title: Cortical Sensory Responses Are Enhanced by the Higher-Order Thalamus.
abstract: 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.
authors.affiliation: Institute for Neuroscience, Technische Universität München, Biedersteiner Straβe 29, 80802 Munich, Germany.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Mease
authors.affiliation: Institute for Neuroscience, Technische Universität München, Biedersteiner Straβe 29, 80802 Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Metz
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straβe 22, 81675 Munich, Germany. Electronic address: alexander.groh@gmail.com.
authors.forename: Alexander
authors.initials: A
authors.lastname: Groh
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000502:physiology*; D013003:Somatosensory Cortex / Q000378:metabolism*; D013788:Thalamus / Q000378:metabolism*