scholarly journals The Mechanisms of Movement Control and Time Estimation in Cervical Dystonia Patients

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Pavel Filip ◽  
Ovidiu V. Lungu ◽  
Daniel J. Shaw ◽  
Tomas Kasparek ◽  
Martin Bareš
Keyword(s):  
Basal Ganglia ◽  
Cervical Dystonia ◽  
Visual Information ◽  
Movement Control ◽  
Time Estimation ◽  
Neural Representation ◽  
Cerebellar Dysfunction ◽  
Millisecond Range ◽  
Representation Of Time

Traditionally, the pathophysiology of cervical dystonia has been regarded mainly in relation to neurochemical abnormities in the basal ganglia. Recently, however, substantial evidence has emerged for cerebellar involvement. While the absence of neurological “cerebellar signs” in most dystonia patients may be considered at least provoking, there are more subtle indications of cerebellar dysfunction in complex, demanding tasks. Specifically, given the role of the cerebellum in the neural representation of time, in the millisecond range, dysfunction to this structure is considered to be of greater importance than dysfunction of the basal ganglia. In the current study, we investigated the performance of cervical dystonia patients on a computer task known to engage the cerebellum, namely, the interception of a moving target with changing parameters (speed, acceleration, and angle) with a simple response (pushing a button). The cervical dystonia patients achieved significantly worse results than a sample of healthy controls. Our results suggest that the cervical dystonia patients are impaired at integrating incoming visual information with motor responses during the prediction of upcoming actions, an impairment we interpret as evidence of cerebellar dysfunction.

The Role of Online Visual Feedback for the Control of Target-Directed and Allocentric Hand Movements

2011 ◽  
Vol 105 (2) ◽  
pp. 846-859 ◽  
Author(s):  
Lore Thaler ◽  
Melvyn A. Goodale
Keyword(s):  
Visual Feedback ◽  
Visual Information ◽  
Sensory Feedback ◽  
Sensory Information ◽  
Movement Control ◽  
Sensorimotor Control ◽  
Hand Movements ◽  
Cast Doubt ◽  
Target Locations

Studies that have investigated how sensory feedback about the moving hand is used to control hand movements have relied on paradigms such as pointing or reaching that require subjects to acquire target locations. In the context of these target-directed tasks, it has been found repeatedly that the human sensory-motor system relies heavily on visual feedback to control the ongoing movement. This finding has been formalized within the framework of statistical optimality according to which different sources of sensory feedback are combined such as to minimize variance in sensory information during movement control. Importantly, however, many hand movements that people perform every day are not target-directed, but based on allocentric (object-centered) visual information. Examples of allocentric movements are gesture imitation, drawing, or copying. Here we tested if visual feedback about the moving hand is used in the same way to control target-directed and allocentric hand movements. The results show that visual feedback is used significantly more to reduce movement scatter in the target-directed as compared with the allocentric movement task. Furthermore, we found that differences in the use of visual feedback between target-directed and allocentric hand movements cannot be explained based on differences in uncertainty about the movement goal. We conclude that the role played by visual feedback for movement control is fundamentally different for target-directed and allocentric movements. The results suggest that current computational and neural models of sensorimotor control that are based entirely on data derived from target-directed paradigms have to be modified to accommodate performance in the allocentric tasks used in our experiments. As a consequence, the results cast doubt on the idea that models of sensorimotor control developed exclusively from data obtained in target-directed paradigms are also valid in the context of allocentric tasks, such as drawing, copying, or imitative gesturing, that characterize much of human behavior.

Proactive Interference and Intertrial Interval in Short-Term Retention of Temporal Visual Information

1986 ◽  
Vol 63 (2) ◽  
pp. 839-846 ◽  
Author(s):  
Michel Guay
Keyword(s):  
Proactive Interference ◽  
Visual Information ◽  
Short Term Memory ◽  
Time Estimation ◽  
Short Term ◽  
Term Memory ◽  
Term Retention ◽  
Retention Intervals ◽  
Variable Errors

The main purpose was to examine the role of proactive interference in temporal short-term memory when subjects experienced time under a conscious cognitive strategy for time estimation, made without time-aiding techniques. Visual durations of 1, 4, and 8 sec. were estimated by 18 subjects under the method of reproduction. Three retention intervals were used: immediate reproduction, 15, and 30 sec. of rest. The three intertrial intervals were immediate, 15, and 30 sec. Constant error was used as an index of bias. The constant errors provided no indication that proactive interference was operating in temporal short-term memory. The lack of proactive interference was not associated with intertrial intervals; even when the intertrial intervals were shortened to 1 sec. no proactive interference was observed. Variable error was used to evaluate effects of forgetting. The variable errors for the 4- and 8-sec. durations seemed amenable to a trace-decay explanation.

