photosensitivity is encountered in 5% of patients with epilepsy , with increased prevalence in association with genetic generalized epilepsies ( gges ) . as patients with genetic generalized epilepsies ( gges ) are not typically evaluated for epilepsy surgery , generalized photoparoxysmal ( ppr ) or photoconvulsive ( pcr ) responses have not been recorded with intracranial electroencephalography ( ic - eeg ) . however , photoepileptic responses were reported in two patients with medically refractory localization - related epilepsy undergoing ic - eeg monitoring for resective surgery , . in these cases , intermittent light stimulation ( ils ) triggered habitual complex partial seizures but not generalized photoepileptic responses . while magnetoencephalography ( meg ) and functional mri studies of photosensitivity in gges provide insight into the networks underlying generalized pprs and pcrs , the mechanisms are still largely unknown , , . an 18-year - old right - handed young man with medically refractory localization - related epilepsy since age 3  years old was evaluated for epilepsy surgery at the south texas comprehensive epilepsy center in san antonio , texas . the patient provided consent for this presentation of his clinical history , mri , and video - eeg findings . he had focal left - sided myoclonic seizures , focal seizures with left - sided or bilateral tonic activity , and associated loss of awareness , as well as secondary generalized tonic  clonic seizures ( gtcss ) following left head version , often triggered by decreased sleep and excessive fatigue . his brain mri showed right inferior frontal gyrus cortical dysplasia abutting the motor cortex . on scalp video - eeg monitoring , habitual partial seizures as well as focal and generalized interictal epileptic discharges ( ieds ) were recorded . intracranial electrodes were implanted to confirm the right frontal onset of his spontaneous clinical seizures and map the motor cortex . subdural electrodes over parietal and occipital regions were implanted in order to study the relationship of the epileptogenic dysplastic cortex and the suspected generalized photosensitivity and epilepsy phenotypes . his ic - eeg evaluation ( nihon kohden , japan ; sampling rate : 500  hz , 1- to 70-hz frequency bandpass ) included both subdural grid and strip electrodes ( pmt , minnesota , usa ; 8    8 grid with closely spaced electrodes 2  mm in diameter , 5-mm spacing ; all other electrodes were 3  mm in diameter , 10-mm spacing ) implanted through a right craniotomy . an 8    8 contact grid ( ifg ) was placed over the right inferior perirolandic area , covering the area of cortical dysplasia , while a 5    2 contact grid ( sfg ) covered the more superior sensorimotor cortices ( fig .  1 ) . anteriorly , there were three 1    6 contact frontal strips ( sf712 , mf712 , if16 ) and a 1    6 superomedial strip ( aih16 ) , while posteriorly , there were two 1    12 strips , an occipital strip ( o112 ) and a parietal strip ( p ) , which was reduced to eight contacts ( 512 ) . medially , the o strip crossed the calcarine sulcus , and a posterior interhemispheric 1    6 contact strip ( pih16 ) traversed the supplementary motor area , reaching the posterior cingulate . an additional 1    4 contact strip ( g ) was used as a ground and reference . antiepileptic medications were rapidly tapered ( carbamazepine when video - eeg monitoring was initiated , lacosamide 24  h later ) . our patient underwent ils and hyperventilation on a daily basis , procedures that are routinely performed in order to provoke seizures . as soon as the patient exhibited generalized pcrs during ils , he was asked whether he wanted to continue with the procedure , and he invariably agreed . intermittent light stimulation provoked only generalized myoclonic seizures , never activating any of his habitual focal seizures with loss of awareness or any type of gtcss . extraoperative electrocortical stimulation activated face motor cortex rostral to the epileptogenic zone on ifg and hand and arm motor cortices at sfg5 and 7 , respectively . he underwent a resection of the right frontal lesion covered by ifg , and cortical dysplasia was confirmed by pathological examination . after resolution of a transient left facial paresis , he remains seizure - free at more than three years postoperatively off antiepileptic medications . intermittent light stimulation was performed at ascending and descending frequencies of 130  hz for 10  s at each frequency . he was exposed to ils 13 times during a period of nine days until he exhibited his first habitual seizure ( fig .  