Cerebellar ataxia and muscle spindle sensitivity

1993 ◽  
Vol 70 (5) ◽  
pp. 1853-1862 ◽  
Author(s):  
M. Gorassini ◽  
A. Prochazka ◽  
J. L. Taylor
Keyword(s):  
Muscle Spindle ◽  
Full Range ◽  
Motor Task ◽  
Movement Control ◽  
Cerebellar Nuclei ◽  
Reversible Inactivation ◽  
System 2 ◽  
Fusimotor System ◽  
Cerebellar Symptoms ◽  
Stretch Sensitivity

1. The cerebellum has long been known to participate in movement control. One of the enduring theories of cerebellar function is that it "tunes" and coordinates sensorimotor traffic in other parts of the CNS. In particular, it has been implicated in the control of the sensitivity of muscle spindle stretch receptors through the fusimotor system. 2. The stretch sensitivity of spindle primary endings can be varied approximately over a 10-fold range by fusimotor efferent action. For many years it has been believed that cerebellar dysfunction is associated with reduced drive to the fusimotor system and that this in turn causes hypotonia by reducing the reflex excitation of alpha-motoneurons by spindle afferents. 3. The data on which this hypothesis is based were obtained in anesthetized or decerebrate animals. Little direct information is available on animals or humans performing voluntary movements and exhibiting ataxia or other cerebellar symptoms. 4. We tested the hypothesis by recording from nine muscle spindle afferents in behaving cats before and during reversible inactivation of cerebellar interpositus and dentate nuclei. In normal cats fusimotor action varies with motor task, greatly altering spindle stretch sensitivity. We investigated whether this same range of task-related sensitivity manifested itself during ataxia. 5. We found that the full range of spindle sensitivity was still present during ataxia. We therefore conclude that the cerebellar nuclei studied are not primarily responsible for fusimotor control, nor is the ataxia primarily caused by disordered proprioceptive sensitivity.

Effects of cerebellar lesions on saccadic eye movements

1976 ◽  
Vol 39 (6) ◽  
pp. 1246-1256 ◽  
Author(s):  
L. Ritchie
Keyword(s):  
Eye Movements ◽  
Macaca Mulatta ◽  
Rhesus Monkeys ◽  
Saccadic Eye Movements ◽  
Motor Systems ◽  
Antagonist Muscle ◽  
Restoring Forces ◽  
System 2 ◽  
Cerebellar Lesions ◽  
Cerebellar Symptoms

1. Areas of cerebellar cortex related to saccadic eye movements were ablated in three Macaca mulatta monkeys trained to fixate visual targets. There followed a postoperative dysmetria of saccadic eye movements which appeared to be the result of an impairment specifically within the saccadic system. 2. Convergent evidence from two experimental paradigms indicated that the saccadic deficit was a function of the position of the eye in the orbit and did not involve retinal error processing. 3. The pattern of this position-dependent dysmetria suggests that the eye was no longer fully compensating for the elastic restoring forces imposed by the orbital medium and antagonist muscle(s). 4. The similarity of these data to saccadic eye movements of human cerebellar patients and arm movements of rhesus monkeys with cerebellar lesions indicates that the inability to compensate for the differential loads placed on motor systems by the mechanics of those systems may explain several cerebellar symptoms.

scholarly journals Dual contributions of cerebellar-thalamic networks to learning and offline consolidation of a complex motor task

2020 ◽  
Author(s):  
Andres P Varani ◽  
Romain W Sala ◽  
Caroline Mailhes-Hamon ◽  
Jimena L Frontera ◽  
Clément Léna ◽  
...  
Keyword(s):  
Motor Learning ◽  
Motor Task ◽  
Cerebellar Nuclei ◽  
Specific Inhibition ◽  
Thalamic Nuclei ◽  
Related Information ◽  
Midline Thalamus ◽  
Ventral Thalamus ◽  
Complex Motor ◽  
Offline Processing

SUMMARYThe contribution of cerebellum to motor learning is often considered to be limited to adaptation, a short-timescale tuning of reflexes and previous learned skills. Yet, the cerebellum is reciprocally connected to two main players of motor learning, the motor cortex and the basal ganglia, via the ventral and midline thalamus respectively. Here, we evaluated the contribution of cerebellar neurons projecting to these thalamic nuclei in a skilled locomotion task in mice. In the cerebellar nuclei, we found task-specific neuronal activities during the task, and lasting changes after the task suggesting an offline processing of task-related information. Using pathway-specific inhibition, we found that dentate neurons projecting to the midline thalamus contribute to learning and retrieval, while interposed neurons projecting to the ventral thalamus contribute to the offline consolidation of savings. Our results thus show that two parallel cerebello-thalamic pathways perform distinct computations operating on distinct timescales in motor learning.

