J Neurophysiol (January 1, 2003). 10.1152/jn.00294.2002
Submitted on Submitted 19 April 2002; accepted in final form 27 August 2002

Responses of Thalamic Neurons to Input From the Male Genitalia

 ¹Department of Anatomical Sciences and Neurobiology University of Louisville, Louisville, Kentucky 40292; and  ²Department of Physiological Sciences, University of Florida Brain Institute, University of Florida, Gainesville, Florida 32610-0144

Hubscher, Charles H. and Richard D. Johnson. Responses of Thalamic Neurons to Input From the Male Genitalia. J. Neurophysiol. 89: 2-11, 2003. There have been relatively few electrophysiological studies, in any species, describing the supraspinal processing of inputs from the male genital tract. The thalamus was the focus of the present study. In 11 urethan-anesthetized male rats, subregions of the thalamus were surveyed for neuronal responses to the search stimulus, bilateral electrical stimulation of the dorsal nerve of the penis (DNP). A total of 133 DNP-responsive neurons were found and further tested for degree of somatovisceral convergence from other peripheral structures. Histological reconstruction of the recording sites revealed that the penile-responsive neurons were distributed among various thalamic subregions. These thalamic subregions included the medial-dorsal nuclei and ventral and lateral thalamic subregions (majority of neurons responsive to both tactile and pinch stimulation of the penis) as well as intralaminar, posterior and reticular subregions (majority responsive to pinch only). Taken together, the data demonstrate the existence of thalamic neurons with inputs from the male genitalia with widespread somatovisceral convergence. These neurons likely contribute to the neural circuitries underlying various aspects of penile sensation associated with reproductive and nociceptive events.