|Office:||3119 Tolman Hall|
|Office Hours:||By Appointment|
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|Institute for Cognitive and Brain Sciences|
Our research focuses on the cognitive neuroscience of action and skilled movement. We conduct experiments involving neurologically healthy and impaired individuals, using a range of methods to develop psychological models of how people produce and learn movements. We use neuroscientific methods to develop these models and characterize the functional role of different parts of the motor pathways. Current techniques include study of neurological patients including patients with Parkinson's disease, focal lesions of the basal ganglia and cerebellum, and split-brain patients, functional MRI, and transcranial magnetic stimulation. We also have a virtual reality system to study movements in artificial worlds.
We are currently exploring how the brain may represent temporal information at a mechanistic level. We have hypothesized that a primary role for the cerebellum is to regulate the temporal aspects of movement. Moreover, the cerebellum also appears to be involved in perceptual tasks that require precise timing. Our work here contrasts with traditional views that based temporal processing on the operation of endogenous oscillatory processes. Rather, we hypothesize that the cerebellum may be conceptualized as a network of interval-based timing elements, with these elements tuned to specific intervals that are task-specific. This hypothesis involves research with healthy and neurologically impaired humans.
This decade has seen a great deal of interest in higher-level functions of the cerebellum, inspired by various results in the neuroimaging literature as well as intriguing findings that this structure is abnormal in autistic individuals. Functional hypotheses include the idea that this structure is essential for attention shifting, internal speech, and/or preparation of response alternatives. We are testing these hypotheses in our patient population.
Another primary area of research involves the study of motor control and motor learning. In addition to the neural mechanisms associated with the temporal control of movement, we also study other aspects of movement coordination such as force control and spatial trajectory planning, looking at these variables in uni- and bimanual movements. We have conducted behavioral and neuroimaging studies comparing explicit and implicit motor sequence learning. This work suggests separable psychological and neural systems associated with these two forms of motor learning. Our current work is designed to clarify differences between the systems in terms of how they represent learned associations.
I am also interested in how responses are selected. One critical issue here is whether there is a central control system that evaluates all possible responses and chooses the one that is most appropriate given the current context. Or, the selection process may be a more distributed process involving local competitions between alternative actions. Our research on this problem involves behavioral and neuroimaging studies with healthy individuals, as well as neuropsychological studies with various groups including split-brain patients. This latter group allows us to observe response selection when the major pathway between the two hemispheres has been severed.
For a list of publications available for downloading please click on the link below