Functional connectivity in the brain estimated by analysis of gamma events.
It is known that gamma activity is generated by local networks. In this paper we introduced a new approach for estimation of functional connectivity between neuronal networks by measuring temporal relations between peaks of gamma event amplitudes. We have shown in freely moving rats that gamma events recorded between electrodes 1.5 mm apart in the majority of cases, are generated by different neuronal modules interfering with each other. The map of functional connectivity between brain areas during the resting state, created based on gamma event temporal relationships is in agreement with anatomical connections and with maps described by fMRI methods during the resting state. The transition from the resting state to exploratory activity is accompanied by decreased functional connectivity between most brain areas. Our data suggest that functional connectivity between interhemispheric areas depends on GABAergic transmission, while intrahemispheric functional connectivity is kainate receptor dependent. This approach presents opportunities for merging electrographic and fMRI data on brain functional connectivity in normal and pathological conditions.
Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America ; Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
Anatol
A
Bragin
Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
Joel
J
Almajano
Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
Farshad
F
Kheiri
Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America ; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America ; Department of Psychiatry and Biobehavioral Scienses, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America ; Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
Jerome
J
Engel
D000818:Animals; D001921:Brain / Q000502:physiology*; D058256:Brain Waves / Q000502:physiology*; D018728:Entorhinal Cortex / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D008297:Male; D019579:Neocortex / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012146:Rest / Q000502:physiology; D013826:Theta Rhythm / Q000502:physiology