Author: Sam Sooter | Majors: Physics, Mathematics | Semester: Fall 2024

The overarching goal of my research is to determine how large populations of neurons in
cerebral cortex give rise to complex computations. For example, how does a mouse process
sensory input, choose among a variety of possible motor responses, and execute the chosen
response? I investigate the hypothesis that cortex operates close to a special dynamical state
called “criticality” that is thought to optimize many aspects of computation. I have developed
new tools to assess proximity to criticality with unprecedented time resolution, making it possible
to track how rapidly evolving behavioral conditions (e.g. transitions between high and low
arousal states) affect nearness to criticality.

In early October, I traveled to the Society for Neuroscience (SfN) conference in Chicago to
present a poster on this work. SfN is an enormous conference, with more than 20 thousand
people and nearly as many posters. This makes it a great opportunity to engage with parts of
the neuroscience community that I normally wouldn’t encounter. For example, one of my favorite
posters used optogenetic stimulation techniques to show that feedback from cortex to locus
coeruleus (a brain region associated with arousal) is necessary for sustaining arousal events.
Another very cool poster showed that artificially inducing periodic up/down states (something
normally observed only during deep sleep) in cortical activity of an awake animal reduces sleep
pressure and rescales synapses in the same way that ordinary sleep does. That is, they found a
new kind of artificial sleep! Engaging with the poster presenters by aggressively asking
questions was one of my favorite parts of SfN.

Presenting my poster at SfN.

Presenting my poster was also very helpful for my professional development. A crucial part of
being a scientist is communicating your work to other scientists, and the unstructured
environment of a poster talk is excellent training for this. I was delighted by the activity around
my poster– there were no pauses for the full four-hour presentation window. (And unlike when I
presented at SfN last year, my voice remained intact the whole time!) Meeting some of the
leaders in brain criticality research while presenting my poster was another highlight. Maybe
more important though was meeting many other like-minded trainees over lunches, at posters,
and so on. Science is inherently social, so more connections usually means more research, impact, and success.

I will soon have to decide between two diverging academic routes: physics or computational
neuroscience. (This is a little dramatic, admittedly– pursuing a physics PhD wouldn’t exclude me
from doing computational neuroscience research.) SfN and future conferences will be critical to
this decision. It’s hard to find questions more interesting, though, than “How does a mouse
work?” Nobody knows, but the recent revolution in nearly brainwide recordings of single-neuron
activity makes this question more answerable than ever. I hope to make just a small contribution
to the effort to understand brain function. Outside of neuroscience, I’m broadly interested in the
collective behavior of living systems with many interacting parts (e.g. animal flocks). How does
computation emerge from interactions between many small, simple things?