Population coding of grasp and laterality-related information in the macaque fronto-parietal network

Abstract

Preparing and executing grasping movements demands the coordination of sensory information across multiple scales. The position of an object, required hand shape, and which of our hands to extend must all be coordinated in parallel. The network formed by the macaque anterior intraparietal area (AIP) and hand area (F5) of the ventral premotor cortex is essential in the generation of grasping movements. Yet, the role of this circuit in hand selection is unclear. We recorded from 1342 single- and multi-units in AIP and F5 of two macaque monkeys (Macaca mulatta) during a delayed grasping task in which monkeys were instructed by a visual cue to perform power or precision grips on a handle presented in five different orientations with either the left or right hand, as instructed by an auditory tone. In AIP, intended hand use (left vs. right) was only weakly represented during preparation, while hand use was robustly present in F5 during preparation. Interestingly, visual-centric handle orientation information dominated AIP, while F5 contained an additional body-centric frame during preparation and movement. Together, our results implicate F5 as a site of visuo-motor transformation and advocate a strong transition between hand-independent and hand-dependent representations in this parieto-frontal circuit.

Neural coding of intended and executed grasp force in macaque areas AIP, F5, and M1

“…7f,g). For all brain areas, condition-independent parameters explained most of the variance (60–79%), similar to what was found in other neurophysiological studies 28,30 . Furthermore, EMG variance was explained mostly by condition-independent parameters (93–95%).…”

Reduced neural representation of arm/hand actions in the medial posterior parietal cortex

“…To obtain this picture, we used three different V6A populations recorded in three different tasks according to the same used in the previous studies 12–14 . Although the ideal approach would be to have a unique neural population, a recent study comparing the neural population features of area AIP and F5 by dPCA using two distinct populations 23 supports the idea that it is reliable to extract a unique neural feature from different groups of neurons. In the present study, to go beyond the limitations of having different neural populations, we performed a dPCA analysis considering symmetrical number of variables in all tasks (see Supplementary Information).…”

A review of grasping as the movements of digits in space

“…This applies to all of the methods that have been used to study the involvement of various (networks of) brain areas in the control of grasping (for reviews, see, for instance, Fattori et al 2017;Gallivan and Culham 2015;Janssen and Scherberger 2015). Thus it should apply to perturbations of brain activity by stimulating such brain areas (Davare et al 2006;Schettino et al 2015) as well as to relating the activity in such areas to variations in object properties and locations (Cavina-Pratesi et al 2010Fabbri et al 2014;Grol et al 2007;Króliczak et al 2008;Michaels and Scherberger 2018;Overduin et al 2015;Rouse and Schieber 2016;Takahashi et al 2017;Verhagen et al 2008). Some of the above-mentioned studies included reaching movements toward the same objects or locations as were used for grasping, to better understand the variations with location (Cavina-Pratesi et al 2010Fabbri et al 2014), but the digits in the two kinds of movements were never confronted with comparable constraints.…”