Bilateral projections from rat MI whisker cortex to the neostriatum, thalamus, and claustrum: forebrain circuits for modulating whisking behavior.

Full Abstract

In rats, whisking behavior is characterized by high-frequency synchronous movements and other stereotyped patterns of bilateral coordination that are rarely seen in the bilateral movements of the limbs. This suggests that the motor systems controlling whisker and limb movements must have qualitative or quantitative differences in their interhemispheric connections. To test this hypothesis, anterograde tracing methods were used to characterize the bilateral distribution of projections from the whisker and forepaw regions in the primary motor (MI) cortex. Unilateral tracer injections in the MI whisker or forepaw regions revealed robust projections to the corresponding MI cortical area in the contralateral hemisphere. Both MI regions project bilaterally to the neostriatum, but the corticostriatal projections from the whisker region are denser and more evenly distributed across both hemispheres than those from the MI forepaw region. The MI whisker region projects bilaterally to several nuclei in the thalamus, whereas the MI forepaw region projects almost exclusively to the ipsilateral thalamus. The MI whisker region sends dense projections to the contralateral claustrum, but those to the ipsilateral claustrum are less numerous. By contrast, the MI forepaw region sends few projections to the claustrum of either hemisphere. Bilateral deposits of different tracers in MI revealed overlapping projections to the neostriatum, thalamus, and claustrum when the whisker regions were injected, but not when the forepaw regions were injected. These results suggest that the bilateral coordination of the whiskers depends, in part, on MI projections to the contralateral neostriatum, thalamus, and claustrum. Copyright 2009 Wiley-Liss, Inc.

Author information

Author/s: Alloway, Kevin D (KD); Smith, Jared B (JB); Beauchemin, Kyle J (KJ); Olson, Michelle L (ML);

Affiliation: Department of Neural & Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033-2255, USA. kda1(-atsign-)psu.edu

Grants: NS052689 (Agency:NINDS NIH HHS) ; NS37532 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: The Journal of comparative neurology (J Comp Neurol), published in United States. (Language: eng)

Reference: 2009-Aug; vol 515 (issue 5) : pp 548-64

Dates: Created 2009/06/15; Completed 2009/08/10;

PMID: 19479997, status: MEDLINE (last retrieval date: 8/21/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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