title: Electrical stimulation of the left and right human fusiform gyrus causes different effects in conscious face perception.
abstract: Neuroimaging and electrophysiological studies across species have confirmed bilateral face-selective responses in the ventral temporal cortex (VTC) and prosopagnosia is reported in patients with lesions in the VTC including the fusiform gyrus (FG). As imaging and electrophysiological studies provide correlative evidence, and brain lesions often comprise both white and gray matter structures beyond the FG, we designed the current study to explore the link between face-related electrophysiological responses in the FG and the causal effects of electrical stimulation of the left or right FG in face perception. We used a combination of electrocorticography (ECoG) and electrical brain stimulation (EBS) in 10 human subjects implanted with intracranial electrodes in either the left (5 participants, 30 FG sites) or right (5 participants, 26 FG sites) hemispheres. We identified FG sites with face-selective ECoG responses, and recorded perceptual reports during EBS of these sites. In line with existing literature, face-selective ECoG responses were present in both left and right FG sites. However, when the same sites were stimulated, we observed a striking difference between hemispheres. Only EBS of the right FG caused changes in the conscious perception of faces, whereas EBS of strongly face-selective regions in the left FG produced non-face-related visual changes, such as phosphenes. This study examines the relationship between correlative versus causal nature of ECoG and EBS, respectively, and provides important insight into the differential roles of the right versus left FG in conscious face perception.
authors.affiliation: Laboratory of Behavioral and Cognitive Neurology, Department of Neurology and Neurological Sciences, Stanford Human Intracranial Cognitive Electrophysiology Program.
authors.forename: Vinitha
authors.initials: V
authors.lastname: Rangarajan
authors.affiliation: Stanford Human Intracranial Cognitive Electrophysiology Program.
authors.forename: Dora
authors.initials: D
authors.lastname: Hermes
authors.affiliation: Laboratory of Behavioral and Cognitive Neurology, Department of Neurology and Neurological Sciences, Stanford Human Intracranial Cognitive Electrophysiology Program.
authors.forename: Brett L
authors.initials: BL
authors.lastname: Foster
authors.affiliation: Stanford Human Intracranial Cognitive Electrophysiology Program, Vision and Perception Neuroscience Laboratory, Department of Psychology, Stanford, California 94305.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Weiner
authors.affiliation: Stanford Human Intracranial Cognitive Electrophysiology Program, Vision and Perception Neuroscience Laboratory, Department of Psychology, Stanford, California 94305, Psychological Sciences Research Institute, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium, and.
authors.forename: Corentin
authors.identifier: http://orcid.org/0000-0001-8917-4346
authors.initials: C
authors.lastname: Jacques
authors.affiliation: Stanford Human Intracranial Cognitive Electrophysiology Program, Vision and Perception Neuroscience Laboratory, Department of Psychology, Stanford, California 94305, Stanford Neuroscience Institute, Stanford University, Stanford, California 94305.
authors.forename: Kalanit
authors.initials: K
authors.lastname: Grill-Spector
authors.affiliation: Laboratory of Behavioral and Cognitive Neurology, Department of Neurology and Neurological Sciences, Stanford Human Intracranial Cognitive Electrophysiology Program, Stanford Neuroscience Institute, Stanford University, Stanford, California 94305 jparvizi@stanford.edu.
authors.forename: Josef
authors.initials: J
authors.lastname: Parvizi
mesh_terms: D004558:Electric Stimulation; D005074:Evoked Potentials, Visual / Q000502:physiology; D005145:Face; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: electrical brain stimulation; electrocorticography; face perception; fusiform gyrus; lateralization