Reduced Timing Variability in Patients with Unilateral Cerebellar Lesions during Bimanual Movements

1996 ◽  
Vol 8 (2) ◽  
pp. 107-118 ◽  
Author(s):  
E. A. Franz ◽  
R. B. Ivry ◽  
L. L. Helmuth
Keyword(s):  
Process Model ◽  
Ipsilateral Side ◽  
Bimanual Movements ◽  
Timing Variability ◽  
Temporal Aspects ◽  
Coupling Constraints ◽  
Temporal Coupling ◽  
Cerebellar Lesions ◽  
Bimanual Tapping

Timing variability on a repetitive tapping task was studied in subjects with unilateral cerebellar lesions. During unimanual tapping, within-hand variability was larger when tapping with the ipsilesional hand in comparison to tapping with the contralesional hand. However, variability in the impaired hand was greatly reduced when subjects tapped with two hands together. The improvement in within-hand variability during bimanual tapping was associated with a reduction in central variability rather than response implementation variability according to the two-process model of Wing and Kristofferson (1973). It is proposed that (1) each half of the cerebellum independently regulates the temporal aspects of movements on the ipsilateral side and (2) temporal coupling constraints require these separate signals to be integrated prior to response implementation for bimanual movements.

Dissociation of Spatial and Temporal Coupling in the Bimanual Movements of Callosotomy Patients

1996 ◽  
Vol 7 (5) ◽  
pp. 306-310 ◽  
Author(s):  
Elizabeth A. Franz ◽  
James C. Eliassen ◽  
Richard B. Ivry ◽  
Michael S. Gazzaniga
Keyword(s):  
Corpus Callosum ◽  
Execution Time ◽  
Normal Subjects ◽  
Neural Mechanisms ◽  
Movement Onset ◽  
Temporal Synchrony ◽  
Bimanual Movements ◽  
Limb Coordination ◽  
Temporal Coupling ◽  
Spatial Interference

The neural mechanisms of limb coordination were investigated by testing callosotomy patients and normal control subjects on bimanual movements Normal subjects produced deviations in the trajectories when spatial demands for the two hands were different, despite temporal synchrony in the onset of bimanual movements Callosotomy patients did not produce spatial deviations, although their hands moved with normal temporal synchrony Normal subjects but not callosotomy patients exhibited large increases in planning and execution time for movements with different spatial demands for the two hands relative to movements with identical spatial demands for the two hands This neural dissociation indicates that spatial interference in movements results from callosal connections, whereas temporal synchrony in movement onset does not rely on the corpus callosum

Reduced Timing Variability during Bimanual Coupling: A Role for Sensory Information

2003 ◽  
Vol 56 (2) ◽  
pp. 329-350 ◽  
Author(s):  
Knut Drewing ◽  
Gisa Aschersleben
Keyword(s):  
Auditory Feedback ◽  
Sensory Information ◽  
Left Hand ◽  
Timing Variability ◽  
Bimanual Coupling ◽  
Hand Tapping ◽  
Bimanual Tapping ◽  
Action Timing ◽  
Action Goals

On a repetitive tapping task, the within-hand variability of intertap intervals is reduced when participants tap with two hands as compared to one-hand tapping. Because this bimanual advantage can be attributed to timer variance (Wing—Kristofferson model, 1973a, b), separate timers have been proposed for each hand, whose outputs are then averaged (Helmuth & Ivry, 1996). An alternative notion is that action timing is based on its sensory reafferences (Aschersleben & Prinz, 1995; Prinz, 1990). The bimanual advantage is then due to increased sensory reafference. We studied bimanual tapping with the continuation paradigm. Participants first synchronized their taps with a metronome and then continued without the pacing signal. Experiment 1 replicated the bimanual advantage. Experiment 2 examined the influence of additional sensory reafferences. Results showed a reduction of timer variance for both uni- and bimanual tapping when auditory feedback was added to each tap. Experiment 3 showed that the bimanual advantage decreased when auditory feedback was removed from taps with the left hand. Results indicate that the sensory reafferences of both hands are used and integrated into timing. This is consistent with the assumption that the bimanual advantage is at least partly due to the increase in sensory reafference. A reformulation of the Wing—Kristofferson model is proposed to explain these results, in which the timer provides action goals in terms of sensory reafferences.