Differences in spectral profiles between rostral and caudal premotor cortex when hand-eye actions are decoupled

2013 ◽  
Vol 110 (4) ◽  
pp. 952-963 ◽  
Author(s):  
Patricia F. Sayegh ◽  
Kara M. Hawkins ◽  
Kari L. Hoffman ◽  
Lauren E. Sergio
Keyword(s):  
Visual Stimulus ◽  
Rhesus Macaques ◽  
Premotor Cortex ◽  
Standard Condition ◽  
Motor Task ◽  
Movement Control ◽  
Oscillatory Activity ◽  
Visually Guided ◽  
Control Research ◽  
Spectral Profiles

The aim of this research was to understand how the brain controls voluntary movement when not directly interacting with the object of interest. In the present study, we examined the role of premotor cortex in this behavior. The goal of this study was to characterize the oscillatory activity within the caudal and rostral subdivisions of dorsal premotor cortex (PMdc and PMdr) with a change from the most basic reaching movement to one that involves a simple dissociation between the actions of the eyes and hand. We were specifically interested in how PMdr and PMdc respond when the eyes and hand are decoupled by moving along different spatial planes. We recorded single-unit activity and local field potentials within PMdr and PMdc from two rhesus macaques during performance of two types of visually guided reaches. During the standard condition, a visually guided reach was performed whereby the visual stimulus guiding the movement was the target of the reach itself. During the nonstandard condition, the visual stimulus provided information about the direction of the required movement but was not the target of the motor output. We observed distinct task-related and topographical differences between PMdr and PMdc. Our results support functional differences between PMdr and PMdc during visually guided reaching. PMdr activity appears more involved in integrating the rule-based aspects of a visually guided reach, whereas PMdc is more involved in the online updating of the decoupled reach. More broadly, our results highlight the necessity of accounting for the nonstandard nature of a motor task when interpreting movement control research data.

The effect of bilateral cold block of the primate face primary somatosensory cortex on the performance of trained tongue-protrusion task and biting tasks

1993 ◽  
Vol 70 (3) ◽  
pp. 985-996 ◽  
Author(s):  
L. D. Lin ◽  
G. M. Murray ◽  
B. J. Sessle
Keyword(s):  
Somatosensory Cortex ◽  
Primary Motor Cortex ◽  
Movement Control ◽  
Primary Somatosensory Cortex ◽  
Emg Activity ◽  
Success Rates ◽  
Tongue Protrusion ◽  
Reversible Inactivation ◽  
Control Series ◽  
Holding Period

1. Studies using ablation, intracortical microstimulation (ICMS) and surface stimulation, and single-neuron recordings have suggested that the primate primary somatosensory cortex (SI) may play an important role in movement control. Our aim was to determine whether bilateral inactivation of face SI would indeed interfere with the control of tongue or jaw-closing movements. 2. Effects of reversible inactivation by cooling of face SI was investigated in two monkeys trained to perform both a tongue-protrusion task and a biting task. The cooling experiments were carried out after the orofacial representation within SI was identified by systematically defining the mechanoreceptive field of single neurons recorded in face SI. The deficits in the tongue or jaw-closing movement were evaluated by the success rates for the monkeys' performance of both tasks and by the force and electromyographic (EMG) activity recorded from the masseter, genioglossus, and digastric muscles associated with the tasks. 3. During bilateral cooling of face SI, there was a statistically significant reduction in the success rates for the performance of the tongue-protrusion task in comparison with control series of trials while the thermodes used to cool face SI were kept at 37 degrees C. Detailed analyses of force and EMG activity showed that the principal deficit was the inability of the monkeys to maintain a steady tongue-protrusive force in the force holding period during each trial and to exert a consistent tongue-protrusion force between different trials. The task performance returned to control protocol levels at 4 min after commencement of rewarming. 4. Identical cooling conditions did not significantly affect the success rates for the performance of the biting task. Although the extent of the deficit was not severe enough to cause a significant reduction in successful rates for the biting task, cooling did significantly affect the ability of the monkeys to maintain a steady force in the holding period during each trial and to exert a consistent force between different trials. In one monkey the success rate of the biting task was also not affected by bilaterally cooling of face SI with a pair of larger thermodes placed on the dura over most of the face SI, face primary motor cortex (face MI), and adjacent cortical regions.(ABSTRACT TRUNCATED AT 400 WORDS)

Movement Control and Maturation in Elementary-Grade Children

1975 ◽  
Vol 41 (1) ◽  
pp. 151-154 ◽  
Author(s):  
Robert Kerr
Keyword(s):  
Significant Relationship ◽  
Movement Time ◽  
Motor Task ◽  
Movement Control ◽  
Arm Movement ◽  
Skeletal Age ◽  
Fine Motor ◽  
X Rays ◽  
Fitts Law ◽  
Elementary Grade

Serial tapping by 5-, 7- and 9-yr.-old boys and girls, as measured by Fitts' Law, was recorded. 60 Ss performed a reciprocal tapping task and were assessed developmentally via hand-wrist X-rays. No significant relationship was found between the fine motor task and skeletal age. The results of the motor task suggest an improvement in movement time, with age, due to an ability to plan subsequent movements rather than simply an increase in speed of arm movement.

