[image: VVTNS.png] https://www.wwtns.online <https://streaklinks.com/A9c7PbbpKY7PxB6PaAJWGD3-/https%3A%2F%2Fwww.wwtns.onl...> - on twitter: wwtns@TheoreticalWide You are cordially invited to the lecture Ulises Pereira Oblinovic Allen Institute Neural dynamics outside task-coding dimensions shape decision trajectories The lecture will be held on zoom on Wednesday, June 11, 2025, at *11:00 am EDT * To receive the link: https://www.wwtns.online/register-page *Abstract: *Decision-making unfolds within high-dimensional neural population activity, yet traditional analyses focus on low-dimensional coding subspaces that represent task-relevant variables. Whether these coding dimensions causally drive decisions or merely reflect them remains unclear. Here, we investigate the mechanistic role of residual dimensions—neural activity patterns orthogonal to coding subspaces—in shaping choice behavior. We developed a recurrent neural network model that fits large-scale neural recordings and behavior, disentangling coding and residual subspaces at the single-trial level. Applied to anterior lateral motor cortex (ALM) and motor thalamus recordings during a delayed response task, the model reveals that perturbations along residual dimensions—but not the choice axis—reliably flip decisions, recapitulating a recent paradoxical effect observed with targeted two-photon optogenetic manipulations: activity outside the task-coding subspace exerts stronger causal influence on behavior than perturbations aligned with the choice axis. These effects arise from transient, high-dimensional feedforward trajectories shaped by residual dimensions and converging onto discrete attractor states. Crucially, residual dimensions drive dynamics in coding dimensions, rather than the reverse. To probe the trial-to-trial impact of residual activity, we modeled single-trial deviations as low-dimensional inputs that shift trajectories relative to trial-averaged dynamics. This framework captures decision variability mechanistically: errors emerge when fluctuations in residual dimensions steer dynamics toward incorrect attractors. Extending the model to include thalamocortical loops, we find that inter-area communication operates primarily through residual—not choice-selective—pathways. Together, these results challenge the classical view that decisions are governed by low-dimensional, task-aligned dynamics alone, revealing a causal and computationally essential role for residual dimensions in decision-making. *About VVTNS : Launched as the World Wide Theoretical Neuroscience Seminar (WWTNS) in November 2020 and renamed in homage to Carl van Vreeswijk in Memoriam (April 20, 2022), Speakers have the occasion to talk about theoretical aspects of their work which cannot be discussed in a setting where the majority of the audience consists of experimentalists. The seminars, **held on Wednesdays at 11 am ET,** are 45-50 min long followed by a discussion. The talks are recorded with authorization of the speaker and are available to everybody on our YouTube channel.* ᐧ -- *Il n'y a ni obligation ni pression à traiter ou répondre à ce mail en dehors des heures de travail* "В каждой шутке есть доля шутки" 'Life is good ..' (Carl van Vreeswijk, 1962-2022) --------------------------------------- David Hansel Directeur de Recherche au CNRS Co-Group leader Cerebral Dynamics Plasticity and Learning lab., CNRS 45 rue des Saints Peres 75270 Paris Cedex 06 Tel (Cell): +33 607508403 - Fax (33).1.49.27.90.62 *CONFIDENTIALITY AND PRIVACY NOTICE:* *This message and the documents that might be attached, are addressed exclusively to their(s) recipient(s) and may contain privileged or confidential information. The access to this information by people other than those designated is not authorized. If you are not the indicated recipient, you are notified that the use, disclosure and / or copying without authorization is prohibited under current legislation. If you have received this message in error, please kindly inform the sender immediately and proceed to its destruction.* ᐧ