Self-generated rapid taps directed to the opposite forearm in man: anticipatory reduction in the muscle activity of the target arm

Strüppler, A.; Gerilovsky, L; Jakob, C.

doi:10.1016/0304-3940(93)90812-y

Cited by 23 publications

(6 citation statements)

References 6 publications

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“…APAs were arguably one of the first examples of predictive control (Belen'kii et al 1967) when a voluntary action is performed on the background of a postural task. Further, similar adjustments have been reported for tasks involving postural components limited to a limb in tasks that did not involve standing (Dufosse et al, 1985; Struppler et al, 1993). …”

Section: Discussionsupporting

confidence: 76%

Early postural adjustments in preparation to whole-body voluntary sway

Klous

Mikulić

Latash

2012

Journal of Electromyography and Kinesiology

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We studied postural adjustments associated with a quick voluntary postural sway under two conditions, self-paced and simple reaction-time. Standing subjects were required to produce quick discrete shifts of the center of pressure (COP) forward. About 400–500 ms prior to the instructed COP shift, there were deviations of the COP in the opposite direction (backwards) accompanied by changes in the activation levels of several postural muscles. Under the reaction-time conditions, the timing of those early postural adjustments did not change (repeated measures MANOVA: p>0.05) while its magnitude increased significantly (confirmed by repeated measures MANOVA: p<0.05). These observations are opposite to those reported for anticipatory postural adjustments under simple reaction time conditions (a significant change in the timing without major changes in the magnitude). We conclude that there are two types of feed-forward postural adjustments. Early postural adjustments prepare the body for the planned action and/or expected perturbation. Some of these preparatory actions may be mechanically necessary. Later, anticipatory postural adjustments generate net forces and moments of force acting against those associated with the expected perturbation. Both types of adjustments fit well the referent configuration hypothesis, which offers a unified view on movement-posture control.

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Section: Discussionsupporting

confidence: 76%

Early postural adjustments in preparation to whole-body voluntary sway

Klous

Mikulić

Latash

2012

Journal of Electromyography and Kinesiology

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“…Recently, some studies have suggested that it is not sufficient to have a predictable postural perturbation for the CNS to be able to generate anticipatory postural adjustments. 34 36 In particular, if a perturbation coincides in time with a metronome or even if it is triggered by the subject by pressing a button, no anticipatory postural adjustments occur. To get these reactions, a major action by a large muscle group, including proximal muscles, is required.…”

Section: Anticipatory Adjustments During Loadings and Unloadingsmentioning

confidence: 99%

Anticipatory postural adjustments during self inflicted and predictable perturbations in Parkinson's disease.

Latash

Aruin

Neyman

et al. 1995

Journal of Neurology, Neurosurgery & Psychiatry

159

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This study investigated the relation between impaired anticipatory postural adjustments and bradykinesia in Parkinson's disease. Patients with Parkinson's disease and age matched controls stood on a platform. In one series of experiments, they performed fast, discrete shoulder flexion or extension movements. In another series, they were required to press a trigger with the right thumb and thus to release a load that was suspended from a bar which they were holding in front of them in extended arms. One more series included catching a load on the same bar. Anticipatory changes in the activity of postural muscles before fast voluntary movements occurred in patients and controls although the patients showed higher variability of anticipatory patterns. During load dropping and catching, control subjects had reproducible, although smaller, anticipatory changes in postural muscle activity. Such changes were absent in all but one patient. Two sources of these postural perturbations were analysed. The anticipatory postural adjustments in different muscle groups may counteract perturbations of different origin. The distal to proximal sequencing of joint involvement in postural reactions may be related to different reference points and working points associated with these tasks compared with reaching limb movements. The deficit in anticipatory postural adjustments in Parkinson's disease is likely to be unrelated to bradykinesia and is more likely to reflect the deficits in the basic processes of preparation and initiation of a motor act. (J Neurol Neurosurg Psychiatry 1995;58:326-334)

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“…In particular, no APAs were seen when the subjects watched the experimenter triggering the unloading of a known load held by the subject while self-initiated unloading of the same load induced APAs [4]. Similarly, it was reported that no APAs were seen when an experimenter delivered a perturbation at the wrist synchronized with a metronome [24]. However, in experiments when subjects were asked to catch different loads released from different heights by an experimenter, APAs have been seen prior to the load impact in the arm muscles [17,22] and in the trunk and leg muscles [8,18,22].…”

Section: Introductionmentioning

confidence: 96%