🚨🚨🚨#TWEEPRINT TIME🚨🚨🚨 @leaduncker and I are thrilled to share our investigation of motor cortical dynamics using optogenetic and electrical perturbations, now on @biorxiv_neursci

Direct neural perturbations reveal a dynamical mechanism for robust computation

With co-authors @xulunasun, @SaurabhsNeurons, @EricMTrautmann, @ilka_diester, Charu Ramakrishnan, with @shenoystanford and Maneesh Sahani, and essential support from @KarlDeisseroth and the lab (@OferYizhar, @liefefenno!). Thanks to A Nurmikko, I Ozden, J Wang for co-ax optrodes!

We used neural perturbations to identify the dynamics in the primate motor cortex that govern reaching movements. We deliver optogenetic excitation and electrical microstimulation (ICMS) to perturb neural states, record the surrounding neurons with electrodes and Neuropixels.

𝗞𝗲𝘆 𝘁𝗮𝗸𝗲𝗮𝘄𝗮𝘆𝘀: (𝟭) We reveal that task-related dynamical sensitivity is restricted to a self-contained, low-dimensional subspace of the ambient high-dimensional neural circuit, which has implications for multi-task learning, interference, noise robustness, etc.

(𝟮) We show that the task dynamics space ≠ the task activity space identified via PCA (or TDR). The task dynamics space is actually oriented so as to be robust to strong non-normal amplification within cortical circuits.

(𝟯) Lastly, we identify a fundamental difference in how broad, unstructured optogenetic excitation (in this context) and electrical microstimulation (ICMS) engage with cortical dynamics, revealing a new mechanism by which stimulation may evoke behavioral effects (see below!)

In this paper, we use direct perturbations of neural activity in the motor cortex of NHPs, in order to advance the paradigm of computation through neural dynamics (CTD), an important framework for studying computation in both biological and artificial recurrent neural circuits.

Some reviews:

@SaurabhsNeurons, @MattGolub_Neuro, @SussilloDavid, @shenoystanford:

https://www.annualreviews.org/doi/abs/10.1146/annurev-neuro-092619-094115

@leaduncker, Sahani: