title: Corresponding ECoG and fMRI category-selective signals in human ventral temporal cortex.
abstract: Functional magnetic resonance imaging (fMRI) and electrocorticography (ECoG) research have been influential in revealing the functional characteristics of category-selective responses in human ventral temporal cortex (VTC). One important, but unanswered, question is how these two types of measurements might be related with respect to the VTC. Here we examined which components of the ECoG signal correspond to the fMRI response by using a rare opportunity to measure both fMRI and ECoG responses from the same individuals to images of exemplars of various categories including faces, limbs, cars and houses. Our data reveal three key findings. First, we discovered that the coupling between fMRI and ECoG responses is frequency and time dependent. The strongest and most sustained correlation is observed between fMRI and high frequency broadband (HFB) ECoG responses (30-160 hz). In contrast, the correlation between fMRI and ECoG signals in lower frequency bands is temporally transient, where the correlation is initially positive, but then tapers off or becomes negative. Second, we find that the strong and positive correlation between fMRI and ECoG signals in all frequency bands emerges rapidly around 100 ms after stimulus onset, together with the onset of the first stimulus-driven neural signals in VTC. Third, we find that the spatial topology and representational structure of category-selectivity in VTC reflected in ECoG HFB responses mirrors the topology and structure observed with fMRI. These findings of a strong and rapid coupling between fMRI and HFB responses validate fMRI measurements of functional selectivity with recordings of direct neural activity and suggest that fMRI category-selective signals in VTC are associated with feed-forward neural processing.
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA 94305, USA; Psychological Sciences Research Institute (IPSY), Université Catholique de Louvain, 10 Place du Cardinal Mercier, 1348 Louvain-la-Neuve, Belgium; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA. Electronic address: corentin.g.jacques@uclouvain.be.
authors.forename: Corentin
authors.initials: C
authors.lastname: Jacques
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Witthoft
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Weiner
authors.affiliation: Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA.
authors.forename: Brett L
authors.initials: BL
authors.lastname: Foster
authors.affiliation: Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA.
authors.forename: Vinitha
authors.initials: V
authors.lastname: Rangarajan
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA.
authors.forename: Dora
authors.initials: D
authors.lastname: Hermes
authors.affiliation: Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA; Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA.
authors.forename: Kai J
authors.initials: KJ
authors.lastname: Miller
authors.affiliation: Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA; Stanford Neuroscience Institute, SNI, Stanford University, Stanford, CA 94305, USA.
authors.forename: Josef
authors.initials: J
authors.lastname: Parvizi
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA 94305, USA; Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP), USA; Stanford Neuroscience Institute, SNI, Stanford University, Stanford, CA 94305, USA.
authors.forename: Kalanit
authors.initials: K
authors.lastname: Grill-Spector
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003210:Concept Formation / Q000502:physiology*; D000069280:Electrocorticography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000098:blood supply* / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Electrocorticography; Functional neuroimaging; High-frequency broadband gamma; Object recognition; Ventral stream