Imagine you are walking in a dangerous location at night. The last time you were here, you heard gunshots fired in this alley. You suddenly hear a loud noise. Your heart rate quickly accelerates, your mind races and your pupil dilates. You scan your surroundings and realize that this time the noise was caused by some kids playing with fireworks. No guns this time… But if it were dangerous, you would have been in high alert to tackle this situation.
The Adhikari lab studies brain circuits that control reactions to different types of threats. The resulting data provides important insights about both adaptive behaviors to avoid threat and pathological anxiety disorders.
Lab members are constantly analyzing the levels of danger in the environment and reacting accordingly. These reactions include a myriad of changes, including changes in behavior, heart rate, circulating hormones, etc. These reactions are vital to avoid and escape danger, and are thus paramount for survival. However, the same brain circuits that control these key survival reactions can become overactive, leading to highly debilitating anxiety disorders.
- When you have to escape from a threat you have to quickly evaluate the layout of your environment to identify and use the most efficient escape route. Doing so requires careful integration of spatial navigation skills and the urge to escape. Prior work has identified brain regions that cause simple escape-related actions (such as aimless running or jumping). However it was unknown how the brain can create complex escape actions that adapt to the geometry of the environment (such as when you need to locate and use one particular fire exit to flee the building). The Adhikari lab identified a small group of cells buried deep within the hypothalamus of the brain that can control these versatile complex escapes that are so important for survival. These findings may provide insights into panic attacks, as panic is known to arise due to over-activation of circuits that control escape.
- An area in the brain called the hippocampus has patterns of neural activity that can very accurately represent external space. It works like an internal GPS. The Adhikari lab found that if something threatening happens in a particular region of an environment, this “GPS” representation changes in a very interesting way. The resolution and spatial accuracy of the GPS increases near the threatening location for as many days as a mouse remains scared. When the mouse stops displaying fear towards the threatening location the GPS representation reverts back to its prior lower spatial resolution. This finding provides insights as to what could be happening in the brains of people who have gone through traumatic experiences.