Marc Sommer, Ph.D.
Assistant Professor, Neuroscience- Ph.D. Massachusetts Institute of Technology (1995)
- Office: 115 Mellon Institute
- Telephone:412-268-4486
- Fax:412-268-5060
- E-mail: masommer@pitt.edu
- Website:
Neuronal circuits mediating perception, cognition, and action in primates.
Research Summary:
The overall goal of Dr. Sommer's laboratory is to establish how brain areas interact as circuits. We want to understand how the activity coursing through widespread networks gives rise to our perceptions, decisions, and actions. Most of our work focuses on the circuits that allow us to see and move our eyes. Using neurophysiological methods of single neuron recording, electrical microstimulation, and reversible inactivation, we study signal processing in the brains of awake, behaving rhesus monkeys.
Recently we demonstrated that one pathway from the brainstem to the prefrontal cortex conveys feedback information about actions, allowing us to keep track of our quick eye movements, known as saccades. Self-monitoring of one's actions is crucial for both visual perception and movement generation. On the visual side, we need this feedback to tell whether objects in the visual world truly move of their own accord or just appear to move as their images jump across the retina during a saccade. On the motor side, we need internal feedback about actions in order to perform fast, complex behaviors "on the fly" when sensory feedback might be too slow or noisy.
Our current projects examine circuits that link the prefrontal cortex with the cerebellum and basal ganglia. Also, we are planning to study disrupted networks in animal models of disconnection syndromes such as schizophrenia. We hope that our results lead to new treatments for such syndromes, perhaps through the strategic placement of therapeutic agents, stimulation probes, or lesions. Students rotating in our laboratory will learn the fundamentals of primate neurophsyiology, the design of pychophysical experiments, and the analysis of neuronal data.
Selected Publications:
Sommer, M. A., and Wurtz, R. H. A pathway in primate brain for internal monitoring of movements. Science, 296:1480-1482, 2002.
Sommer, M. A. The role of the thalamus in motor control. Current Opinion in Neurobiology, 13:663-670, 2003.
Sommer, M. A., and Wurtz, R. H. What the brain stem tells the frontal cortex. I. Oculomotor signals sent from superior colliculus to frontal eye field via mediodorsal thalamus. Journal of Neurophysiology, 91:1381-1402, 2004.
Sommer, M. A., and Wurtz, R. H. What the brain stem tells the frontal cortex. II. Role of the SC-MD-FEF pathway in corollary discharge. Journal of Neurophysiology, 91:1403-1423, 2004.
Sommer, M.A., and Wurtz, R.H. Influence of the thalamus on spatial visual processing in frontal cortex. Nature, 444:374-377, 2006.