Neuronal Clusters in the Primate Motor Cortex during Interceptin of Moving Targets.

Two rhesus monkeys were trained to intercept a moving target at a fixed location with a feedback cursor controlled bya 2-D manipulandum. The direction from which the target appeared, the time from the target onset to its arrival at the interception point, and the target acceleration were randomized for each trial, thus requiring the animal to adjust its movement according to the visual input on a trail-by-trail basis. The two animals adopted different strategies, similar to those identified previously in human subjects. Single-cell activity was recorded from the arm area of the primary motor cortex in these two animals, and the neurons were classified based on the temporal patterns in their activity, using a nonhierarchical cluster analysis. Results of this analysis revealed differences in the complexity and diversity of motor cortical activity between the two animals that paralleled those of behavioral strategies. Most clusters displayed activity closedly related to the kinematics of hand movements. In addition, some clusters displayed patterns of activation that conveyed additional information necessary for successful performance of the task, such as the initial target velocity and the interval between successive submovements, suggesting that such information is represented in selective subpopulations of neurons in the primary motor cortex. These results also suggest that conversion of information about target motion into movement-related signals takes place in a broad network of cortical areas including the primary motor cortex.

Download Full-text

Systematic Changes in Directional Tuning of Motor Cortex Cell Activity With Hand Location in the Workspace During Generation of Static Isometric Forces in Constant Spatial Directions

Journal of Neurophysiology ◽

10.1152/jn.1997.78.2.1170 ◽

1997 ◽

Vol 78 (2) ◽

pp. 1170-1174 ◽

Cited By ~ 54

Author(s):

Lauren E. Sergio ◽

John F. Kalaska

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Discharge Rate ◽

Cell Activity ◽

Force Production ◽

Static Force ◽

Force Output ◽

Directional Tuning ◽

Cortex Cell ◽

Isometric Forces

Sergio, Lauren E. and John F. Kalaska. Systematic changes in directional tuning of motor cortex cell activity with hand location in the workspace during generation of static isometric forces in constant spatial directions. J. Neurophysiol. 78: 1170–1174, 1997. We examined the activity of 46 proximal-arm-related cells in the primary motor cortex (MI) during a task in which a monkey uses the arm to exert isometric forces at the hand in constant spatial directions while the hand is in one of nine different spatial locations on a plane. The discharge rate of all 46 cells was significantly affected by both hand location and by the direction of static force during the final static-force phase of the task. In addition, all cells showed a significant interaction between force direction and hand location. That is, there was a significant modulation in the relationship between cell activity and the direction of exerted force as a function of hand location. For many cells, this modulation was expressed in part as a systematic arclike shift in the cell's directional tuning at the different hand locations, even though the direction of static force output at the hand remained constant. These effects of hand location in the workspace indicate that the discharge of single MI cells does not covary exclusively with the level and direction of force output at the hand. Sixteen proximal-arm-related muscles showed similar effects in the task, reflecting their dependence on various mechanical factors that varied with hand location. The parallel changes found for both MI cell activity and muscle activity for static force production at different hand locations are further evidence that MI contributes to the transformation between extrinsic and intrinsic representations of limb movement.

Download Full-text

Parallel Information Processing in Motor Systems: Intracerebral Recordings of Readiness Potential and CNV in Human Subjects

Neural Plasticity ◽

10.1155/np.2000.65 ◽

2000 ◽

Vol 7 (1-2) ◽

pp. 65-72 ◽

Cited By ~ 14

Author(s):

Ivan Rektor

Keyword(s):

