I am a neuroscientist who studies how brains process information.
One part of the work in my lab examines how cerebral cortical circuits use their massive recurrent connectivity to compute. Put another way, in the cortex, 'what do all the short wires do?"
We also examine the computations behind perceptual decisions, studying which areas are involved in decision-making tasks, and how patterns of neural activity encode information about sensation and decision. A goal is to understand all the pathways involved in perceptual decisions and how they perform their computations.
One current focus in my lab is deploying a new method, two-photon holographic stimulation, to pick out selected neurons and make them fire. This approach uses two high-powered lasers and genetic delivery of an algal protein to both image neuronal activity and change activity. With holographic stimulation, we create – play back – patterns of neural spiking activity, something that has never before been possible.
Three different patterns of neural activity induced by three different laser patterns. Red spots here show neurons firing when hit with the holographically-shaped laser. (layer 2/3 of V1; blue-red colorscale is ± 50% dF/F.)
Images: Green spots, image 1, are neurons. We picked out three groups of neurons. We then hit those three groups of neurons with a laser to make them fire (red spots, lower panels; each of the four squares shows the same view.) We picked three letters to show we can write arbitrary patterns into this neural network.
(h/t Z Zhou, A Li, N Friedman, P LaFosse, Y Deng)
Other aspects of our approach: we study behavior using psychophysical assays while recording neural activity with two-photon imaging and silicon-probe electrophysiology. We make inferences about network function by testing hypotheses in computational simulations. We use statistical models and data science methods to analyze the large data sets we collect.
For more details on past and current work, check the Research page.
Affiliations
I have run a lab at NIMH since 2016, where I am Chief, Unit of Neural Computation and Behavior (aka the Histed lab.) Before that, I was research faculty at the University of Chicago, a postdoc at Harvard Medical School, and completed at PhD at MIT in 2005. At various times I have worked to perform market analyses for new inventions, worked as an intern for a criminal defense attorney, and been an unexceptional paperboy.
Other interests
I am also interested in how information flows through societies and influences collective human behavior, in particular via modern mass media. I have written about policy initiatives to support journalism and improve democracy.
A longtime interest of mine is how the brain responds to stimulation. I've used electrical and optical methods to change activity of neurons in working brains. Stimulating neurons reveals how the activity of some neurons affects both the activity of other neurons and behavior. In general, brain stimulation methods are powerful because they provide causal information, allowing us to determine whether one neuron influences another or whether instead they are merely correlated due to another influence or input. That kind of causal inference (see also the 2021 economics Nobel!) is especially important in brains, because of the extreme interconnectivity between many neurons and brain regions.