Neural and genetic basis of dexterous hand movements

Hand dexterity has uniquely developed in higher primates and is thought to rely on the direct corticomotoneuronal (CM) pathway. Recent studies have shown that rodents and carnivores lack the direct CM pathway but can control certain levels of dexterous hand movements through various indirect CM pathways. Some homologous pathways also exist in higher primates, and among them, propriospinal (PrS) neurons in the mid-cervical segments (C3-C4) are significantly involved in hand dexterity. When the direct CM pathway was lesioned caudal to the PrS and transmission of cortical commands to hand motoneurons via the PrS neurons remained intact, dexterous hand movements could be significantly recovered. This recovery model was intensively studied, and it was found that, in addition to the compensation by the PrS neurons, a large-scale reorganization in the bilateral cortical motor-related areas and mesolimbic structures contributed to recovery. Future therapeutic strategies should target these multihierarchical areas.

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Towards closed-loop decoding of dexterous hand movements using a virtual integration environment

2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society ◽

10.1109/iembs.2008.4649504 ◽

2008 ◽

Cited By ~ 4

Author(s):

Vikram Aggarwal ◽

Girish Singhal ◽

Jiping He ◽

Marc H. Schieber ◽

Nitish V. Thakor

Keyword(s):

Closed Loop ◽

Hand Movements ◽

Virtual Integration ◽

Dexterous Hand

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CLASSIFICATION OF DEXTEROUS HAND MOVEMENTS BASED ON MYOELECTRIC SIGNALS USING NEURAL NETWORKS

Anais do V Congresso Brasileiro de Eletromiografia e Cinesiologia e X Simpósio de Engenharia Biomédica ◽

10.29327/cobecseb.78982 ◽

2018 ◽

Cited By ~ 1

Author(s):

J.V. Mayor ◽

A.F. Rodacki ◽

T. Bastos

Keyword(s):

Neural Networks ◽

Hand Movements ◽

Myoelectric Signals ◽

Dexterous Hand

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Rudimentary Dexterity Corresponds With Reduced Ability to Move in Synergy After Stroke: Evidence of Competition Between Corticoreticulospinal and Corticospinal Tracts?

Neurorehabilitation and Neural Repair ◽

10.1177/1545968320943582 ◽

2020 ◽

Vol 34 (10) ◽

pp. 904-914

Author(s):

Merav R. Senesh ◽

Karina Barragan ◽

David J. Reinkensmeyer

Keyword(s):

Motor System ◽

Corticospinal Tract ◽

Arm Movements ◽

Hand Movements ◽

Clinical Assessments ◽

Corticospinal Tracts ◽

Dexterous Hand ◽

Moderate Range ◽

Exclusive Or ◽

At Will

Objective When a stroke damages the corticospinal tract (CST), it has been hypothesized that the motor system switches to using the corticoreticulospinal tract (CRST) resulting in abnormal arm synergies. Is use of these tracts mutually exclusive, or can the motor system spontaneously switch between them depending on the type of movement it wants to make? If the motor system can share control at will, then people with a rudimentary ability to make dexterous movements should be able to perform synergistic arm movements as well. Methods We analyzed clinical assessments of 319 persons’ abilities to perform “out-of-synergy” and “in-synergy” arm movements after chronic stroke using the Upper Extremity Fugl-Meyer (UEFM) scale. Results We identified a moderate range of arm impairment (UEFM = ~30-40) where subjects had a rudimentary ability to make out-of-synergy (~23%-50% on the out-of-synergy score) and dexterous hand movements (~3-10 blocks on Box and Blocks Test). Below this range persons could perform in-synergy but not out-of-synergy or dexterous movements. In the moderate range, however, scoring better on out-of-synergy movements correlated with scoring worse on in-synergy movements ( P = .001, r ≈ −0.6). Conclusion Rudimentary dexterity corresponded with reduced ability to move the arm in-synergy. This finding supports the idea that CST and CRST compete and has implications for rehabilitation therapy.

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Postural Representations of the Hand in Primate Sensorimotor Cortex

10.1101/566539 ◽

2019 ◽

Cited By ~ 2

Author(s):

James M. Goodman ◽

Gregg A. Tabot ◽

Alex S. Lee ◽

Aneesha K. Suresh ◽

Alexander T. Rajan ◽

...

Keyword(s):

Motor System ◽

Sensory System ◽

Reaching Movements ◽

Hand Movements ◽

Time Varying ◽

Neural Responses ◽

Neural Basis ◽

Functional Roles ◽

Hand Control ◽

Dexterous Hand

SummaryDexterous hand control requires not only a sophisticated motor system but also a sensory system to provide tactile and proprioceptive feedback. To date, the study of the neural basis of proprioception in cortex has focused primarily on reaching movements, at the expense of hand-specific behaviors such as grasp. To fill this gap, we record both the time-varying hand kinematics and the neural activity evoked in somatosensory and motor cortices as monkeys grasp a variety of different objects. We find that neurons in somatosensory cortex, as well as in motor cortex, preferentially track postures of multi-joint combinations spanning the entire hand. This contrasts with neural responses during reaching movements, which preferentially track movement kinematics of the arm rather than its postural configuration. These results suggest different representations of arm and hand movements likely adapted to suit the different functional roles of these two effectors.

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Effects of early versus late rehabilitative training on manual dexterity after corticospinal tract lesion in macaque monkeys

Journal of Neurophysiology ◽

10.1152/jn.00814.2012 ◽

2013 ◽

Vol 109 (12) ◽

pp. 2853-2865 ◽

Cited By ~ 23

Author(s):

Yoko Sugiyama ◽

Noriyuki Higo ◽

Kimika Yoshino-Saito ◽

Yumi Murata ◽

Yukio Nishimura ◽

...

Keyword(s):

Success Rate ◽

Corticospinal Tract ◽

Movement Analysis ◽

Hand Movements ◽

Optimal Time ◽

Vertical Slit ◽

Macaque Monkeys ◽

Task Success ◽

Hand Performance ◽

Dexterous Hand

Dexterous hand movements can be restored with motor rehabilitative training after a lesion of the lateral corticospinal tract (l-CST) in macaque monkeys. To maximize effectiveness, the optimal time to commence such rehabilitative training must be determined. We conducted behavioral analyses and compared the recovery of dexterous hand movements between monkeys in which hand motor training was initiated immediately after the l-CST lesion (early-trained monkeys) and those in which training was initiated 1 mo after the lesion (late-trained monkeys). The performance of dexterous hand movements was evaluated by food retrieval tasks. In early-trained monkeys, performance evaluated by the success rate in a vertical slit task (retrieval of a small piece of food through a narrow vertical slit) recovered to the level of intact monkeys during the first 1–2 mo after the lesion. In late-trained monkeys, the task success rate averaged ∼30% even after 3 mo of rehabilitative training. We also evaluated hand performance with the Klüver board task, in which monkeys retrieved small spherical food pellets from cylindrical wells. Although the success rate of the Klüver board task did not differ between early- and late-trained monkeys, kinematic movement analysis showed that there was a difference between the groups: late-trained monkeys with an improved success rate frequently used alternate movement strategies that were different from those used before the lesion. These results suggest that early rehabilitative training after a spinal cord lesion positively influences subsequent functional recovery.

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