title: Effect of the environment on the dendritic morphology of the rat auditory cortex.
abstract: The present study aimed to identify morphological correlates of environment-induced changes at excitatory synapses of the primary auditory cortex (A1). We used the Golgi-Cox stain technique to compare pyramidal cells dendritic properties of Sprague-Dawley rats exposed to different environmental manipulations. Sholl analysis, dendritic length measures, and spine density counts were used to monitor the effects of sensory deafness and an auditory version of environmental enrichment (EE). We found that deafness decreased apical dendritic length leaving basal dendritic length unchanged, whereas EE selectively increased basal dendritic length without changing apical dendritic length. On the contrary, deafness decreased while EE increased spine density in both basal and apical dendrites of A1 Layer 2/3 (LII/III) neurons. To determine whether stress contributed to the observed morphological changes in A1, we studied neural morphology in a restraint-induced model that lacked behaviorally relevant acoustic cues. We found that stress selectively decreased apical dendritic length in the auditory but not in the visual primary cortex. Similar to the acoustic manipulation, stress-induced changes in dendritic length possessed a layer-specific pattern displaying LII/III neurons from stressed animals with normal apical dendrites but shorter basal dendrites, while infragranular neurons (Layers V and VI) displayed shorter apical dendrites but normal basal dendrites. The same treatment did not induce similar changes in the visual cortex, demonstrating that the auditory cortex is an exquisitely sensitive target of neocortical plasticity, and that prolonged exposure to different acoustic as well as emotional environmental manipulation may produce specific changes in dendritic shape and spine density.
authors.affiliation: Laboratory of Cell and Synaptic Physiology, School for Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas, USA.
authors.forename: Mitali
authors.initials: M
authors.lastname: Bose
authors.forename: Pablo
authors.initials: P
authors.lastname: Muñoz-Llancao
authors.forename: Swagata
authors.initials: S
authors.lastname: Roychowdhury
authors.forename: Justin A
authors.initials: JA
authors.lastname: Nichols
authors.forename: Vikram
authors.initials: V
authors.lastname: Jakkamsetti
authors.forename: Benjamin
authors.initials: B
authors.lastname: Porter
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Byrapureddy
authors.forename: Humberto
authors.initials: H
authors.lastname: Salgado
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kilgard
authors.forename: Francisco
authors.initials: F
authors.lastname: Aboitiz
authors.forename: Alexies
authors.initials: A
authors.lastname: Dagnino-Subiabre
authors.forename: Marco
authors.initials: M
authors.lastname: Atzori
mesh_terms: D000818:Animals; D001303:Auditory Cortex / Q000166:cytology* / Q000473:pathology / Q000502:physiology*; D003638:Deafness / Q000473:pathology / Q000503:physiopathology; D003712:Dendrites / Q000473:pathology / Q000502:physiology*; D049229:Dendritic Spines / Q000473:pathology / Q000502:physiology; D004777:Environment; D016057:Evoked Potentials, Auditory, Brain Stem; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology* / Q000473:pathology / Q000502:physiology*; D009483:Neuropsychological Tests; D017966:Pyramidal Cells / Q000166:cytology / Q000473:pathology / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000502:physiology; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000473:pathology / Q000503:physiopathology; D014793:Visual Cortex / Q000166:cytology / Q000473:pathology / Q000503:physiopathology