Neural coding of action in three dimensions: Task‐ and time‐invariant reference frames for visuospatial and motor‐related activity in parietal area V6A. Issue 17 (28th February 2020)

• Record Type: Journal Article
• Authors: Hadjidimitrakis, Kostas; Ghodrati, Masoud; Breveglieri, Rossella; Rosa, Marcello G. P.; Fattori, Patrizia
• Is Part Of: Journal of comparative neurology. Volume 528:Issue 17(2020)
• Page Start: 3108
• Page End: 3122
• Publication Date: 2020-02-28
• Subjects: depth -- MATLAB (RRID: SCR_001622) -- posterior parietal cortex -- reach -- reference frame -- visuomotor transformation; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24889
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: Goal‐directed movements involve a series of neural computations that compare the sensory representations of goal location and effector position, and transform these into motor commands. Neurons in posterior parietal cortex (PPC) control several effectors (e.g., eye, hand, foot) and encode goal location in a variety of spatial coordinate systems, including those anchored to gaze direction, and to the positions of the head, shoulder, or hand. However, there is little evidence on whether reference frames depend also on the effector and/or type of motor response. We addressed this issue in macaque PPC area V6A, where previous reports using a fixate‐to‐reach in depth task, from different starting arm positions, indicated that most units use mixed body/hand‐centered coordinates. Here, we applied singular value decomposition and gradient analyses to characterize the reference frames in V6A while the animals, instead of arm reaching, performed a nonspatial motor response (hand lift). We found that most neurons used mixed body/hand coordinates, instead of "pure" body‐, or hand‐centered coordinates. During the task progress the effect of hand position on activity became stronger compared to target location. Activity consistent with body‐centered coding was present only in a subset of neurons active early in the task. Applying the same analyses to a population of V6A neurons recorded during the fixate‐to‐reach task yielded similar results. These findings suggest that V6A neurons use consistent reference frames between spatial and nonspatial motor responses, a functional property that may allow the integration of spatial awareness and movement control. Abstract : Visually guided action requires integrating information from multiple sources and encoding flexible action representations. We look at objects that we might reach, but also use them as a cue to act in another spatial location. This research article examines the sensorimotor transformations in parietal cortex occurring when we perform various actions in three‐dimensional space.