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The role of the lateral hypothalamus and orexin in ingestive behavior: a model for the translation of past experience and sensed deficits into motivated behaviors.

Hurley SW, Johnson AK - Front Syst Neurosci (2014)

Bottom Line: The LHA also receives inputs from brain areas involved in reward-related learning and orexin neuron activation can become conditioned to environmental stimuli that are associated with rewards.In turn, this information is "fed into" mesolimbic circuitry to influence the performance of motivated behaviors.This hypothesis may foster experiments that will result in an improved understanding of LHA function.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Iowa Iowa City, IA, USA.

ABSTRACT
The hypothalamus has been recognized for its involvement in both maintaining homeostasis and mediating motivated behaviors. The present article discusses a region of the hypothalamus known as the lateral hypothalamic area (LHA). It is proposed that brain nuclei within the LHA including the dorsal region of the lateral hypothalamus (LHAd) and perifornical area (PeF) provide a link between neural systems that regulate homeostasis and those that mediate appetitive motivated behaviors. Functional and immunohistochemical data indicate that the LHA promotes many motivated behaviors including food intake, water intake, salt intake, and sexual behavior. Anatomical tracing experiments demonstrate that the LHA is positioned to receive inputs from brain areas involved in regulating body fluid and energy homeostasis. Regions within the LHA send dense projections to the ventral tegmental area (VTA), providing a pathway for the LHA to influence dopaminergic systems generally recognized to be involved in motivated behaviors and their reinforcement. Furthermore, the LHA contains neurons that synthesize orexin/hypocretin, a neuropeptide that promotes many appetitive motivated behaviors. The LHA also receives inputs from brain areas involved in reward-related learning and orexin neuron activation can become conditioned to environmental stimuli that are associated with rewards. Therefore, it is hypothesized that the LHA integrates signaling from areas that regulate body fluid and energy balance and reward-related learning. In turn, this information is "fed into" mesolimbic circuitry to influence the performance of motivated behaviors. This hypothesis may foster experiments that will result in an improved understanding of LHA function. An improved understanding of LHA function may aid in treating disorders that are associated with an excess or impairment in the expression of ingestive behavior including obesity, anorexia, impairments in thirst, salt gluttony, and salt deficiency.

No MeSH data available.


Related in: MedlinePlus

Unpublished data from authors. Retrograde labeling from the LHAd and PeF to the LT and arcuate nucleus of the hypothalamus. 2% Fluoro-Gold in physiological saline was iontophoresed into the PeF and LHAd (A). Retrograde labeling was observed across the LT and in the ARH. Specifically, significant retrograde-labeling was seen in the annulus of the SFO (B), anterior SFO (C), stalk of the SFO (D), dorsal and ventral MnPO (E, F), OVLT (G), and ARH (H). Images were taken at different magnifications to compensate for the size of the brain area. Panels (A), (B), and (G) were taken at 10x and (C), (D), (E), (F), and (H) were taken at 20x. f = fornix, v = ventricle, ac = anterior commissure.
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Figure 2: Unpublished data from authors. Retrograde labeling from the LHAd and PeF to the LT and arcuate nucleus of the hypothalamus. 2% Fluoro-Gold in physiological saline was iontophoresed into the PeF and LHAd (A). Retrograde labeling was observed across the LT and in the ARH. Specifically, significant retrograde-labeling was seen in the annulus of the SFO (B), anterior SFO (C), stalk of the SFO (D), dorsal and ventral MnPO (E, F), OVLT (G), and ARH (H). Images were taken at different magnifications to compensate for the size of the brain area. Panels (A), (B), and (G) were taken at 10x and (C), (D), (E), (F), and (H) were taken at 20x. f = fornix, v = ventricle, ac = anterior commissure.

Mentions: Anatomical and immunohistochemical studies support the idea that the LHA aids in integrating signaling from orexigenic peptides with neurocircuitry involved in motivation and reward. Neuropeptide Y (NPY) is expressed in ARH neurons (Hahn et al., 1998) and this neuropeptide induces feeding (Schwartz et al., 2000). Interestingly, NPY neurons send dense projections that are in apposition with orexin neurons located in the LHA (Broberger et al., 1998). Treatments that induce hunger such as hypoglycemia or administration of orexigenic peptides including ghrelin and NPY induce c-fos expression in orexin-containing neurons (Moriguchi et al., 1999; Niimi et al., 2001; Toshinai et al., 2003). Additionally, compromising orexin neurotransmission attenuates feeding induced by administration of either NPY or ghrelin. Neurons in the dorsomedial ARH, a region of the ARH that contains a majority of NPY neurons, also project to the PeF and possibly the LHAd (Figure 2; Hahn and Swanson, 2010).