The role of the cerebellum and basal ganglia in time estimation - lessons from PET studies

NeuroImage ◽  
2001 ◽  
Vol 13 (6) ◽  
pp. 987
Author(s):  
Markus Jueptner ◽  
Michael Krukenberg ◽  
Bernhard Mueller ◽  
Walter Jentzen
Keyword(s):  
Basal Ganglia ◽  
Time Estimation

Two Strategies for Learning a Visually Guided Motor Task

1982 ◽  
Vol 55 (3) ◽  
pp. 1003-1016 ◽  
Author(s):  
B. L. Day ◽  
C. D. Marsden
Keyword(s):  
Visual Information ◽  
Tracking Error ◽  
Motor Task ◽  
Movement Control ◽  
Visually Guided ◽  
Tracking Tasks ◽  
The Mean ◽  
Target Move ◽  
Mean Reaction Time

The principal question asked is whether in a visually-guided motor task, a subject tracking a known target employs a different strategy of movement to that used when tracking an unknown target. 22 subjects performed a series of 150 visual tracking tasks each 5 sec. long. The target-move-ment patterns used for the first 50 trials were all different, but for the remaining 100 trials they were identical. Subjects, however, were not informed of the repetition until the final 50 trials. When the task was made repetitive, even though the subjects were unaware of the repetition, learning occurred as evidenced by a progressive reduction in tracking error, although tracking lag remained above the mean reaction-time. Once subjects were aware of the repetition, tracking lags often reached zero or even negative values and tracking error dropped even further. It is argued that the former learning is confined to subconscious improvement in the intermittent response to visual inspection of tracking error, whereas the latter is achieved by adopting a truly predictive mode of tracking. Further experiments were devised to evaluate the role of visual information in movement control when using the predictive strategy. The main finding was that even when moving predictively, visual information was used to regulate motor output, largely to modify the timing of the predictive response to synchronize with the stimulus.

scholarly journals Neural representation of time in cortico-basal ganglia circuits

2009 ◽  
Vol 106 (45) ◽  
pp. 19156-19161 ◽  
Author(s):  
Dezhe Z. Jin ◽  
Naotaka Fujii ◽  
Ann M. Graybiel
Keyword(s):  
Basal Ganglia ◽  
Neural Representation ◽  
Representation Of Time

scholarly journals Time, Memory, and the Legacy of Howard Eichenbaum

2018 ◽  
Author(s):  
Charan Ranganath
Keyword(s):  
Episodic Memory ◽  
Temporal Structure ◽  
Neural Representation ◽  
The Past ◽  
To Come ◽  
New Research ◽  
Situational Information ◽  
New Framework ◽  
Representation Of Time

Over the past 15 years, there has been an explosion of new research on the role of the hippocampus in representation of information about time in memory. Much of this work was inspired by the ideas and research of Howard Eichenbaum, who made major contributions to our understanding of the neurobiology of episodic memory and the neural representation of time. In this paper, I will review evidence regarding the role of time in understanding hippocampal function. This review will cover a broad range of evidence from studies of humans and nonhuman animals with a narrative arc that follows Howard’s major discoveries. These studies demonstrate that the hippocampus encodes information in relation to an episodic context, and that time, as well as space, serves to define these contexts. Moreover, the research has shown that the hippocampus can encode temporal, spatial, and situational information in parallel. Building on this work, I present a new framework for understanding temporal structure in human episodic memory. I conclude by outlining current controversies and new questions that must be addressed by the field in the years to come.

scholarly journals Role of Primate Cerebellar Hemisphere in Voluntary Eye Movement Control Revealed by Lesion Effects

2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Movement Control ◽  
Cerebellar Hemisphere ◽  
Target Velocity ◽  
Eye Movement Control ◽  
Pursuit Eye Movements ◽  
Catch Up

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.

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