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Motor Programs (motor + program)

Distribution by Scientific Domains

Medical Sciences	62%
Life Sciences	25%

Selected Abstracts

Planning of rapid aiming movements and the contingent negative variation: Are movement duration and extent specified independently?

PSYCHOPHYSIOLOGY, Issue 3 2009
Hartmut Leuthold
Abstract In the present study we investigated motor programming constraints implied by the Generalized Motor Program (GMP) view. A response precuing task was used in which participants performed aiming movements of either short or long duration to either a near or a far target position. Precues provided either no advance information or partial information about extent or duration or fully specified the aiming movement. Reaction time (RT) decreased and late Contingent Negative Variation (CNV) amplitude increased with the amount of advance information. In contrast to predictions of the GMP view, the extent precue led to faster responses and larger CNV amplitude than the duration precue. We conclude that late CNV amplitude reflects independent parameter specification processes at an abstract level at which GMP's motor programming constraints do not apply. [source]

Respiratory units of motor production and song imitation in the zebra finch

DEVELOPMENTAL NEUROBIOLOGY, Issue 2 2002
Michele Franz
Abstract Juvenile male zebra finches (Taeniopygia guttata) learn a stereotyped song by imitating sounds from adult male tutors. Their song is composed of a series of syllables, which are separated by silent periods. How acoustic units of song are translated into respiratory and syringeal motor gestures during the song learning process is not well understood. To learn about the respiratory contribution to the imitation process, we recorded air sac pressure in 38 male zebra finches and compared the acoustic structures and air sac pressure patterns of similar syllables qualitatively and quantitatively. Acoustic syllables correspond to expiratory pressure pulses and most often (74%) entire syllables are copied using similar air sac pressure patterns. Even notes placed within different syllables are generated with similar air sac pressure patterns when only segments of syllables are copied (9%). A few of the similar syllables (17%) are generated with a modified pressure pattern, typically involving addition or deletion of an inspiration. The high similarity of pressure patterns for like syllables indicates that generation of particular sounds is constrained to a narrow range of air sac pressure conditions. Following presentation of stroboscope flashes, song was typically interrupted at the end of an expiratory pressure pulse, confirming that expirations and, therefore, syllables are the smallest unit of motor production of song. Silent periods, which separate syllables acoustically, are generated by switching from expiration to inspiration. Switching between respiratory phases, therefore, appears to play a dominant role in organizing the stereotyped motor program for song production. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 129,141, 2002 [source]

Spontaneously changing muscular activation pattern in patients with cervical dystonia

MOVEMENT DISORDERS, Issue 6 2001
A. Münchau MD
Abstract The objective of this study was to determine stability of the neck muscle activation pattern in a given dystonic head position in patients with cervical dystonia (CD). We assessed 26 patients with CD and botulinum toxin (BT) treatment failure before surgical denervation. None of them had received BT injections for at least 4 months. To relate dystonic head position to underlying neck muscle activity, we used synchronised video and poly-electromyographic (EMG) recording over a period of 10 minutes. The muscle activation pattern during constant ("stable") maximal dystonic excursions was analysed. EMG data of nine patients was excluded from the analysis, as these patients had a constantly changing head position or marked head tremor. In the remaining 17 patients, who had a fairly stable dystonic position, muscular activation patterns during the recording spontaneously changed in nine (Group A) while in eight it remained stable (Group B). There was no significant difference in demographic variables between the two groups other than a male predominance in Group A. However, the retrospectively determined initial response to BT treatment (before BT treatment failure had occurred) was significantly worse in Group A as compared with Group B. Neck muscle activation patterns can spontaneously change in CD patients despite constant dystonic head position, implying an inherent variability of the underlying central motor program in some patients. This should be considered when BT treatment response is unsatisfactory, and should also be taken into account when interpreting results of EMG recordings of neck muscles in these patients. © 2001 Movement Disorder Society. [source]

Eastchester clapping sign: A novel test of parietal neglect,

ANNALS OF NEUROLOGY, Issue 1 2009
Lyle W. Ostrow MD
Hand clapping is a motor program mastered in infancy. Inspired by a question posed by an Eastchester High School AP Psychology class, we present a case series of 14 patients with hemispatial neglect who, when asked to clap, repeatedly performed one-handed motions stopping abruptly at the midline of the visual hemispace, as if pantomiming slapping an invisible board. In contrast, hemiplegic patients without neglect will reach across and clap against their plegic hands. This phenomenon provides an easy, rapid, and unambiguous test for neglect, applicable to patients of any ethnicity or age. Ann Neurol 2009;66:114,117 [source]

