Neural representations of the target (goal) of visually guided arm movements in three motor areas of the monkey

1990 ◽  
Vol 64 (1) ◽  
pp. 164-178 ◽  
Author(s):  
G. E. Alexander ◽  
M. D. Crutcher
Keyword(s):  
Primary Motor Cortex ◽  
Cell Activity ◽  
Motor Area ◽  
Visually Guided ◽  
Spatial Features ◽  
Tracking Tasks ◽  
Neural Representations ◽  
Preparatory Activity ◽  
Standard Task ◽  
The Right

1. This study was designed to determine whether the supplementary motor area (SMA), the primary motor cortex (MC), and the putamen, all of which are components of the basal ganglia-thalamocortical “motor circuit,” contain neural representations of the target or goal of a movement, independent of specific features of the movement itself. Four rhesus monkeys were trained to perform two visuomotor delayed step-tracking tasks in which the subject used a cursor to track targets on a display screen by making flexion and extension movements of the elbow. Single-cell activity was recorded from the SMA, MC, and putamen while the monkeys performed the two tasks. In the Standard task, the cursor and the forearm moved in the same direction. The Cursor/Limb Inversion task was identical to the Standard task except that there was an inverse relationship between the directions of movement of the forearm and cursor. Together, these tasks dissociated the spatial features of the target or goal of the movement from those of the movement itself. Both tasks also included features that made it possible to distinguish neuronal activity related to the preparation for movement from that related to movement execution. A total of 554 directionally selective, task-related neurons were tested with both tasks (SMA, 207; MC, 198; putamen, 149). 2. Two types of directionally selective preparatory activity were seen in each motor area. Cells with target-dependent preparatory activity showed selective discharge prior to all preplanned movements of the cursor toward one of the side targets (right or left), irrespective of whether the limb movement involved extension or flexion of the elbow. Comparable proportions of target-dependent preparatory cells were seen in the SMA (36%), MC (40%), and putamen (38%). Cells with limb-dependent preparatory activity showed selective discharge prior to all preplanned elbow movements in a particular direction (extension or flexion), irrespective of whether the target to which the cursor was moved was located on the right or left side of the display. The SMA contained a higher proportion of limb-dependent preparatory cells (40%) than either MC (15%) or putamen (9%). 3. Two types of directionally selective movement-related activity were also seen in each motor area.(ABSTRACT TRUNCATED AT 400 WORDS)

Preparation for movement: neural representations of intended direction in three motor areas of the monkey

1990 ◽  
Vol 64 (1) ◽  
pp. 133-150 ◽  
Author(s):  
G. E. Alexander ◽  
M. D. Crutcher
Keyword(s):  
Primary Motor Cortex ◽  
Discharge Rate ◽  
Cell Activity ◽  
Visually Guided ◽  
Constant Torque ◽  
Preparatory Set ◽  
Behavioral Paradigm ◽  
Torque Load ◽  
Preparatory Activity ◽  
Motor Areas

1. The purpose of this study was to compare the functional properties of neurons in three interrelated motor areas that have been implicated in the planning and execution of visually guided limb movements. All three structures, the supplementary motor area (SMA), primary motor cortex (MC), and the putamen, are components of the basal ganglia-thalamocortical “motor circuit.” The focus of this report is on neuronal activity related to the preparation for movement. 2. Five rhesus monkeys were trained to perform a visuomotor step-tracking task in which elbow movements were made both with and without prior instruction concerning the direction of the forthcoming movement. To dissociate the direction of preparatory set (and limb movement) from the task-related patterns of tonic (and phasic) muscular activation, some trials included the application of a constant torque load that either opposed or assisted the movements required by the behavioral paradigm. Single-cell activity was recorded from the arm regions of the SMA, MC, and putamen contralateral to the working arm. 3. A total of 741 task-related neurons were studied, including 222 within the SMA, 202 within MC, and 317 within the putamen. Each area contained substantial proportions of neurons that manifested preparatory activity, i.e., cells that showed task-related changes in discharge rate during the postinstruction (preparatory) interval. The SMA contained a larger proportion of such cells (55%) than did MC (37%) or the putamen (33%). The proportion of cells showing only preparatory activity was threefold greater in the SMA (32%) than in MC (11%). In all three areas, cells that showed only preparatory activity tended to be located more rostrally than cells with movement-related activity. Within the arm region of the SMA, the distribution of sites from which movements were evoked by microstimulation showed just the opposite tendency: i.e., microexcitable sites were largely confined to the caudal half of this region. 4. The majority of cells with task-related preparatory activity showed selective activation in anticipation of elbow movements in a particular direction (SMA, 86%; MC, 87%; putamen, 78%), and in most cases the preparatory activity was found to be independent of the loading conditions (80% in SMA, 83% in MC, and 84% in putamen).(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Cognitive control affects motor learning through local variations in GABA within the primary motor cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuki Maruyama ◽  
Masaki Fukunaga ◽  
Sho K. Sugawara ◽  
Yuki H. Hamano ◽  
Tetsuya Yamamoto ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Motor Cortex ◽  
Motor Learning ◽  
Cognitive Control ◽  
Primary Motor Cortex ◽  
Resonance Spectroscopy ◽  
Motor Sequence ◽  
Sensorimotor Network ◽  
Preparatory Activity ◽  
The Right

