Connectionists: SCGB Virtual Postdoc/Student Meeting: Wednesday, December 1 by Olivia Gozel

[Laura Long]

The Simons Collaboration on the Global Brain (SCGB) hosts postdoc/student
meetings to bring together trainees interested in neural coding and
dynamics to discuss ideas and data. In addition to regional meetings in New
York, Boston, and the Bay Area, SCGB holds a Global virtual series to
connect systems and computational neuroscientists across the world. We
would love to see you at our next Global meeting! Please see event details
and the Zoom link below.



SCGB Global Postdoc/Student Meeting:
https://www.eventbrite.com/e/scgb-global-postdocstudent-meeting-tickets-209429538387

Wednesday, December 1st, 12pm Eastern Time

https://simonsfoundation.zoom.us/j/94767192583?pwd=TXBKNXJQYzdGTmRUZTFlUUYzNnkvUT09

    Passcode: 429535



*Olivia Gozel*
Postdoctoral Researcher, Doiron Laboratory
The University of Chicago
*Between-area communication through the lens of within-area neuronal
dynamics*
Neuronal dynamics range from asynchronous spiking to richly patterned
spatio-temporal activity and are modulated by external and internal
sources. Numerous experimental datasets show that the shared variability
can be well described by a small number of latent variables, indicating
coordinated trial-to-trial fluctuations within the population. Besides,
cortical areas are connected through long-range excitatory projections, and
it has been shown that there exists a communication subspace between
connected but distinct brain areas that predicts spiking activity in a
downstream area using upstream activity. However, little is known about the
effect of neuronal dynamics on interactions between brain areas.
Using a layered spiking network with within- and between-layer spatially
structured connectivity, we show that pattern formation decreases
within-area dimensionality similarly when spatio-temporal patterns emerge
within a population or when they are inherited from a connected population.
Yet, the fidelity of communication from an upstream to a downstream area,
as estimated by a linear reduced-rank regression measure, is affected by
the origin of pattern formation. Specifically, downstream activity is
poorly predicted by upstream activity when spatio-temporal patterns emerge
downstream, while it is particularly well predicted when shared
fluctuations are mostly inherited from the upstream area. Interestingly,
examination of spiking activity reveals that, even in the scenario with
apparent disrupted communication, the downstream area is effectively driven
by upstream activity, as expected from the strong feedforward connection
strengths between layers. A mismatch in within-area dimensionality between
upstream and downstream areas appears to underlie the seemingly weak
communication. These results expose the limitations of linear measures when
analyzing the flow of information in brain circuits with diverse neuronal
dynamics.


*Please note that this meeting is open to all neuroscience postdocs and PhD
students, regardless of location or SCGB affiliation (sorry, no PIs). *After
Q&A with the speaker, we will open breakout rooms for anyone interested in
staying to chat, network, or further discuss the talk. In addition to these
breakouts, SCGB Scientific Staff will be available for "office hours" to
chat and answer questions about SCGB programs and support.

Registration on EventBrite is encouraged but not required:
https://www.eventbrite.com/e/scgb-global-postdocstudent-meeting-tickets-209429538387
Please contact Laura Long at llong at simonsfoundation.org with any questions.
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