Mentor: Dr. Earl Thomas
This summer's research project will focus on how the septum and the amygdala work. The amygdala and septum are structures in the brain that are involved with anxiety. The amygdala helps stimulate symptoms of anxiety (anxiogenic) and the septum helps inhibit symptoms of anxiety (anxiolytic). Some chemicals that help regulate anxiety are Benzodiazepines (BZD) and GABA. BZDs are anxiolytics that are used to help relieve symptoms of anxiety. When BZDs bind to their receptors they help facilitate the binding of GABA to their receptors. GABA is an inhibitory neurotransmitter found in the amygdala. Previous literature states that the activation of the amygdala causes the stimulation of the septum. Once the septum is activated it will cause the amygdala to become inactive. The question is, do the septum and GABA neurotransmitter work together to inhibit the amygdala? It is hypothesized that the septum controls GABA and inhibits the amygdala via GABA. So both GABA and the septum are needed to help inactivate the amygdala. To test this hypothesis a GABA antagonist, Picrotoxin, will be injected into a rat. This will prevent GABA from working and so even though the septum will be stimulated the actions of the amygdala will still be active. Without GABA the septum has no affect on the amygdala.
This research will be conducted by first stimulating the septum and then recording the reaction in the amygdala. Two electrodes will be placed in the brain. A stimulating electrode will be placed in the septum and a recording electrode will be placed in the amygdala. A single cell in the amygdala will be found by the recording electrode. Once a single cell is found in the amygdala then the stimulating electrode will activate the septum and the reaction in the amygdala is recorded. After the control situation is recorded a GABA antagonist will be injected into the rat. It is proposed that the antagonist will inhibit GABA and the rate of the action potential of the single cell in the amygdala should not change when the septum is stimulated, compared to the control. A histological report will ensure that both electrodes were placed in the correct structures of the brain.