Structural and functional features of the taste system change dramatically during development. While much has been learned by studying normal developmental processes, complementary experiments using experimental manipulations during critical phases of development have been of great value in learning how the taste system is organized.
The specific aims of this proposal use genetic knockout mouse models and early dietary manipulations with coordinated techniques of peripheral taste nerve recordings, central nervous system tract tracing, single cell fills of targeted brainstem neurons, in vivo central tast neuron neurophysiology, and in vitro patch-clamp experiments to study the role of activity-independent and activity-dependent factors on gustatory brainstem circuit development. Morphological studies examine 1) the terminal field organization of afferent nerves in the first synaptic relay in the brain, in the nucleus of the solitary tract (NTS), and 2) examine the dendritic characteristics of relay neurons in the NTS that project to the next central relay in mic, and putative inhibitory interneurons. Neurophysiological studies will examine 1) the influences of altered taste-elicited activity during development and early dietary manipulations on taste responses through in vivo single NTS cell recordings, and 2) influences on the intrinsic membrane properties and synaptic properties of NTS cells through in vitro patch- clamp slice recordings. The overall focus of this proposal is on how the central gustatory system is assembled and then refined by experience. Findings from these studies will provide new and important information about the development and plasticity of the peripheral and central gustatory system, and about the development of taste preferences and aversions. They will also be useful in determining the role that the maternal diet and taste-elicited activity have on organizing the developing sense of taste.
One of the fundamental questions in neuroscience is how circuits in the brain are formed during development and how they are modified by experience. The proposed research program seeks to define fundamental aspects of how circuit development in the gustatory brainstem is influenced by neural activity and by non- activity dependent factors. Since taste plays a key role in food acceptance and rejection, our work may lead to new insights into how preferences and aversions are formed during development and how modifiable these circuits are through experience.
|Sun, Chengsan; Dayal, Arjun; Hill, David L (2015) Expanded terminal fields of gustatory nerves accompany embryonic BDNF overexpression in mouse oral epithelia. J Neurosci 35:409-21|
|Graham, Dustin M; Sun, Chengsan; Hill, David L (2014) Temporal signatures of taste quality driven by active sensing. J Neurosci 34:7398-411|
|Wang, Siting; Corson, James; Hill, David et al. (2012) Postnatal development of chorda tympani axons in the rat nucleus of the solitary tract. J Comp Neurol 520:3217-35|
|Reddaway, Rebecca B; Davidow, Andrew W; Deal, Sarah L et al. (2012) Impact of chorda tympani nerve injury on cell survival, axon maintenance, and morphology of the chorda tympani nerve terminal field in the nucleus of the solitary tract. J Comp Neurol 520:2395-413|
|Corson, Sara L; Hill, David L (2011) Chorda tympani nerve terminal field maturation and maintenance is severely altered following changes to gustatory nerve input to the nucleus of the solitary tract. J Neurosci 31:7591-603|
|Thomas, J E; Hill, D L (2008) The effects of dietary protein restriction on chorda tympani nerve taste responses and terminal field organization. Neuroscience 157:329-39|
|Mangold, Jamie E; Hill, David L (2008) Postnatal reorganization of primary afferent terminal fields in the rat gustatory brainstem is determined by prenatal dietary history. J Comp Neurol 509:594-607|
|May, Olivia L; Erisir, Alev; Hill, David L (2008) Modifications of gustatory nerve synapses onto nucleus of the solitary tract neurons induced by dietary sodium-restriction during development. J Comp Neurol 508:529-41|
|May, Olivia L; Erisir, Alev; Hill, David L (2007) Ultrastructure of primary afferent terminals and synapses in the rat nucleus of the solitary tract: comparison among the greater superficial petrosal, chorda tympani, and glossopharyngeal nerves. J Comp Neurol 502:1066-78|
|Mangold, Jamie E; Hill, David L (2007) Extensive reorganization of primary afferent projections into the gustatory brainstem induced by feeding a sodium-restricted diet during development: less is more. J Neurosci 27:4650-62|
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