Decoupling the actions of the eyes from the hand alters beta and gamma synchrony within SPL

2014 ◽  
Vol 111 (11) ◽  
pp. 2210-2221 ◽  
Author(s):  
Patricia F. Sayegh ◽  
Kara M. Hawkins ◽  
Bogdan Neagu ◽  
J. Douglas Crawford ◽  
Kari L. Hoffman ◽  
...  
Keyword(s):  
Local Field ◽  
Rhesus Macaques ◽  
Motor Task ◽  
Field Potential ◽  
Low Frequency ◽  
Movement Control ◽  
Reaching Movements ◽  
State Planning ◽  
Hand Orientation ◽  
Visuomotor Transformations

Eye-hand coordination is crucial for our ability to interact with the world around us. However, much of the visually guided reaches that we perform require a spatial decoupling between gaze direction and hand orientation. These complex decoupled reaching movements are in contrast to more standard eye and hand reaching movements in which the eyes and the hand are coupled. The superior parietal lobule (SPL) receives converging eye and hand signals; however, what is yet to be understood is how the activity within this region is modulated during decoupled eye and hand reaches. To address this, we recorded local field potentials within SPL from two rhesus macaques during coupled vs. decoupled eye and hand movements. Overall we observed a distinct separation in synchrony within the lower 10- to 20-Hz beta range from that in the higher 30- to 40-Hz gamma range. Specifically, within the early planning phase, beta synchrony dominated; however, the onset of this sustained beta oscillation occurred later during eye-hand decoupled vs. coupled reaches. As the task progressed, there was a switch to low-frequency and gamma-dominated responses, specifically for decoupled reaches. More importantly, we observed local field potential activity to be a stronger task (coupled vs. decoupled) and state (planning vs. execution) predictor than that of single units alone. Our results provide further insight into the computations of SPL for visuomotor transformations and highlight the necessity of accounting for the decoupled eye-hand nature of a motor task when interpreting movement control research data.

scholarly journals Effect of Reversible Inactivation of Superior Colliculus on Head Movements

2008 ◽  
Vol 99 (5) ◽  
pp. 2479-2495 ◽  
Author(s):  
Mark M. G. Walton ◽  
Bernard Bechara ◽  
Neeraj J. Gandhi
Keyword(s):  
Superior Colliculus ◽  
Reaction Times ◽  
Movement Control ◽  
Head Movements ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
Reversible Inactivation ◽  
The Gaze ◽  
Made In

Because of limitations in the oculomotor range, many gaze shifts must be accomplished using coordinated movements of the eyes and head. Stimulation and recording data have implicated the primate superior colliculus (SC) in the control of these gaze shifts. The precise role of this structure in head movement control, however, is not known. The present study uses reversible inactivation to gain insight into the role of this structure in the control of head movements, including those that accompany gaze shifts and those that occur in the absence of a change in gaze. Forty-five lidocaine injections were made in two monkeys that had been trained on a series of behavioral tasks that dissociate movements of the eyes and head. Reversible inactivation resulted in clear impairments in the animals’ ability to perform gaze shifts, manifested by increased reaction times, lower peak velocities, and increased durations. In contrast, comparable effects were not found for head movements (with or without gaze shifts) with the exception of a very small increase in reaction times of head movements associated with gaze shifts. Eye-head coordination was clearly affected by the injections with gaze onset occurring relatively later with respect to head onset. Following the injections, the head contributed slightly more to the gaze shift. These results suggest that head movements (with and without gaze shifts) can be controlled by pathways that do not involve SC.

scholarly journals Effects of Muscimol Inactivation of the Cerebellar Nuclei on Precision Grip

2004 ◽  
Vol 91 (3) ◽  
pp. 1240-1249 ◽  
Author(s):  
Joël Monzée ◽  
Trevor Drew ◽  
Allan M. Smith
Keyword(s):  
Grip Force ◽  
Dentate Nucleus ◽  
Precision Grip ◽  
Three Dimensional ◽  
Cerebellar Nuclei ◽  
Motor Deficits ◽  
Intention Tremor ◽  
Interpositus Nucleus ◽  
Reversible Inactivation ◽  
Cell Recording

