title: Biphasic plasticity of dendritic fields in layer V motor neurons in response to motor learning.
abstract: Motor learning is associated with plastic reorganization of neural networks in primary motor cortex (M1) that advances through stages. An initial increment in spine formation is followed by pruning and maturation one week after training ended. A similar biphasic course was described for the size of the forelimb representation in M1. This study investigates the evolution of the dendritic architecture in response to motor skill training using Golgy-Cox silver impregnation in rat M1. After learning of a unilateral forelimb-reaching task to plateau performance, an increase in dendritic length of layer V pyramidal neurons (i.e. motor neurons) was observed that peaked one month after training ended. This increment in dendritic length reflected an expansion of the distal dendritic compartment. After one month dendritic arborization shrinks even though animals retain task performance. This pattern of evolution was observed for apical and basal dendrites alike - although the increase in dendritic length occurs faster in basal than in apical dendrites. Dendritic plasticity in response to motor training follows a biphasic course with initial expansion and subsequent shrinkage. This evolution takes fourth as long as the biphasic reorganization of spines or motor representations.
authors: Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zurich, Frauenklinikstrasse 26, 8032 Zurich, Switzerland.
authors: C
authors: C
authors: Gloor
authors: Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zurich, Frauenklinikstrasse 26, 8032 Zurich, Switzerland; Department of Neurology, Johns Hopkins University, 1550 Orleans Street, Baltimore, MD 21231, USA. Electronic address: andreas.luft@uzh.ch.
authors: A R
authors: AR
authors: Luft
authors: Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zurich, Frauenklinikstrasse 26, 8032 Zurich, Switzerland.
authors: J A
authors: JA
authors: Hosp
mesh_terms: D000818:Animals; D003712:Dendrites / Q000502:physiology*; D005552:Forelimb / Q000502:physiology; D007858:Learning / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans
keywords: Dendritic plasticity; Golgi–Cox staining; Motor cortex; Motor learning; Rats; Skilled-reaching task