Arm movements induced by electrical microstimulation in the superior colliculus of the macaque monkey (original) (raw)
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Arm Movements Evoked by Electrical Stimulation in the Motor Cortex of Monkeys
Journal of Neurophysiology, 2005
Electrical stimulation of the motor cortex in monkeys can evoke complex, multijoint movements including movements of the arm and hand. In this study, we examined these movements in detail and tested whether they showed adaptability to differing circumstances such as to a weight added to the hand. Electrical microstimulation was applied to motor cortex using pulse trains of 500-ms duration (matching the approximate duration of a reach). Arm movement was measured using a high-resolution three-dimensional tracking system. Movement latencies averaged 80.2 ms. Speed profiles were typically smooth and bell-shaped, and the peak speed covaried with movement distance. Stimulation generally evoked a specific final hand position. The convergence of the hand from disparate starting positions to a narrow range of final positions was statistically significant for every site tested (91/91). When a weight was fixed to the hand, for some stimulation sites (74%), the evoked movement appeared to compe...
Structural and functional definition of the motor cortex in the monkey (Macaca fascicularis)
The Journal of Physiology, 1982
1. The details of the organization of the motor cortex and its anterior and posterior border were investigated in three monkeys by a combination of techniques including intracortical microstimulation (i.c.m.s.), electrophysiological recording of cutaneous and muscle afferent inputs to single cortical neurones, and electrophysiological and anatomical identification of corticospinal neurones; in addition, data from these methods were related to cortical cytoarchitecture.2. Almost 5000 individual cortical loci were tested with i.c.m.s. in the unanaesthetized monkeys. In this paper, we particularly consider the organization of the forelimb motor representation, and its relation to the representation of other parts of the body. I.c.m.s. thresholds of about 5 μA were common for evoking twitch movements and e.m.g. responses in distal forelimb and face, jaw and tongue muscles, but proximal forelimb, trunk and hind‐limb movements also sometimes had such low thresholds.3. The fingers were fou...
An automatic experimental apparatus to study arm reaching in New World monkeys
Journal of Neuroscience Methods, 2016
Background: Several species of the New World monkeys have been used as experimental models in biomedical and neurophysiological research. However, a method for controlled arm reaching tasks has not been developed for these species. New Method: We have developed a fully automated, pneumatically driven, portable, and reconfigurable experimental apparatus for arm-reaching tasks suitable for these small primates. Results: We have utilized the apparatus to train two owl monkeys in a visually-cued arm-reaching task. Analysis of neural recordings demonstrates directional tuning of the M1 neurons. Comparison with Existing Method(s): Our apparatus allows automated control, freeing the experimenter from manual experiments. Conclusion: The presented apparatus provides a valuable tool for conducting neurophysiological research on New World monkeys.
1. The experiments were designed to investigate the effects of longitudinal muscle displacements on neurones of the motor cortex of anaesthetized Cebus monkeys and thus test the hypothesis that signals from muscle spindles may modify motor cortical output. The effects of sinusoidal stretching of the extensor digitorum communis (EDO) at frequencies varying from 6 to 300 Hz and of step and rhomboidal stretches were studied in neurones of the motor cortex. For comparison, neurones of the primary receiving area for low-threshold muscle afferents, cortical area 3a, were also included in this study. Neurones of the motor cortex were subdivided into corticospinal (PT) neurones and non-corticospinal (non-PT) neurones.
The Journal of Comparative Neurology, 1996
We used intracortical microstimulation to investigate the lateral premotor cortex and neighboring areas in 14 hemispheres of owl monkeys, focusing on the somatotopic distribution of evoked movements, thresholds for forelimb movements, and the relative representation of proximal and distal forelimb movements. We elicited movements from the dorsal and ventral premotor areas (PMD, PMV), the caudal and rostral divisions of primary motor cortex (M1c, M1r), the frontal eye field (FEF), the dorsal oculomotor area (OMD; area 8b), the supplementary motor area (SMA), and somatosensory cortex (areas 3a and 3b). Area PMD was composed of architectonically distinguishable caudal and rostral subdivisions (PMDc, PMDr). Stimulation of PMD elicited movements of the hindlimb, forelimb, neck and upper trunk, face, and eyes. Hindlimb and forelimb movements were represented in the caudalmost part of PMDc. Face, neck, and eye movements were represented in the lateral and rostral parts of PMDc and in PMDr. Stimulation of PMV elicited forelimb and orofacial movements, but not hindlimb movements. Both proximal and distal forelimb movements were elicited from PMDc and PMV, although PMD stimulation elicited mainly shoulder and elbow movements, while PMV stimulation evoked primarily wrist and digit movements. Distal movements were evoked more frequently from PMV than from M1r or M1c. Across cases, the median forelimb thresholds for PMDc and PMV were 60 and 36 microA, respectively, values that differ significantly from each other and from the value of 11 microA obtained for M1r. Our observations indicate that premotor cortex is much more responsive to electrical stimulation than commonly thought, and contains a large territory from which eye movements can be elicited. These results suggest that in humans, much of the electrically excitable cortex located on the precentral gyrus, including cortex sometimes considered part of the frontal eye field, is probably homologous to the premotor cortex of nonhuman primates.
