Cortical Sensory Responses Are Enhanced by the Higher-Order Thalamus

Cell Rep. 2016 Jan 12;14(2):208-15. doi: 10.1016/j.celrep.2015.12.026. Epub 2015 Dec 31.


In the mammalian brain, thalamic signals reach the cortex via two major routes: primary and higher-order thalamocortical pathways. While primary thalamocortical nuclei transmit sensory signals from the periphery, the function of higher-order thalamocortical projections remains enigmatic, in particular their role in sensory processing in the cortex. Here, by optogenetically controlling the thalamocortical pathway from the higher-order posteromedial thalamic nucleus (POm) during whisker stimulation, we demonstrate the integration of the two thalamocortical streams by single pyramidal neurons in layer 5 (L5) of the mouse barrel cortex under anesthesia. We report that POm input mainly enhances sub- and suprathreshold activity via net depolarization. Sensory enhancement is accompanied by prolongation of cortical responses over long (800-ms) periods after whisker stimulation. Thus, POm amplifies and temporally sustains cortical sensory signals, possibly serving to accentuate highly relevant sensory information.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebral Cortex / physiology*
  • Mice
  • Neurons / physiology*
  • Somatosensory Cortex / metabolism*
  • Thalamus / metabolism*