title: Norepinephrine is necessary for experience-dependent plasticity in the developing mouse auditory cortex.
abstract: Critical periods are developmental windows during which the stimuli an animal encounters can reshape response properties in the affected system to a profound degree. Despite this window's importance, the neural mechanisms that regulate it are not completely understood. Pioneering studies in visual cortex initially indicated that norepinephrine (NE) permits ocular dominance column plasticity during the critical period, but later research has suggested otherwise. More recent work implicating NE in experience-dependent plasticity in the adult auditory cortex led us to re-examine the role of NE in critical period plasticity. Here, we exposed dopamine β-hydroxylase knock-out (Dbh(-/-)) mice, which lack NE completely from birth, to a biased acoustic environment during the auditory cortical critical period. This manipulation led to a redistribution of best frequencies (BFs) across auditory cortex in our control mice, consistent with prior work. By contrast, Dbh(-/-) mice failed to exhibit the expected redistribution of BFs, even though NE-deficient and NE-competent mice showed comparable auditory cortical organization when reared in a quiet colony environment. These data suggest that while intrinsic tonotopic patterning of auditory cortical circuitry occurs independently from NE, NE is required for critical period plasticity in auditory cortex.
authors: Graduate Program in Neuroscience, Department of Biology, and.
authors: Kathryn N
authors: KN
authors: Shepard
authors: Department of Human Genetics, Emory University, Atlanta, Georgia 30322.
authors: L Cameron
authors: LC
authors: Liles
authors: Graduate Program in Neuroscience, Department of Human Genetics, Emory University, Atlanta, Georgia 30322.
authors: David
authors: D
authors: Weinshenker
authors: Graduate Program in Neuroscience, Department of Biology, and robert.liu@emory.edu.
authors: Robert C
authors: RC
authors: Liu
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000254:growth & development* / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D001931:Brain Mapping; D003423:Critical Period, Psychological; D004299:Dopamine beta-Hydroxylase / Q000235:genetics / Q000378:metabolism; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D007858:Learning / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009473:Neuronal Plasticity / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology*; D010898:Pitch Perception / Q000502:physiology
chemical_list: D004299:Dopamine beta-Hydroxylase; D009638:Norepinephrine
keywords: auditory cortex; critical period; norepinephrine; sound exposure; tonotopy