Condition-Dependent Neural Dimensions Progressively Shift during Reach to Grasp

• Published in: Cell reports (Cambridge) Vol. 25; no. 11; pp. 3158 - 3168.e3
• Main Authors: Rouse, Adam G., Schieber, Marc H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 11.12.2018; Elsevier
• Subjects: Action Potentials - physiology; Animals; Behavior, Animal; demixed PCA; dimensionality reduction; grasping; Hand Strength - physiology; Macaca mulatta; manipulation; Motor Activity; neural population; neural variability; Neurons - physiology; population dynamics; primary motor cortex; Principal Component Analysis; reaching; state space; Task Performance and Analysis; Time Factors; grasping; dimensionality reduction; state space; reaching; neural variability; neural population; demixed PCA; manipulation; population dynamics; primary motor cortex
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2018.11.057

Neural population space analysis was performed to assess the dimensionality and dynamics of the neural population in the primary motor cortex (M1) during a reach-grasp-manipulation task in which both the reach location and the object being grasped were varied. We partitioned neural activity into three components: (1) general task-related activity independent of location and object, (2) location- and/or object-related activity, and (3) noise. Neural modulation related to location and/or object was only one-third the size of either general task modulation or noise. The neural dimensions of location and/or object-related activity overlapped with both the general task and noise dimensions. Rather than large amplitude modulation in a fixed set of dimensions, the active dimensions of location and/or object modulation shifted progressively over the time course of a trial. [Display omitted] •Neural modulation related to location and/or object is smaller than general task modulation•Neural dimensions of location and/or object overlap with those of the general task•Neural dimensions of location and/or object modulation shift as a trial progresses in time•Noise is large but evenly distributed across neural dimensions and time Rouse and Schieber show that during reach-grasp-manipulate movements, M1 activity related to location and object occurs not in a fixed set but rather in a shifting set of neural dimensions that overlap with those of general task and noise activity.