Gold Lab People
1991 Sc.B. Neuroscience, Brown University
1997 Ph.D. Neuroscience, Stanford University
Co-mentored by Joe Kable
Currently, I am studying how the activity of neurons in the brainstem nucleus locus coeruleus (LC) is linked with coordinated activity in cortical neural circuits. Release of norepinephrine from LC modulates neurons in cortex that mediate perception and behavior. Specifically, I make simultaneous recordings of neurons in LC and in anterior cingulate cortex (ACC) while monkeys perform either fixation or choice tasks. I also record pupil fluctuations since these can provide a non-invasive measure of the level of activity in the LC-NE system (Joshi et al., 2016). See my Google Scholar and Researchgate pages.
I study the neuroscience of perceptual decision making. I am currently setting up a Psychophysics experiment in which I ask human subjects to watch a cloud of moving dots and tell me in what direction the dots are moving at the end of the viewing period. The viewing period is quite short, it lasts between 100 and 400 milliseconds, and some trials contain a change-point; that is, a change in the direction of motion of the dots. My questions of interest are: 1) When the stimulus is noisy and can undergo abrupt state changes, how does our brain process it to make a judgement about it? In particular, what happens around a change-point? 2) How do we weigh evidence before and after the change-point, and how does our expectation of a change-point modulate this? For now, I am measuring and analyzing people's answers and the dilation of their pupils. I use reverse kernel analysis to assess the effect of a change-point on the weights people apply to the incoming stream of sensory evidence. I am also interested in the mathematical modeling of these decision processes. The drift-diffusion model is typically used to describe the sequential accumulation of evidence performed at the neuronal level. But the ways in which change-points and their statistics affect this drift-diffusion model is still an open question. Aside from this, I am very keen on improving digital tools for scientists. A side project of mine is to develop a note-management app, IndieK, to help us "find back quickly notes that we wrote in the past". Also please see my personal website here.
Co-mentored by Yale Cohen
I am studying the how a non-invasive form of neurostimulation called transcranial magnetic stimulation (TMS) alters neural activity and behavior. TMS to specific regions of the lateral prefrontal cortex is used in depression treatment. To this end, I am studying the influence of TMS on 1) regions of the cingulate cortex that are implicated in depression by using neural recording in monkeys and 2) behavioral deficits common to depression patients by using a computer-based task in both human and animal studies. In particular, I am focusing on the ability of individuals to adjust their behavior in response to changing, value-related information. Importantly, the ability to adapt to changing conditions is also associated with activity in the cingulate cortex. Using a combination of non-human primate and human studies, I aim to understand how TMS to lateral prefrontal cortex works mechanistically in the brain so that this information can eventually be used to improve depression treatment outcomes.
Co-mentored by Michael Platt.
Co-mentored by Long Ding
Currently I am studying the integration of information to make decisions in various contexts. One project I’m working on is investigating the effect of delay on spatial integration in humans: does delay affect how well we can use the information available to us? My other project investigate how context affects spatial information integration: how is the same visual evidence interpreted in different contexts? The behavioral effects have been studied in humans but I am extending the paradigm to NHP work so as to examine how neural tuning and connections may be altered by context to produce different behavioral outputs to identical inputs.
Co-supervised by Long Ding
Co-supervised by Long Ding
Long Ding [website]
Chi-Tat "Jeff" Law
Matt Nassar [website]
Bob Wilson [website]