Basal Ganglia ◽

Motor Cortex ◽

Primary Motor Cortex ◽

Human Subjects ◽

Anterior Cingulate ◽

Readiness Potential ◽

Task Context ◽

Subcortical Structures ◽

Depth Electrodes ◽

Simultaneous Activation

We performed intracerebral recordings of Readiness Potential (RP) and Contingent Negative Variation (CNV) with simple repetitive distal limb movement in candidates for epilepsy surgery. In 26 patients (in Paris), depth electrodes were located in various cortical structures; in eight patients (in Brno), in the basal ganglia and the cortex. RPs were displayed in the conteral primary motor cortex, conteral somato-sensory cortex, and bilaterally in the SMA and the caudal part of the anterior cingulate cortices. CNVs were recorded in the same cortical regiom as the RP, as well as in the ipsilateral primary motor cortex, and bilaterally in the premotor fronto-lateral, parietal superior, and middle temporal regions. In the basal ganglia, the RP was recorded in the putamen in six of seven patients, and in the head of the caudate nucleus and the pallidum in the only patient with electrodes in these recording sites. We suggest that our results are consistent with a long-lasting, simultaneous activation of cortical and subcortical structures, before and during self-paced and stimulus-triggered movements. The particular regiom that are simultaneously active may be determined by the task context.

Download Full-text

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

10.1101/19008128 ◽

2019 ◽

Cited By ~ 1

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.

Download Full-text

Neural Activity in Primary Motor Cortex Related to Mechanical Loads Applied to the Shoulder and Elbow During a Postural Task

Journal of Neurophysiology ◽

10.1152/jn.2001.86.4.2102 ◽

2001 ◽

Vol 86 (4) ◽

pp. 2102-2108 ◽

Cited By ~ 57

Author(s):

D. William Cabel ◽

Paul Cisek ◽

Stephen H. Scott

Keyword(s):

Motor Cortex ◽

Neural Activity ◽

Primary Motor Cortex ◽

Cell Activity ◽

Motor Patterns ◽

Mechanical Loads ◽

Central Target ◽

Extensor Torque ◽

Vector Sum ◽

Joint Loads

Whole-arm motor tasks performed by nonhuman primates have become a popular paradigm to examine neural activity during motor action, but such studies have traditionally related cell discharge to hand-based variables. We have developed a new robotic device that allows the mechanics of the shoulder and elbow joints to be manipulated independently. This device was used in the present study to examine neural activity in primary motor cortex (MI) in monkeys ( macaca mulatta) actively maintaining their hand at a central target as they compensated for loads applied to the shoulder and/or elbow. Roughly equal numbers of neurons were sensitive to mechanical loads only at the shoulder, only at the elbow, or loads at both joints. Neurons possessed two important properties. First, cell activity during multi-joint loads could be predicted from its activity during single-joint loads as a vector sum in a space defined by orthogonal axes for the shoulder and elbow. Second, most neurons were related to flexor torque at one joint coupled with extensor torque at the other, a distribution that paralleled the observed activity of forelimb muscles. These results illustrate that while MI activity may be described by independent axes representing each mechanical degree-of-freedom, neural activity is also strongly influenced by the specific motor patterns used to perform a given task.

Download Full-text

Cutaneous Inputs Can Activate the Ipsilateral Primary Motor Cortex During Bimanual Sensory-Driven Movements in Humans

Journal of Neurophysiology ◽

10.1152/jn.00937.2003 ◽

2004 ◽

Vol 92 (6) ◽

pp. 3200-3209 ◽

Cited By ~ 7

Author(s):

Satoshi Shibuya ◽

Yukari Ohki

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Cortical Excitability ◽

Human Subjects ◽

Random Sequence ◽

Virtual Object ◽

Active Motor ◽

Finger Forces ◽

The Right ◽

Transient Force

Using transcranial magnetic stimulation (TMS), we examined whether sensory input from a finger affects activity of the ipsilateral primary motor cortex (M1) when human subjects hold a virtual object bimanually and whether this ipsilateral activation varies under different contexts. Subjects used both index fingers to hold two plates, which were subjected to unpredictable pulling loads from torque motors. Loads were delivered in a random sequence to either plate or concurrently to both, although the latter occurred most frequently. Finger forces vertical to the plates and surface electromyographs from the first dorsal interosseous muscles were recorded bilaterally during the task. TMS was sometimes applied over the finger area of the left M1 at variable times relative to load onset to examine cortical excitability. Strength of TMS was set around the active motor threshold of the right finger muscle while subjects waited for loading to the handheld plates. When one plate was singly loaded, the M1 contralateral to the loaded finger was activated, causing automatic force increases in the finger. In addition, the ipsilateral M1 was activated during such loading, associated with transient force increases in the contralateral nonloaded finger. Activations in the ipsilateral M1 were also observed during concurrent loading, when activations were stronger than those following single loading of the contralateral plate. Ipsilateral activations weakened when concurrent loading was less frequent. These results suggest interactions between bilateral sensorimotor cortices during bimanual coordinated movements, with strength varying by context.

