Area of Research
Neurobiology of Learning & Memory, Cognitive/Systems Neuroscience, Animal Models of Psychiatric Disorders
Study of the neural basis of cognitive and emotional behavior
We study the neural mechanisms that give particular sensory stimuli emotional value, leading to emotional behavior. Using the primate visual system as an experimental platform, our basic approach is to conduct neurophysiological experiments in rhesus monkeys performing a variety of tasks involving emotional learning. We generally use conditioning techniques to give otherwise neutral stimuli emotional significance.
We are investigating the physiological responses of amygdala neurons during emotional learning. The amygdala is a limbic brain structure likely to be critical to the process of associating sensory stimuli with emotional values. Simultaneously, we employ quantitative measurements of emotional learning and behavior in the monkey. We are testing the hypothesis that modulations in amygdala neural activity are correlated with the monkeys' emotional learning, behavior, and decision making.
Future studies are planned in three general directions. First, we plan to study how orbitofrontal cortex contributes to emotional learning and behavior on the tasks we employ. Parts of orbitofrontal cortex are intimately connected to the amygdala, and our goal is to understand the distinct processing in these brain areas. Second, we plan to investigate how stimuli in other sensory modalities become associated with emotional value in the amygdala. The amygdala receives input from multiple sensory modalities, and therefore representations of emotional value in the amygdala may exist across sensory modalities, perhaps even in the same cells. Finally, we plan to use pharmacological manipulations to try to understand the critical synaptic mechanisms underlying emotional learning. These experiments may deepen our understanding of psychopharmacology by linking synaptic mechanisms to both neurophysiology and to emotional behavior.
Morrison SE, Salzman CD. The convergence of information about rewarding and aversive stimuli in single neurons. Journal of Neuroscience 2009, 29(37): 11471-11483.
Belova MA, Paton JJ, Salzman CD. (2008). Moment-to-moment tracking of state value in the amygdala. J Neurosci, 28, 10023-10030.
Belova MA, Paton JJ, Morrison SE, Salzman CD. Expectation modulates neural responses to pleasant and aversive stimuli in primate amygdala. Neuron. 2007 Sep 20;55(6):970-84.
Paton J.J., Belova M.A., Morrison S.E., Salzman C.D. (2006). The primate amygdala represents the positive and negative value of visual stimuli during learning. Nature, 439: 865-870.
Salzman, C.D. and Newsome, W.T. (1994). Neural mechanisms for forming a perceptual decision. Science, 264: 231-237.
Murasugi, C.M., Salzman, C.D. and Newsome, W.T. (1993). Microstimulation in visual area MT: effects of varying pulse amplitude and frequency. J Neurosci., 13(4): 1719-1729.
Salzman, C.D., Murasugi, C.M., Britten, K.H. and Newsome, W.T. (1992). Microstimulation in visual area MT: effects on direction discrimination performance. J Neurosci., 12(6): 2331-2355.
Newsome, W.T., Britten, K.H., Salzman C.D. and Movshon, J.A. (1990). Neuronal mechanisms of motion perception. Cold Spring Harb Quant Biol., 55: 697-705.
Salzman, C.D., Britten, K.H. and Newsome, W.T. (1990). Cortical microstimulation influences perceptual judgements of motion direction. Nature, 346: 174-177.