Date on Master's Thesis/Doctoral Dissertation
Anatomical Sciences and Neurobiology
Anatomical Sciences and Neurobiology, PhD
Committee Co-Chair (if applicable)
Gustatory system; somatostatin neurons; central amygdala; nucleus of solitary tract; parabrachial nucleus; lateral hypothalamus
The nucleus of solitary tract (NST) and parabrachial nucleus (PBN) represent the first and second central synapses of ascending gustatory information. Neural processing in these nuclei is influenced by descending input from forebrain regions such as the central nucleus of the amygdala (CeA). In mice, we have shown that somatostatin (Sst) expressing neurons of CeA that project to NST and PBN are largely distinct cell populations and optogenetic inhibition of the CeA/Sst-to-NST subpopulation increases the intake of high concentrations of quinine with no apparent effect on sucrose intake. Synaptic connectivity of these cells is needed to understand the possible mechanisms underlying these behavioral responses. Our lab has previously demonstrated that CeA/Sst terminals within the PBN expressed GABA and made synaptic contacts largely with non-GABAergic neural elements. To determine whether CeA/sst terminals within the NST also express GABA, we used electron microscopy combined with cre-dependent anterograde transported virus injections (AAV9-DIO-dApex2) into the CeA of Sst-cre mice and post-embedding immunogold labelling for GABA. We found that majority of CeA/sst terminals in NST express GABA and synapsed with non-GABAergic targets. These results suggest that CeA/Sst cells provide monosynaptic input to second order NST projection neurons (non-GABAergic) and that this direct feedback inhibition is necessary for appropriate responding to bitter taste quality
Bartonjo, Jane Jeruto, "Connectivity of amygdala somatostatin-expressing neurons and their role in taste-guided behavior." (2023). Electronic Theses and Dissertations. Paper 4158.
Retrieved from https://ir.library.louisville.edu/etd/4158