Caloric and Optokinetic Nystagmus in Cerebellar Patients

1976 ◽  
Vol 85 (1) ◽  
pp. 136-138 ◽  
Author(s):  
Malcolm H. Stroud ◽  
Erol Rauchbach
Keyword(s):  
Opposite Direction ◽  
Optokinetic Nystagmus ◽  
Dominant Role ◽  
Fast Component ◽  
Vestibular Nystagmus ◽  
Ipsilateral Side ◽  
Far Lateral ◽  
Cerebellar Lesions ◽  
Straight Ahead

In certain cerebellar lesions, optokinetic tracking is deficient, especially on tracking or following to the ipsilateral side. However, in many cases optokinetic nystagmus can occur, and apparently in better degree than would be expected from a study of pendulum tracking. This may be due to the patient leading into the stimulus and picking it up as soon as it is presented in far lateral gaze (in the direction of the fast component) and allowing the drift caused by the tone deficit to assist the tracking. An added vestibular tone can eliminate such a pseudo reflex. Induced vestibular nystagmus is enhanced and assumes a more dominant role so that optokinetic nystagmus is overcome, not only on gaze to the side of the tracking, but also on straight ahead gaze and even on some deviation of the eyes in the opposite direction.

Cerebellar Involvement in Anticipating the Consequences of Self-Produced Actions During Bimanual Movements

2005 ◽  
Vol 93 (2) ◽  
pp. 801-812 ◽  
Author(s):  
Jörn Diedrichsen ◽  
Timothy Verstynen ◽  
Steven L. Lehman ◽  
Richard B. Ivry
Keyword(s):  
Short Term ◽  
Bimanual Movements ◽  
Cerebellar Damage ◽  
Bimanual Actions ◽  
Learned Behaviors ◽  
Short Term Adaptation ◽  
Cerebellar Lesions ◽  
Cerebellar Involvement ◽  
Healthy Participants ◽  
Bimanual Unloading

Anticipatory postural adjustments (APA) during bimanual actions can be observed when participants hold an object in one hand and then lift it with the other hand. The postural force used to hold the object is reduced in anticipation of unloading, indicating an accurate prediction of the change in load. We examined patients with unilateral or bilateral cerebellar damage as well as two individuals lacking the corpus callosum on the bimanual unloading task. The acallosal patients showed an intact APA, suggesting subcortical integration of motor signals for anticipatory adjustments during bimanual actions. Contrary to the hypothesis that the cerebellum is critical for predicting and compensating for the consequences of our actions, we found that the well-learned APA in this task was largely intact in cerebellar patients. However, cerebellar damage abolished short-term adaptation of the APA, and the patients were unable to acquire an APA in a similar but previously untrained situation. These results indicate that while over-learned anticipatory adjustments are preserved after cerebellar lesions, adaptation of this response and the acquisition of a novel coordination requires the cerebellum ipsilateral to the postural hand. Furthermore, this structure appears to be essential for the accurate timing of previously learned behaviors. The patients with cerebellar damage showed poorly timed adjustments with the APA beginning earlier than in healthy participants.

Visual Suppression of Vestibular Nystagmus after Cerebellar Lesions

1975 ◽  
Vol 84 (3) ◽  
pp. 318-326 ◽  
Author(s):  
Setsuko Takemori
Keyword(s):  
Visual System ◽  
Cerebellar Cortex ◽  
Dentate Nucleus ◽  
Complete Loss ◽  
Vestibular Nystagmus ◽  
Short Term ◽  
Vestibular Reflexes ◽  
Ipsilateral Side ◽  
Visual Suppression ◽  
Cerebellar Lesions

Visual suppression of calorically induced vestibular nystagmus was observed following discrete lesions of various structures in the cerebellum. Unilateral lesions of the flocculus resulted in a complete loss or a significant reduction in visual suppression when the quick phase of the nystagmus was directed to the ipsilateral side of the lesions, and bilateral flocculus lesions caused a bilateral loss of suppression. Nodulus lesions resulted in a loss of suppression, and this loss tended to recover in time. Lesions of the dentate nucleus resulted in a very short term loss of suppression. Extirpation or lesions of the uvula, vermis, para-flocculus, cerebellar cortex, or the fastigial or interpositus nuclei had no observed effect on the visual suppression of vestibular nystagmus. The results of this study suggest that the flocculus and nodulus function as intermediators through which the visual system can modify or alter vestibular reflexes. Also, this phenomenon, that is, loss of visual suppression after the flocculus and nodulus lesion, is very useful to diagnose the localized lesion in the cerebellum.

