Connections of the lateral hypothalamic area juxtadorsomedial region in the male rat

Abstract

The connections of the lateral hypothalamic area juxtadorsomedial region (LHAjd) were investigated in a series of pathway-tracing experiments involving iontophoretic co-injection of the tracers Phaseolus vulgaris-leucoagglutinin (PHA-L; for outputs) and cholera toxin B subunit (CTB; for inputs). Results revealed that the LHAjd has connections with some 318 distinct gray matter regions encompassing all four subsystems—motor, sensory, cognitive, and behavioral state—included in a basic structure–function network model of the nervous system. Integration of these subsystems is necessary for the coordination and control of emotion and behavior, and in that regard the connections of the LHAjd indicate that it may have a prominent role. Furthermore, the LHAjd connections, together with the connections of other LHA differentiations studied similarly to date, indicate a distinct topographic organization that suggests each LHA differentiation has specifically differing degrees of involvement in the control of multiple behaviors. For the LHAjd, its involvement to a high degree in the control of defensive behavior, and to a lesser degree in the control of other behaviors, including ingestive and reproductive, is suggested. Moreover, the connections of the LHAjd suggest that its possible role in the control of these behaviors may be very broad in scope because they involve the somatic, neuroendocrine, and autonomic divisions of the nervous system. In addition, we suggest that connections between LHA differentiations may provide, at the level of the hypothalamus, a neuronal substrate for the coordinated control of multiple themes in the behavioral repertoire.

Melanin-concentrating hormone inputs to the nucleus accumbens originate from distinct hypothalamic sources and are apposed to GABAergic and cholinergic cells in the Long-Evans rat brain

“…Because we highlight the hypothalamus-Acb axis regarding MCH participation, the present findings can also reinforce the structural basis of the role for MCH in modulating the reward value attributed to cocaine, which was claimed by Chung et al (2009). Swanson (1987) and Hahn and Swanson (2012) proposed the division of the hypothalamus into neuroendocrine [periventricular], neurovegetative [medial] and associative/limbic [lateral] zones, each one influencing the motivated behavior in a particular and different way. Our findings provide anatomical/hodological evidence that AcbSh is involved in these three different aspects of motivated behavior regarding the participation of MCH.…”

Appetitive associative learning recruits a distinct network with cortical, striatal, and hypothalamic regions

“…However, in order to be able to sample reliably from the same regions across different brains, we defined three larger areas for analysis: perifornical, lateral, and ventral (Figure 2). The perifornical area (LHApf) (Levels 27-30, −2.00 to −3.25 mm) we defined here contained the juxtadorsomedial and suprafornical nuclei (Swanson, 2004; Hahn and Swanson, 2010, 2012). The lateral area (LHAl) (Levels 27-30, −2.00 to −3.25 mm) included the region lateral to the LHApf, and was bordered dorsally by a line that matches the dorsal end of the third ventricle and ventrally by the ventral edge of the fornix.…”

Central Autonomic System

“…13) (Cechetto and Saper, 1988). Recent studies using anterograde tracing with PHA-L have attempted to dissect the projections from different lateral hypothalamic fields (e.g., the region just lateral to the paraventricular nucleus vs. that just dorsal to the fornix, and that just lateral to the dorsomedial nucleus) (Hahn and Swanson, 2010;Hahn and Swanson, 2012). These studies have found some evidence for topographic organization, confirming that the long descending projections to the autonomic sites in the pons and medulla appear to come from the tuberal region.…”