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Epileptic Disorders

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Visual word form area hyperexcitability associated with focal epileptiform activity in a case of reading epilepsy Volume 24, issue 6, December 2022

Figure 1.

Spike quantification and source analysis. (A) Dataset of reading spikes obtained in the reading task, using 10-20 IS with C1/2 and C5/6 with average reference and bilateral facial EMG, revealed bursts of dissimilar spikes, more prominent over the left frontal and central areas, with occasionally contralateral involvement and bilateral or lateralized perioral myoclonic jerks (arrows). A comparison of spikes between resting state and reading is presented in the histogram (upper right panel). (B) Spike types identified during sleep (center), with the corresponding average topography and source (left). (C) Topographies of the spikerelated independent components. EMG: electromyogram; IS: international system.

Figure 2.

Spike connectivity analysis. ADTF information flow at the peak of spike-related ICs while sleeping (A) and during the reading task (B). The flow of information reads from column to row in the connectivity matrix (below) and along arrows in the head model. The T3 and T5 spike-related ICs consistently act as outflow sources. C) ERP protocol to assess cortical excitability to orthographic and nonorthographic stimuli, using HR-EEG (124ch) and the sLORETA source localization method (upper panel). Visual presentation of words and pseudowords induced N170 activation in the occipital-temporal areas (right upper panel), which were of higher amplitude for orthographic than for non-orthographic visual stimuli in the left hemisphere (lower center panel). Activation of the left VWFA to words (red) was greater than for pseudowords (blue) (right lower panel). ADTF: adaptative directed transfer function; ERP: eventrelated potentials; HR-EEG: high-resolution electroencephalography; ICs: independent components; VWFA: visual word form area.