Macro- and mesoscale analysis of connections between the cingulate region and the lateral hypothalamic area: Tracer co-injection and chemoarchitectural studies in the adult male rat
Hypothalamic research since the middle of the 20th century shaped the view that the lateral hypothalamic area (LHA) has a central role in controlling appetitive drives. The LHA is anatomically positioned to receive converging axonal inputs which relay information about the body’s metabolic state as well as descending projections from the cerebral hemispheres, which encode cognitive and emotional states that influence feeding. Cerebral inputs are capable of initiating feeding despite the presence of competing satiety signals. Recent work has shown that medial prefrontal cortical areas can drive feeding in sated animals, possibly by engaging hypothalamic hypocretin/orexin (H/O)-expressing neurons, which are known to send projections to the cortex. Neuroanatomical tract tracing was used, in rats, to test the hypothesis that there are bidirectional monosynaptic connections between the medial prefrontal cortex and the lateral hypothalamic area. To further examine hypothalamic-cortical interactions, prefrontal targets of H/O-containing axons were described with cell-type precision by using immunohistochemistry and neuronal reconstructions. Collectively, these experiments produced the highest spatial resolution maps of prefrontal chemoarchitecture and connections with the LHA. Additionally, they provide novel probe targets for future functional studies, which includes a previously unappreciated connection between the infralimbic cortical area and the terete part of the hypothalamic tuberal nucleus.
Negishi, Kenichiro, "Macro- and mesoscale analysis of connections between the cingulate region and the lateral hypothalamic area: Tracer co-injection and chemoarchitectural studies in the adult male rat" (2016). ETD Collection for University of Texas, El Paso. AAI10250925.