2 ) . photic driving responses ( pdrs ) were elicited at all frequencies at contacts o13 , never extending beyond electrodes o16 below 9  hz . at ils frequencies 930  hz , pdrs involved p57 ( medial parietal ) electrodes . photoparoxysmal responses presented as focal spikes at o7 ( lateral occipitoparietal ) at all frequencies , occurring within 200  ms of pdr onset . off aeds , p58 spikes were encountered at ils frequencies >  9  hz , often preceding o7 spikes , with secondary propagation to contacts pih12 ( posterior cingulate ) and aih2 ( medial frontal convexity ) , or in the form of generalized , frontally - predominant , spike - and - wave complexes within 200400  ms of pdr onset . similarly , pcrs recorded in 34 stimulations consisted of either a repetitive low - amplitude myoclonus , affecting the upper more than the lower extremities , and the trunk and face to a lesser extent , which lasted until the end of the stimulus ( type 1 ) , or a brief generalized myoclonic seizure affecting the face and entire body ( type 2 ) . type 1 pcr was associated with propagation of the ictal discharge to contacts p7/8 and 12 , pih12 and 56 , as well as sfg5/7/8 and 10 within 8001200  ms of pdr onset ( fig . type 2 pcr was associated with a generalized spike - and - wave discharge triggered only at ils frequencies of 1525  hz about 6001000  ms after pdr onset ( fig . the frontally predominant discharges were preceded by p57 ( medial parietal ) spiking but with lead from contacts pih12 ( posterior cingulate ) . the ictal discharge also involved contacts p10 , sfg3/4/6/8 , pih14 , and aih12 , as well as the entire sf , mf , and if strips . although the electrode distribution was distinct for each type of pcr , both types of pcrs could be observed during the same stimulus and always in the setting of a medial parietal pdr or spiking . during pcrs , the pdr was briefly visible more anteriorly , at pih12 and/or 56 , at sfg3/5/7/8 and 10 , and at aih2 , but only after onset of the myoclonus . while the right frontal cortex demonstrated continuous periodic ieds interictally , these were not altered by ils or photoepileptic responses . following one gtcs , our patient demonstrated a cluster of spontaneous generalized myoclonic seizures , and the associated ictal discharge involved the same electrodes as the type 2 pcr , with the exception of the o and p strips . our patient with medically refractory partial epilepsy due to focal cortical dysplasia demonstrated generalized and pcrs , which were recorded by ic - eeg for the first time . despite the focal cortical dysplasia underlying his refractory partial epilepsy , our patient had spontaneous generalized myoclonic seizures , as well as generalized pprs and pcrs , which were electroclinically distinct from his focal ieds and seizures . evidence of persistent generalized ieds and pprs even after successful epilepsy surgery further supports the presence of a separate gge phenotype . the coexistence of genetic generalized and symptomatic focal epilepsies has been described in the setting of ic - eeg evaluations and eeg  fmri studies , . in one surgical case series , as in our patient , the generalized epilepsy phenotype persisted despite the successful treatment of the focal epilepsy . photoparoxysmal responses were characterized by activation of multifocal discharges in the parieto - occipital , posterior cingulate , and medial prefrontal cortices , demonstrating a posterior - to - anterior propagation or by a frontally predominant generalized discharge . the prominent parietal activation during pprs reflects findings of cortical synchronization in meg and fmri studies , . photoconvulsive responses were characterized by either a bilateral upper extremity myoclonus lasting throughout the stimulus associated with activation of the motor cortices ( type 1 ) or a brief generalized myoclonic seizure associated with a frontally - predominant generalized ictal discharge extensively involving the premotor cortices ( type 2 ) . regional posterior - to - anterior propagation was noted in the type 1 pcr , from the parietal lobe cortices to the motor and premotor cortices . the type 2 pcr did not demonstrate a similar corticocortical propagation ; rather , the emergence of a generalized spike - and - wave discharge suggests activation of a cortical  subcortical network , albeit with a lead from the posterior cingulate region and after medial parietal spiking . both types of pcrs could occur during the same stimulus but could involve different cortical areas , suggesting activation of distinct corticocortical or cortical  subcortical networks . regardless of the pathway , pcrs only occurred when pdrs involved the medial parietal cortices . furthermore , spiking during ils was first noted in occipital and parietal regions prior to the sensorimotor cortices and frontal lobes . nonetheless , it is important to point out that our observations are limited to a single case , and pprs or pcrs may be expressed differently in people with pure genetic generalized epilepsies , and particular pathways may be specific to some gge syndromes . the interpretation of our data may also be limited by temporal and spatial eeg sampling . increased eeg sampling rates and high - frequency filter settings may have helped demonstrate synchronization of gamma - frequency activity across larger cortical areas even before the appearance of photoepileptic responses . more closely spaced medial ( interhemispheric ) coverage may have yielded better spatial resolution of potential cortical generators and propagation of the ictal discharge . furthermore , thalamic sampling was not clinically indicated but may have elucidated potential cortical  subcortical interactions in each type of pcr . in summary , photosensitivity appears to be associated with pdrs extending beyond the primary visual areas . the parietal lobes appear to play an important role in the generation of generalized pprs and pcrs , regardless of their electroclinical characterization . the authors declare that they have no conflicts of interest in the publication of this report .