Feed-forward information and zero-lag synchronization in the sensory thalamocortical circuit are modulated during stimulus perception

Significance The direction of information flow between brain circuits may be key in cognitive functions. We addressed this problem by evaluating a directional correlation measure between simultaneously recorded neurons from somatosensory thalamus (ventral posterolateral nucleus, VPL) and somatosensory cortex (S1) sharing the same cutaneous receptive field while monkeys judged presence or absence of tactile stimuli. During stimulus presence, feed-forward (VPL → S1) information increased as a function of stimulus amplitude, while feed-back (S1 → VPL) information was unaffected. Simultaneously, zero-lag interaction emerged with increasing stimulus amplitude, contributing to thalamocortical synchronization. Furthermore, VPL → S1 information decreased during error trials. Also, both VPL → S1 and zero-lag interactions decreased when monkeys were not required to report stimulus presence. Thus, directional and coordinated information in the thalamocortical circuit is associated with stimulus perception.