scholarly journals Importance of the Primary Motor Cortex in Development of Human Hand/Finger Dexterity

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Eiichi Naito ◽  
Tomoyo Morita ◽  
Minoru Asada

Abstract Hand/finger dexterity is well-developed in humans, and the primary motor cortex (M1) is believed to play a particularly important role in it. Here, we show that efficient recruitment of the contralateral M1 and neuronal inhibition of the ipsilateral M1 identified by simple hand motor and proprioceptive tasks are related to hand/finger dexterity and its ontogenetic development. We recruited healthy, right-handed children (n = 21, aged 8–11 years) and adults (n = 23, aged 20–26 years) and measured their brain activity using functional magnetic resonance imaging during active and passive right-hand extension–flexion tasks. We calculated individual active control-related activity (active–passive) to evaluate efficient brain activity recruitment and individual task-related deactivation (neuronal inhibition) during both tasks. Outside the scanner, participants performed 2 right-hand dexterous motor tasks, and we calculated the hand/finger dexterity index (HDI) based on their individual performance. Participants with a higher HDI exhibited less active control-related activity in the contralateral M1 defined by the active and passive tasks, independent of age. Only children with a higher HDI exhibited greater ipsilateral M1 deactivation identified by these tasks. The results imply that hand/finger dexterity can be predicted by recruitment and inhibition styles of the M1 during simple hand sensory–motor tasks.

2000 ◽  
Vol 83 (1) ◽  
pp. 528-536 ◽  
Author(s):  
H. Henrik Ehrsson ◽  
Anders Fagergren ◽  
Tomas Jonsson ◽  
Göran Westling ◽  
Roland S. Johansson ◽  
...  

Most manual grips can be divided in precision and power grips on the basis of phylogenetic and functional considerations. We used functional magnetic resonance imaging to compare human brain activity during force production by the right hand when subjects used a precision grip and a power grip. During the precision-grip task, subjects applied fine grip forces between the tips of the index finger and the thumb. During the power-grip task, subjects squeezed a cylindrical object using all digits in a palmar opposition grasp. The activity recorded in the primary sensory and motor cortex contralateral to the operating hand was higher when the power grip was applied than when subjects applied force with a precision grip. In contrast, the activity in the ipsilateral ventral premotor area, the rostral cingulate motor area, and at several locations in the posterior parietal and prefrontal cortices was stronger while making the precision grip than during the power grip. The power grip was associated predominately with contralateral left-sided activity, whereas the precision-grip task involved extensive activations in both hemispheres. Thus our findings indicate that in addition to the primary motor cortex, premotor and parietal areas are important for control of fingertip forces during precision grip. Moreover, the ipsilateral hemisphere appears to be strongly engaged in the control of precision-grip tasks performed with the right hand.


Author(s):  
Yuhan Luo ◽  
Yaomin Guo ◽  
Linchang Zhong ◽  
Ying Liu ◽  
Chao Dang ◽  
...  

1997 ◽  
Vol 78 (3) ◽  
pp. 1516-1530 ◽  
Author(s):  
Ruth E. Martin ◽  
Gregory M. Murray ◽  
Pentti Kemppainen ◽  
Yuji Masuda ◽  
Barry J. Sessle

