scholarly journals A computational model based on cortico-spinal fMRI for asymmetrically organized motor corticospinal networks in humans

2021 ◽  
Author(s):  
Eiji Takasawa ◽  
Mitsunari Abe ◽  
Kenji Takagishi ◽  
Hirotaka Chikuda ◽  
Takashi Hanakawa
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Hand Movement ◽  
Hand Preference ◽  
Synaptic Connections ◽  
Spinal Motoneurons ◽  
Functional Magnetic Resonance ◽  
Hand Dexterity ◽  
Spinal Fmri ◽  
Dexterous Hand

Abstract Evolution of the direct connection from primary motor cortex to motoneurons in the spinal cord parallels acquisition of hand dexterity and lateralization of hand preference. Recent studies indicated that the phylogenetically older pathway consisting of multi-synaptic connections from primary motor cortex to spinal motoneurons also participate in controlling dexterous hand movement. However, it remains unknown how the two corticospinal pathways work in concert to control unilateral hand movement with lateralized preference. Using corticospinal functional magnetic resonance imaging, we discovered the asymmetric organization of the two corticospinal networks that modelled monosynaptic or polysynaptic control from primary motor cortices over spinal motoneurons. Moreover, the degree of the involvement of the two corticospinal networks paralleled the lateralization of hand preference. The present results pointed to the functionally lateralized motor nervous system that underlies the behavioural asymmetry of handedness, a uniquely human trait which could have phylogenetically differentiated humans from other primates.

scholarly journals Periinfarct rewiring supports recovery after primary motor cortex stroke

2021 ◽  
pp. 0271678X2110029
Author(s):  
Mitsouko van Assche ◽  
Elisabeth Dirren ◽  
Alexia Bourgeois ◽  
Andreas Kleinschmidt ◽  
Jonas Richiardi ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Spatial Scales ◽  
Premotor Cortex ◽  
Core Network ◽  
Small Spatial Scale ◽  
The Core ◽  
Hand Dexterity ◽  
Motor Network ◽  
Motor Improvement

After stroke restricted to the primary motor cortex (M1), it is uncertain whether network reorganization associated with recovery involves the periinfarct or more remote regions. We studied 16 patients with focal M1 stroke and hand paresis. Motor function and resting-state MRI functional connectivity (FC) were assessed at three time points: acute (<10 days), early subacute (3 weeks), and late subacute (3 months). FC correlates of recovery were investigated at three spatial scales, (i) ipsilesional non-infarcted M1, (ii) core motor network (M1, premotor cortex (PMC), supplementary motor area (SMA), and primary somatosensory cortex), and (iii) extended motor network including all regions structurally connected to the upper limb representation of M1. Hand dexterity was impaired only in the acute phase ( P = 0.036). At a small spatial scale, clinical recovery was more frequently associated with connections involving ipsilesional non-infarcted M1 (Odds Ratio = 6.29; P = 0.036). At a larger scale, recovery correlated with increased FC strength in the core network compared to the extended motor network (rho = 0.71; P = 0.006). These results suggest that FC changes associated with motor improvement involve the perilesional M1 and do not extend beyond the core motor network. Core motor regions, and more specifically ipsilesional non-infarcted M1, could hence become primary targets for restorative therapies.

scholarly journals Decorrelation of cortical inputs and motoneuron output

2011 ◽  
Vol 106 (5) ◽  
pp. 2688-2697 ◽  
Author(s):  
Francesco Negro ◽  
Dario Farina
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Small Population ◽  
Spectral Lines ◽  
Spinal Motoneurons ◽  
Force Output ◽  
Cortical Input ◽  
Motoneuron Pool ◽  
Discharge Rates ◽  
Cortical Inputs

Oscillations in the primary motor cortex are transmitted through the corticospinal tract to the motoneuron pool. This pathway is believed to produce an effective and direct command from the motor cortex to the spinal motoneurons for the modulation of the force output. In this study, we used a computational model of a population of motoneurons to investigate the factors that can influence the transmission of the cortical input to the output of motoneurons, since it can be quantified by coherence analysis. The simulations demonstrated that, despite the nonlinearity of the motoneurons, oscillations present in the cortical input are transmitted to the output of the motoneuron pool at the same frequency. However, the interference introduced by the nonlinearity of the system increases the variability of the oscillations in output, introducing spectral lines whose frequency depends on the input frequencies and the motoneuron discharge rates. Moreover, an additional source of synaptic input common to all motoneurons but independent from the corticospinal component decorrelates the cortical input and motoneuron output and, thus, decreases the magnitude of the estimated coherence, even if the effective cortical drive does not change. These results indicate that the corticospinal input can effectively be sampled by a small population of motoneurons. However, the transmission of a corticospinal drive to the motoneuron pool is influenced by the nonlinearity of the spiking processes of the active motoneurons and by synaptic inputs common to the motoneuron population but independent from the cortical input.