AbstractThe primary motor cortex (M1) is crucial for motor learning; however, its interaction with other brain areas during motor learning remains unclear. We hypothesized that the fronto-parietal execution network (FPN) provides learning-related information critical for the flexible cognitive control that is required for practice. We assessed network-level changes during sequential finger tapping learning under speed pressure by combining magnetic resonance spectroscopy and task and resting-state functional magnetic resonance imaging. There was a motor learning-related increase in preparatory activity in the fronto-parietal regions, including the right M1, overlapping the FPN and sensorimotor network (SMN). Learning-related increases in M1-seeded functional connectivity with the FPN, but not the SMN, were associated with decreased GABA/glutamate ratio in the M1, which were more prominent in the parietal than the frontal region. A decrease in the GABA/glutamate ratio in the right M1 was positively correlated with improvements in task performance (p = 0.042). Our findings indicate that motor learning driven by cognitive control is associated with local variations in the GABA/glutamate ratio in the M1 that reflects remote connectivity with the FPN, representing network-level motor sequence learning formations.

scholarly journals Sensorimotor Robotic Measures of tDCS- and HD-tDCS-Enhanced Motor Learning in Children

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Lauran Cole ◽  
Sean P. Dukelow ◽  
Adrianna Giuffre ◽  
Alberto Nettel-Aguirre ◽  
Megan J. Metzler ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Learning ◽  
Primary Motor Cortex ◽  
Medium Effect ◽  
Sensorimotor Function ◽  
Anodal Tdcs ◽  
Visually Guided ◽  
Direction Error ◽  
Visually Guided Reaching ◽  
The Right

Transcranial direct-current stimulation (tDCS) enhances motor learning in adults. We have demonstrated that anodal tDCS and high-definition (HD) tDCS of the motor cortex can enhance motor skill acquisition in children, but behavioral mechanisms remain unknown. Robotics can objectively quantify complex sensorimotor functions to better understand mechanisms of motor learning. We aimed to characterize changes in sensorimotor function induced by tDCS and HD-tDCS paired motor learning in children within an interventional trial. Healthy, right-handed children (12–18 y) were randomized to anodal tDCS, HD-tDCS, or sham targeting the right primary motor cortex during left-hand Purdue pegboard test (PPT) training over five consecutive days. A KINARM robotic protocol quantifying proprioception, kinesthesia, visually guided reaching, and an object hit task was completed at baseline, posttraining, and six weeks later. Effects of the treatment group and training on changes in sensorimotor parameters were explored. Twenty-four children (median 15.5 years, 52% female) completed all measures. Compared to sham, both tDCS and HD-tDCS demonstrated enhanced motor learning with medium effect sizes. At baseline, multiple KINARM measures correlated with PPT performance. Following training, visually guided reaching in all groups was faster and required less corrective movements in the trained arm (H(2) = 9.250,p=0.010). Aspects of kinesthesia including initial direction error improved across groups with sustained effects at follow-up (H(2) = 9.000,p=0.011). No changes with training or stimulation were observed for position sense. For the object hit task, the HD-tDCS group moved more quickly with the right hand compared to sham at posttraining (χ2(2) = 6.255,p=0.044). Robotics can quantify complex sensorimotor function within neuromodulator motor learning trials in children. Correlations with PPT performance suggest that KINARM metrics can assess motor learning effects. Understanding how tDCS and HD-tDCS enhance motor learning may be improved with robotic outcomes though specific mechanisms remain to be defined. Exploring mechanisms of neuromodulation may advance therapeutic approaches in children with cerebral palsy and other disabilities.

Functional reorganization oF the primary motor cortex in a patient with a large arteriovenous malFormation involving the precentral gyrus

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Milan Radoš ◽  
Ines Nikić ◽  
Marko Radoš ◽  
Ivica Kostović ◽  
Patrick Hof ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Right Hemisphere ◽  
Motor Area ◽  
Lower Limbs ◽  
Motor Deficits ◽  
Precentral Gyrus ◽  
Functional Reorganization ◽  
The Right ◽  
The Brain

