Lundy Lab
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About
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.
Current Projects
Neural Mechanisms of Central Taste Processing: Interoception includes processes by which an organism senses, integrates, interprets, and regulates internal signals that contribute to physiological processes such as eating. In this context, more is known about ascending brain pathways for postoral signals than about descending pathways (e.g. central regulators) that alter processing of this sensory information. Importantly, eating is not only regulated by postoral sensory signals conveyed to the brain by the vagus nerve but also by orosensory signals transmitted by gustatory nerves. The nucleus of the solitary tract (NST) and the parabrachial nucleus (PBN) are initial processing hubs for taste and postoral sensory activity. Both structures also receive descending projections from the same central regulators including the hypothalamus, amygdala, bed nucleus of the stria terminalis, and insular cortex. Advantages of the taste system as a model include stimuli that are easy to apply, behavioral responses that are easily measured, and some prior insight into how central regulators influence taste coding. Nevertheless, major gaps exist in understanding the relevant neural mechanisms and their contribution to intake driven by oral and postoral signals. My labs current project will use somatostatin (Sst)-cre mice in conjunction with cre-dependent retrograde viruses to label and optogenetically manipulate central nucleus of the amygdala (CeA)/Sst/GABA pathways. Specifically, we will determine how CeA/Sst/GABA-to-PBN neurons: (1) influence ingestive behavior driven by oral and postoral sensory activity using microstructural analyses of licking, (2) influence coding of taste information in the PBN using in vivo extracellular recordings, and (3) modulate and are modulated by distinct CeA/Sst/GABA-to-NST neurons using in vitro intracellular recordings.
Recent Publications
Target-specific projections of amygdala somatostatin-expressing neurons to the hypothalamus and brainstem.
Bartonjo JJ, Lundy RF.Chem Senses. 2022 Jan 1;47:bjac009. doi: 10.1093/chemse/bjac009.PMID: 35522083
Distinct Populations of Amygdala Somatostatin-Expressing Neurons Project to the Nucleus of the Solitary Tract and Parabrachial Nucleus.
Bartonjo JJ, Lundy RF.Chem Senses. 2020 Nov 7;45(8):687-698. doi: 10.1093/chemse/bjaa059.PMID: 32940663
Comparison of GABA, Somatostatin, and Corticotrophin-Releasing Hormone Expression in Axon Terminals That Target the Parabrachial Nucleus.
Lundy R.Chem Senses. 2020 May 21;45(4):275-282. doi: 10.1093/chemse/bjaa010.PMID: 32107535
Team
- Abigail Muccilli, Research Assistant II