Peripheral inputs and early unit activity in area 5 of the monkey during a trained forelimb movement
Brain Research, 1985
Previous studies on area 5 in the monkey showed that an early neuronal activity up to 300 ms before the onset of movement was encountered in this cortical area after deafferentation of the trained forelimb (C1-T7). This present work indicates that none of the EMG activity recorded in other parts of the body may account for these early changes and lends weight to the hypothesis that their activation is purely central.
Behavioural brain research, 2002
Reaching and grasping has been widely studied in both macaques and humans, mainly with the aim of finding similar patterns of behavior in the two species. Little attention has yet been given to how morphological and behavioral differences between the two species might affect the kinematics of the movement. In this study, we present a careful analysis of the similarities and differences between humans’ and macaques’ prehension movements and discuss these with respect to both the control system and the biomechanics of the arm. Five humans and five macaques performed the same task, namely grasping small feeding objects using a precision grip. Macaques were observed in unconstrained conditions, free to adjust their body posture. The behavioral protocol for macaques revealed a postural preference for sitting and keeping the elbow slightly flexed when applying a precision grip. In agreement with the literature, kinematics revealed general features of movement common to both humans and macaques. However, within a similar timeframe, macaques produced steeper and wider excursion of the elbow and of the wrist, smaller abduction of the shoulder joint and larger displacement of the torso than humans did. The three-joint limb revealed stronger irregularities for the macaques. We hypothesize that the larger kinematic irregularities and the specific elbow–shoulder posture in macaques result in part from an effort of the control system to compensate for different biomechanical constraints, namely for limited shoulder-joint excursion, in order to achieve a similar range of comfort of motion. Finally, we briefly consider the influence of primitive neural circuits responsible for arm motion during locomotion and speculated on their influence on the control of reaching in macaques. © 2002 Elsevier Science B.V. All rights reserved.
The Journal of Comparative Neurology, 2000
In the present study, somatotopic organization, architectonic features, and patterns of connections were used to define motor areas in the frontal and cingulate cortex of the prosimian primate Galago garnetti. Sites throughout portions of the motor cortex were electrically stimulated with microelectrodes at the approximate depth of layer V. In some of the same animals, injections in primary motor cortex (M1), and in the spinal cord, revealed patterns of connections with physiologically identified motor areas. Results were related to cortical architecture in brain sections processed for Nissl, myelin, cytochrome oxidase, acetylcholinesterase, or neurofilaments. Evidence was obtained for a number of fields previously identified in simian primates, including M1, dorsal premotor field with caudal (PMDc) and rostral (PMDr) divisions, ventral premotor area (PMV), supplementary motor area (SMA), presupplementary motor area (pre-SMA), frontal eye field (FEF), and cingulate motor areas, CMAr and CMAc located rostrally and caudally, respectively. In addition, we distinguished area 6Ds of Preuss and Goldman-Rakic (1991a) between PMV and PMDc, and a more posterior cingulate sensorimotor area (CSMA) with motor connections that may correspond to the supplementary sensory area of monkeys. Areas M1, SMA, PMDc, PMV, CMAr, CMAc, and CSMA projected to the spinal cord, while all of these areas and 6Ds projected to M1. Although area M1 had the lowest stimulation thresholds for evoked movements, movements were also evoked from the other motor areas, as well as from somatosensory areas 3a and 3b. These results indicate that prosimian galagos have a complex of motor areas that closely resembles that in monkeys and suggest that at least 10 motor fields emerged early in primate evolution.