Our laboratory utilizes multi-level analyses toward understanding (i) the effects of stress on brain and behavior, and (ii) the neuronal mechanisms underlying basic associative learning in mammalian brain.  These investigations consist of employing lesion, pharmacological, and in vitro and in vivo neurophysiological techniques. 

***Click HIGHLIGHTED words to view figures and video clips***

Neurocognitive Effects of Stress.

Stress is a biologically significant factor that, by altering brain cell properties, can disturb cognitive processes such as learning and memory. Extensive research indicates that the hippocampus is not only crucially involved in memory formation, but is also highly sensitive to stress. Specifically, stress has been shown to impair both hippocampal-dependent memory tasks and long-term potentiation (LTP) in rodents. We discovered that, in contrast to its effect on LTP, stress enhances long-term depression (LTD) in the hippocampus, and these effects on hippocampal plasticity are mediated via N-methyl-D-aspartate (NMDA) receptors. We also found that the amygdala (video) is central to manifesting stress-related behaviors and changes in hippocampal functioning (Fig. 1). Currently, our lab is investigating stress effects on multiple brain-memory systems (spatial, emotive, motor) and hippocampal place cells (video). Recently, we developed a computer vision-based automated figure-8 maze (video) to investigate stress effects on working memory and decision-making processes.

Neuronal Mechanisms Underlying Basic Associate Learning.

To understand how the brain encodes new information, two Pavlovian conditioning tasks are utilized: eyeblink conditioning and fear conditioning in rats.

Ethobehavioral Studies of Fear and Stress.

Recently, our laboratory began employing a predator-like Robogator (video) (programmable LEGO Mindstorms robot) and a closed economy (video) (self-contained living setting comprised of safe nest and dangerous foraging zones) to investigate rat's foraging behavior in semi-naturalistic, dynamic fear environments. This novel approach might be useful in revealing how fear (and stress) influences risky decision making in humans, in screening drug effects, and in addressing the neuronal basis of the basic approach-avoid conflicts that contribute to human psychopathologies.