Introducing the brain: controlling hunger (Introduction)

by David Turell , Friday, November 17, 2023, 18:00 (162 days ago) @ David Turell

From the underside of the hippocampus:

https://www.sciencedaily.com/releases/2023/11/231116141050. aus

"A hunger hormone produced in the gut can directly impact a decision-making part of the brain in order to drive an animal's behaviour,...

"The study in mice, published in Neuron, is the first to show how hunger hormones can directly impact activity of the brain's hippocampus when an animal is considering food.

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"'We found that a part of the brain that is crucial for decision-making is surprisingly sensitive to the levels of hunger hormones produced in our gut, which we believe is helping our brains to contextualise our eating choices."

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"The researchers were focusing on brain activity in the ventral hippocampus (the underside of the hippocampus), a decision-making part of the brain which is understood to help us form and use memories to guide our behaviour.

"The scientists found that activity in a subset of brain cells in the ventral hippocampus increased when animals approached food, and this activity inhibited the animal from eating.

"But if the mouse was hungry, there was less neural activity in this area, so the hippocampus no longer stopped the animal from eating. The researchers found this corresponded to high levels of the hunger hormone ghrelin circulating in the blood.

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"This finding has demonstrated how ghrelin receptors in the brain are put to use, showing the hunger hormone can cross the blood-brain barrier (which strictly restricts many substances in the blood from reaching the brain) and directly impact the brain to drive activity, controlling a circuit in the brain that is likely to be the same or similar in humans.

"Dr MacAskill added: "It appears that the hippocampus puts the brakes on an animal's instinct to eat when it encounters food, to ensure that the animal does not overeat -- but if the animal is indeed hungry, hormones will direct the brain to switch off the brakes, so the animal goes ahead and begins eating.'"

Comment: this shows necessary crossings of the blood-brain barrier. The complexity of this mechanism requires design. It is irreducibly complex.