in our sample.

 Total brain volumes were extracted in SPM12. To obtain measures of pituitary gland volume, this structure was manually delineated by two raters who were blind to any identifying subject or group information on coronal slices of the Pre, Post and Post + 2 years sessions of the primiparous women using MRIcron (http://www.mccauslandcenter.sc.edu/mricro/mricron/), according to the delineation criteria described in MacMaster et al.70. Inter-rater reliability was determined on the basis of ten repeated ROI delineations (intraclass correlation coefficient: 0.935).

 For 5 MRI scans, the pituitary gland could not reliably be delineated due to local inhomogeneity or contrast issues, and these scans were therefore excluded, rendering a total of 23 Pre, 23 Post and 10 Post + 2 years volumes. As the missing volumes did not correspond to the same individuals across sessions, that left 22 Pre-Post pairs, 9 Pre–Post + 2 years pairs and 10 Post–Post + 2 years pairs for the longitudinal comparisons.

 These measures were analyzed in SPSS 23 (IBM). A normal distribution of the data and equal variances were confirmed using Shapiro-Wilk and Levene's tests, respectively. The results are described in Supplementary Figure 3 and Supplementary Tables 2 and 3.

 Surface-based analyses.

 To examine changes in surface area and cortical thickness, surface-based morphometry was conducted in FreeSurfer 5.3 (http://surfer.nmr.mgh.harvard.edu/). The images were reprocessed from raw data for this approach. To investigate changes in these surface-based measures across sessions, the images were processed with the longitudinal stream implemented in FreeSurfer71, 72. The longitudinal preprocessing pipeline involves an initial cross-sectional processing of the images of each of the time points, which includes motion correction, removal of nonbrain tissue, transformation into stereotaxic (MNI) space, intensity correction, volumetric segmentation and cortical surface reconstruction73, 74, and parcellation75. The extraction of the brain for surface-based processing was based on the segmentation algorithm implemented in SPM8. All further steps were performed in FreeSurfer 5.3. Individual surfaces were inspected for accuracy, and minor manual edits were performed where needed, usually involving the removal of sections of nonbrain tissue. The next step in the longitudinal stream was the creation of a probabilistic individual base template based on the cross-sectional images for each participant, which is unbiased with respect to any of the time points. Subsequent processing of each time point was then initialized using the processed results from the unbiased template71, 72. Surface maps were resampled, mapped to a common surface, and smoothed using a full-width at half-maximum kernel of 15 mm. A cross-sectional approach was also applied on the baseline images to confirm the absence of pre-existing baseline differences between the PRG and CTR groups.

 Longitudinal change in cortical surface area and thickness in each hemisphere was calculated as symmetrized percent change (i.e., the rate of change between the time points with respect to the average thickness or area across the time points), and examined using one-sample t-tests. Cluster statistics were obtained using Monte Carlo simulations with a vertex-wise −log 10 (P) of 4 (corresponding to P < 0.0001) and a cluster-wise threshold of P < 0.05.

 Discriminant analyses with leave-one-out cross-validation were performed in SPSS 23 (IBM) using the changes in average cortical thickness and surface area values across the regions of GM volume change to examine the predictive value of these surface-based measures for group classification.

 Functional MRI analyses.

 Analyses of the functional MRI data were performed in SPM12. The functional images were first corrected for differences in slice acquisition timing and realigned to the first volume. Subjects with head motion exceeding 3 mm (for translations) or 3° (for rotations) were excluded from the analyses (1 woman). Then, the anatomical images were co-registered to the mean functional image and normalized into MNI (ICBM) space using nonlinear registration61. Finally, the normalization parameters and a full-width at half-maximum smoothing kernel of 12 mm were applied to the functional images.

 At the first level of analysis, general linear models were used to model voxel-wise changes in BOLD response for the conditions of interest, also including the movement parameters extracted during the realignment and regressors based on temporal basis functions. The first-level parameter estimates for the linear contrast 'own baby pictures > other baby pictures' were entered into a second-level model and one-sample t-tests were performed to examine whether new mothers show a differential pattern of neural activity in response to pictures of their own or other babies. For completeness, the reverse contrast ('other baby pictures > own baby pictures') was also examined. Additional explorations of the data based on facial expression are provided in Supplementary Table 23. In addition to the whole-brain FWE-corrected threshold, the fMRI results were also investigated and are reported at an uncorrected threshold of P < 0.0001 and an extent threshold of 10 voxels to allow a further inspection of the similarity of the regions of strongest neural responsiveness to the women's babies to the pattern of GM volume changes across pregnancy.

