HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 94/4/2630    most recent 00161.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Shumway, C. Articles by Bower, J. M. Search for Related Content PubMed PubMed Citation Articles by Shumway, C. Articles by Bower, J. M.

Mechanisms Underlying Reorganization of Fractured Tactile Cerebellar Maps After Deafferentation in Developing and Adult Rats

Computation and Neural Systems Program, California Institute of Technology, Pasadena, California

Submitted 15 February 2005; accepted in final form 21 June 2005

Our previous studies showed that fractured tactile cerebellar maps in rats reorganize after deafferentation during development and in adulthood while maintaining a fractured somatotopy. Several months after deafferentation of the infraorbital branch of the trigeminal nerve, the missing upper lip innervation is replaced in the tactile maps in the granule cell layer of crus IIa. The predominant input into the denervated area is always the upper incisor representation. This study examined whether this reorganization was caused by mechanisms intrinsic to the cerebellum or extrinsic, i.e., occurring in somatosensory structures afferent to the cerebellum. We first compared normal and deafferented maps and found that the expansion of the upper incisor is not caused by a preexisting bias in the strength or abundance of upper incisor input in normal animals. We then mapped tactile representations before and immediately after denervation. We found that the pattern of reorganization observed in the cerebellum several months later is not caused by unmasking of a silent or weaker upper incisor representation. Both results indicate that the reorganization is not a result of subsequent growth or sprouting mechanism within the cerebellum itself. Finally, we compared postlesion maps in the cerebellum and the somatosensory cortex. We found that the upper incisor representation significantly expands in both regions and that this expansion is correlated, suggesting that reorganization in the cerebellum is a passive consequence of reorganization in afferent cerebellar pathways. This result has important developmental and functional implications.

This article has been cited by other articles:

				D. Restuccia, G. D. Marca, M. Valeriani, M. G. Leggio, and M. Molinari Cerebellar damage impairs detection of somatosensory input changes. A somatosensory mismatch-negativity study Brain, January 1, 2007; 130(1): 276 - 287. [Abstract] [Full Text] [PDF]