Compensatory motor function of the somatosensory cortex for the motor cortex temporarily impaired by cooling in the monkey

Having been occupied with the study of the minute representation of motor function in the cortex of the Bonnet Monkey ( Macacus sinicus ), it seemed to us extremely necessary to investigate the character of such representation in the cortex of an anthropoid Ape, in order that we might form a more correct estimate of the mode of localisation in Man. A comparative study of the brains and habits of the more easily obtainable anthropoids showed clearly that for our object the Orang was more suitable than the Chimpanzee, in being likely to afford results nearer to those presumed to exist in Man. We therefore procured a young Orang which, in the opinion of Professor D. J. Cunningham, of Trinity College, Dublin, was about 21/2 years old. In addition to excitation of the cortex, we also investigated the movements obtained by stimulating the fibres of the internal capsule.

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Recovery of Motor Function After Lesions in Motor Cortex of Monkey

Novartis Foundation Symposia - Ciba Foundation Symposium 34 - Outcome of Severe Damage to the CNS ◽

10.1002/9780470720165.ch5 ◽

2008 ◽

pp. 65-84 ◽

Cited By ~ 7

Author(s):

Perry Black ◽

Ronald S. Markowitz ◽

Salvatore N. Cianci

Keyword(s):

Motor Cortex ◽

Motor Function ◽

Recovery Of Motor Function

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Somatosensory cortical excitability changes precede those in motor cortex during human motor learning

Journal of Neurophysiology ◽

10.1152/jn.00383.2019 ◽

2019 ◽

Vol 122 (4) ◽

pp. 1397-1405 ◽

Cited By ~ 6

Author(s):

Hiroki Ohashi ◽

Paul L. Gribble ◽

David J. Ostry

Keyword(s):

Motor Cortex ◽

Motor Learning ◽

Evoked Potentials ◽

Somatosensory Cortex ◽

Somatosensory Evoked Potentials ◽

Motor Skill ◽

Cortical Excitability ◽

Motor Evoked Potentials ◽

Human Motor ◽

Motor Cortical

Motor learning is associated with plasticity in both motor and somatosensory cortex. It is known from animal studies that tetanic stimulation to each of these areas individually induces long-term potentiation in its counterpart. In this context it is possible that changes in motor cortex contribute to somatosensory change and that changes in somatosensory cortex are involved in changes in motor areas of the brain. It is also possible that learning-related plasticity occurs in these areas independently. To better understand the relative contribution to human motor learning of motor cortical and somatosensory plasticity, we assessed the time course of changes in primary somatosensory and motor cortex excitability during motor skill learning. Learning was assessed using a force production task in which a target force profile varied from one trial to the next. The excitability of primary somatosensory cortex was measured using somatosensory evoked potentials in response to median nerve stimulation. The excitability of primary motor cortex was measured using motor evoked potentials elicited by single-pulse transcranial magnetic stimulation. These two measures were interleaved with blocks of motor learning trials. We found that the earliest changes in cortical excitability during learning occurred in somatosensory cortical responses, and these changes preceded changes in motor cortical excitability. Changes in somatosensory evoked potentials were correlated with behavioral measures of learning. Changes in motor evoked potentials were not. These findings indicate that plasticity in somatosensory cortex occurs as a part of the earliest stages of motor learning, before changes in motor cortex are observed. NEW & NOTEWORTHY We tracked somatosensory and motor cortical excitability during motor skill acquisition. Changes in both motor cortical and somatosensory excitability were observed during learning; however, the earliest changes were in somatosensory cortex, not motor cortex. Moreover, the earliest changes in somatosensory cortical excitability predict the extent of subsequent learning; those in motor cortex do not. This is consistent with the idea that plasticity in somatosensory cortex coincides with the earliest stages of human motor learning.

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