TY - JOUR
T1 - Layer-specific interhemispheric functional connectivity in the somatosensory cortex of rats
T2 - resting state electrophysiology and fMRI studies
AU - Baek, Kwangyeol
AU - Shim, Woo Hyun
AU - Jeong, Jaeseung
AU - Radhakrishnan, Harsha
AU - Rosen, Bruce R.
AU - Boas, David
AU - Franceschini, Maria
AU - Biswal, Bharat B.
AU - Kim, Young R.
N1 - Funding Information:
The authors thank Drs. Jitendra Sharma and Robert Haslinger for their valuable comments on this manuscript. This work was supported by grants from the National Institutes of Health (Grant Number 5R01EB002066, R01 EB001954) and a Korea Science and Engineering Foundation (KOSEF) grant that was funded by the Korean government (Grant number NRF-2006-2005399, M10644000028-06N4400-02810).
Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - 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 bi-hemispheric functional connectivity via electrophysiology and rsfMRI in the primary sensory cortex of rats anesthetized by α-chloralose. 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.
AB - 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 bi-hemispheric functional connectivity via electrophysiology and rsfMRI in the primary sensory cortex of rats anesthetized by α-chloralose. 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.
KW - Cortical layers
KW - Interhemispheric connectivity
KW - Local field potential
KW - Resting state fMRI
KW - Spontaneous activity
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U2 - 10.1007/s00429-015-1073-0
DO - 10.1007/s00429-015-1073-0
M3 - Article
C2 - 26077581
AN - SCOPUS:84931057443
VL - 221
SP - 2801
EP - 2815
JO - Brain Structure and Function
JF - Brain Structure and Function
SN - 1863-2653
IS - 5
ER -