The Brain’s Built-In Anxiometer

Scaling of Ventral Hippocampal Activity during Anxiety

Researchers from the University of Bern and the University of Pittsburgh have discovered that the ventral hippocampus (vH) in the brain acts like an emotional gauge, scaling its activity in response to rising anxiety levels. The findings, published in The Journal of Neuroscience, shed new light on how the brain processes fear and stress, potentially paving the way for better treatments for anxiety disorders.

To explore this the team designed a custom maze that allowed them to control anxiety levels in mice. They found that the vH didn’t just react to fear, but instead it adjusted its neural activity proportionally to the intensity of the anxiety.

To test the role of the vH further, researchers used optogenetics to temporarily silence the region. For the optogenetic manipulation the researchers used a Cobolt 06-DPL at 561 nm to deliver continuous light pulses to inhibit CaMKIIα-expressing neurons (which plays a key role in synaptic plasticity, learning, and memory).

In additional silicon probe experiments, the same laser was used to stimulate neurons for short bursts across multiple trials, allowing researchers to measure how vH neurons responded to light-induced inhibition.

The result was a significant reduction in anxiety-related behaviors, confirming the vH’s central role in emotional regulation.

The new insight could help us better understand the neural basis of anxiety and develop more targeted therapies.