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. INDEXING TERMShypothalamus; periaqueductal gray; hippocampal formation; behavior; motivation An emerging view of the lateral hypothalamic area (LHA) reveals a highly regionally differentiated neuronal architecture with correspondingly differentiated axonal connections characterized by an extensive divergent and convergent topographic organization (Swanson, 2004;Goto et al., 2005;Swanson et al., 2005;Hahn, 2010;Hahn and Swanson, 2010). Such an organization calls for an equivalently extensive comparative analysis of the underlying organization of the severally parceled LHA (16 provisional LHA regions within the hypothalamic lateral zone) (Swanson, 2004). In a previous article (Hahn and Swanson, 2010), we presented the results of a high-resolution analysis of the axonal inputs and outputs of the lateral hypothalamic area (LHA) juxtaparaventricular (LHAjp) and suprafornical (LHAs) regions-two differentiations of the hypothalamic lateral zone middle group within NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript respectively a medial (LHAjp) and perifornical (LHAs) tier of a recently revised parcellation for the LHA (Swanson, 2004;Swanson et al., 2005).The previous work showed that the LHAjp and LHAs have interregional connections with several hundred distinct gray matter regions encompassing all four subsystems (motor, sensory, cognitive, and...

Macroscale intrinsic network architecture of the hypothalamus

“…Comparing the current MRCC analysis to an earlier-alludedto hypothalamic structure-function model (11,35) facilitates exploration of possible functional interpretations. To elaborate, the earlier model identifies subgroupings based on structural and functional properties, giving five divisions: (i) a neuroendocrine motor zone associated with pituitary gland control; (ii) medial zone nuclei forming part of a putative behavior control column; (iii) a highly interconnected group of five rostrally located regions and the three regions of the DMH that together are considered to form a theoretical "visceromotor network" (35) for generating patterned autonomic and neuroendocrine motor output; (iv) a periventricular region related to (and possibly expanding) the visceromotor network, defined essentially by what remains of the periventricular and medial zones after subtracting the neuroendocrine motor zone, medial zone nuclei, and visceromotor network; and (v) a lateral zone associated prominently with the behavior control column, which is supported by more recent data (18)(19)(20)36).…”

“…Hypothalamic cytoarchitecture is highly differentiated, generally more so than other central nervous system (CNS) divisions (17). Illustrative of hypothalamic connectional complexity, one of its major subdivisions-the lateral hypothalamic area (LHA)contains the most highly connected CNS regions identified to date [in terms of macroscale connections (macroconnections)] (18)(19)(20).…”

Hypothalamus-Olfactory System Crosstalk: Orexin A Immunostaining in Mice

“…In rats, orexin neuron cell bodies are located in the perifornical nucleus, and in the dorsal and lateral hypothalamic areas (LHA; Peyron et al, 1998; Nambu et al, 1999). Interestingly, it has been suggested that differentiations in each LHA are involved in the control of specific behavior, with the involvement of the LHA suprafornical region in the control of food intake behavior (Hahn and Swanson, 2010, 2012). High resolution studies of the orexin neuron population in the LH have been carried out (Swanson et al, 2005) showing the extreme complexity of this brain area.…”

“…Many studies have demonstrated that it could act by modulating olfactory sensitivity according to satiety (Aimé et al, 2007; Julliard et al, 2007; Prud’homme et al, 2009, for review: Palouzier-Paulignan et al, 2012). The cytological, connectional (Hahn and Swanson, 2010, 2012), immunohistological, and molecular (Peyron et al, 1998; Sakurai et al, 2005; Swanson et al, 2005) characterization of the lateral hypothalamus (LH) has already been performed. These studies suggest the existence of a functional loop between olfactory centers and the hypothalamus, which could explain the modulation of olfaction depending on energy balance.…”

Neuronal circuits in the hypothalamus controlling gonadotrophin‐releasing hormone release: the neuroanatomical projections of kisspeptin neurons

“…The anterograde tracers may be used to establish the anatomical relationships between various components of neural networks when combined with retrograde tracing methods. Both PHA-L and the high molecular weight BDA 10 kDa are excellent anterograde tracers that have been used in many tracing studies reported to date (Krajewski et al 2010;Hahn & Swanson, 2012). These tracers are delivered stereotactically into the desired location to label neuronal cell bodies and axons selectively.…”