Layer-specific interhemispheric functional connectivity in the somatosensory cortex of rats: resting state electrophysiology and fMRI studies

Kwangyeol Baek, Woo Hyun Shim, Jaeseung Jeong, Harsha Radhakrishnan, Bruce R. Rosen, David Boas, Maria Franceschini, Bharat B. Biswal, Young R. Kim
2015 Brain Structure and Function  
The spontaneous cerebral hemodynamic fluctuations observed during the resting state have been frequently visualized using functional magnetic resonance imaging (rsfMRI). However, the neuronal populations and neuroelectric characteristics underlying the functional connectivity of cerebrohemodynamic activities are poorly understood. We investigated the characteristics of bihemispheric functional connectivity via electrophysiology and rsfMRI in the primary sensory cortex of rats anesthetized by
more » ... hloralose. Unlike the evoked responses, the spontaneous electrophysiological activity was concentrated in the infragranular layers and could be classified into subtypes with distinctive current sources and sinks. Both neuroelectric and rsfMRI signals were interhemispherically correlated in a layer-specific manner, suggesting that there are independent neural inputs to infragranular and granular/supragranular layers. The majority of spontaneous electrophysiological activities were bilaterally paired with delays of up to *50 ms between each pair. The variable interhemispheric delay implies the involvement of indirect, multi-neural pathways. Our findings demonstrated the diverse activity patterns of layer-specific electrophysiological substrates and suggest the recruitment of multiple, non-specific brain regions in construction of interhemispheric functional connectivity.
doi:10.1007/s00429-015-1073-0 pmid:26077581 pmcid:PMC4681693 fatcat:f6ovcrie6fbz3brpv4d5xwvzxe