In vivo Calcium Imaging the Infralimbic Cortex During Aversive Learning and Extinction
Ivy Chen ’21, Eden Forbes ’21, Abigail Jenkins ’22, Hero Liu ’22, and Professor Josh de Leeuw (Cognitive Science), Professor Hadley Bergstrom (Psychological Science), Professor Bojana Zupan (Psychological Science), Professor Lori Newman (Psychological Science)
Functionality of the infralimbic (IL) subregion of the medial prefrontal cortex is required for aversive memory extinction. However, how groups of neurons (ensembles) in the IL respond over the course of aversive learning and extinction is unknown. This question is important because it is thought that coordinated ensemble activity underlies learning and memory. To address this question, a fluorescent miniaturized microscope (i.e., “the miniscope”) combined with a genetically encoded calcium sensor (GCaMP) transfected in the IL was used to record changes in calcium signaling dynamics at cellular resolution during aversive learning and extinction. With the acquired data, we are currently in the process of examining coordinated patterns of calcium signaling as well as freezing behavior using the open-source data analysis packages Minian and DeepLabCut, respectively. Frames gathered from miniscope imaging during the experiment will be used to track patterns of calcium signals from individual cells over the course of an entire behavioral session and across days using the Minian pipeline. From the behavioral videos, eight points (snout, left ear, right ear, middle of spine, base of tail, two points on tail, and tip of tail) on the mouse were labeled using DeepLabCut to create a skeleton which follows the animal’s movements based on a grid system. This information will be used to classify types of behavior (specifically freezing patterns) based on the body orientation and the velocity of movement. We are tracking changes in this behavior along with the neural activity over the course of fear conditioning and three days of conditioned stimulus extinction. These data will enable the analysis of ensemble activity in the IL while the animal learns and extinguishes an associative aversive stimulus.