Joshua
Gold, Ph.D.
Assist. Professor, Dept of Neuroscience
116 Johnson Pavilion
Phone: (215) 746-0028
Fax: (215) 573-9050
Email: jigold@mail.med.upenn.edu
Click here for selected publications since Dr. Gold's arrival at Penn
RESEARCH INTERESTS
How the brain forms decisions about sensory stimuli: What are the underlying
neural computations? Where are the circuits that perform these computations?
How are these circuits shaped by experience?
RESEARCH TECHNIQUES
Single and multiple electrode recordings in awake, behaving monkeys; threshold
psychophysics; computational modeling.
RESEARCH SUMMARY
Recent advances in neuroscience have begun to shed light on how the brain
represents sensory information and issues motor commands. My interest is
in how the two are linked: How does the brain interpret sensory information
to guide behavior? To study this link, which is central to perception, decision-making
and other aspects of higher brain function, we conduct electrophysiological
experiments on monkeys trained to perform demanding visual-discrimination
tasks. The goals of these experiments are to identify the neural circuits
involved in forming these perceptual decisions, to expose the underlying
computations and to address how these computations are shaped by experience.
One task that we use extensively requires the monkey to discriminate the
direction of random-dot motion and to indicate its direction decision with
an eye movement to one of two choice targets. By varying the strength of
motion, we can manipulate the ease or difficulty of the task and induce
the monkeys to work near psychophysical threshold. This manipulation draws
out the decision process and introduces errors, which allows us to examine
the perceptual decision as it evolves over time and to dissociate the monkey's
behavioral response from the sensory processing.
In previous experiments, decisions linked to specific eye movements were
shown to be evident in the circuits that prepare the eye-movement response.
We are building on these results with two new lines of inquiry. First, we
are investigating whether principles of sensory-motor integration that we
have learned using the direction-discrimination task can be generalized
to more abstract decisions (that is, decisions not linked to specific actions).
Second, we will forge new connections to the study of plasticity and learning
by studying how experience shapes the neural computations responsible for
forming these perceptual decisions.
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