title: Corticofugal feedback for auditory midbrain plasticity elicited by tones and electrical stimulation of basal forebrain in mice.
abstract: The auditory cortex (AC) is the major origin of descending auditory projections and is one of the targets of the cholinergic basal forebrain, nucleus basalis (NB). In the big brown bat, cortical activation evokes frequency-specific plasticity in the inferior colliculus and the NB augments this collicular plasticity. To examine whether cortical descending function and NB contributions to collicular plasticity are different between the bat and mouse and to extend the findings in the bat, we induced plasticity in the central nucleus of the mouse inferior colliculus by a tone paired with electrical stimulation of the NB (hereafter referred to as tone-ES(NB)). We show here that tone-ES(NB) shifted collicular best frequencies (BFs) towards the frequency of the tone paired with ES(NB) when collicular BFs were different from tone frequency. The shift in collicular BF was linearly correlated to the difference between collicular BFs and tone frequencies. The changes in collicular BFs after tone-ES(NB) were similar to those found in the big brown bat. Compared with cortical plasticity evoked by tone-ES(NB), the pattern of collicular BF shifts was identical but the shifting range of collicular BFs was narrower. A GABA(A) agonist (muscimol) or a muscarinic acetylcholine receptor antagonist (atropine) applied to the AC completely abolished the collicular plasticity evoked by tone-ES(NB). Therefore, our findings strongly suggest that the AC plays a critical role in experience-dependent auditory plasticity through descending projections.
authors.affiliation: Department of Physiology and Biophysics, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, N.W., Rm193B, Calgary, Alberta, T2N 4N1, Canada.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jacqueline J
authors.initials: JJ
authors.lastname: Hakes
authors.forename: Stephan P
authors.initials: SP
authors.lastname: Bonfield
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001303:Auditory Cortex / Q000502:physiology / Q000528:radiation effects*; D001306:Auditory Pathways / Q000187:drug effects / Q000502:physiology*; D001309:Auditory Threshold / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005246:Feedback / Q000502:physiology*; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D007245:Inferior Colliculi / Q000502:physiology / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009118:Muscimol / Q000494:pharmacology; D009473:Neuronal Plasticity / Q000528:radiation effects*
chemical_list: D018755:GABA Agonists; D018727:Muscarinic Antagonists; D009118:Muscimol; D001285:Atropine