Download Full-text

Single Cell Activity in the Auditory Cortex of Rhesus Monkeys: Behavioral Dependency

Science ◽

10.1126/science.177.4047.449 ◽

1972 ◽

Vol 177 (4047) ◽

pp. 449-451 ◽

Cited By ~ 81

Author(s):

J. M. Miller ◽

D. Sutton ◽

B. Pfingst ◽

A. Ryan ◽

R. Beaton ◽

...

Keyword(s):

Auditory Cortex ◽

Single Cell ◽

Rhesus Monkeys ◽

Cell Activity ◽

Single Cell Activity

Download Full-text

Greater Reduction in Contralesional Hand Use After Frontoparietal Than Frontal Motor Cortex Lesions in Macaca mulatta

Frontiers in Systems Neuroscience ◽

10.3389/fnsys.2021.592235 ◽

2021 ◽

Vol 15 ◽

Author(s):

Warren G. Darling ◽

Marc A. Pizzimenti ◽

Diane L. Rotella ◽

Jizhi Ge ◽

Kimberly S. Stilwell-Morecraft ◽

...

Keyword(s):

Motor Cortex ◽

Rhesus Monkeys ◽

Primary Motor Cortex ◽

Premotor Cortex ◽

Motor Task ◽

Fine Motor ◽

Motor Tasks ◽

Stroke Patients ◽

Anterior Portion ◽

Fine Motor Function

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 < 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.

Download Full-text

Neuronal activity in the primate premotor, supplementary, and precentral motor cortex during visually guided and internally determined sequential movements

Journal of Neurophysiology ◽

10.1152/jn.1991.66.3.705 ◽

1991 ◽

Vol 66 (3) ◽

pp. 705-718 ◽

Cited By ~ 423

Author(s):

H. Mushiake ◽

M. Inase ◽

J. Tanji

Keyword(s):

Motor Cortex ◽

Neuronal Activity ◽

Primary Motor Cortex ◽

Premotor Cortex ◽

Cell Activity ◽

Motor Task ◽

Delay Period ◽

Visual Signal ◽

Visually Guided ◽

Transitional Phase

1. Single-cell activity was recorded from three different motor areas in the cerebral cortex: the primary motor cortex (MI), supplementary motor area (SMA), and premotor cortex (PM). 2. Three monkeys (Macaca fuscata) were trained to perform a sequential motor task in two different conditions. In one condition (visually triggered task, VT), they reached to and touched three pads placed in a front panel by following lights illuminated individually from behind the pads. In the other condition (internally guided task, IT), they had to remember a predetermined sequence and press the three pads without visual guidance. In a transitional phase between the two conditions, the animals learned to memorize the correct sequence. Auditory instruction signals (tones of different frequencies) told the animal which mode it was in. After the instruction signals, the animals waited for a visual signal that triggered the first movement. 3. Neuronal activity was analyzed during three defined periods: delay period, premovement period, and movement period. Statistical comparisons were made to detect differences between the two behavioral modes with respect to the activity in each period. 4. Most, if not all, of MI neurons exhibited similar activity during the delay, premovement, and movement periods, regardless of whether the sequential motor task was visually guided or internally determined. 5. More than one-half of the SMA neurons were preferentially or exclusively active in relation to IT during both the premovement (55%) and movement (65%) periods. In contrast, PM neurons were more active (55% and 64% during the premovement and movement periods) in VT. 6. During the instructed-delay period, a majority of SMA neurons exhibited preferential or exclusive relation to IT whereas the activity in PM neurons was observed equally in different modes. 7. Two types of neurons exhibiting properties of special interest were observed. Sequence-specific neurons (active in a particular sequence only) were more common in SMA, whereas transition-specific neurons (active only at the transitional phase) were more common in PM. 8. Although a strict functional dichotomy is not acceptable, these observations support a hypothesis that the SMA is more related to IT, whereas PM is more involved in VT. 9. Some indications pointing to a functional subdivision of PM are obtained.

Download Full-text