Topology of synaptic connectivity constrains neuronal stimulus representation, predicting two complementary coding strategies

Michael W. Reimann* (Corresponding Author), Henri Riihimaki, Jason Smith, Janis Lazovskis, Christoph Pokorny, Ran Levi

*Corresponding author for this work

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In motor-related brain regions, movement intention has been successfully decoded from in-vivo spike train by isolating a lower-dimension manifold that the high-dimensional spiking activity is constrained to. The mechanism enforcing this constraint remains unclear, although it has been hypothesized to be implemented by the connectivity of the sampled neurons. We test this idea and explore the interactions between local synaptic connectivity and its ability to encode information in a lower dimensional manifold through simulations of a detailed microcircuit model with realistic sources of noise. We confirm that even in isolation such a model can encode the identity of different stimuli in a lower-dimensional space. We then demonstrate that the reliability of the encoding depends on the connectivity between the sampled neurons by specifically sampling populations whose connectivity maximizes certain topological metrics. Finally, we developed an alternative method for determining stimulus identity from the activity of neurons by combining their spike trains with their recurrent connectivity. We found that this method performs better for sampled groups of neurons that perform worse under the classical approach, predicting the possibility of two separate encoding strategies in a single microcircuit.
Original languageEnglish
Article numbere0261702
JournalPloS ONE
Issue number1
Early online date12 Jan 2022
Publication statusPublished - 12 Jan 2022

Bibliographical note

Funding: This study was supported by funding to the Blue Brain Project, a research center of the Ecole polytechnique federale de Lausanne (EPFL), from the Swiss government’s ETH Board of the Swiss Federal Institutes of Technology. RL is supported by an EPSRC grant EP/P025072/ and a collaboration agreement 832 with Ecole Polytechnique Federale de Lausanne. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


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