B.S., University of California, Irvine
Ph.D., Wake Forest University School of Medicine
I joined the Rutgers faculty in 1986, a fortuitous time of expansion and hiring by the university that elevated Rutgers to the prestigious Association of American Universities. My research has benefited from a campus environment rich with neuroscientists, embedded within a Psychology department. Behavioral sophistication, coupled with precision measures of brain activity, enhance the value of our findings. My research team comprises postdoctoral fellows, and graduate and undergraduate students.
I study the behavioral correlations of dopamine, which are as fascinating and as compelling as any in behavioral neuroscience. Adaptations within the brain’s dopamine system to stimuli that are crucial for survival (food, water, sex) are at the heart of the evolutionary process. It appears that nature selected for the mesolimbic dopamine system, which is strategically connected to emotional and mnemonic structures and to premotor areas, enabling conditioned stimuli to guide goal-directed, instrumental behavior. Addictive drugs, which stimulate dopamine transmission, are hypothesized to produce neuroadaptations in this system which enable drug-associated stimuli to produce craving and relapse to drug seeking behavior. In support of that hypothesis, we discovered that neurons in the mesolimbic system of rats acquire persistent responsiveness to cocaine-associated cues and express these responses during relapse to cocaine seeking. Our long-term goals are to further reveal neural mechanisms of relapse, both 1) in order to develop medications for treating cocaine addiction and 2) in order to identify possible genetic differences between cue-responsive versus cue-unresponsive subjects.
Adjacent to the mesolimbic dopamine system is the nigrostriatal dopamine system, which links sensorimotor structures to premotor areas. Dopamine transmission in this system is necessary for virtually all observable behavior, as evidenced by Parkinson’s disease and its animal models, in which nigrostriatal dopamine neurons are destroyed. Among the sensorimotor impairments following this destruction, acquisition of motor habits (stimulus-response habits) is impaired in humans and animals. It is hypothesized that activity in the nigrostriatal system is necessary for acquiring the many habitual, skilled movements performed automatically by individuals on a daily basis. In support of that hypothesis, we discovered that neurons in the nigrostriatal system of rats are active during the acquisition of a motor habit, but not after the habit has been formed. This change is a form of neuroplasticity that sheds light on the neuroadaptations facilitated by dopamine.