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: 94/3/1727    most recent 00228.2005v2 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 Web of Science 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 Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Pluto, C. P. Articles by Lane, R. D. Search for Related Content PubMed PubMed Citation Articles by Pluto, C. P. Articles by Lane, R. D.

Reducing Contralateral SI Activity Reveals Hindlimb Receptive Fields in the SI Forelimb-Stump Representation of Neonatally Amputated Rats

Department of Anatomy and Neurobiology, Medical College of Ohio, Toledo, Ohio

Submitted 2 March 2005; accepted in final form 24 March 2005

In adult rats that sustained forelimb amputation on the day of birth, >30% of multiunit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) also respond to cutaneous hindlimb stimulation when cortical GABA_A+B receptors are blocked (GRB). This study examined whether hindlimb receptive fields could also be revealed in forelimb-stump sites by reducing one known source of excitatory input to SI GABAergic neurons, the contralateral SI cortex. Corpus callosum projection neurons connect homotopic SI regions, making excitatory contacts onto pyramidal cells and interneurons. Thus in addition to providing monosynaptic excitation in SI, callosal fibers can produce disynaptic inhibition through excitatory synapses with inhibitory interneurons. Based on the latter of these connections, we hypothesized that inactivating the contralateral (intact) SI forelimb region would "unmask" normally suppressed hindlimb responses by reducing the activity of SI GABAergic neurons. The SI forelimb-stump representation was first mapped under normal conditions and then during GRB to identify stump/hindlimb responsive sites. After GRB had dissipated, the contralateral (intact) SI forelimb region was mapped and reversibly inactivated with injections of 4% lidocaine, and selected forelimb-stump sites were retested. Contralateral SI inactivation revealed hindlimb responses in 60% of sites that were stump/hindlimb responsive during GRB. These findings indicate that activity in the contralateral SI contributes to the suppression of reorganized hindlimb receptive fields in neonatally amputated rats.

This article has been cited by other articles:

				R. D. Lane, C. P. Pluto, C. L. Kenmuir, N. L. Chiaia, and R. D. Mooney Does Reorganization in the Cuneate Nucleus Following Neonatal Forelimb Amputation Influence Development of Anomalous Circuits Within the Somatosensory Cortex? J Neurophysiol, February 1, 2008; 99(2): 866 - 875. [Abstract] [Full Text] [PDF]

				T. Karayannis, I. Huerta-Ocampo, and M. Capogna GABAergic and Pyramidal Neurons of Deep Cortical Layers Directly Receive and Differently Integrate Callosal Input Cereb Cortex, May 1, 2007; 17(5): 1213 - 1226. [Abstract] [Full Text] [PDF]

				S. Glazewski, B. L. Benedetti, and A. L. Barth Ipsilateral Whiskers Suppress Experience-Dependent Plasticity in the Barrel Cortex J. Neurosci., April 4, 2007; 27(14): 3910 - 3920. [Abstract] [Full Text] [PDF]

				M. Tommerdahl, S. B. Simons, J. S. Chiu, O. Favorov, and B. L. Whitsel Ipsilateral input modifies the primary somatosensory cortex response to contralateral skin flutter. J. Neurosci., May 31, 2006; 26(22): 5970 - 5977. [Abstract] [Full Text] [PDF]

				Y. Hlushchuk and R. Hari Transient Suppression of Ipsilateral Primary Somatosensory Cortex during Tactile Finger Stimulation J. Neurosci., May 24, 2006; 26(21): 5819 - 5824. [Abstract] [Full Text] [PDF]

				T. A. Woolsey Should One Hand (Paw) Really Not Know What the Other Is Doing? Focus on "Reducing Contralateral SI Activity Reveals Hindlimb Receptive Fields in the SI Forelimb-Stump Representation of Neonatally Amputated Rats" J Neurophysiol, September 1, 2005; 94(3): 1666 - 1667. [Full Text] [PDF]