My work with Dr. Adam Hantman focuses on the neural circuits mediating successful performance of a skilled motor behavior – prehension (1). Prior studies have shown that consistent sequential activity of the primary motor cortex (M1) neural ensemble is required for successful performance across trials (2-3). Although M1 appears to store the memory engram for prehension, it is not known how M1 initiates and later terminates the command of the action. In the case of cued reaching, sensory inputs likely initiate the M1 engram (4). Activity from upstream frontal motor cortex (5) may be important for initiating, maintaining M1 activity throughout, and terminating (6) the movement. Cortical regions may also communicate via subcortical structures such as the thalamus, claustrum, and/or amygdala. Thus, we are studying long-range inputs to M1 that are important for successful prehension. We utilize optogentic and pharmacogenetic tools in combination with cell-type specificity to manipulate neural pathways of interest. Intracellular, single-unit and multi-unit electrophysiology inform us about the dynamics of neural activity during normal behavior and under the influence of the circuit manipulations. This work serves to gain insight into how the brain initiates, performs, and terminates learned complex motor skills.
My postdoctoral work, under the supervision of Dr. Albert Lee at Janelia Research Campus - HHMI, was focused on studying the intracellular and network level phenomena underlying declarative memory formation in the mammalian hippocampus. The experiments involved in vivo intracellular and multi-site extracellular electrophysiological recordings of hippocampal CA1 pyramidal neurons in awake, behaving rats and mice. Interestingly, not only is the rodent brain engaged during spatial memory tasks in real environments, but also in virtual reality environments. Motivated by this finding, we developed a head-fixed spatial navigation system for rodents (1), wherein the subjects explore virtual environments during recording. This project provided new insights into the sub-threshold membrane potential dynamics of CA1 neurons underlying spatial navigation and novel memory formation (2).
My graduate doctoral work, under the supervision of Dr. Manual Castro-Alamancos at Drexel College of Medicine, focused on the neural circuits underlying successful performance of a learned sensorimotor task – active avoidance of fear (1). Using pharmacological reversible and irreversible lesions, we took advantage of the rodent vibrissa system to probe the neural circuits required for successful avoidance behavior. Intriguingly, we found that two alternative ascending sensory pathways, one to the superior colliculus (trigeminotectal) and one to the thalamus (trigeminothalamic), were alone able to detect the sensory whisker stimulus necessary for successful avoidance behavior (2). To gain further insight into the mechanisms of signal detection and active avoidance, we utilized intracellular, single, and multi-unit electrophysiology to further study the somatosensory responses of neurons in the superior colliculus of anesthetized (3) and awake behaving (4-5) rats. This project provided new insights into the neural circuits required for successful signal detection and performance of a somatosensory-based active avoidance behavior.