My research program is focused on understanding the biology of emotional (fear) learning and emotional memories.   Working side-by-side with me, undergraduates study the brain regions and the neural pathways that are important for fear-related learning. We are also working on several projects investigating how commonly used drugs influence fear-related learning processes.  This work primarily involves a combination of neuroanatomical, pharmacological, and behavioral studies. Our ultimate research goal is to understand how the brain controls anxiety disorders (i.e., phobias, posttraumatic stress disorder, panic disorder), which are characterized by intense fear.   In order to effectively treat anxiety disorders we must have a better understanding of how the brain controls fear.  As part of their training in my lab, students are encouraged to present their research at undergraduate research conferences.  Students also routinely publish their research with me.

A Bit More Detail
    We take a functional neuroanatomical approach towards understanding how the amygdala, hippocampus, and nucleus accumbens mediate fear-related processes. This primarily entails defining the anatomy, chemistry (neurotransmitters), and behavioral function of neural pathways that underlie emotional learning and memory. Classical (Pavlovian) fear conditioning is one of the leading behavioral paradigms for investigating the brain regions that control the acquisition, consolidation, and expression of emotional learning. We also use classical conditioning ("fear conditioning") to investigate the brain regions and neural pathways underlying fear-related learning.  During classical conditioning, an emotionally-neutral conditioned stimulus (CS), such a tone, is followed by an emotionally-charged (aversive) unconditioned stimulus (US), usually a very brief and very mild footshock. The CS, because of its association with the emotionally-charged US, acquires aversive properties and comes to elicit responses characteristically elicited by threatening stimuli. Thus, following a small number of temporal pairings of the CS and US, conditioned fear (i.e., "emotional learning") is elicited by the tone in the ABSENCE of the US (footshock). Learned fear is also elicited by contextual cues in the conditioning environment (e.g., conditioning chamber).  The effects of conditioning can be measured in a variety of ways including measuring freezing responses, or changes in autonomic (e.g., heart rate, blood pressure) or endocrine (e.g., measuring "stress hormones") activity. We measure freezing responses, which are operationally defined as the absence of all movement except respiratory-related. Freezing is a behavioral fear response that is exhibited by a variety of mammals and is highly correlated with other measures of conditioned fear (ie., autonomic, endocrine).
     There is an overwhelming amount of evidence demonstrating that the amygdala, and auditory brain regions (i.e., auditory thalamus, auditory midbrain) that are connected with the amygdala, are a vital part of the neural circuitry through which fear responses are conditioned and expressed to auditory stimuli. Lesions experimentally placed in the amygdala or in auditory brain regions that are connected with the amygdala interfere with fear conditioning to acoustic stimuli. One commonly accepted prerequisite for emotional learning to occur (via classical conditioning), is the convergence or intersection of neural pathways conveying information about the CS (tone) and information about the US (footshock) during fear conditioning. Evidence from several laboratories indicates that CS-US convergence during classical conditioning is occurring in the amygdala. In fact, the amygdala is believed to be one of the primary neural sites where fear-related learning takes place, and where fear-related memories may be stored. If we are to fully understand how emotional learning occurs at the neural level during classical conditioning, we must identify the pathways (CS and US) that transmit sensory information to the amygdala during emotional learning (classical conditioning). We are currently investigating  how commonly used drugs (i.e., cannabinoids) influence various aspects of emotional learning.  We are also examining the neuromodulatory role of adenosine for fear-related learning and memory.  An important next step will be to determine the specific brain regions that these drugs and neuromodulators act on to influence the acquisition, consolidation, and expression of fear-related learning.

Why study the biology of fear?
     In order to understand the detailed mechanisms of emotional learning, it is important to first identify the anatomical routes that conveys somatosensory (footshock) and auditory (tone) information to the amygdala during classical fear conditioning. Once these routes have been identified, it will then be possible to determine which neurotransmitters and neuromodulators influence US and CS information sent to the amygdala during emotional learning. Moreover, it will be possible to determine where various substances (e.g., adenosine, cannabinoids) that influence fear learning act in the fear conditioning neural circuits.  The ultimate goal of research on this emotion is to uncover neural mechanisms that will further our understanding of how the brain controls fear.  A clear understanding of the neural mechanisms underlying fear-related learning and memory is an essential prerequisite to treating anxiety disorders (e.g., phobias, panic disorder...), which are characterized by intense fear, and are believed to be the result of a malfunction in the neural control of fear.