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Efferent projections of Vglut2 , Foxp2 , and Pdyn parabrachial neurons in mice
Author(s) -
Huang Dake,
Grady Fillan S.,
Peltekian Lila,
Geerling Joel C.
Publication year - 2021
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.24975
Subject(s) - neuroscience , biology , forebrain , stria terminalis , thalamus , glutamatergic , parabrachial nucleus , lateral parabrachial nucleus , efferent , basal forebrain , zona incerta , basal ganglia , brainstem , amygdala , glutamate receptor , central nervous system , receptor , genetics , afferent
The parabrachial nucleus (PB) is a complex structure located at the junction of the midbrain and hindbrain. Its neurons have diverse genetic profiles and influence a variety of homeostatic functions. While its cytoarchitecture and overall efferent projections are known, we lack comprehensive information on the projection patterns of specific neuronal subtypes in the PB. In this study, we compared the projection patterns of glutamatergic neurons here with a subpopulation expressing the transcription factor Foxp2 and a further subpopulation expressing the neuropeptide Pdyn . To do this, we injected an AAV into the PB region to deliver a Cre‐dependent anterograde tracer (synaptophysin‐mCherry) in three different strains of Cre‐driver mice. We then analyzed 147 neuroanatomical regions for labeled boutons in every brain ( n = 11). Overall, glutamatergic neurons in the PB region project to a wide variety of sites in the cerebral cortex, basal forebrain, bed nucleus of the stria terminalis, amygdala, diencephalon, and brainstem. Foxp2 and Pdyn subpopulations project heavily to the hypothalamus, but not to the cortex, basal forebrain, or amygdala. Among the few differences between Foxp2 and Pdyn cases was a notable lack of Pdyn projections to the ventromedial hypothalamic nucleus. Our results indicate that genetic identity determines connectivity (and therefore, function), providing a framework for mapping all PB output projections based on the genetic identity of its neurons. Using genetic markers to systematically classify PB neurons and their efferent projections will enhance the translation of research findings from experimental animals to humans.