Neural activity pattern(s) underlying brain interhemispheric propagation: An optogenetic fMRI study

Abstract

The sensory system is topographically organized by highly interconnected excitatory thalamo-cortical and interhemispheric cortical-cortical projections. However, little is known at present regarding the existence of spatiotemporal neural activity pattern(s) that may dictate the propagation of activity between cortices at both hemispheres. Here, we employed a novel paired-pulse optogenetic fMRI stimulation paradigm to reveal a temporally-specific neural activity pattern initiated from the somatosensory thalamus that could drive activity propagation from the ipsilateral to contralateral cortex. We found that propagation from the ipsilateral to contralateral somatosensory cortex was facilitated when paired optogenetic stimulation pulses were spaced at 100ms, but not 50ms.