title: Motor cortex gates vibrissal responses in a thalamocortical projection pathway.
abstract: Higher-order thalamic nuclei receive input from both the cerebral cortex and prethalamic sensory pathways. However, at rest these nuclei appear silent due to inhibitory input from extrathalamic regions, and it has therefore remained unclear how sensory gating of these nuclei takes place. In the rodent, the ventral division of the zona incerta (ZIv) serves as a relay station within the paralemniscal thalamocortical projection pathway for whisker-driven motor activity. Most, perhaps all, ZIv neurons are GABAergic, and recent studies have shown that these cells participate in a feedforward inhibitory circuit that blocks sensory transmission in the thalamus. The present study provides evidence that the stimulation of the vibrissa motor cortex suppresses vibrissal responses in ZIv via an intra-incertal GABAergic circuit. These results provide support for the proposal that sensory transmission operates via a top-down disinhibitory mechanism that is contingent on motor activity.
authors.affiliation: Centre de Recherche Université Laval Robert-Giffard, Québec City, Canada G1J 2G3.
authors.forename: Nadia
authors.initials: N
authors.lastname: Urbain
authors.forename: Martin
authors.initials: M
authors.lastname: Deschênes
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D001710:Biotin / Q000031:analogs & derivatives; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D003911:Dextrans; D005260:Female; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010812:Physical Stimulation; D020656:Posterior Thalamic Nuclei / Q000033:anatomy & histology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology; D020530:Subthalamus / Q000033:anatomy & histology / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014110:Touch / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D003911:Dextrans; C076397:biotinylated dextran amine; D005680:gamma-Aminobutyric Acid; D001710:Biotin