Encoding of Both Reaching and Grasping Kinematics in Dorsal and Ventral Premotor Cortices

Abstract

Classically, it has been hypothesized that reach-to-grasp movements arise from two discrete parietofrontal cortical networks. As part of these networks, the dorsal premotor cortex (PMd) has been implicated in the control of reaching movements of the arm, whereas the ventral premotor cortex (PMv) has been associated with the control of grasping movements of the hand. Recent studies have shown that such a strict delineation of function along anatomical boundaries is unlikely, partly because reaching to different locations can alter distal hand kinematics and grasping different objects can affect kinematics of the proximal arm. Here, we used chronically implanted multielectrode arrays to record unit-spiking activity in both PMd and PMv simultaneously while rhesus macaques engaged in a reach-to-grasp task. Generalized linear models were used to predict the spiking activity of cells in both areas as a function of different kinematic parameters, as well as spike history. To account for the influence of reaching on hand kinematics and vice versa, we applied demixed principal components analysis to define kinematics synergies that maximized variance across either different object locations or grip types. We found that single cells in both PMd and PMv encode the kinematics of both reaching and grasping synergies, suggesting that this classical division of reach and grasp in PMd and PMv, respectively, does not accurately reflect the encoding preferences of cells in those areas.

Terminal organization of the corticospinal projection from the lateral premotor cortex to the cervical enlargement (C5–T1) in rhesus monkey

“…Contemporary neurophysiological recording studies have shown that LPMCd neurons are active during the preparation, initiation and execution phases of arm movements (see Hoshi & Tanji, for review). More recent unit recording work reported single neurons in LPMCd encode the kinematics of both reaching and grasping movements (Takahashi et al, ), grip type and grasp time course (Hao et al, ) and moderate their activity according to object dimensions and applied forces (Hendrix, Mason, & Ebner, ). Other current studies indicate that LPMCd neurons are active during both visually‐guided and memory‐guided sequential arm pointing movements but make a significant contribution only to the generation of cortically mediated memory‐guided arm movement sequences (Ohbayashi, Picard, & Strick, ).…”

“…For nearly a century, unraveling the functional contribution of LPMCd to voluntary motor behavior has been a priority of cortical motor system investigators. Early lesion studies in nonhuman primates demonstrated lateral premotor cortex injury alters the ability to execute complex purposeful voluntary upper extremity movements (Fulton, 1935(Fulton, , 1949Jacobsen, 1934Jacobsen, , 1935 (Takahashi et al, 2017), grip type and grasp time course (Hao et al, 2014) and moderate their activity according to object dimensions and applied forces (Hendrix, Mason, & Ebner, 2009). Other current studies indicate that LPMCd neurons are active during both visually-guided and memory-guided sequential arm pointing movements but make a significant contribution only to the generation of cortically mediated memory-guided arm movement sequences (Ohbayashi, Picard, & Strick, 2016 which mainly involves proximal joints (Kurata & Hoffman, 1994).…”

Dynamic Musculoskeletal Functional Morphology: Integrating diceCT and XROMM

“…Muscle kinetics are frequently integrated with synchronized recordings of skeletal kinematics from high‐speed cameras and kinetics from implants or external sensors. Systems such as Vicon (Vicon Motion Systems, Oxford UK) permit the study of rigid body kinematics, joint kinematics, instantaneous axis of rotation (which influences dynamic torque), and whole muscle length change (Reed and Ross, ; Ross et al, ; Ross and Iriarte‐Diaz, ; Takahashi et al, ; Iriarte‐Diaz et al, ). Although light‐based motion capture technology can generate large data sets of multiple skeletal segments and allow assessment of the distribution of kinematic variance across species, individuals, and behaviors (Iriarte‐Diaz et al, ; Ross et al, ; Iriarte‐Diaz et al, ), it cannot provide data on internal kinematics of soft tissues such as individual fibers or structures obscured by skin (e.g., oropharyngeal structures).…”

Development of semi-automatic procedure for detection and tracking of fiducial markers for orofacial kinematics during natural feeding

“…By combining electrophysiological signals with high fidelity kinematics during feeding, a new opportunity will be open to study neural processes of orofacial apparatus motor control as it has been done in other types of complex movements such as 3D reach-to-grasp kinematics [12], [13]. Such knowledge will enhance our understanding of the neural control of feeding behaviors in conditions of health and disease.…”