Cross-Modal influences of somatosensory area siv on auditory responses in field areas of the cat
Poster

Leslie Keniston
Department of Anatomy and Neurobiology - VCU School of Medicine

Ruth Clemo
Department of Anatomy and Neurobiology - VCU School of Medicine

Alex Meredith
Department of Anatomy and Neurobiology - VCU School of Medicine

     Abstract ID Number: 114
     Full text: Not available
     Last modified: May 22, 2003

Abstract
Recent studies in our lab have demonstrated a novel cross-modal projection from auditory (FAES) to the adjoining somatosensory (SIV) representation resulting in the suppression of SIV somatosensory responses by FAES activity. Because a cortico-cortical projection in one direction is generally matched by a reciprocal projection, we sought to determine the cross-modal influence of a projection from SIV to FAES. Orthograde tracers placed in SIV revealed labeled boutons in a bilaminar distribution that favored the supragranular layers within the medial aspect of FAES. Retrograde tracers injected into FAES marked pyramidal-shaped neurons in SIV. These anatomical features are consistent with a feedback-type projection. A total of 269 FAES neurons were tested for their responses to electrical activation of stimulating electrodes placed in SIV, of which one was orthodromically activated. When activation of SIV was paired with acoustic stimulation of FAES neurons, a large number (34/73; 46.6%) showed a significant response decrease when compared with auditory activation alone, while comparatively fewer (7/73; 9.6%) revealed a significant response increase. These data reveal the same inhibitory and excitatory forms of cross-modal effects that were observed in the FAES-to-SIV projection, indicating that these projections are indeed reciprocal. Supported by NS39460.