Whisking-Related Changes in Neuronal Firing and Membrane Potential Dynamics in the Somatosensory Thalamus of Awake Mice.
The thalamus transmits sensory information to the neocortex and receives neocortical, subcortical, and neuromodulatory inputs. Despite its obvious importance, surprisingly little is known about thalamic function in awake animals. Here, using intracellular and extracellular recordings in awake head-restrained mice, we investigate membrane potential dynamics and action potential firing in the two major thalamic nuclei related to whisker sensation, the ventral posterior medial nucleus (VPM) and the posterior medial group (Pom), which receive distinct inputs from brainstem and neocortex. We find heterogeneous state-dependent dynamics in both nuclei, with an overall increase in action potential firing during active states. Whisking increased putative lemniscal and corticothalamic excitatory inputs onto VPM and Pom neurons, respectively. A subpopulation of VPM cells fired spikes phase-locked to the whisking cycle during free whisking, and these cells may therefore signal whisker position. Our results suggest differential processing of whisking comparing thalamic nuclei at both sub- and supra-threshold levels.
Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France. Electronic address: nadia.urbain@inserm.fr.
Nadia
N
Urbain
Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France.
Paul A
PA
Salin
Physiopathologie des Réseaux Neuronaux du Cycle Sommeil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France.
Paul-Antoine
PA
Libourel
Integrated Physiology of Brain Arousal Systems, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France.
Jean-Christophe
JC
Comte
Integrated Physiology of Brain Arousal Systems, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR5292, Université Claude-Bernard-Lyon 1, 69372 Lyon, France.
Luc J
LJ
Gentet
Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
Carl C H
CCH
Petersen
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004569:Electroencephalography; D004576:Electromyography; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D019579:Neocortex / Q000166:cytology / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology; D013788:Thalamus / Q000166:cytology / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology*