title: Electrical stimulation of human fusiform face-selective regions distorts face perception.
abstract: Face-selective neural responses in the human fusiform gyrus have been widely examined. However, their causal role in human face perception is largely unknown. Here, we used a multimodal approach of electrocorticography (ECoG), high-resolution functional magnetic resonance imaging (fMRI), and electrical brain stimulation (EBS) to directly investigate the causal role of face-selective neural responses of the fusiform gyrus (FG) in face perception in a patient implanted with subdural electrodes in the right inferior temporal lobe. High-resolution fMRI identified two distinct FG face-selective regions [mFus-faces and pFus-faces (mid and posterior fusiform, respectively)]. ECoG revealed a striking anatomical and functional correspondence with fMRI data where a pair of face-selective electrodes, positioned 1 cm apart, overlapped mFus-faces and pFus-faces, respectively. Moreover, electrical charge delivered to this pair of electrodes induced a profound face-specific perceptual distortion during viewing of real faces. Specifically, the subject reported a "metamorphosed" appearance of faces of people in the room. Several controls illustrate the specificity of the effect to the perception of faces. EBS of mFus-faces and pFus-faces neither produced a significant deficit in naming pictures of famous faces on the computer, nor did it affect the appearance of nonface objects. Further, the appearance of faces remained unaffected during both sham stimulation and stimulation of a pair of nearby electrodes that were not face-selective. Overall, our findings reveal a striking convergence of fMRI, ECoG, and EBS, which together offer a rare causal link between functional subsets of the human FG network and face perception.
authors.affiliation: Laboratory of Behavioral and Cognitive Neurology, Department of Neurology and Neurological Sciences, Université Catholique de Louvain, 1348 Louvain, Belgium. jparvizi@stanford.edu
authors.forename: Josef
authors.initials: J
authors.lastname: Parvizi
authors.forename: Corentin
authors.initials: C
authors.lastname: Jacques
authors.forename: Brett L
authors.initials: BL
authors.lastname: Foster
authors.forename: Nathan
authors.initials: N
authors.lastname: Witthoft
authors.forename: Nathan
authors.initials: N
authors.lastname: Withoft
authors.forename: Vinitha
authors.initials: V
authors.lastname: Rangarajan
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Weiner
authors.forename: Kalanit
authors.initials: K
authors.lastname: Grill-Spector
mesh_terms: D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D004558:Electric Stimulation / Q000009:adverse effects; D004569:Electroencephalography; D005145:Face; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed; D014795:Visual Pathways / Q000098:blood supply
chemical_list: D010100:Oxygen