bal and rivalry efficiency between the hemispheres, whereas female brains possess considerably better local efficiency within the RHS.
Handedness has been implicated in determining which hemisphere is naturally dominant. Due to decussation the dominant hemisphere is opposite to the main hand/foot. Left-handed and ambidextrous individuals have been shown to have more efficient hemispheric interactions.
Damage to the RHS has been shown to drastically increase the likelihood of self-inflicted harm and suicide as calculative ideas such as the prospect of future are lost. RHS damage has also been shown to drastically decrease social performance and appropriateness as these behaviors stem from inhibition of boisterous activities which is no longer possible in these patients.
Lateralized cognitive processes
For example, structurally, the lateral sulcus generally is longer in the left hemisphere than in the right hemisphere, and functionally, Broca's area and Wernicke's area are located in the left cerebral hemisphere for about 95% of right-handers, but about 70% of left-handers.
Language functions such as grammar, vocabulary and literal meaning are typically lateralized to the left hemisphere, especially in right handed individuals. While language production is left-lateralized in up to 90% of right-handed subjects, it is more bilateral, or even right lateralized in approximately 50% of left-handers. In contrast, prosodic language functions, such as intonation and accentuation, often are lateralized to the right hemisphere of the brain.
The processing of visual and auditory stimuli, spatial manipulation, facial perception, and artistic ability are represented bilaterally. Numerical estimation, comparison and online calculation depend on bilateral parietal regions while exact calculation and fact retrieval are associated with left parietal regions, perhaps due to their ties to linguistic processing. Dyscalculia is a neurological syndrome associated with damage to the left temporo-parietal junction. This syndrome is associated with poor numeric manipulation, poor mental arithmetic skill, and the inability to either understand or apply mathematical concepts.
Depression is linked with a hyperactive right hemisphere, with evidence of selective involvement in "processing negative emotions, pessimistic thoughts and unconstructive thinking styles", as well as vigilance, arousal and self-reflection, and a relatively hypoactive left hemisphere, "specifically involved in processing pleasurable experiences" and "relatively more involved in decision-making processes". Additionally, "left hemisphere lesions result in an omissive response bias or error pattern whereas right hemisphere lesions result in a commissive response bias or error pattern." The delusional misidentification syndromes, reduplicative paramnesia and Capgras delusion are also often the result of right hemisphere lesions.
Lateralization of language processes
Hemispheric lateralization refers to the distinction of functions of the right and left hemispheres of the brain. If one hemisphere is more heavily involved in a specific function, it is often referred to as being dominant (Bear et al., 2007). Language and speech understanding and function is commonly accepted by linguists and neuroscientists to be a heavily lateralized function. Many specific aspects of language are found to be localized in the left hemisphere, while less so in the right hemisphere as the left hemisphere is most often dominant. This was proposed first through early work in patients with aphasia and language deficits found to have specific areas with lesions and damage.
When looking at patients that have unilateral hemisphere damage, in either the right or left hemisphere their language deficits can be studied. For example; when the left hemisphere has been damaged or lesioned, the right hemisphere is used to take over some functions via brain plasticity, and this damage of the one hemisphere and compensation by the opposite hemisphere creates language understanding and production changes and deficits th