Neuropsychological Studies of Mind and BrainSince the inception of the Institute for Cognitive Studies, a major paradigmatic development at UC, Berkeley has involved researchers studying the neural basis of behavior through the study of patients with neurological disorders. This focus reflects the emergence of cognitive neuroscience as an important field of study in psychology and cognitive science. Cognitive neuroscience represents an interdisciplinary approach to understanding the relationship of brain and behavior. The tools of cognitive neuroscience involve behavioral studies with normal and neurologically impaired individuals as well as various physiological procedures that can be employed with human and non-human populations. The latter include single-cell recording procedures with awake, behaving primates, electrophysiological studies with humans, and new neuroimaging techniques to observe in vivo the neural correlates of cognition. The goals of cognitive neuroscience are bi-directional. Not only do these procedures provide new insights for the development of functional hypotheses concerning the role of different neural structures involved in various cognitive processes, but the physiological results provide important constraints for constructing theories of information processing.
Profs. Shimamura, Knight, and D'Esposito are interested in higher-level aspects of cognition, the so-called executive functions. Their work addresses the role of the prefrontal cortex in ensuring that goal-oriented behavior occurs in a coordinated fashion. An important aspect of their work centers on the idea that the prefrontal cortex exerts inhibitory control over representations stored in more posterior parts of the cortex to give priority to task-relevant information. Prof. Knight's work primarily involves surface recordings of neural activity in healthy and neurologically-impaired people. One important result has been the finding that damage to prefrontal cortex produces enhanced responses recorded over posterior cortex to task-irrelevant stimuli. These findings suggest that the prefrontal cortex acts as a gate, inhibiting the irrelevant information. Prof. Shimamura's behavioral studies demonstrate some of the cognitive deficits that result from this failure of inhibition. For example, patients with prefrontal patients do not have a general problem with memory, but are unable to inhibit previously-relevant associations and therefore show a marked inflexibility in thought. His studies with neurologically healthy, populations suggest that part of the aging process involves a similar loss of inhibitory control. Prof. D'Esposito's neuroimaging studies provide converging evidence for the role of prefrontal cortex in coordinating processing in distributed brain regions. These three researchers plan extensive collaborative studies on the role of the frontal lobes in cognitive control functions using a mixture of behavioral and physiological methods with both normal and neurologically impaired populations.
Profs. Ivry and Jordan study how people control and acquire skilled actions. This work has focused on the nature of the representations of movement, seeking to define the level at which learning operates. Does it occur at the level of the muscles or does it occur at a more abstract level, one that corresponds to a representation of the desired goal for an action. Prof. Ivry's work entails behavioral and neuroimaging studies with normal and neurologically healthy populations. An important aspect of this work is the focus on developing functional hypotheses concerning the contribution of different neural systems to coordinated action, as well as exploring the general issue of the similarities and differences between motor and non-motor (cognitive) learning. Prof. Jordan's computational models of motor learning provide an important link between abstract models of learning with the dynamical systems that characterize our biomechanical bodies. In a similar vein, Prof. Russell of Computer Science and ICS addresses general computational principles for learning in both biological and robotic systems. Profs. Ivry, Jordan, and Russell plan more extensive collaborations in the coming years to explore further the computational, behavioral, and neural bases of motor control and skill learning.