Grant: Discovery Grants Program - Individual

Male sexual behavior is a rewarding behavior that consists of multiple elements, of which ejaculation appears to be the most rewarding. However, the neural pathways for relay of ejaculation-related sensory information to the brain are currently unclear. Recently, our laboratory identified one candidate pathway in the position to relay ejaculation-related signals from the pelvic organs to the brain, via the lumbar spinal cord. Specifically, a population of cells in the lumbar spinal cord that are involved in the control of ejaculation, form a nodal point in this spinothalamic pathway. These lumbar spinothalamic cells receive inputs from the reproductive organs and in turn provide inputs to a medial subdivision of the subparafascicular thalamic nucleus (SPFp; Coolen et al., 2003). This pathway contains multiple neuropeptides and transmitters and expresses neural activation only following ejaculation and not following other components of sexual behaviour, in support of its involvement in processing and relay of ejaculation-related signals (Coolen et al., 2003). Our long term goal is to better understand the functional significance of this spinothalamic pathway for male sexual behaviour. In particular, the significance of this pathway and the processing of sensory information related to ejaculation for sexual reward will be investigated in the current proposal.The objectives of our proposal are to 1. further investigate the functional role of the neurotransmitters in the LSt-SPFp pathway and 2. test the involvement of SPFp efferents for sexual reward and behaviour. Studies in Aim 1 will determine the effects of infusions into the medial SPFp of ligands or antagonists to the receptors for the neurotransmitters expressed in this pathway, on the expression of sexual behaviour and the development of conditioned sexual reward. In Aim 2, the hypothesis that SPFp outputs to forebrain areas are critical for sex behavior and reward will be tested by activation of the SPFp. Together, these studies will fill an important gap in our understanding of the neural circuits mediating sexual behaviour and reward.