The Neural Basis of Reward. Reward is a concept related to the hedonic, or pleasurable, properties of a stimulus. Such values are central to guiding behavior; thus, we seek out stimuli that are hedonically positive and avoid those that are negative. My lab is interested in determining the neural processes that mediate our ability to assign value to sensory stimuli. My research model--the gustatory system--has some notable advantages for studying the neural basis of hedonic value. The adequate stimuli are simple soluble chemicals, some of which have inherent positive or negative hedonic properties. This provides a benchmark against which the neural and behavioral responses to other stimuli can be judged. The behavioral response to taste stimuli vary, even reverse, depending upon internal state and experience. Finally, gustatory neurons in the pons develop not only a standard thalamocortical projection, but also project directly into the limbic system. I believe this approach is fundamental and, therefore, expected to shed light on the central mechanisms of other learned and innate motivated behaviors like substance abuse, thirst, hunger, and sex.
" Neural Mechanisms of Central Taste Processing: The goal is to determine the anatomical pathways and neurotransmitters that mediate the influence of descending forebrain projections on brainstem taste processing. Prior research has shown that taste elicited activity in the brainstem is altered by conditions that change gustatory hedonic value and consequent behavior. Descending projections from cortical and limbic system nuclei reach second and third order gustatory nuclei in the brainstem and, thus, provide an anatomical substrate for these neurophysiological effects. In fact, previous work in my lab has demonstrated that electrical stimulation of the lateral hypothalamus, central nucleus of the amygdala, and insular gustatory cortex modulates third order neuron processing of taste information. I suspect that these prominent descending projections from cortical and limbic system nuclei play a significant role in hedonic processing.
Zhang, C., Kang, Y., Lundy, R.F. Terminal field specificity of forebrain efferent axons to the pontine parabrachial nucleus and medullary reticular formation. Br. Res. 1368:108-118, 2011.
Panguluri, S.K., Bhatnagar, S., Kumar, A., McCarthy, J.J., Mittal, A., Cooper, N.G., Lundy, R.F., Kumar, A. Genomic profiling of messenger RNA and microRNAs reveals novel mechanisms of TWEAK-induced skeletal muscle wasting. PLoS ONE 5(1): e8760, 2010.
Kang, Y. and R.F. Lundy, Jr. Amygdalofugal influence on processing of taste information in the nucleus of the solitary tract of the rat. J. Neurophysiol. 104:726-741, 2010.
Bhatnagar, S., Panguluri, S.K., Lundy, R.F., Kumar, A. Tumor necrosis factor-α regulates distinct molecular pathways and gene networks in cultured skeletal muscle cells PLoS ONE 5(10): e13262, 2010.
Kang, Y. and R.F. Lundy, Jr. Terminal field specificity of forebrain efferent axons to brainstem gustatory nuclei. Br. Res. 1248:76-85, 2009.
Panguluri, S.K., Saggu, S. and Lundy, R.F. Comparison of somatostatin and corticotrophin releasing hormone immunoreactivity in forebrain neurons projecting to gustatory and non gustatory regions of the parabrachial nucleus in rat. Br. Res. 1298:57-69, 2009.
Saggu, S. and Lundy, R.F. Forebrain neurons that project to the gustatory parabrachial nucleus in rat lack glutamic acid decarboxylase. Am. J. Physiol. 294:R52-R57, 2008.
Lundy, R.F. Gustatory Hedonic Value: Potential Function for Forebrain Control of Brainstem Taste Processing. Neurosci. Biobehav. Rev. 32:1601-1606, 2008.
Mungarndee, S.S., R.F. Lundy, Jr., and R. Norgren. Expression of FOS during sham sucrose intake in rats with central gustatory lesions. Am J Physiol Regul Integr Comp Physiol 295: R751-R763, 2008.
Frank, M.E., R.F. Lundy, Jr., and R.J. Contreras. Cracking taste codes by tapping into sensory neuron impulse traffic. Prog. Neurobiol. 86:245-263, 2008.
Mungarndee, S.S., Lundy Jr., R.F. and Norgren, R. (2006) Central gustatory lesions and learned taste aversions: Unconditioned stimuli. Physiol. Behav. 87:542-551.
Lundy Jr., R.F. and Norgren, R. (2004) Activity in the hypothalamus, amygdala, and cortex generates bilateral and convergent modulation of pontine gustatory neurons. J. Neurophysiol. 91: 1143-1157.
Lundy Jr., R.F. and Norgren, R. (2004) Gustatory System. In: The Rat Nervous System, Third edition, Ed. George Paxinos, Academic Press, San Diego.
Lundy Jr., R.F., Caloiero, V., Bradley, C., Liang, N.C., and Norgren, R. (2004) Furosemide-induced food avoidance: Evidence for a conditioned response. Physiol. Behav. 81: 397-408.
Caloiero, V. and Lundy Jr., R.F. (2004) A novel method for induction of sodium appetite. Br. Res. Bull. 64: 1-7.
Norgren, R., Grigson, P.S, Hajnal, A. and Lundy Jr., R.F. (2003) Motivational modulation of taste. In: Cognition and Emotion in the Brain: First edition, Ed. Taketoshi Ono, Gen Matsumoto, Rodolfo R. Llinas, Alain Berthoz, Ralph Norgren, Hisao Nishijo, and Ryoi Tamura, Elsevier, The Netherlands.
Lundy Jr., R.F. and Norgren, R. (2001) Pontine gustatory activity is altered by electrical stimulation in the central nucleus of the amygdala. J. Neurophysiol. 85: 770-783.
Lundy Jr., R.F. and Contreras, R.J. (1999) Gustatory neuron types in rat geniculate ganglion. J. Neurophysiol. 82: 2970-2988.