Hypothalamus, appetite, attachment, and anorexia:
It is not intended to discuss eating disorders on CorticalBrain.com given. During working on the site, however, It was found that the ventromedial hypothalamus in responsible for energy regulation (the intake of food) and that this same area also controls female sexual receptivity. Also, as with illnesses diagnosed as OCD, it seems that frustration over attachment issues and dopamine dysregulation may play a role in eating-disorder symptoms. We discuss dopamine in both Parts 2 and 3 of CorticalBrain.com. We also discuss attachment issues in Depression, Obsessions, and Compulsions: Concepts in Ethology and Attachment Theory, in part 3 of CorticalBrain.com. Also in Part 3 is a page called OCD Treatments Including Antipsychotic Medications which includes a subsection particularly relevant to the treatment of eating disorders called Antipsychotics and eating disorders.
In Affective Neuroscience, regarding the hypothalamus and appetite, Panksepp eloquently writes: "The essence of energy regulation is well hidden from scientific view, apparently in the deep metabolic recesses of the hypothalamus." He later describes experiments that illustrate the role of the hypothalamus in consummatory behavior. In these experiments, researchers joined two rats together in a "parabiotic union," a state that sometimes occurs in human identical conjoined twins whose bodies are fused together during development in the uterus. In the experiments, the two conjoined rats thereafter share each other's blood supply. Panksepp writes: "Each of these normal animals gradually ate less, and eventually each contained only half the body fat that a normal rat contains. … The critical area of the brain that probably receives this signal is the ventromedial hypothalamus… ."
Panksepp points out that lesions in the ventromedial hypothalamus "have long been known to produce overeating and eventual obesity,… ." When researchers joined an animal lesioned in this way with a nonlesioned partner, the lesioned animal overate and became obese. In contrast, the animal with a normal hypothalamus detected the abundant nutrition the lesioned animal consumed, and thus lost its appetite completely and became emaciated. The hypothalamus is not, however, a simple on-off switch. Panksepp explains that the ventromedial hypothalamus contains "a long-term metabolic detector by which overall energy balance is regulated."
The ventromedial hypothalamus "also controls female sexual receptivity," notes Panksepp. He explains that "reproduction is generally reduced by starvation" since, metabolically speaking, "it is not wise to have children when food is scarce!" He points out that the "onset of female puberty is also triggered to some extent by weight" since from a metabolic viewpoint, "if one has abundant food, one should begin to reproduce earlier." This dual function reveals, explains Panksepp, "how closely energy detectors and female sexual receptivity systems are coupled in the brain."
Regarding anorexia and other eating disorders, the University of Maryland Medical Center provides patients with helpful educational material. According to the material, the hypothalamus-pituitary-adrenal axis and associated neurotransmitters—including serotonin, norepinephrine, and dopamine—that regulate stress, mood, and appetite are being investigated for a possible role in eating disorders. It is interesting that the educational material also cites what is called attachment issues as a possible cause of eating disorders. Regarding attachment and anorexia, an observation Panksepp makes in Affective Neuroscience takes on additional meaning. He writes: "One long-term emotion that is especially incompatible with normal appetite is separation distress. When young animals are socially isolated, they typically lose weight even if they have free access to lots of food. When the young are reunited with their kin, and a mood of apparent contentment is reestablished, appetite returns." We discuss separation distress specifically in Part 2 of CorticalBrain.com in PANIC/LOSS: an Innate Brain System.
Scientists have found that damage to another very specific area of the hypothalamus, the lateral hypothalamus, severely reduces feeding behavior. Panksepp explains how this area of the brain was at first thought to contain a "feeding system." Research has shown, however, that neurons in this area of the brain, as Panksepp puts it, "elaborate seeking strategies, which require a great deal of sensory and motor integration" and that resulting routines "are governed by interactions with the basal ganglia [corpus striata complex]… ." We will discuss the corpus striata complex in the next subsection. Panksepp points out that massive lesions in the lateral hypothalamus produce animals that have difficulty doing anything. He writes: "They typically have an abnormally high metabolic rate and proceed on a downhill course toward death unless they are given extended nursing care."
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