Changes in brain activity characterizing impaired speech production after brain damage have usually been investigated by comparing aphasic speakers with healthy subjects because prestroke data are normally not available. However, when interpreting the results of studies of stroke patients versus healthy controls, there is an inherent difficulty in disentangling the contribution of neuropathology from other sources of between-subject variability. In the present work, we had an unusual opportunity to study an aphasic patient with severe anomia who had incidentally performed a picture naming task in an ERP study as a control subject one year before suffering a left hemisphere stroke. The fortuitous recording of this patient's brain activity before his stroke allows direct comparison of his pre- and poststroke brain activity in the same language production task. The subject did not differ from other healthy subjects before his stroke, but presented major electrophysiological differences after stroke, both in comparison to himself before stroke and to the control group. ERP changes consistently appeared after stroke in a specific time window starting about 250 msec after picture onset, characterized by a single divergent but stable topographic configuration of the scalp electric field associated with a cortical generator abnormally limited to left temporal posterior perilesional areas. The patient's pattern of anomia revealed a severe lexical–phonological impairment and his ERP responses diverged from those of healthy controls in the time window that has previously been associated with lexical–phonological processes during picture naming. Given that his prestroke ERPs were indistinguishable from those of healthy controls, it seems highly likely that the change in his poststroke ERPs is due to changes in language production processes as a consequence of stroke. The patient's neurolinguistic deficits, combined with the ERPs results, provide unique evidence for the role of left temporal cortex in lexical–phonological processing from about 250 to 450 msec during word production.

We recorded intracranial local field potentials from structurally intact human visual cortex during several face processing tasks in a patient before brain surgery. Intracranial local field potentials were measured from subdural electrodes implanted in a right fusiform region with face-sensitive activity and a more medial location in posterior parahippocampal gyrus with house-selective activity. This electrode implantation allowed us to compare neural responses with different facial properties within two adjacent but functionally distinct cortical regions. Five experiments were conducted to determine the temporal dynamics of perceptual (Experiments 1 and 5), emotional (Experiments 2 and 3), and social (Experiment 4) effects on face-specific responses in the right fusiform. Our findings showed an early negative deflection (N200) that primarily reflected category-selective perceptual encoding of facial information, whereas higher order effects of face individuation, emotional expression, and gaze direction produced selective modulations in the same face-specific region during a later time period (from 200 to 1000 msec after onset). These results shed new lights on the time course of face recognition mechanisms in human visual cortex and reveal for the first time anatomically overlapping but temporally distinct influences of identity or emotional/social factors on face processing in right fusiform gyrus, which presumably reflect top–down feedback effects from distant brain areas.