Spatial selectivity in human ventrolateral prefrontal cortex

The functional organization of lateral prefrontal cortex is not well understood, and there is debate as to whether the dorsal and ventral aspects mediate distinct spatial and non-spatial functions, respectively. We show for the first time that recordings from human ventrolateral prefrontal cortex show spatial selectivity, supporting the idea that ventrolateral prefrontal cortex is involved in spatial processing. Our results also indicate that prefrontal cortex may be a source of control signals for neuroprosthetic applications

Single-Unit Responses Selective for Whole Faces in the Human Amygdala

The human amygdala is critical for social cognition from faces, as borne out by impairments in recognizing facial emotion following amygdala lesions and differential activation of the amygdala by faces. Single-unit recordings in the primate amygdala have documented responses selective for faces, their identity, or emotional expression, yet how the amygdala represents face information remains unknown. Does it encode specific features of faces that are particularly critical for recognizing emotions (such as the eyes), or does it encode the whole face, a level of representation that might be the proximal substrate for subsequent social cognition? We investigated this question by recording from over 200 single neurons in the amygdalae of seven neurosurgical patients with implanted depth electrodes. We found that approximately half of all neurons responded to faces or parts of faces. Approximately 20% of all neurons responded selectively only to the whole face. Although responding most to whole faces, these neurons paradoxically responded more when only a small part of the face was shown compared to when almost the entire face was shown. We suggest that the human amygdala plays a predominant role in representing global information about faces, possibly achieved through inhibition between individual facial features

Interictal cerebral metabolism in partial epilepsies of neocortical origin

We performed interietal [18F]fluorodeoxyglucose positron emission tomography (FDG PET) in 24 patients with partial epilepsy of neocortical origin. Two-thirds of patients had regions of hypometabolism. The zone of intracranially recorded electrographic ictal onset was always located in a region of hypometabolism, in those with hypometabolism. Hypometabolic regions in partial epilepsies of neocortical origin were usually associated with structural imaging abnormalities. Regional hypometabolism occasionally occurred without localizing ictal scalp EEG and cerebral magnetic resonance imaging findings, however. FDG PET may be useful in directing placement of intracranial electrodes for presurgical evaluation of refractory neocortical seizures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29049/1/0000082.pd