Interhemispheric correlations of slow spontaneous neuronal fluctuations revealed in human sensory cortex.
Animal studies have shown robust electrophysiological activity in the sensory cortex in the absence of stimuli or tasks. Similarly, recent human functional magnetic resonance imaging (fMRI) revealed widespread, spontaneously emerging cortical fluctuations. However, it is unknown what neuronal dynamics underlie this spontaneous activity in the human brain. Here we studied this issue by combining bilateral single-unit, local field potentials (LFPs) and intracranial electrocorticography (ECoG) recordings in individuals undergoing clinical monitoring. We found slow (<0.1 Hz, following 1/f-like profiles) spontaneous fluctuations of neuronal activity with significant interhemispheric correlations. These fluctuations were evident mainly in neuronal firing rates and in gamma (40-100 Hz) LFP power modulations. Notably, the interhemispheric correlations were enhanced during rapid eye movement and stage 2 sleep. Multiple intracranial ECoG recordings revealed clear selectivity for functional networks in the spontaneous gamma LFP power modulations. Our results point to slow spontaneous modulations in firing rate and gamma LFP as the likely correlates of spontaneous fMRI fluctuations in the human sensory cortex.
Nir
Yuval
Y
Department of Neurobiology, Weizmann Institute of Science, 240 Herzl Street, Rehovot 76100, Israel.
Mukamel
Roy
R
Dinstein
Ilan
I
Privman
Eran
E
Harel
Michal
M
Fisch
Lior
L
Gelbard-Sagiv
Hagar
H
Kipervasser
Svetlana
S
Andelman
Fani
F
Neufeld
Miri Y
MY
Kramer
Uri
U
Arieli
Amos
A
Fried
Itzhak
I
Malach
Rafael
R
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000166:cytology* / Q000503:physiopathology; D004566:Electrodes; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012890:Sleep / Q000502:physiology; D013223:Statistics as Topic; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
D010100:Oxygen