Our Research

Through the skeletomuscular system, we measure adaptive reflexes characteristic of behaviors involved in emotional regulation. We use electromyography (EMG) as a noninvasive measure of startle activity. The startle response is an integrative motor reflex to sudden auditory stimuli, observed in all mammalian species, that is mediated by a simple and short neural pathway that is directly connected to the amygdala (an area of the brain that regulates fear behaviors). Exaggerated startle is a predictor of emotion dysregulation and anxiety risk.

We use a fear conditioning model and tools in psychophysiology to measure emotion regulation. Fear conditioning is based on a simple Pavlovian conditioning model in which a neutral conditioned stimulus (CS, i.e., a shape presented on a computer screen) is paired with an aversive unconditioned stimulus (US, i.e., a forceful airblast directed at the throat). After a number of pairings, the association is formed so that the CS alone elicits the conditioned response (CR, i.e., a fear response). This basic model is used in animal as well as human research to investigate mechanisms of fear learning and memory. In fear-potentiated startle (FPS), the magnitude of the startle reflex increases during aversive CS presentations.

We will use a fear discrimination paradigm that measures startle amplitude in the presence of a reinforced conditioned stimulus (CS+) that is paired with a US, as well as during exposure to a nonreinforced conditioned stimulus (CS-) that is never paired with a US. The use of the nonreinforced CS-, which serves as a safety cue, allows us to experimentally test differences in safety signal processing (emotion regulation) between experimental groups. Hence, the FPS discrimination paradigm is an extremely powerful paradigm for studying the mechanisms of fear learning and memory. It allows for stringent experimental control over the delivery of aversive stimuli, and the fear responses can be easily quantified.

Some critical brain regions involved in fear learning in memory are the amygdala and the prefrontal cortex. The amygdala regulates the acquisition of fear memories and the expression of learned fear behaviors. Fear-potentiated startle is a direct measure of amygdala activity. The prefrontal cortex is a higher order brain region that regulates amygdala activity based on the situation or context surrounding the fear stimulus. It plays a critical role in emotion regulation by suppressing amygdala activity during perceived safe conditions.

People with anxiety disorders and/or emotion regulation deficits often show heightened amygdala activity (indicated by exaggerated startle) as well as a reduction in prefrontal activity. These deficits result in maladaptive fear behaviors during inappropriate circumstances.