 To create images, the statistical maps were projected onto the PALS surface provided in Caret software (http://brainvis.wustl.edu/wiki/index.php/Caret:Download). Slice overlays were created using MRIcron (http://www.mccauslandcenter.sc.edu/mricro/mricron/).

 Data availability.

 Source files for the figures are provided in FigShare (http://dx.doi.org/10.6084/m9.figshare.4216809). ||||| FILE - In this Friday, Nov. 11, 2011 file photo, a mother holds her newborn baby at a hospital in Corpus Christi, Texas. A study released Monday, Dec. 19, 2016 shows pregnancy affects not only a woman’s... (Associated Press)

 FILE - In this Friday, Nov. 11, 2011 file photo, a mother holds her newborn baby at a hospital in Corpus Christi, Texas. A study released Monday, Dec. 19, 2016 shows pregnancy affects not only a woman’s... (Associated Press)

 NEW YORK (AP) — Pregnancy affects not only a woman's body: It changes parts of her brain too, a new study says.

 When researchers compared brain scans of women before and after pregnancy, they spotted some differences in 11 locations. They also found hints that the alterations help women prepare for motherhood.

 For example, they might help a mother understand the needs of her infant, Elseline Hoekzema, a study author at Leiden University in the Netherlands, explained via email.

 The women were also given memory tests, and they showed no signs of decline.

 Hoekzema, a neuroscientist, began working on the study while at the Autonomous University of Barcelona in Spain. She and colleagues present the results in a paper released Monday by the journal Nature Neuroscience.

 The study includes data on 25 Spanish women scanned before and after their first pregnancies, along with 20 women who didn't get pregnant during the study. The brain changes in the pregnancy group emerged from comparisons of those two groups.

 The results were consistent: A computer program could tell which women had gotten pregnant just by looking at results of the MRI scans.

 And the changes, first documented an average of 10 weeks after giving birth, were mostly still present two years after childbirth. That's based on follow-up with 11 study participants.

 Further work showed they're a motherhood thing: No brain changes were seen in first-time fathers.

 Based on prior research findings, the researchers think the brain changes happened during pregnancy rather than after childbirth.

 What's going on? Hoekzema and colleagues think the differences result from sex hormones that flood the brain of a pregnant woman. In the 11 places, the MRI data indicate reductions in volume of the brain's gray matter, but it's not clear what that means. For example, it could reflect loss of brain cells or a pruning of the places where brain cells communicate, called synapses.

 Losing some synapses is not necessarily a bad thing. It happens during a hormonal surge in adolescence, producing more specialized and efficient brain circuits. The researchers suspect that could be happening in the pregnant women.

 Some study results hint that such upgrades may prepare a woman for motherhood. One analysis linked brain changes to how strongly a woman felt emotionally attached to her infant. And when women viewed pictures of their babies, several brain regions that reacted the most were ones that showed pregnancy-related change.

 In addition, the affected brain areas overlapped with circuitry that's involved in figuring out what another person is thinking and feeling. That's a handy ability for a mother tending to an infant.

 The idea of synapses being pruned in pregnancy makes a lot of sense, commented Bruce McEwen of Rockefeller University in New York, who studies hormonal effects on the brain but didn't participate in what he called a terrific study.

 "The brain is being shaped all the time," he said, and "sex hormones are part of the whole orchestra of processes that change the brain structurally."

 ___

 Follow Malcolm Ritter at http://twitter.com/malcolmritter His recent work can be found at http://bigstory.ap.org/content/malcolm-ritter |||||

– Pregnancy affects not only a woman's body: It changes parts of her brain, too, a new study published in Nature Neuroscience says. The study includes data on 25 Spanish women scanned before and after their first pregnancies, along with 20 women who didn't get pregnant during the study. The brain changes in the pregnancy group emerged from comparisons of those two groups. The results were consistent: A computer program could tell which women had gotten pregnant just by looking at results of the MRI scans. And the changes, first documented an average of 10 weeks after giving birth, were mostly still present two years after childbirth. (Based on prior research findings, the researchers think the brain changes happened during pregnancy). No brain changes were seen in first-time fathers, reports the AP. What's going on? Elseline Hoekzema, a study author at Leiden University in the Netherlands, and colleagues think the differences result from sex hormones that flood the brain of a pregnant woman. In 11 places in the brain, the MRI data indicate reductions in volume of the brain's gray matter, but it's not clear what that means. For example, it could reflect a pruning of the places where brain cells communicate, called synapses. Losing some synapses is not necessarily a bad thing. It happens during a hormonal surge in adolescence, producing more specialized and efficient brain circuits. The researchers suspect that could be happening in the pregnant women, perhaps to prepare a woman for motherhood. One analysis linked brain changes to how strongly a woman felt emotionally attached to her infant.


