Steven L. Small

Steven L. Small, M.D., Ph.D.

Professor and Co-Director of the Brain Research Imaging Center (BRIC)

Department of Neurology
Department of Psychology
Committee on Neurobiology
Committee on Computational Neuroscience

Address: Billings Q-310
Mailing:   MC-2030
Phone:      (773)702-1133
Fax:           (773) 834-7610
Web:        http://home.uchicago.edu/~slsmall

Functional organization of normal and impaired cerebral cortex

Our laboratory uses functional magnetic resonance imaging (fMRI) to study the organization of the normal human cerebral cortex and the changes that it undergoes after neurological injury, particularly stroke. Cortical damage has profound effects on such functions as learning, memory, language, and complex motor activity. Damage to structures that must communicate with the cortex or damage to the communication channels themselves also causes serious impairments. It is our belief that by studying the neuroanatomical substrate of recovery from injury, we will be able to construct a theory of neurological rehabilitation that is grounded in basic neuroscience.

Our current projects are in the areas of language and motor function, and are concerned with both the normal anatomy of these functions and their recovery after stroke. In the study of normal adults, we have found that the language areas of the brain are more widely distributed than previously thought, extending to brain regions that are anatomically removed from those originally postulated by Broca, Wernicke, and Déjérine, and extending to both cerebral hemispheres. In the motor system, we have found that left and right handed people use somewhat different brain networks when making simple and complex finger movements. Further, the brain seems to encode such finger movements by both individual muscle and pattered movement, suggesting that the widely published motor map of Penfield might not reflect accurately on the variability and overlap in motor representations of the cortex.

In our studies of stroke recovery, we perform longitudinal behavioral testing and brain imaging during the first six months of recovery. During this time, patients' performance improves and their pattern of brain activity changes. We are still trying to discover if specific patterns of brain recovery are associated with good recovery of function. In a stroke patient with a reading impairment, we have shown that learning a particular reading strategy (mapping letters onto sounds) both improved reading skill and also changed the brain to emphasize certain regions (occipital/temporal) over others (inferior parietal).

References

Harris, A.E., Ermentrout, G.B. and Small, S.L. (1997). A model of ocular dominance column development by competition for trophic factor. Proc Natl Acad Sci U.S.A., 94: 9944-9949

Small, S.L., Flores, D. and Noll, D.C. (1998). Different neural circuits subserve reading before and after therapy for acquired dyslexia. Brain and Language, 62: 298-308.

Harris, A.E., Ermentrout, G.B. and Small, S.L. (2000). A model of ocular dominance column development by competition for trophic factor: effects of excess trophic factor with monocular deprivation and effects of antagonist of trophic factor. J Comput Neurosci., 8: 227-250.

Hlustik, P., Solodkin, A., Gullapalli, R.P., Noll, D.C., and Small, S.L. (2001). Somatotopy in human primary motor and somatosensory hand areas revisited. Cerebral Cortex, in press.

Updated 7/28/03