A single monkey was trained to perform a grasp, lift, and hold task in which a stationary hand- held object was sometimes subjected to brief, predictable force-pulse perturbations. The displacement, grip, and lifting forces were measured as well the three-dimensional forces and torques to quantify specific motor deficits after reversible inactivation of the cerebellar nuclei. A prior single-cell recording study in the same monkey provided the stereotaxic coordinates used to guide intranuclear injections of muscimol. In total, 34 penetrations were performed at 28 different loci throughout the cerebellar nuclei. On each penetration, two 1.0-μl injections of 5 μg/μl muscimol, were made 1.0 mm apart either within the nuclei or in the white matter just lateral or posterior to the dentate nucleus. Injections in the region corresponding to the anterior interpositus nucleus produced pronounced dynamic tremor and dysmetric movements of the ipsilateral arm when the animal performed unrestrained reaching and grasping movements. In contrast, no relatively short-latency (15-20 min.) deficits were observed after injection in the dentate nucleus, although some effects were observed after several hours. When tested in a primate chair with the forearm supported and restrained at the wrist and elbow, the monkey performed the lift and hold task without tremor or dysmetria. However, with the restraint removed, the forces and torques applied to the manipulandum were poorly controlled and erratic. The monkey's arm was ataxic and a 5-Hz intention tremor was clearly visible. In addition, the animal was generally unable to compensate for the predictable perturbations and the anticipatory grip force increases were absent. However, overall the results suggest that reversible cerebellar nuclear inactivation with muscimol has little effect on isolated distal movements of the wrist and fingers.

Cerebellar Damage Impairs Automaticity of a Recently Practiced Movement

2002 ◽  
Vol 87 (3) ◽  
pp. 1336-1347 ◽  
Author(s):  
Catherine E. Lang ◽  
Amy J. Bastian
Keyword(s):  
Dual Task ◽  
Critical Role ◽  
Motor Task ◽  
Movement Control ◽  
Vigilance Task ◽  
Auditory Task ◽  
Cerebellar Damage ◽  
Movement Performance ◽  
Position Data ◽  
Dual Task Paradigm

It has been suggested that the cerebellum plays a critical role in learning to make movements more “automatic” (i.e., requiring less attention to the details of a movement). We hypothesized that cerebellar damage compromises learning of movement automaticity, resulting in increased attentional demands for movement control. The purpose of our study was to determine whether cerebellar damage disrupts the ability to make a practiced movement more automatic. We developed a dual task paradigm using two tasks that did not have overlapping sensory or motor requirements for execution. Our motor task required subjects to maintain an upright posture while performing a figure-8 movement using their arm. This motor task was chosen to simulate requirements of everyday movements (e.g., standing while reaching for objects), but it was novel enough to require practice for improvement. Our secondary task was an auditory vigilance task where subjects listened to letter sequences and were asked to identify the number of times a target letter was heard. We tested controls and people with cerebellar damage as they practiced the movement task alone and then performed it with the auditory task. We recorded 3D position data from the arm, trunk, and leg during the movement task. Errors were recorded for both the movement and the letter tasks. Our results show that cerebellar subjects can improve the movement to a very limited extent with practice. Unlike controls, the motor performance of cerebellar subjects deteriorates to prepractice levels when attention is focused away from the movement during dual task trials. Control subjects' insensitivity to dual task interference after practice was due to learned movement automaticity and was not a reflection of better dual task performance generally. Overall, our findings suggest that the cerebellum may be important for shifting movement performance from an attentionally demanding (unpracticed) state to a more automatic (practiced) state.

scholarly journals A neurocomputational model of the basal ganglia for the analysis of motor deficits after dopaminergic loss in Parkinson's disease

2021 ◽  
Author(s):  
Ilaria Gigi ◽  
Rosa Senatore ◽  
Angelo Marcelli
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Motor Learning ◽  
Early Stage ◽  
Motor Task ◽  
Movement Control ◽  
Neural System ◽  
Motor Deficits ◽  
Cortical Function

The basal ganglia (BG) are part of a basic feedback circuit, regulating cortical function, such as voluntary movement control, via their influence on thalamocortical projections. BG disorders, namely Parkinson's disease (PD), characterized by the loss of neurons in the substantia nigra (SN), involve the progressive loss of motor functions. The process that leads to these neural alterations is still unknown. At the present, PD cannot be cured, but an early diagnosis (ED) could allow to better manage its symptoms and evolution. A branch of neuroscience research is currently investigating the possibility of using motor alterations, e.g. handwriting, caused by the disease as diagnostic signs in the early stage of the disease, expression of small entity of SN lesion. In the present work, we propose a neurocomputational model to investigate the behaviour of the simulated neural system after several degrees of lesion, with the aim of evaluating, if possible, which is the smallest lesion compromising motor learning. The performance of the network in learning a novel motor task has been analyzed, in physiological and pathological conditions. The proposed neural network proves that there may exist abnormalities of motor learning process, due to alterations in the BG, which do not yet involve the presence of symptoms typical of the confirmed diagnosis, since the network shows having some difficulties in motor learning already with 20% DA depletion.

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