Article:
FILE - In this March 18, 2015 file photo, former Associated Press Vice President and Senior Managing Editor Mike Oreskes poses for a photo at AP headquarters, in New York. Oreskes, current vice president... (Associated Press)

 FILE - In this March 18, 2015 file photo, former Associated Press Vice President and Senior Managing Editor Mike Oreskes poses for a photo at AP headquarters, in New York. Oreskes, current vice president of news and editorial director at National Public Radio, Oreskes has resigned as chief of NPR’s... (Associated Press)

 FILE - In this March 18, 2015 file photo, former Associated Press Vice President and Senior Managing Editor Mike Oreskes poses for a photo at AP headquarters, in New York. Oreskes, current vice president of news and editorial director at National Public Radio, Oreskes has resigned as chief of NPR’s... (Associated Press) FILE - In this March 18, 2015 file photo, former Associated Press Vice President and Senior Managing Editor Mike Oreskes poses for a photo at AP headquarters, in New York. Oreskes, current vice president... (Associated Press)

 NEW YORK (AP) — Michael Oreskes has resigned as chief of NPR's newsroom following accusations of sexual harassment that dated back to the 1990s.

 Oreskes said in a statement Wednesday that he was deeply sorry to the people he hurt. He said: "my behavior was wrong and inexcusable, and I accept full responsibility."

 He said he told Jarl Mohn, president and CEO of NPR, on Wednesday morning that he would step down. Earlier, Oreskes had been placed on leave and Mohn appointed Chris Turpin as the temporary news chief.

 Two women had accused Oreskes of suddenly kissing them when they were discussing job prospects with him in the 1990s, when he was Washington bureau chief of The New York Times. ||||| NEW YORK -- Michael Oreskes has resigned as chief of NPR's newsroom following accusations of sexual harassment that dated back to the 1990s.

 Oreskes said in a statement Wednesday that he was deeply sorry to the people he hurt. He said: "my behavior was wrong and inexcusable, and I accept full responsibility."

 He said he told Jarl Mohn, president and CEO of NPR, on Wednesday morning that he would step down.

 On Tuesday, Oreskes had been placed on leave after a publication reported he abruptly kissed two women who were seeking jobs while he was Washington bureau chief at The New York Times in the 1990s. The women formally complained to NPR and told their stories to The Washington Post, speaking on condition of anonymity.

 Mohn subsequently appointed Chris Turpin as the temporary news chief.

 Oreskes was a vice president and senior managing editor at The Associated Press from 2008 until he joined NPR in 2015. ||||| NPR's Head Of News Placed On Leave After Past Harassment Allegations Surface

 NPR has placed its senior vice president for news, Michael Oreskes, on leave after fielding accusations that he sexually harassed two women seeking career opportunities nearly two decades ago, when he worked at The New York Times.

 Enlarge this image toggle caption Chuck Zoeller/AP Chuck Zoeller/AP

 The allegations from the two women were first reported by The Washington Post on Tuesday afternoon. They included similar accounts of unwanted and unexpected kisses during business meetings.

 Meanwhile, a current NPR employee is going public with her account of filing a formal complaint with the network's human resources division in October 2015. Rebecca Hersher says she considers the incident less severe but nevertheless felt it crossed a line and made her uncomfortable. At the time a 26-year-old assistant producer on Weekend All Things Considered, she said Oreskes hijacked a career counseling session into a three-hour-long dinner that delved into deeply personal territory.

 Oreskes did not respond to multiple efforts to reach him for comment. NPR executives say that they cannot address individual personnel matters but that they take concerns of sexual harassment or other inappropriate workplace behavior seriously.

