FacultyFaculty AssociatesBroad FellowsPostdoctoral
James G. Boswell Professor of Neuroscience
B.S., University of California (Davis), 1973; Ph.D., University
of California (San Francisco), 1979.
mail code: 216-76
Vision, Neuroprosthetics, Action Planning, Decision Making
While the concept of artificial intelligence has received a great deal of attention in the popular press, the actual determination of the neural basis of intelligence and behavior has proven to be a very difficult problem for neuroscientists. Our behaviors are dictated by our intentions, but we have only recently begun to understand how the brain forms intentions to act. The posterior parietal cortex is situated between the sensory and the movement regions of the cerebral cortex and serves as a bridge from sensation to action. We have found that an anatomical map of intentions exists within this area, with one part devoted to planning eye movements and another part to planning arm movements. The action plans in the arm movement area exist in a cognitive form, specifying the goal of the intended movement rather than particular signals to various muscle groups.
One project in the lab is to develop a cognitive-based neural prosthesis for paralyzed patients. This prosthetic system is designed to record the electrical activity of nerve cells in the posterior parietal cortex of paralyzed patients, interpret the patients’ intentions from these neural signals using computer algorithms, and convert the “decoded” intentions into electrical control signals to operate external devices such as a robot arm, autonomous vehicle or a computer.
- Coordinate Frames
We have been examining the coordinate frame for coordinated movements of the hand and eyes. In the dorsal premotor cortex we find a novel, “relative” coordinate frame is used for hand-eye coordination. Neurons in this cortical area encode the position of the eye to the target, the position of the hand to the target, and the relative position of the hand to the eye. A similar relative coding may be used for other tasks which involve the movements of multiple body parts such as bimanual movements.
- Decision Making
We have been examining decision making in parietal-frontal circuits. One interesting finding is that some parietal areas form default movement plans in ambiguous situations and then only one plan remains once the monkeys make a decision. Other parietal areas carry only the movement plan once the decision has been made. We also find that frontal and parietal areas contain a corticocortical sub-circuit specialized for decision making that appears to coordinate activity between areas based on the decisions. Ongoing experiments are exploring how and where motor decisions are made.
- fMRI in Monkeys
We have successfully performed functional magnetic resonance imaging (fMRI) experiments in awake, behaving monkeys. This development is important since this type of experiment is done routinely in humans and monitors the changes in blood flow during different cognitive and motor tasks. However, a direct correlation of brain activity with blood flow cannot be achieved in humans, but can in monkeys. Thus, the correlation of cellular recording and functional MRI activation in monkeys will provide us with a better understanding of the many experiments currently being performed in humans. A 4.7 Tesla vertical magnet for monkey imaging has recently been installed at Caltech. We are using this magnet, combined with neural recordings, to examine the correlation between neural activity and fMRI signals.