Thalamic Control of Cortical Sensory Processing During Active Sensing - Project Summary
Most of our sensations accompany motor directed behavior as we touch, scan, and interact with our
environment. This sensorimotor integration is most apparent in somatosensation, where our tactile
perceptions of texture are felt during active sensation, such as rubbing a finger across a surface. However,
it is unclear how even basic sensory thalamocortical circuits control self -generated motion and active
sensation. In particular, thalamic dysfunction has been linked to many neurological sensorimotor disorders
including Huntington’s Disease, Parkinson’s Disease, and Essential Tremor. The work proposed for this
fellowship will therefore be significant because it will elucidate how specific thalamic nuclei regulate information
during active sensation in order to generate a better framework of non-pathological thalamocortical sensory
processing. This project will specifically determine how the mouse paralemniscal whisker thalamic nucleus
(Posterior Medial or POm) modulates ongoing sensory signals in the primary sensory cortex (Aim 1) and
sensory detectability during an active sensing task (Aim 2). Due to both motor and sensory input, the
paralemniscal thalamic nuclei may be vital for basic sensorimotor integration in active sensing. This work
will be innovative because it will examine the paralemniscal system as a sensory gate while combining
novel methods for population cortical recording and manipulation of the thalamocortical circuit during
behavior. This project will use specific genetically engineered mice to target light sensitive protein channels
to silence and to drive ongoing paralemniscal thalamic activity, while providing sensory input to the
whiskers. The central hypothesis for this work is that the paralemniscal thalamic system is a sensory gate
that controls the activation of downstream cortical processes and the detectability of stimulus information
during active sensation. Aim 1 will determine how three different paralemniscal thalamic states (control,
silenced, and active) shape sensory cortical response to sensory stimuli using local field potential
electrophysiology and a genetically encoded voltage indicator (Arclight). Aim 2 will determine the behavioral
relevance of the paralemniscal pathway by reversibly lesioning paralemniscal function during an active and
passive detection task while recording neural correlates. The impact of this work will be to expand the current
framework of thalamocortical sensorimotor integration to develop better treatment options during states of
thalamic dysfunction and complex neurological disease. This award will provide the additional funding and
support required for the success of this proposed work through additional experimental, analytical, and
scientific training.
