FIGHT, FLIGHT, AND FIRING: INVESTIGATING THE EFFECTS OF AVERSIVE STIMULI ON GLUTAMATERGIC CELL ACTIVITY IN THE MEDIAL ZONA INCERTA

It has been established that context-specific locomotor behaviours are controlled by brain regions that respond to internal and external cues, which are then translated to the brainstem to execute a movement. However, the integration of these higher command centres with downstream brainstem locomotor areas is not well understood. One such higher brain region is the medial zona incerta (mZI), a critical subcortical region for sensorimotor integration and creating complex locomotor behaviours. Our previous work shows that the mZI contributes to the contextual control of movement. Here, I examined the activity of mZI glutamatergic neurons using a battery of behavioural tests. vGLUT2-Cre mice (n=20, 10 female/10 male) were injected with Cre-dependent AAV-GCaMP8. Ca2+ transients from mZI vGLUT2 neurons were recorded using fibre photometry from freely moving mice during an array of behavioural tests (open field, hole board, elevated plus maze, looming shadow test, air puff, aversive noise, and footshock). In male mice, glutamatergic mZI activity increased significantly with the onset of air puff, aversive noise, and footshock stimulations. The increase in glutamatergic mZI activity suggests that the mZI is involved in responding to aversive stimuli. My next step is to explore sex differences in glutamatergic mZI activity and behavioural responses to aversive stimuli and directly examine neuronal activation using activity-dependent markers. This will confirm whether glutamatergic mZI populations are activated by specific stimuli, in a sex-dependent manner.