Case studies in neuroscience

the central and somatosensory contributions to finger interdependence and coordination: Lessons from a study of a "deafferented person"

Cristian Cuadra, Ali Falaki, Robert L. Sainburg, Fabrice R. Sarlegna, Mark Latash

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We tested finger force interdependence and multifinger force-stabilizing synergies in a patient with large-fiber peripheral neuropathy (“deafferented person”). The subject performed a range of tasks involving accurate force production with one finger and with four fingers. In one-finger tasks, nontask fingers showed unintentional force production (enslaving) with an atypical pattern: Very large indices for the lateral (index and little) fingers and relatively small indices for the central (middle and ring) fingers. Indices of multifinger synergies stabilizing total force and of anticipatory synergy adjustments in preparation to quick force pulses were similar to those in age-matched control females. During constant force production, removing visual feedback led to a slow force drift to lower values (by ~25% over 15 s). The results support the idea of a neural origin of enslaving and suggest that the patterns observed in the deafferented person were reorganized based on everyday manipulation tasks. The lack of significant changes in the synergy index shows that synergic control can be organized in the absence of somatosensory feedback. We discuss the control of the hand in deafferented persons within the _-model of the equilibrium-point hypothesis and suggest that force drift results from an unintentional drift of the control variables to muscles toward zero values.

Original languageEnglish (US)
Pages (from-to)2083-2087
Number of pages5
JournalJournal of neurophysiology
Volume121
Issue number6
DOIs
StatePublished - Jun 1 2019

Fingerprint

Neurosciences
Fingers
Social Adjustment
Sensory Feedback
Peripheral Nervous System Diseases
Hand
Muscles

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Physiology

Cite this

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title = "Case studies in neuroscience: the central and somatosensory contributions to finger interdependence and coordination: Lessons from a study of a {"}deafferented person{"}",
abstract = "We tested finger force interdependence and multifinger force-stabilizing synergies in a patient with large-fiber peripheral neuropathy (“deafferented person”). The subject performed a range of tasks involving accurate force production with one finger and with four fingers. In one-finger tasks, nontask fingers showed unintentional force production (enslaving) with an atypical pattern: Very large indices for the lateral (index and little) fingers and relatively small indices for the central (middle and ring) fingers. Indices of multifinger synergies stabilizing total force and of anticipatory synergy adjustments in preparation to quick force pulses were similar to those in age-matched control females. During constant force production, removing visual feedback led to a slow force drift to lower values (by ~25{\%} over 15 s). The results support the idea of a neural origin of enslaving and suggest that the patterns observed in the deafferented person were reorganized based on everyday manipulation tasks. The lack of significant changes in the synergy index shows that synergic control can be organized in the absence of somatosensory feedback. We discuss the control of the hand in deafferented persons within the _-model of the equilibrium-point hypothesis and suggest that force drift results from an unintentional drift of the control variables to muscles toward zero values.",
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Case studies in neuroscience : the central and somatosensory contributions to finger interdependence and coordination: Lessons from a study of a "deafferented person". / Cuadra, Cristian; Falaki, Ali; Sainburg, Robert L.; Sarlegna, Fabrice R.; Latash, Mark.

In: Journal of neurophysiology, Vol. 121, No. 6, 01.06.2019, p. 2083-2087.

Research output: Contribution to journalArticle

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