title: Occipital gamma-oscillations modulated during eye movement tasks: simultaneous eye tracking and electrocorticography recording in epileptic patients.
abstract: We determined the spatio-temporal dynamics of cortical gamma-oscillations modulated during eye movement tasks, using simultaneous eye tracking and intracranial electrocorticography (ECoG) recording. Patients with focal epilepsy were instructed to follow a target moving intermittently and unpredictably from one place to another either in an instantaneous or smooth fashion during extraoperative ECoG recording. Target motion elicited augmentation of gamma-oscillations in the lateral, inferior and polar occipital regions in addition to portions of parietal and frontal regions; subsequent voluntary eye movements elicited gamma-augmentation in the medial occipital region. Such occipital gamma-augmentations could not be explained by contaminations of ocular or myogenic artifacts. The degree of gamma-augmentation was generally larger during saccade compared to pursuit trials, while a portion of the polar occipital region showed pursuit-preferential gamma-augmentations. In addition to the aforementioned eye movement task, patients were asked to read a single word popping up on the screen. Gamma-augmentation was elicited in widespread occipital regions following word presentation, while gamma-augmentation in the anterior portion of the medial occipital region was elicited by an involuntary saccade following word presentation rather than word presentation itself. Gamma-augmentation in the lateral, inferior and polar occipital regions can be explained by increased attention to a moving target, whereas gamma-augmentation in the anterior-medial occipital region may be elicited by images in the peripheral field realigned following saccades. In functional studies comparing brain activation between two tasks, eye movement patterns during tasks may need to be considered as confounding factors.
authors.affiliation: Department of Pediatrics, Wayne State University, Detroit Medical Center, Detroit, Michigan 48201, USA.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Nagasawa
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Matsuzaki
authors.forename: Csaba
authors.initials: C
authors.lastname: Juhász
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Hanazawa
authors.forename: Aashit
authors.initials: A
authors.lastname: Shah
authors.forename: Sandeep
authors.initials: S
authors.lastname: Mittal
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sood
authors.forename: Eishi
authors.initials: E
authors.lastname: Asano
mesh_terms: D000293:Adolescent; D001288:Attention / Q000502:physiology; D002648:Child; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D012438:Saccades / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology; D055815:Young Adult