Preparedness for landing after a self-initiated fall

Castellote, Juan M.; Queralt, Ana; Valls‐Solé, Josep

doi:10.1152/jn.01111.2011

Cited by 9 publications

(7 citation statements)

References 49 publications

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“…Previous reports have addressed StartReact effects only with high-intensity stimuli, and have sought startle signs mainly in either proximal or distal upper limb muscles, while only few reports have explored both proximal and distal muscles simultaneously [ 19 , 39 , 47 , 62 ]. By means of simple tasks, just flexing the elbow (FLEX) or pinching a pen (PINCH), differences in the StartReact effect across intensities became apparent between proximal and distal muscles.…”

Section: Discussionmentioning

confidence: 99%

“…In RT paradigms it may not only elicit a startle reaction, but also accelerate the onset of the prepared task, the so-called StartReact effect [ 8 , 9 ]. Auditory stimuli comprise the modality most extensively studied in the field of startle reactions [ 10 , 11 , 12 , 13 ] and of the StartReact effect [ 8 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. The auditory domain has also been used to disentangle the underlying mechanisms of accelerated voluntary motor responses ascribed either to a high-intensity stimuli alone, or to an additional StartReact effect [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…Studies of RT have long been used to test the functional integrity of the nervous system [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Discovery of the StartReact effect has allowed for exploring and characterizing different movement patterns prepared by the brain that we use in daily life, such as gait [ 35 , 36 , 37 ], sit to stand [ 38 ], interception of objects [ 39 ], avoidance of obstacles [ 40 ], preparation to stop a fall [ 19 ], or accurate movements [ 41 ], to cite some. The often remarkable acceleration of response latencies by the StartReact effect has opened a debate about which part of the central nervous system may trigger the prepared voluntary responses.…”

Section: Introductionmentioning

confidence: 99%

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StartReact effects in first dorsal interosseous muscle are absent in a pinch task, but present when combined with elbow flexion

Castellote

Kofler²

2018

PLoS ONE

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ObjectiveTo provide a neurophysiological tool for assessing sensorimotor pathways, which may differ for those involving distal muscles in simple tasks from those involving distal muscles in a kinetic chain task, or proximal muscles in both.MethodsWe compared latencies and magnitudes of motor responses in a reaction time paradigm in a proximal (biceps brachii, BB) and a distal (first dorsal interosseous, FDI) muscle following electrical stimuli used as imperative signal (IS) delivered to the index finger. These stimuli were applied during different motor tasks: simple tasks involving either one muscle, e.g. flexing the elbow for BB (FLEX), or pinching a pen for FDI (PINCH); combined tasks engaging both muscles by pinching and flexing simultaneously (PINCH-FLEX). Stimuli were of varying intensity and occasionally elicited a startle response, and a StartReact effect.ResultsIn BB, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities for non-startling trials, while for trials containing startle responses, latencies were uniformly shortened and response amplitudes similarly augmented across all IS intensities in both FLEX and PINCH-FLEX. In FDI, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities in both PINCH and PINCH-FLEX for non-startling trials, but, unlike in BB for the simple task, in PINCH for trials containing startle responses as well. In PINCH-FLEX, FDI latencies were uniformly shortened and amplitudes similarly increased across all stimulus intensities whenever startle signs were present.ConclusionsOur results suggest the presence of different sensorimotor pathways supporting a dissociation between simple tasks that involve distal upper limb muscles (FDI in PINCH) from simple tasks involving proximal muscles (BB in FLEX), and combined tasks that engage both muscles (FDI and BB in PINCH-FLEX), all in accordance with differential importance in the control of movements by cortical and subcortical structures.SignificanceSimple assessment tools may provide useful information regarding the differential involvement of sensorimotor pathways in the control of both simple and combined tasks that engage proximal and distal muscles.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

StartReact effects in first dorsal interosseous muscle are absent in a pinch task, but present when combined with elbow flexion

Castellote

Kofler²

2018

PLoS ONE

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“…More recent work with human subjects has shown that humans can adapt to a loss of visual input (Santello et al 2001;Liebermann and Goodman 2007;Goroso 2009, 2011;Castellote et al 2012). For example, humans can perform coordinated drop-landings immediately after removal of continuous visual feedback and experience only slight changes to EMG and kinematic patterns (Santello et al 2001;Liebermann and Goodman 2007).…”

Section: The Importance Of Sensory Feedback For Landingmentioning

confidence: 99%

Biomechanics and Control of Landing in Toads

Gillis

Ekstrom

Azizi

2014

Integrative and Comparative Biology

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Anything that jumps must land, but unlike during jumping when muscles produce energy to accelerate the body into the air, controlled landing requires muscles to dissipate energy and decelerate the body. Among anurans, toads (genus Bufo) exhibit highly coordinated landing behaviors, using their forelimbs to stabilize the body after touch-down as they lower their hindlimbs to the ground. Moreover, toads land frequently, as they cover distances by stringing together long series of relatively short hops. We have been using toads as a model to understand the biomechanics and motor control strategies of coordinated landing. Our results show that toads prepare for landing differently depending on how far they hop. For example, the forelimbs are extended farther prior to impact after long hops than after short ones. Such kinematic alterations are mirrored by predictable modulation of the recruitment intensity of forelimb muscles before impact, such that longer hops lead to higher levels of pre-landing recruitment of muscles. These differences in kinematics and muscular activity help to control the most flexed configuration of the elbow that is achieved after impact, which in turn constrains the extent to which muscles involved in dissipating energy are stretched. Indeed, a combination of in vivo and in vitro experiments has shown that the elbow-extending anconeus muscle, which is stretched during landing as the elbow flexes, rarely reaches lengths longer than those on the plateau of the muscle's length-tension curve (where damage becomes more likely). We have also been studying how movements of the hindlimbs after take-off help to stabilize animals during landing. In particular, the immediate and rapid flexion of a toad's knees after take-off leads to a repositioning of the animal's center of mass (COM) that better aligns it with ground-reaction forces (GRFs) at impact and reduces torques that would destabilize the animal. Finally, recent work on sensory feedback involved in preparation for landing demonstrates that vision is not required for coordinated landing. Toads can effectively utilize proprioceptive and/or vestibular information during take-off to help inform themselves about landing conditions, but may also use other sensory modalities after take-off to modulate landing behavior.

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“…Early analyses hypothesized that the rapid release of SAS-induced responses is the result of triggering subcortically stored information with faster neural transmissions (Carlsen et al, 2004; see also Castellote et al, 2012; Nonnekes et al, 2014). However, recent transcranial magnetic stimulation (TMS) studies show that the StartReact effect may not be limited to subcortically stored programs, but can also be observed in cortically dependent processes (Alibiglou and MacKinnon, 2012; Stevenson et al, 2014).…”

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confidence: 99%