Section: Research

Teresa Mitchell, Ph.D.

Research Interests

Projects:

• Perceptual Development Lab
• Multimodal Analyses of Face Processing in Autism & Down Syndrome
• The Balance Between Top-Down and Bottom-Up Attentional Processes in Autism

Cross-Modal Development and Plasticity

Dr. Mitchell's research centers around a central theme: what happens to the brain and behavior when development differs from the norm, and how can the course and outcome of that atypical development shed light on basic principles of developmental change?  One important line of work in her laboratory investigates cross-modal plasticity, specifically how and whether the visual modality adapts to compensate for the absence of auditory input and experience.  In these studies, hearing and deaf individuals of the same age perform tasks in which they attend to and respond to particular visual information, such as random-dot motion, color, or faces.  The aim is to document what functions differ between the deaf and hearing populations, and when in development those differences appear.  Three major techniques are used in the laboratory:  1) behavioral measures such as reaction time and accuracy, 2) event-related potentials (ERPs), or the recording of the brain’s electrical activity in response to the stimuli and tasks, or 3) functional MRI, which tracks changes in the flow of oxygenated blood throughout the brain in response the stimuli and tasks.  These measures are powerful for assessing whether visual performance differs between deaf and hearing individuals, and for providing clues as to what the neural substrates of those differences are.  Past research has shown that deaf individuals are faster and/or more accurate in responding to motion and produce larger ERPs and fMRI signals than hearing individuals, but that deaf and hearing individuals produce similar responses to color stimuli.  This suggests that visual compensation is not global and may be specific to certain functions and/or visual pathways.  Recent work shows that this population difference seems to emerge during elementary school years, which suggests that the compensation is a product of cumulative visual experience in the absence of auditory input.  This research program has important implications for understanding how intrinsic maturational timetables and extrinsic experiential factors interact across the course of development to influence the structure and function of brain and behavior.

Office: Shriver
Phone: 781-642-0253
Fax: 781-642-0238
E-mail: Teresa.Mitchell@umassmed.edu

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