Temporal Coordination during Bimanual Reach-to-Grasp Movements: The Role of Vision

2009 ◽  
Vol 62 (7) ◽  
pp. 1328-1342 ◽  
Author(s):  
Jennifer L. Bruyn ◽  
Andrea H. Mason
Keyword(s):  
Visual Attention ◽  
Visual Feedback ◽  
Visual Information ◽  
Reach To Grasp ◽  
Temporal Coordination ◽  
Bimanual Movements ◽  
Bimanual Task ◽  
Temporal Aspects ◽  
Precision Grasping

The performance of bimanual movements involving separate objects presents an obvious challenge to the visuo-motor system: Visual feedback can only be obtained from one target at a time. To overcome this challenge overt shifts in visual attention may occur so that visual feedback from both movements may be used directly (Bingham, Hughes, & Mon-Williams, 2008; Riek, Tresilian, Mon-Williams, Coppard, & Carson, 2003). Alternatively, visual feedback from both movements may be obtained in the absence of eye movements, presumably by covert shifts in attention (Diedrichsen, Nambisan, Kennerley, & Ivry, 2004). Given that the quality of information falls with increasing distance from the fixated point, can we obtain the level of information required to accurately guide each hand for precision grasping of separate objects without moving our eyes to fixate each target separately? The purpose of the current study was to examine how the temporal coordination between the upper limbs is affected by the quality of visual information available during the performance of a bimanual task. A total of 11 participants performed congruent and incongruent movements towards near and/or far objects. Movements were performed in natural, fixate-centre, fixate-left, and fixate-right vision conditions. Analyses revealed that the transport phase of incongruent movements was similar across vision conditions for the temporal aspects of both the transport and grasp, whereas the spatial aspects of grasp formation were influenced by the quality of visual feedback. We suggest that bimanual coordination of the temporal aspects of reach-to-grasp movements are not influenced solely by overt shifts in visual attention but instead are influenced by a combination of factors in a task-constrained way.

Intercerebellar Coupling Contributes to Bimanual Coordination

2007 ◽  
Vol 19 (4) ◽  
pp. 704-719 ◽  
Author(s):  
Bettina Pollok ◽  
Markus Butz ◽  
Joachim Gross ◽  
Alfons Schnitzler
Keyword(s):  
Dynamic Imaging ◽  
Behavioral Changes ◽  
Functional Coupling ◽  
Analysis Tool ◽  
Task Execution ◽  
Bimanual Movements ◽  
Tomographic Map ◽  
Surface Electromyograms ◽  
Bimanual Tapping ◽  
Shed Light

Compared to unimanual task execution, simultaneous bimanual tapping tasks are associated with a significantly reduced intertap variability. It has been suggested that this bimanual advantage is based on the integration of timing signals which otherwise control each hand independently. Although its functional and anatomic foundations are poorly understood, functional coupling between cerebellar hemispheres might be behind this process. Because the execution of fast alternating fingertaps increases intertap variability, it is hypothesized that intercerebellar coupling is reduced in such tasks. To shed light on the functional significance of intercerebellar coupling, 14 right-handed subjects performed unimanual right, bimanual simultaneous, and bimanual alternating synchronization tasks with respect to a regular auditory pacing signal. In all conditions, within-hand intertap interval was 500 msec. Continuous neuromagnetic activity, using a 122-channel wholehead neuromagnetometer and surface electromyograms of the first dorsal interosseus muscle of both hands, were recorded. For data analysis, we used the analysis tool Dynamic Imaging of Coherent Sources, which provides a tomographic map of cerebromuscular and cerebrocerebral coherence. Analysis revealed a bilateral cerebello-thalamo-cortical network oscillating at alpha (8–12 Hz) and beta (13–24 Hz) frequencies associated with bimanual synchronization. In line with our hypothesis, coupling between cerebellar hemispheres was restricted to simultaneous task execution. This result implies that intercerebellar coupling is key for the execution of simultaneous bimanual movements. Although the criticality of a specific magneto-encephalography pattern for behavioral changes should be interpreted with caution, data suggest that intercerebellar coupling possibly represents the functional foundation of the bimanual advantage.

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