Cortical sensory suppression during arousal is due to the activity-dependent depression of thalamocortical synapses.
The thalamus serves as a gate that regulates the flow of sensory inputs to the neocortex, and this gate is controlled by neuromodulators from the brainstem reticular formation that are released during arousal. Here we show in rats that sensory-evoked responses were suppressed in the neocortex by activating the brainstem reticular formation and during natural arousal. Sensory suppression occurred at the thalamocortical connection and was a consequence of the activity-dependent depression of thalamocortical synapses caused by increased thalamocortical tonic firing during arousal. Thalamocortical suppression may serve as a mechanism to focus sensory inputs to their appropriate representations in neocortex, which is helpful for the spatial processing of sensory information.
Castro-Alamancos
Manuel A
MA
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4. manuel_castro@bic.mni.mcgill.ca
Oldford
Elizabeth
E
D000818:Animals; D001143:Arousal / Q000502:physiology*; D004594:Electrophysiology; D008564:Membrane Potentials / Q000502:physiology; D017551:Microdialysis; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D019579:Neocortex / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000502:physiology; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D013238:Stereotaxic Techniques; D013569:Synapses / Q000502:physiology*; D013788:Thalamus / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology
D011963:Receptors, GABA-A