Martin, Ruth E., Gregory M. Murray, Pentti Kemppainen, Yuji Masuda, and Barry J. Sessle. Functional properties of neurons in the primate tongue primary motor cortex during swallowing. J. Neurophysiol. 78: 1516–1530, 1997. Recent studies conducted in our laboratory have suggested that the tongue primary motor cortex (i.e., tongue-MI) plays a critical role in the control of voluntary tongue movements in the primate. However, the possible involvement of tongue-MI in semiautomatic tongue movements, such as those in swallowing, remains unkown. Therefore the present study was undertakein in attempts to address whether tongue-MI plays a role in the semiautomatic tongue movements produced during swallowing. Extracellular single neuron recordings were obtained from tongue-MI, defined by intracortical microstimulation (ICMS), in two awake monkeys as they performed three types of swallowing (swallowing of a juice reward after successful tongue task performance, nontask-related swallowing of a liquid bolus, and nontask-related swallowing of a solid bolus) as well as a trained tongue-protrusion task. Electromyographic activity was recorded simultaneously from various orofacial and laryngeal muscles. In addition, the afferent input to each tongue-MI neuron and ICMS-evoked motor output characteristics at each neuronal recording site were determined. Neurons were considered to show swallow and/or tongue-protrusion task-related activity if a statistically significant difference in firing rate was seen in association with these behaviors compared with that observed during a control pretrial period. Of a total of 80 neurons recorded along 40 microelectrode penetrations in the ICMS-defined tongue-MI, 69% showed significant alterations of activity in relation to the swallowing of a juice reward, whereas 66% exhibited significant modulations of firing in association with performance of the trained tongue-protrusion task. Moreover, 48% showed significant alterations of firing in relation to both swallowing and the tongue-protrusion task. These findings suggest that the region of cortex involved in swallowing includes MI and that tongue-MI may play a role in the regulation of semiautomatic tongue movement, in addition to trained motor behavior. Swallow-related tongue-MI neurons exhibited a variety of swallow-related activity patterns and were distributed throughout the ICMS-defined tongue-MI at sites where ICMS evoked a variety of types of tongue movements. These findings are consistent with the view that multiple efferent zones for the production of tongue movements are activated in swallowing. Many swallow-related tongue-MI neurons had an orofacial mechanoreceptive field, particularly on the tongue dorsum, supporting the view that afferent inputs may be involved in the regulation of the swallowing synergy.


2017 ◽  
Vol 23 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Christian Hyde ◽  
Ian Fuelscher ◽  
Jarrad A.G. Lum ◽  
Jacqueline Williams ◽  
Jason He ◽  
...  

AbstractObjectives:It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT).Methods:Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users).Results:hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation).Conclusions:These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. (JINS, 2017,23, 185–193)


2007 ◽  
Vol 98 (4) ◽  
pp. 2008-2021 ◽  
Author(s):  
Kiyoshi Kurata

The ventral premotor cortex (PMv) and the primary motor cortex (MI) of monkeys participate in various sensorimotor integrations, such as the transformation of coordinates from visual to motor space, because the areas contain movement-related neuronal activity reflecting either visual or motor space. In addition to relationship to visual and motor space, laterality of the activity could indicate stages in the visuomotor transformation. Thus we examined laterality and relationship to visual and motor space of movement-related neuronal activity in the PMv and MI of monkeys performing a fast-reaching task with the left or right arm, toward targets with visual and motor coordinates that had been dissociated by shift prisms. We determined laterality of each activity quantitatively and classified it into four types: activity that consistently depended on target locations in either head-centered visual coordinates (V-type) or motor coordinates (M-type) and those that had either differential or nondifferential activity for both coordinates (B- and N-types). A majority of M-type neurons in the areas had preferences for reaching movements with the arm contralateral to the hemisphere where neuronal activity was recorded. In contrast, most of the V-type neurons were recorded in the PMv and exhibited less laterality than the M-type. The B- and N-types were recorded in the PMv and MI and exhibited intermediate properties between the V- and M-types when laterality and correlations to visual and motor space of them were jointly examined. These results suggest that the cortical motor areas contribute to the transformation of coordinates to generate final motor commands.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Assia Jaillard ◽  
Chantal Delon martin ◽  
Leeanne Carey ◽  
Laurent Lalamalle ◽  
Marc J Hommel ◽  
...  