AbstractIt is known that the brain can compensate for deficits induced by acquired and developmental lesions through functional reorganization of the remaining parenchyma. Arteriovenous malformations (AVM) usually appear prenatally before a functional regional organization of the brain is fully established and patients generally do not present with motor deficits even when the AVM is located in the primary motor area indicating the redistribution of functions in cortical areas that are not pathologically altered. Here we present reorganization of the motor cortex in a patient with a large AVM involving most of the left parietal lobe and the paramedian part of the left precentral gyrus that is responsible for controlling the muscles of the lower limbs. Functional MRI showed that movements of both the right and left feet activated only the primary motor cortex in the right hemisphere, while there was no activation in the left motor cortex. This suggests that complete ipsilateral control over the movements of the right foot had been established in this patient. A reconstruction of the corticospinal tract using diffusion tensor imaging showed a near-complete absence of corticospinal fibers from the part of the left precentral gyrus affected by the AVM. From this clinical presentation it can be concluded that full compensation of motor deficits had occurred by redistributing function to the corresponding motor area of the contralateral

Activation of the Dorsal Premotor Cortex and Pre-Supplementary Motor Area of Humans During an Auditory Conditional Motor Task

2000 ◽  
Vol 84 (3) ◽  
pp. 1667-1672 ◽  
Author(s):  
Kiyoshi Kurata ◽  
Toshiaki Tsuji ◽  
Satoshi Naraki ◽  
Morio Seino ◽  
Yoshinao Abe
Keyword(s):  
Resting State ◽  
Primary Motor Cortex ◽  
Supplementary Motor Area ◽  
Premotor Cortex ◽  
Motor Task ◽  
Motor Area ◽  
Dorsal Premotor Cortex ◽  
The Right ◽  
Opposition Movements ◽  
Motor Areas

Using functional magnetic resonance imaging (fMRI), we measured regional blood flow to examine which motor areas of the human cerebral cortex are preferentially involved in an auditory conditional motor behavior. As a conditional motor task, randomly selected 330 or 660 Hz tones were presented to the subjects every 1.0 s. The low and high tones indicated that the subjects should initiate three successive opposition movements by tapping together the right thumb and index finger or the right thumb and little finger, respectively. As a control task, the same subjects were asked to alternate the two opposition movements, in response to randomly selected tones that were presented at the same frequencies. Between the two tasks, MRI images were also scanned in the resting state while the tones were presented in the same way. Comparing the images during each of the two tasks with images during the resting state, it was observed that several frontal motor areas, including the primary motor cortex, dorsal premotor cortex (PMd), supplementary motor area (SMA), and pre-SMA, were activated. However, preferential activation during the conditional motor task was observed only in the PMd and pre-SMA of the subjects' left (contralateral) frontal cortex. The PMd has been thought to play an important role in transforming conditional as well as spatial visual cues into corresponding motor responses, but our results suggest that the PMd along with the pre-SMA are the sites where more general and extensive sensorimotor integration takes place.

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

1991 ◽  
Vol 66 (3) ◽  
pp. 705-718 ◽  
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.

Neuronal activity in cortical motor areas related to ipsilateral, contralateral, and bilateral digit movements of the monkey

1988 ◽  
Vol 60 (1) ◽  
pp. 325-343 ◽  
Author(s):  
J. Tanji ◽  
K. Okano ◽  
K. C. Sato
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Primary Motor Cortex ◽  
Cell Activity ◽  
Left Hand ◽  
Hand Muscles ◽  
Cortical Motor ◽  
Key Press ◽  
The Right ◽  
Induced Changes

1. Single cell activity was studied in the precentral (PCM), premotor (PM), and supplementary (SMA) motor cortex of the monkey to compare magnitudes of activity changes in relation to ipsilateral, contralateral, and bilateral digit movements. 2. Three Japanese monkeys were trained to press a small key with the right or left hand, or with both hands, in accordance with visual instruction signals given 2.6-5.4 s before a visual movement-trigger signal. Great care was taken to train the animal to use only the required part of the limb. As a result of extensive training, electromyographic (EMG) studies revealed that muscle activities before the key press were limited to the digit and hand muscles of the limb instructed to move. No overt increase or decrease in activity was detectable in the proximal limb or body muscles in relation to the key-press movements or instructions. 3. Even though the movement was thus limited to distal forelimb, distinct ipsilateral relationships were observed in 8.2% of the task-related PCM neurons. They changed their activity before ipsilateral and bilateral (but not before contralateral) key press. 4. A majority of the neurons recorded from the digit area of PCM (mostly limited to the anterior bank of the central sulcus) exhibited a contralateral relationship; namely the activity increased or decreased before the onset of the contralateral and bilateral key-press movements. In most of them, the magnitudes of the activity changes before the contralateral and bilateral movements were similar. 5. In proximal limb and trunk areas of PCM and also in the somatosensory cortex, no neurons were found to exhibit distinct relations to any of the key-press movements. 6. In both SMA and PM, a number of neurons exhibited relationships of the type never or only rarely observed in the primary motor cortex. Thirty-seven percent of SMA and 62% of PM neurons exhibited premovement activity changes before all of the key-press movements. The movement-specific type of activity was observed in 28% of SMA and 16% of PM neurons. In these neurons, the activity changes were observed in relation to only one of the right or left key-press movements or exclusively in relation to the bilateral key press. Neuronal activity resembling the majority of the PCM neurons (contralateral type) was observed in 31% of SMA and 13% of PM neurons. 7. Instruction-induced changes in activity were more often found in the secondary than in the primary motor area.(ABSTRACT TRUNCATED AT 400 WORDS)

