Journal Article

Differential visually-induced gamma-oscillations in human cerebral cortex

Nishida, Masaaki, Rothermel, Robert, Sood, Sandeep, Juhász, Csaba, Asano, Eishi, Fukuda, Miho

2009

Overview

Using intracranial electrocorticography, we determined how cortical gamma-oscillations (50–150 Hz) were induced by different visual tasks in nine children with focal epilepsy. In all children, full-field stroboscopic flash-stimuli induced gamma-augmentation in the anterior-medial occipital cortex (starting on average at 31 ms after stimulus presentation) and subsequently in the lateral-polar occipital cortex; minimal gamma-augmentation was noted in the inferior occipital-temporal cortex; occipital gamma-augmentation was followed by gamma-attenuation in three children. Central-field picture-stimuli induced sustained gamma-augmentation in the lateral-polar occipital cortex (starting on average at 69 ms) and subsequently in the inferior occipital-temporal cortex in all children and in the posterior frontal cortex in three children; the anterior-medial occipital cortex showed no gamma-augmentation but rather gamma-attenuation. Electrical stimulation of the anterior-medial occipital cortex induced a phosphene in the peripheral-field or eye deviation to the contralateral side, whereas that of the lateral-polar occipital cortex induced a phosphene in the central-field. In summary, full-field, simple and short-lasting visual information might be preferentially processed by the anterior-medial occipital cortex, and subsequently by the lateral-polar occipital cortex. Gamma-attenuation following augmentation in the striate cortex might be associated with a relative refractory-period to flash-stimuli or feed-forward inhibition by other areas. Central-field complex visual information might be processed by a network involving the lateral-polar occipital cortex and the inferior occipital-temporal cortex. A plausible interpretation of posterior frontal gamma-augmentation during central-field picture stimuli includes activation of the frontal-eye-field for visual searching. Gamma-attenuation in the anterior-medial occipital cortex during central-field picture-stimuli might be associated with relative inattention to the peripheral visual field during central-field object visualization.

• Publisher: Elsevier Inc,Elsevier Limited
• Subject: Adolescent / Biological Clocks / Brain / Brain Mapping / Cerebral Cortex - physiopathology / Child / Child, Preschool / Electrocardiography - methods / Electrodes / Epilepsy - physiopathology / Evoked Potentials, Visual / Female / Humans / Male / Medical imaging / Photic Stimulation - methods / Stroboscopy - methods / Studies / Surgery