The decision-making part of the brain can directly be impacted by a hunger hormone produced in the gut. This drives one’s eating choices, according to a new study published in the journal Neuron. The study, led by researchers from University College London, was conducted in mice. This is a first-of-its-kind study, as it shows how hunger hormones can directly impact activity in the brain’s hippocampus when an animal is trying to decide which food to eat.
As part of the study, the researchers placed mice in an area that had some food, and observed how the mice reacted when they were hungry or full. At the same time, the researchers imaged the brains of the mice in real time to investigate their neural activity. The researchers observed that all of the mice spent time investigating the food, but only the hungry ones started eating, according to University College London.
The ventral hippocampus, or the underside of the hippocampus, is the decision-making part of the brain. This brain region helps humans and animals form and use memories to guide their behaviour. Therefore, the researchers focused on brain activity in the ventral hippocampus in the mice.
The researchers observed that activity in a subset of brain cells in the ventral hippocampus increased when the animals approached food. This activity was found to inhibit the animal from eating.
However, if the mouse was hungry, there was less neural activity in the ventral hippocampus, as a result of which the hippocampus no longer stopped the animal from eating.
When there was less activity in the ventral hippocampus, there were high levels of the hunger hormone ghrelin circulating in the blood.
The researchers experimentally made the mice behave as if they were full, and activated the ventral hippocampus neurons. Due to increased activity in the ventral hippocampus, the mice stopped eating even if they were hungry.
In order to stop hungry mice from eating, the researchers tried another technique. They removed the receptors for the hunger hormone ghrelin from the neurons in the ventral hippocampus.