The amygdala plays a role in an important pre-attention mechanism in the brain

This pre-attention mechanism is called sensorimotor gating, and it usually prevents cognitive overload

Karine Fénelon, an assistant professor of biology and neuroscientist at the University of Massachusetts Amherst, explained: “Decreased sensorimotor gating is a feature of schizophrenia, which is usually related to attention disorders and can Predict other cognitive deficits

To assess sensorimotor gating, neuroscientists measured the pre-pulse inhibition (PPI) of the auditory startle reflex

For the first time, Fénelon and her team at the University of Massachusetts Amherst-PhD at the time

Fénelon explained: “Until recently, pre-pulse inhibition was thought to depend on midbrain neurons that release acetylcholine transmitters

But there is a "super cool neuroscience tool" — optogenetics — that allows scientists to use light to locate and control genetically modified neurons in various experimental systems

The challenge they face is to use optogenetics to identify which circuit in which part of the brain is involved in PPI

Next, they used optogenetic tools to test whether this connection between the amygdala and brain stem is important for startle suppression

By light-manipulating the amygdala neurons in mice, they showed that the amygdala seems to promote PPI by activating brainstem inhibitory neurons or glycinergic neurons

To illustrate this connection in more detail, Fénelon and the research team used electrophysiology and optogenetic techniques to record the electrical activity of individual neurons extracted from thin brain slices outside the body

She called this discovery a "puzzle piece" for precisely locating the pre-pulse suppression circuit

Journal Reference :

1. Jose Carlos Cano, Wanyun Huang, Karine Fénelon.