Figure 6: Illustration of single-trial neural trajectories extracted from population neural activities.
From: Refinement of learned skilled movement representation in motor cortex deep output layer
(a) The temporals of ten single-trial neural trajectories extracted from first reach success trials by applying GPFA (see Methods) embedded in the top three orthonormalized latent dimensional space (LD1-3) spanning from 800 ms before to 800 ms after the ‘orient’ position, derived from 27 L5b PNs recorded from an representative animal. The black arrows indicate the flow of time series and coloured dots denote different stages of forelimb action. The ellipses indicate the across-trial variability (two s.d. around the mean) at these states. (b) and (d) Top: Neural trajectories of 30 randomly selected first reach success trials with trajectory deviation within mean±s.d. of cumulative Euclidean distance from reference expert trial after DTW, and neural trajectories of 30 randomly selected first reach failure trials, derived from 27 L5b PNs’ activities recorded from the same example animal. The flow of time series is colour gradient coded, from blue (start) to red (end). Bottom: the same neural trajectories shown in three individual latent dimensional space (LD1-3). Arrow indicates ‘orient’ position. (c) and (e) Analysis of the variance of the neural trajectories in LD1-3, quantified by the diagonal matrix of the covariance ellipsoids, showing progressive reduction in the variance in first reach success trials (c) but not in failure trials (e) during training.