REVIEW ARTICLE: Cortical control of eye and head movements: integration of movements and percepts

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2007
L. Longtang Chen
Abstract The cortical control of eye movements is well known. It remains unclear, however, as to how the eye fields of the frontal lobes generate and coordinate eye and head movements. Here, we review the recent advances in electrical stimulation studies and evaluate relevant models. As electrical stimulation is conducted in head-unrestrained, behaving subjects with the evoked eye and head movements sometimes being indistinguishable from natural gaze shifts, a pertinent question becomes whether these movements are evoked by motor programs or sensory percepts. Recent stimulation studies in the visual cortex and the eye fields of the frontal lobes have begun to bring both possibilities to light. In addition, cognitive variables often interact with behavioral states that can affect movements evoked by stimulation. Identifying and controlling these variables are critical to our understanding of experimental results based on electrically evoked movements. This understanding is needed before one can draw inferences from such results to elucidate the neural mechanisms underlying natural and complex movements. [source]

Sensorimotor integration in movement disorders

MOVEMENT DISORDERS, Issue 3 2003
Giovanni Abbruzzese MD
Abstract Although current knowledge attributes movement disorders to a dysfunction of the basal ganglia,motor cortex circuits, abnormalities in the peripheral afferent inputs or in their central processing may interfere with motor program execution. We review the abnormalities of sensorimotor integration described in the various types of movement disorders. Several observations, including those of parkinsonian patients' excessive reliance on ongoing visual information during movement tasks, suggest that proprioception is defective in Parkinson's disease (PD). The disturbance of proprioceptive regulation, possibly related to the occurrence of abnormal muscle-stretch reflexes, might be important for generating hypometric or bradykinetic movements. Studies with somatosensory evoked potentials (SEPs), prepulse inhibition, and event-related potentials support the hypothesis of central abnormalities of sensorimotor integration in PD. In Huntington's disease (HD), changes in SEPs and long-latency stretch reflexes suggest that a defective gating of peripheral afferent input to the brain might impair sensorimotor integration in cortical motor areas, thus interfering with the processing of motor programs. Defective motor programming might contribute to some features of motor impairment in HD. Sensory symptoms are frequent in focal dystonia and sensory manipulation can modify the dystonic movements. In addition, specific sensory functions (kinaesthesia, spatial,temporal discrimination) can be impaired in patients with focal hand dystonia, thus leading to a "sensory overflow." Sensory input may be abnormal and trigger focal dystonia, or defective "gating" may cause an input,output mismatch in specific motor programs. Altogether, several observations strongly support the idea that sensorimotor integration is impaired in focal dystonia. Although elemental sensation is normal in patients with tics, tics can be associated with sensory phenomena. Some neurophysiological studies suggest that an altered "gating" mechanism also underlies the development of tics. This review underlines the importance of abnormal sensorimotor integration in the pathophysiology of movement disorders. Although the physiological mechanism remains unclear, the defect is of special clinical relevance in determining the development of focal dystonia. [source]

Somatosensory disinhibition in dystonia

MOVEMENT DISORDERS, Issue 4 2001
Emma Frasson MD
Abstract Despite the fact that somatosensory processing is inherently dependent on inhibitory functions, only excitatory aspects of the somatosensory feedback have so far been assessed in dystonic patients. We studied the recovery functions of spinal N13, brainstem P14, parietal N20, P27, and frontal N30 somatosensory evoked potentials (SEPs) after paired median nerve stimulation in 10 patients with dystonia and in 10 normal subjects. The recovery functions were assessed (conditioning stimulus: S1; test stimulus: S2) at interstimuls intervals (ISIs) of 5, 20, and 40 ms. SEPs evoked by S2 were calculated by subtracting the SEPs of the S1 only response from the SEPs of the response to the paired stimuli (S1 + S2), and their amplitudes were compared with those of the control response (S1) at each ISI considered. This ratio, (S2/S1)*100, investigates changes in the excitability of the somatosensory system. No significant difference was found in SEP amplitudes for single stimulus (S1) between dystonic patients and normal subjects. The (S2/S1)*100 ratio at the ISI of 5 ms did not significantly differ between dystonic patients and normal subjects, but at ISIs of 20 and 40 ms, this ratio was significantly higher in patients than in normals for spinal N13 and cortical N20, P27, N30 SEPs. These findings suggest that in dystonia there is an impaired inhibition at spinal and cortical levels of the somatosensory system which would lead to an abnormal sensory assistance to the ongoing motor programs, ultimately resulting in the motor abnormalities present in this disease. © 2001 Movement Disorder Society. [source]