 According to The Washington Post, there were two separate complaints about Oreskes from his tenure as Washington bureau chief at The New York Times nearly 20 years ago. Both women tell similar stories: After meeting Oreskes and discussing their job prospects, they said he unexpectedly kissed them on the lips and stuck his tongue in their mouths. The Post did not disclose their names, stating they spoke on condition of anonymity because they did not want to damage future employment prospects. The women also shared their allegations with NPR management in mid-October.

 After joining NPR in the spring of 2015, Oreskes encouraged staffers to reach out to him to discuss their careers during his visit to NPR West in Culver City, Calif. At the time Hersher had been working a series of temporary assignments for NPR, and she took him up on his offer during a subsequent visit to Washington. An afternoon meeting was pushed off into evening and an invitation to dinner at a seafood restaurant near Union Station.

 Hersher, now a reporter and producer on NPR's science desk, says she wanted to tell him about her belief that she would need to leave NPR to transform from a producer to a reporter. Her dinner with Oreskes became increasingly uncomfortable as the conversation veered into personal matters involving relationships and sex. At one point, she says, he referred to a former flame as his first "sex girlfriend."

 Hersher says the conversation made her uncomfortable.

 "From my point of view, every little thing that he or I said pointed to the relative difference in power," she said. "Like he's the one with the power. He's the one who gets to decide what we talk about — and I am trying to keep up."

 Hersher said he gave her what seemed like a nonromantic hug at the train station afterward, and that he did not otherwise touch her or suggest any physical involvement.

 Still, Hersher said Tuesday, the entire evening felt as though it devalued her as a professional. She suddenly questioned why a senior executive would care about her career.

 "I went to the train station, and I called my best friend; I cried on the phone to her," Hersher says. "I went home and then I cried to my boyfriend. It undercut my confidence in a way that was surprising to me."

 Hersher reported the incident to NPR's human resources division. The network formally rebuked Oreskes and informed other top network executives. Hersher said she felt satisfied with the company's response and that she experienced no retribution.

 Two colleagues at NPR confirmed that Hersher told them of the incident at the time. I did considerable reporting on the episode in spring 2016. At that time, Hersher was not willing to go on the record for a news story, and I was unable to confirm a pattern of behavior by Oreskes. The incident did not involve anything physical, and there was no force, retribution or request for a romantic involvement, and Hersher said she believed the network had held Oreskes appropriately accountable.

 At the time, this reporter and editors of that story — who did not include Oreskes or anyone who reported directly to him — concluded that the incident on its own did not rise to the level of national news.

 The new allegations concerning Oreskes' tenure at The Times changed the equation.

 In a note to staff on Tuesday, NPR CEO Jarl Mohn encouraged employees to come forward if they have been harassed.

 "We take these kinds of allegations very seriously," Mohn wrote. "If a concern is raised, we review the matter promptly. We take all appropriate steps to assure a safe, comfortable, and productive work environment for everyone at NPR. ... This is our NPR. And I will stand up for it, and every one of you." |||||Summary:

– In the wake of Harvey Weinstein news, NPR's news chief is the latest to come under fire for alleged past sexual misconduct—and he's now stepped down from his post. Michael Oreskes, 63, resigned Wednesday, per the AP, after two women told the Washington Post about incidents in the late 1990s when he was the DC bureau chief at the New York Times. Both women say while talking to him about possible jobs at the Times, he suddenly planted a kiss on their lips and put his tongue in their mouths. When one woman confronted him about it months later, calling it "totally inappropriate," she says he replied: "I was overcome with passion. I couldn't help myself." Neither woman was hired; they say they were spurred to come forward by the Weinstein allegations. In a statement, NPR notes, "We take these kinds of allegations very seriously," though it wouldn't comment on specifics. Meanwhile, NPR reports on a current employee now making public her own complaint. Science reporter Rebecca Hersher says she filed a grievance against Oreskes in October 2015 after he turned what was supposed to be a career discussion into a "three-hour-long dinner that delved into deeply personal territory." At that meeting, Hersher says, Oreskes steered their talk to relationships and sex, even calling one ex-partner his first "sex girlfriend." Hersher says Oreskes never touched her inappropriately, and she believes he was held "appropriately accountable" after her complaint. But she notes the talk made her uncomfortable and "undercut my confidence in a way that was surprising to me." In a statement Wednesday, Oreske said, "My behavior was wrong and inexcusable, and I accept full responsibility." NPR CEO Jarl Mohn has appointed Christopher Turpin as NPR's temporary news chief, per CBS News. More at the Post and NPR.