Background: While primary motor cortex (M1) has been demonstrated to be crucial for motor recovery in a recent meta-analysis including fMRI and TMS studies, other functional neuroimaging studies have found that activity in a broader sensorimotor cortical network correlate with motor recovery. The heterogeneity of stroke lesions and the small sample size characterizing many studies could account for these discrepancies. Hypothesis : The strength of task-related activity in primary motor cortex predicts motor recovery in a clinically homogenous population of acute lacunar stroke patients. Methods: We used fMRI to investigate the neural mechanisms of stroke recovery. We studied 18 stroke patient (4 females, 14 males) after their first single lacunar stroke (7 right , 11 left hemisphere). The lesions caused pure hemiparesia one week after stroke onset (mean 7.2 days; range 2 -15). Lesions were limited to the deep territory of the anterior choroid artery, involving the corticospinal tract at the level of the internal capsule or the corona radiata ( Figure 1 ). Patients were matched to 18 healthy controls for age and sex. Motor impairment was assessed using the NIH Stroke Scale (NIHSS), the Fugl-Meyer Scale (FMS), Finger Tapping Score (FTS), Purdue Pegboard and simple reaction times 7 days and 6 months after stroke. At 6 months, a global motor recovery score was computed using the FMS and the FTS to assess motor recovery. Functional MRI scans were obtained using a self-paced finger tapping (FT) task implemented as a block design alternating right FT, left FT and rest. Data were processed using SPM8. In the first level analysis “FT minus fixation” contrasts were computed for the impaired hand. At the second level, multiple regression was used to assess the effect of the motor recovery score on the FT-related motor activity (threshold p<0.05 FWE; extent threshold k=5). Age and FT rate recorded during the experiment were included as covariates in the second level model. Results: As a group, the patients showed good recovery at 6 months. Both patients and controls exhibited a typical pattern of FT task-related activity. Activity in primary motor cortex predicted motor recovery at 6 months, after adjustment for age and FT rate. MNI coordinates = [-34,-14,48] See Figure 1 . Conclusions: Primary motor cortex activity, measured soon after stroke onset, predicts motor recovery assessed at 6 months post-stroke. fMRI measurements made in the early phase of stroke recovery could be useful to derive prognostic biomarkers in both clinical practice and clinical trials investigating novel treatments, such as stem cell administration.


2010 ◽  
Vol 31 (12) ◽  
pp. 2160-2168 ◽  
Author(s):  
Friedhelm C. Hummel ◽  
Kirstin Heise ◽  
Pablo Celnik ◽  
Agnes Floel ◽  
Christian Gerloff ◽  
...  

2021 ◽  
Author(s):  
Kevin Patrick Cross ◽  
Douglas J Cook ◽  
Stephen H Scott

An important aspect of motor function is our ability to rapidly generate goal-directed corrections for disturbances to the limb or behavioural goal. Primary motor cortex (M1) is a key region involved in feedback processing, yet we know little about how different sources of feedback are processed by M1. We examined feedback-related activity in M1 to compare how different sources (visual versus proprioceptive) and types of information (limb versus goal) are represented. We found sensory feedback had a broad influence on M1 activity with ~73% of neurons responding to at least one of the feedback sources. Information was also organized such that limb and goal feedback targeted the same neurons and evoked similar responses at the single-neuron and population levels indicating a strong convergence of feedback sources in M1.


2021 ◽  
Vol 15 ◽  
Author(s):  
Warren G. Darling ◽  
Marc A. Pizzimenti ◽  
Diane L. Rotella ◽  
Jizhi Ge ◽  
Kimberly S. Stilwell-Morecraft ◽  
...  

We previously reported that rhesus monkeys recover spontaneous use of the more impaired (contralesional) hand following neurosurgical lesions to the arm/hand representations of primary motor cortex (M1) and lateral premotor cortex (LPMC) (F2 lesion) when tested for reduced use (RU) in a fine motor task allowing use of either hand. Recovery occurred without constraint of the less impaired hand and with occasional forced use of the more impaired hand, which was the preferred hand for use in fine motor tasks before the lesion. Here, we compared recovery of five F2 lesion cases in the same RU test to recovery after unilateral lesions of M1, LPMC, S1 and anterior portion of parietal cortex (F2P2 lesion – four cases). Average and highest %use of the contralesional hand in the RU task in F2 cases were twice that in F2P2 cases (p &lt; 0.05). Recovery in the RU task was closely associated with volume and percentage of lesion to caudal (new) M1 (M1c) in both F2 and F2P2 lesion cases. One F2P2 case, with the largest M1c lesion and a large rostral somatosensory cortex (S1r) lesion developed severe contralesional hand non-use despite exhibiting some recovery of fine motor function initially. We conclude that the degree of reduced use of the contralesional hand is primarily related to the volume of M1c injury and that severe non-use requires extensive injury to M1c and S1r. Thus, assessing peri-Rolandic injury extent in stroke patients may have prognostic value for predicting susceptibility to RU and non-use in rehabilitation.


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