Summer Sheremata

Education

• Ph.D., Boston University
• Post Doc Fellowship, University of California
• George Washington University

Research Interests

• The neural basis of visual short-term memory-   A critical question in human cognition is how the brain maintains information across eye movements and distraction. Without this capacity, we would experience the outside world as a series of disconnected glimpses. Between the visual system and frontal cortex, activity in areas of the dorsal parietal cortex, also involved in visual attention, reflect the number of items held in visual short-term memory. To what degree do the mechanisms  in the parietal cortex that support memory overlap with visual attention mechanisms? What can this brain activity tell us about the processes underlying visual short-term memory and attention?
  Hemispheric asymmetries in visual attention and short-term memory-  From the earliest stages, visual information is separated into left and right visual hemifields, each processed by cortical areas in the opposite, or contralateral, hemisphere. I am currently investigating how the differences in visual field representations across cortical areas result in how we perceive a unified world. How does the right parietal cortex code information not only from the left, or contralateral, hemifield  but from across the visual field? What can asymmetries in healthy individuals reveal about neuropsychological disorders such as hemispatial neglect, which occur predominantly after damage to the right hemisphere? What are the behavioral consequences of these asymmetries in healthy individuals?

  Ventral parietal cortex involvement in memory and attention-  The angular gyrus, adjacent to topogaphically defined parietal cortex, is a part of an attention network that shows reduced activity when we hold visual items in memory. However, this area has also been implicated in a myriad of cognitive functions including binding of visual features in the right hemisphere and binding of visual and semantic information in the left hemisphere. How can we reconcile these functions of the angular gyrus? Can we localize areas of the ventral parietal cortex involved in specific cognitive processes?

Recent Publications

Sheremata, S.L., Shomstein, S. (under review) Task set induces dynamic reallocation of resources in visual short-term memory. 

Sheremata, S.L., Silver, M.A. (2015) Hemisphere-dependent attentional modulation of human parietal visual field representations. Journal of Neuroscience 35(2): 508-17.  pdf

Sheremata, S.L., Shomstein, S. (2014) Hemifield asymmetries differentiate VSTM for single- and multiple-feature objects. Attention, Perception, & Psychophysics 76(6) 1609-19.  pdf

Yoon, J., Sheremata, S.L., Rokem, A., Silver, M.A. (2013) Windows to the soul: Vision science as a tool for studying biological mechanisms of information processing deficits in schizophrenia. Frontiers in Psychopathology 4(681).  pdf

Somers, D.C., Sheremata, S.L. (2013) Attention maps in the brain WIREs Cognitive Science: Cognitive Science 4(4) 327-40.  pdf

Kong, L., Michalka, S.W., Rosen, M.L., Sheremata, S.L., Swisher, J.D., Shinn-Cunningham, B.S., Somers, D.C. (2012) Auditory spatial attention representations in the human cerebral cortex Cerebral Cortex.  pdf

Kosovicheva, A.K., Sheremata, S.L., Rokem, A., Landau, A.N., Silver, M.A. (2012) Cholinergic enhancement reduces orientation-specific surround suppression but not visual crowding Frontiers in Behavioral Neuroscience 6(61).  pdf

Sheremata, S.L., Bettencourt, K.C., Somers, D.C. (2010) Hemispheric asymmetry in visuotopic posterior parietal cortex emerges with visual short-term memory load Journal of Neuroscience 30(38):12581-8.  pdf

Sheremata, S.L., Sakagami M. (2006) Increasing distractor strength improves accuracy Perceptual and Motor Skills 102(2): 509-516.  pdf 

Chen, Y., Levy, D.L., Sheremata, S.L., Holzman, P.S. (2006) Bipolar and schizophrenic patients differ in patterns of visual motion discrimination Schizophrenia Research 88(1-3):208-216.  pdf

Sheremata, S.L., Chen, Y. (2004) Co-administration of atypical antipsychotics and antidepressants disturbs contrast detection in schizophrenia.Schizophrenia Research 70(1):81-89.  pdf

Chen, Y., Levy, D.L., Sheremata, S.L., Holzman, P.S. (2004) Compromised late-stage motion processing in schizophrenia Biological Psychiatry 55(8):834-41.  pdf

Chen, Y., Levy, D.L., Sheremata, S.L., Nakayama, K., Matthysse, S., Holzman, P.S. (2003) Effects of typical, atypical, and no antipsychotic drugs on visual contrast detection in schizophrenia. American Journal of Psychiatry 160(10):1795-801.  pdf

 

Scholarly Activities

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• Lab Website