Thalamocortical [correction of Thalamcortical] optimization of tactile processing according to behavioral state.

We propose a conceptual model that describes the operation of the main thalamocortical loop of the rat somatosensory system. According to this model, the asynchronous convergence of ascending and descending projections dynamically alters the physiological properties of thalamic neurons in the ventral posterior medial (VPM) nucleus as rats shift between three behavioral states. Two of these states are characterized by distinct modes of rhythmic whisker movements. We posit that these simultaneous shifts in exploratory behavioral strategy and in the physiological properties of VPM neurons allow rats to either (i) optimize the detection of stimuli that are novel or difficult to sense or (ii) process complex patterns of multi-whisker stimulation.