Synaptic mechanisms of top-down control in the non-lemniscal inferior colliculus.

Autor:	Oberle HM; Kresge Hearing Research Institute & Department of Otolaryngology, University of Michigan, Ann Arbor, United States.; Neuroscience Graduate Program, University of Michigan, Ann Arbor, United States., Ford AN; Kresge Hearing Research Institute & Department of Otolaryngology, University of Michigan, Ann Arbor, United States., Dileepkumar D; Kresge Hearing Research Institute & Department of Otolaryngology, University of Michigan, Ann Arbor, United States., Czarny J; Kresge Hearing Research Institute & Department of Otolaryngology, University of Michigan, Ann Arbor, United States., Apostolides PF; Kresge Hearing Research Institute & Department of Otolaryngology, University of Michigan, Ann Arbor, United States.; Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, United States.
Jazyk:	angličtina
Zdroj:	ELife [Elife] 2022 Jan 06; Vol. 10. Date of Electronic Publication: 2022 Jan 06.
DOI:	10.7554/eLife.72730
Abstrakt:	Corticofugal projections to evolutionarily ancient, subcortical structures are ubiquitous across mammalian sensory systems. These 'descending' pathways enable the neocortex to control ascending sensory representations in a predictive or feedback manner, but the underlying cellular mechanisms are poorly understood. Here, we combine optogenetic approaches with in vivo and in vitro patch-clamp electrophysiology to study the projection from mouse auditory cortex to the inferior colliculus (IC), a major descending auditory pathway that controls IC neuron feature selectivity, plasticity, and auditory perceptual learning. Although individual auditory cortico-collicular synapses were generally weak, IC neurons often integrated inputs from multiple corticofugal axons that generated reliable, tonic depolarizations even during prolonged presynaptic activity. Latency measurements in vivo showed that descending signals reach the IC within 30 ms of sound onset, which in IC neurons corresponded to the peak of synaptic depolarizations evoked by short sounds. Activating ascending and descending pathways at latencies expected in vivo caused a NMDA receptor-dependent, supralinear excitatory postsynaptic potential summation, indicating that descending signals can nonlinearly amplify IC neurons' moment-to-moment acoustic responses. Our results shed light upon the synaptic bases of descending sensory control and imply that heterosynaptic cooperativity contributes to the auditory cortico-collicular pathway's role in plasticity and perceptual learning. Competing Interests: HO, AF, DD, JC, PA No competing interests declared (© 2021, Oberle et al.)
Databáze:	MEDLINE
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