Dynamical Organization of Directional Tuning in the Primate Premotor and Primary Motor Cortex

2003 ◽  
Vol 89 (2) ◽  
pp. 1136-1142 ◽  
Author(s):  
Yoram Ben-Shaul ◽  
Eran Stark ◽  
Itay Asher ◽  
Rotem Drori ◽  
Zoltan Nadasdy ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Hand Movement ◽  
Movement Direction ◽  
Cortical Surface ◽  
Preferred Direction ◽  
Preparation Period ◽  
Direction Of Movement ◽  
The Mean ◽  
Movement Parameters

Although previous studies have shown that activity of neurons in the motor cortex is related to various movement parameters, including the direction of movement, the spatial pattern by which these parameters are represented is still unresolved. The current work was designed to study the pattern of representation of the preferred direction (PD) of hand movement over the cortical surface. By studying pairwise PD differences, and by applying a novel implementation of the circular variance during preparation and movement periods in the context of a center-out task, we demonstrate a nonrandom distribution of PDs over the premotor and motor cortical surface of two monkeys. Our analysis shows that, whereas PDs of units recorded by nonadjacent electrodes are not more similar than expected by chance, PDs of units recorded by adjacent electrodes are. PDs of units recorded by a single electrode display the greatest similarity. Comparison of PD distributions during preparation and movement reveals that PDs of nearby units tend to be more similar during the preparation period. However, even for pairs of units recorded by a single electrode, the mean PD difference is typically large (45° and 75° during preparation and movement, respectively), so that a strictly modular representation of hand movement direction over the cortical surface is not supported by our data.

scholarly journals Primary Motor Cortex Excitability Is Modulated During the Mental Simulation of Hand Movement

2017 ◽  
Vol 23 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Christian Hyde ◽  
Ian Fuelscher ◽  
Jarrad A.G. Lum ◽  
Jacqueline Williams ◽  
Jason He ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Hand Movement ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Mental Simulation ◽  
Right Hand ◽  
Hand Laterality ◽  
Motor Cortex Excitability

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)

scholarly journals Relationship between Finger Movement Rate and Functional Magnetic Resonance Signal Change in Human Primary Motor Cortex

1996 ◽  
Vol 16 (6) ◽  
pp. 1250-1254 ◽  
Author(s):  
S. M. Rao ◽  
P. A. Bandettini ◽  
J. R. Binder ◽  
J. A. Bobholz ◽  
T. A. Hammeke ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Stimulus Presentation ◽  
Functional Magnetic Resonance ◽  
Movement Rate ◽  
Noninvasive Technique ◽  
Movement Rates ◽  
Signal Change ◽  
Flexion Extension

Functional magnetic resonance imaging (FMRI) is a noninvasive technique for mapping regional brain changes in response to sensory, motor, or cognitive activation tasks. Interpretation of these activation experiments may be confounded by more elementary task parameters, such as stimulus presentation or movement rates. We examined the effect of movement rate on the FMRI response recorded from the contralateral primary motor cortex. Four right-handed healthy subjects performed flexion-extension movements of digits 2–5 of the right hand at rates of 1, 2, 3, 4, or 5 Hz. Results of this study indicated a positive linear relationship between movement rate and FMRI signal change. Additionally, the number of voxels demonstrating functional activity increased significantly with faster movement rates. The magnitude of the signal change at each movement rate remained constant over the course of three 8-min scanning series. These findings are similar to those of previous rate studies of the visual and auditory system performed with positron emission tomography (PET) and FMRI.

scholarly journals Short-term effects of unilateral lesion of the primary motor cortex (M1) on ipsilesional hand dexterity in adult macaque monkeys

2011 ◽  
Vol 217 (1) ◽  
pp. 63-79 ◽  
Author(s):  
Shahid Bashir ◽  
Mélanie Kaeser ◽  
Alexander Wyss ◽  
Adjia Hamadjida ◽  
Yu Liu ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Unilateral Lesion ◽  
Short Term ◽  
Macaque Monkeys ◽  
Hand Dexterity ◽  
Short Term Effects

scholarly journals Primary motor cortex has independent representations for ipsilateral and contralateral arm movements but correlated representations for grasping

2019 ◽  
Author(s):  
John E Downey ◽  
Kristin M Quick ◽  
Nathaniel Schwed ◽  
Jeffrey M Weiss ◽  
George F Wittenberg ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Human Subjects ◽  
Brain Computer Interface ◽  
Hand Movement ◽  
Arm Movement ◽  
Computer Interface ◽  
Contralateral Movement ◽  
Contralateral Motor ◽  
Continuous Movements

AbstractMotor commands for the arms and hands generally originate in contralateral motor cortex anatomically. However, ipsilateral primary motor cortex shows activity related to arm movement despite the lack of direct connections. The extent to which the activity related to ipsilateral movement is independent from that related to contralateral movement is unclear based on conflicting conclusions in prior work. Here we present the results of bilateral arm and hand movement tasks completed by two human subjects with intracortical microelectrode arrays implanted in left primary motor cortex for a clinical brain-computer interface study. Neural activity was recorded while they attempted to perform arm and hand movements in a virtual environment. This enabled us to quantify the strength and independence of motor cortical activity related to continuous movements of each arm. We also investigated the subjects’ ability to control both arms through a brain-computer interface system. Through a number of experiments, we found that ipsilateral arm movement was represented independently of, but more weakly than, contralateral arm movement. However, the representation of grasping was correlated between the two hands. This difference between hand and arm representation was unexpected, and poses new questions about the different ways primary motor cortex controls hands and arms.

Sign in / Sign up

Export Citation Format

Share Document