The role of the lateral hypothalamus and orexin in ingestive behavior: a model for the translation of past experience and sensed deficits into motivated behaviors.

Hurley SW, Johnson AK - Front Syst Neurosci (2014)

Unpublished data from authors. Retrograde labeling from the LHAd and PeF to the LT and arcuate nucleus of the hypothalamus. 2% Fluoro-Gold in physiological saline was iontophoresed into the PeF and LHAd (A). Retrograde labeling was observed across the LT and in the ARH. Specifically, significant retrograde-labeling was seen in the annulus of the SFO (B), anterior SFO (C), stalk of the SFO (D), dorsal and ventral MnPO (E, F), OVLT (G), and ARH (H). Images were taken at different magnifications to compensate for the size of the brain area. Panels (A), (B), and (G) were taken at 10x and (C), (D), (E), (F), and (H) were taken at 20x. f = fornix, v = ventricle, ac = anterior commissure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230038&req=5

Figure 2: Unpublished data from authors. Retrograde labeling from the LHAd and PeF to the LT and arcuate nucleus of the hypothalamus. 2% Fluoro-Gold in physiological saline was iontophoresed into the PeF and LHAd (A). Retrograde labeling was observed across the LT and in the ARH. Specifically, significant retrograde-labeling was seen in the annulus of the SFO (B), anterior SFO (C), stalk of the SFO (D), dorsal and ventral MnPO (E, F), OVLT (G), and ARH (H). Images were taken at different magnifications to compensate for the size of the brain area. Panels (A), (B), and (G) were taken at 10x and (C), (D), (E), (F), and (H) were taken at 20x. f = fornix, v = ventricle, ac = anterior commissure.
Mentions: Anatomical and immunohistochemical studies support the idea that the LHA aids in integrating signaling from orexigenic peptides with neurocircuitry involved in motivation and reward. Neuropeptide Y (NPY) is expressed in ARH neurons (Hahn et al., 1998) and this neuropeptide induces feeding (Schwartz et al., 2000). Interestingly, NPY neurons send dense projections that are in apposition with orexin neurons located in the LHA (Broberger et al., 1998). Treatments that induce hunger such as hypoglycemia or administration of orexigenic peptides including ghrelin and NPY induce c-fos expression in orexin-containing neurons (Moriguchi et al., 1999; Niimi et al., 2001; Toshinai et al., 2003). Additionally, compromising orexin neurotransmission attenuates feeding induced by administration of either NPY or ghrelin. Neurons in the dorsomedial ARH, a region of the ARH that contains a majority of NPY neurons, also project to the PeF and possibly the LHAd (Figure 2; Hahn and Swanson, 2010).

Bottom Line: The LHA also receives inputs from brain areas involved in reward-related learning and orexin neuron activation can become conditioned to environmental stimuli that are associated with rewards.In turn, this information is "fed into" mesolimbic circuitry to influence the performance of motivated behaviors.This hypothesis may foster experiments that will result in an improved understanding of LHA function.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Iowa Iowa City, IA, USA.

ABSTRACT
The hypothalamus has been recognized for its involvement in both maintaining homeostasis and mediating motivated behaviors. The present article discusses a region of the hypothalamus known as the lateral hypothalamic area (LHA). It is proposed that brain nuclei within the LHA including the dorsal region of the lateral hypothalamus (LHAd) and perifornical area (PeF) provide a link between neural systems that regulate homeostasis and those that mediate appetitive motivated behaviors. Functional and immunohistochemical data indicate that the LHA promotes many motivated behaviors including food intake, water intake, salt intake, and sexual behavior. Anatomical tracing experiments demonstrate that the LHA is positioned to receive inputs from brain areas involved in regulating body fluid and energy homeostasis. Regions within the LHA send dense projections to the ventral tegmental area (VTA), providing a pathway for the LHA to influence dopaminergic systems generally recognized to be involved in motivated behaviors and their reinforcement. Furthermore, the LHA contains neurons that synthesize orexin/hypocretin, a neuropeptide that promotes many appetitive motivated behaviors. The LHA also receives inputs from brain areas involved in reward-related learning and orexin neuron activation can become conditioned to environmental stimuli that are associated with rewards. Therefore, it is hypothesized that the LHA integrates signaling from areas that regulate body fluid and energy balance and reward-related learning. In turn, this information is "fed into" mesolimbic circuitry to influence the performance of motivated behaviors. This hypothesis may foster experiments that will result in an improved understanding of LHA function. An improved understanding of LHA function may aid in treating disorders that are associated with an excess or impairment in the expression of ingestive behavior including obesity, anorexia, impairments in thirst, salt gluttony, and salt deficiency.

No MeSH data available.


Related in: MedlinePlus