A motor area rostral to the supplementary motor area (presupplementary motor area) in the monkey: neuronal activity during a learned motor task

1992 ◽  
Vol 68 (3) ◽  
pp. 653-662 ◽  
Author(s):  
Y. Matsuzaka ◽  
H. Aizawa ◽  
J. Tanji
Keyword(s):  
Primary Motor Cortex ◽  
Supplementary Motor Area ◽  
Cell Activity ◽  
Motor Task ◽  
Macaque Monkey ◽  
Motor Area ◽  
Caudal Part ◽  
Reaching Movement ◽  
Trigger Signal ◽  
Rostral Part

1. The rostromesial agranular frontal cortex of macaque monkey (Macaca fuscata), traditionally defined as the supplementary motor area (SMA), was studied using various physiological techniques to delineate two different areas rostrocaudally. 2. Field and unitary responses to electrical stimulation of the primary motor cortex were distinct in the caudal part, but minimal or absent in the rostral part. Intracortical microstimulation readily evoked limb or orofacial movements in the caudal part, but only infrequently in the rostral part. Neuronal responses to visual stimuli prevailed in the rostral part, but somatosensory responses were rare. The opposite was true in the caudal part. 3. The rostral part, roughly corresponding to area 6a beta, was operationally defined as the presupplementary motor area (pre-SMA). The caudal part was redefined as the SMA proper. 4. Single-cell activity in the pre-SMA was quantitatively compared with that in the SMA proper in relation to a trained motor task. 5. Phasic responses to visual cue signals indicating the direction of forthcoming arm-reaching movement were more abundant in the pre-SMA. 6. Activity changes during the preparatory period, which lasted until the occurrence of the trigger signal for the reaching movement, were more frequent in the pre-SMA. 7. Phasic, movement-related activity was more frequent in the SMA, and its onset was often time locked to the movement onset. In the pre-SMA, the occurrences of response time locked to the movement-trigger signal were more frequent than in the SMA. 8. Among neurons in both areas, directional selectivity was found in all the cue, preparatory, and movement-related responses.

scholarly journals Reduced Interhemispheric Coherence in Cerebellar Kainic Acid-Induced Lateralized Dystonia

2020 ◽  
Vol 11 ◽  
Author(s):  
Elena Laura Georgescu Margarint ◽  
Ioana Antoaneta Georgescu ◽  
Carmen Denise Mihaela Zahiu ◽  
Stefan-Alexandru Tirlea ◽  
Alexandru Rǎzvan Şteopoaie ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Kainic Acid ◽  
Primary Motor Cortex ◽  
Low Frequency ◽  
Muscular Activity ◽  
Cerebellar Hemisphere ◽  
Interhemispheric Coherence ◽  
General Locomotor Activity ◽  
Complex Circuits ◽  
The Right

The execution of voluntary muscular activity is controlled by the primary motor cortex, together with the cerebellum and basal ganglia. The synchronization of neural activity in the intracortical network is crucial for the regulation of movements. In certain motor diseases, such as dystonia, this synchrony can be altered in any node of the cerebello-cortical network. Questions remain about how the cerebellum influences the motor cortex and interhemispheric communication. This research aims to study the interhemispheric cortical communication between the motor cortices during dystonia, a neurological movement syndrome consisting of sustained or repetitive involuntary muscle contractions. We pharmacologically induced lateralized dystonia to adult male albino mice by administering low doses of kainic acid on the left cerebellar hemisphere. Using electrocorticography and electromyography, we investigated the power spectral densities, cortico-muscular, and interhemispheric coherence between the right and left motor cortices, before and during dystonia, for five consecutive days. Mice displayed lateralized abnormal motor signs, a reduced general locomotor activity, and a high score of dystonia. The results showed a progressive interhemispheric coherence decrease in low-frequency bands (delta, theta, beta) during the first 3 days. The cortico-muscular coherence of the affected side had a significant increase in gamma bands on days 3 and 4. In conclusion, lateralized cerebellar dysfunction during dystonia was associated with a loss of connectivity in the motor cortices, suggesting a possible cortical compensation to the initial disturbances induced by cerebellar left hemisphere kainate activation by blocking the propagation of abnormal oscillations to the healthy hemisphere. However, the cerebellum is part of several overly complex circuits, therefore other mechanisms can still be involved in this phenomenon.

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