The brain gets tired when it processes too much information or thinks too much.Inhibitory nerves have the function of calming this excited brain.In collaboration with Fukuoka University, a research team at Hokkaido University has succeeded in completely identifying four inhibitory nerves (neurons) that "cool the head" in the memory center of cockroaches.
Nerves that process higher-order information are known to perform highly efficient information processing by reducing the number of active nerves (sparsely), and are called sparse coding.Recently, it has been found that strong inhibition by inhibitory nerves contributes to the realization of sparse activity of higher nerves.In the insect brain, there is a supreme center called the mushroom body, which corresponds to the hippocampus and cerebral cortex of vertebrates.Researchers have previously discovered that the four giant neurons that cover the entire cockroach mushroom body are inhibitory neurons with GABA (an inhibitory neurotransmitter amino acid), but these are complex. It was intertwined and it was difficult to examine the morphology and function of individual nerves.
This time, a method called intracellular recording / staining method was used for American cockroaches.As a result, the four inhibitory neurons were so large that they covered half of the brain, and the details of the different region control of the mushroom body by the division of functions were revealed.In addition, it is assumed that information processing is performed by synchronously promoting activities after a large number of small endogenous neurons in the mushroom body are suppressed all at once.
Cockroach giant neurons are useful as an experimental model for exploring the function of the memory center as a system, and it is expected that the specific role of inhibitory neurons in various physiological functions such as sensory information identification, learning, and sleep will be clarified. It is said that
