The overall goal of our research is to further elucidate the neurobiology of reward and motivation. Behaviors that are
considered rewarding behaviors include natural behaviors such as sexual behavior, aggression, and food intake. Interestingly,
a similar circuitry in the brain that regulates natural reward is also involved in drug addiction and other behaviors that are
compulsive in nature. Therefore, by understanding how the brain regulates natural rewarding behavior, we may reach a better
understanding of what is different in the brainís control of addiction. Our lab studies male sexual behavior that is a strongly
rewarding behavior. In men, sexual climax is closely associated with subjective pleasurable feelings. Likewise, in rats
ejaculation is associated with reward and is the most reinforcing component of sexual behavior. Hence it is surprising that
relatively little is know about the neural circuits mediating ejaculation and the pathways involved in relay and processing of
ejaculation-related cues. Moreover, the neural substrate regulating the rewarding and reinforcing properties are completely
unclear. Therefore, our research has four main focuses:
1) Studies of the spinal control of ejaculation;
2) Investigation of sensory pathways that relay sensory cues related to ejaculation to the forebrain;
3) Identification of genes, proteins, and neurotransmitters involved in regulation of sexual behavior, experience, and reward;
4) Investigation if sexual experience influences addiction to drugs of abuse, and the mechanisms underlying this effect.
To address these questions, our research utilizes a multidisciplinary approach by combining a diversity of techniques, including behavioral analysis, pharmacological and genetic manipulations, cellular imaging, neuroanatomical techniques, confocal and light microscopic analyses, and molecular approaches (including micro array, real time PCR, in situ hybridization, and western blot analysis).
• Smith, J.T., Coolen, L.M., Kriegsfeld, L.J., Sari, I.P., Jaafarzadehshirazi, M.R., Maltby, M., Bateman, K., Goodman R.L., Tilbrook, A.J., Ubuka, T., Bentley, G.E., Clarke I.J., Lehman, M.N. (2008) Variation in kisspeptin and gonadotropin-inhibitory hormone expression and terminal connections to GnRH neurons in the brain: a novel medium for seasonal breeding in the sheep. Endocrinology [Epub ahead of print]
• Dominguez, J.M., Balfour, M.E., Lee, H.S., Brown, J.L., Davis, B.A., Coolen, L.M. (2007) Mating activates NMDA receptors in the medial preoptic area of male rats. Behav. Neurosci. 121(5): 1023-1031.
• Davis, B.A., Fitzgerald, M.E., Brown, J.L., Amstalden, K.A., Coolen, L.M. (2007) Activation of POMC neurons during general arousal but not sexual behaviour in male rats. Behav. Neurosci. 121(5): 1012-1022.
• Straiko, M.M., Gudelsky, G.A., Coolen, L.M. (2007) Treatment with a serotonin-depleting regimen of MDMA prevents conditioned place preference to sex in male rats. Behav. Neurosci. 121(3): 586-593.
• Straiko, M.M., Coolen, L.M., Zemlan, F.P., Gudelsky, G.A. (2007) The effect of amphetamine analogs on cleaved microtubule- associated protein-tau formation in the rat brain. Neuroscience 144(1): 223-231.
• Wang, J., Coolen, L.M., Brown, J.L., Usdin, T.B. (2006) Neurons containing tuberoinfundibular peptide of 39 residues are activated following male sexual behaviour. Neuropeptides 40(6): 403-408.
• Straiko, M.M., Gudelsky, G.A., Coolen, L.M., Harrison, R., Zemlan, F.P.(2006) Treatment with trimethyltin promotes the formation of cleaved tau in the rat brain. J. Neurosci. Res. 84(5): 1116-1123.
• Balfour M.E., Brown J.L., Yu L., and Coolen L.M. (2006) Potential contributions of efferents from medial prefrontal cortex to neural activation following sexual behavior in the male rat. Neuroscience 137(4): 1259-1276.
• Veening J.G., Coolen L.M., de Jong T.R., Joosten H.W., de Boer S.F., Koolhaas J.M., and Olivier B. (2005) Do similar neural systems subserve aggressive and sexual behavior in male rats? Insights from c-Fos and pharmacological studies. Eur. J. Pharmacol. 526(1-3): 226-239.
• Coolen L.M. (2005) Neural control of ejaculation. J. Comp. Neurol. 493(1): 39-45.