RT Journal Article SR Electronic T1 A theory of multineuronal dimensionality, dynamics and measurement JF bioRxiv FD Cold Spring Harbor Laboratory SP 214262 DO 10.1101/214262 A1 Peiran Gao A1 Eric Trautmann A1 Byron Yu A1 Gopal Santhanam A1 Stephen Ryu A1 Krishna Shenoy A1 Surya Ganguli YR 2017 UL http://biorxiv.org/content/early/2017/11/12/214262.abstract AB In many experiments, neuroscientists tightly control behavior, record many trials, and obtain trial-averaged firing rates from hundreds of neurons in circuits containing billions of behaviorally relevant neurons. Di-mensionality reduction methods reveal a striking simplicity underlying such multi-neuronal data: they can be reduced to a low-dimensional space, and the resulting neural trajectories in this space yield a remarkably insightful dynamical portrait of circuit computation. This simplicity raises profound and timely conceptual questions. What are its origins and its implications for the complexity of neural dynamics? How would the situation change if we recorded more neurons? When, if at all, can we trust dynamical portraits obtained from measuring an infinitesimal fraction of task relevant neurons? We present a theory that answers these questions, and test it using physiological recordings from reaching monkeys. This theory reveals conceptual insights into how task complexity governs both neural dimensionality and accurate recovery of dynamic portraits, thereby providing quantitative guidelines for future large-scale experimental design.