Long‐range cortical dynamics: a perspective from the mouse sensorimotor whisker system

Abstract

In the mammalian neocortex, the capacity to dynamically route and coordinate the exchange of information between areas is a critical feature of cognitive function, enabling processes such as higher-level sensory processing and sensorimotor integration. Despite the importance attributed to long-range connections between cortical areas, their exact operations and role in cortical function remain an open question. In recent years, progress has been made in understanding long-range cortical circuits through work focused on the mouse sensorimotor whisker system. In this review, we examine recent studies dissecting long-range circuits involved in whisker sensorimotor processing as an entry point for understanding the rules that govern long-range cortical circuit function.

Context-Dependent Sensory Processing across Primary and Secondary Somatosensory Cortex

“…This explains the behavioral effect of S2 inactivation during the late delay, but not the test, period. Recent studies investigating S1 and S2 during tactile detection or discrimination tasks have demonstrated that choice-related activity emerges through learning (Chen et al, 2015;Yamashita and Petersen, 2016) from an inter-areal loop in which choicerelated activity in S1 is inherited from S2 (Chen et al, 2016;Kwon et al, 2016;Ni and Chen, 2017;Yang et al, 2016). We propose that choice activity described in prior tasks reflects a stimulus-outcome association rather than the decision signal driving behavior.…”

Opposing Influence of Sensory and Motor Cortical Input on Striatal Circuitry and Choice Behavior

“…S1 barrel cortex has long been recognized as a key locus for whisker-guided behaviors. While S1 is densely interconnected with many cortical and subcortical areas, including thalamus, higher-order sensory, motor, and association cortices [45–47], the detailed circuitry and behavioral roles of these pathways are just beginning to be understood [65, 66]. For example, S1 interactions with M1 and S2 are now recognized as important for detection of sensory stimuli, behavioral performance, and learning [53–56, 58, 67, 68].…”

Early fMRI responses to somatosensory and optogenetic stimulation reflect neural information flow

“…Because the temporal order of early BOLD responses reflected information flow among longrange somatosensory regions, our next question was whether the neural activation sequence could be identified by the layerdependent onset times. In S1FL, neurons in L4 are known to respond first during forepaw stimulation due to TC inputs from VPL (33,34), whereas neurons in L2/3 respond first during optogenetic stimulation in M1 due to CC inputs from M1 (33,35). To measure spatiotemporal changes at a laminar resolution, we flattened the cortical section containing S1FL and MI (Fig.…”