onr:"swepub:oai:DiVA.org:umu-23"
Search: onr:"swepub:oai:DiVA.org:umu-23" > Tactile Sensory Con...
- 1 of 1
- Previous record
- Next record
- To hitlist
Tactile Sensory Control of Dexterous Manipulation in Humans
-
- Birznieks, Ingvars (author)
- Umeå universitet,Fysiologi
- (creator_code:org_t)
- ISBN 9173053724
- Umeå : Integrativ medicinsk biologi, 2003
- English 52 s.
- Series: Umeå University medical dissertations, 0346-6612 ; 822
- Doctoral thesis (other academic/artistic)
Abstract
Subject headings
Close
- During dexterous manipulation with the fingertips, forces are applied to objects' surfaces. To achieve grasp stability, these forces must be appropriate given the properties of the objects and the skin of the fingertips, and the nature of the task. It has been demonstrated that tactile sensors in the fingertips provide crucial information about both object properties and mechanical events critical for the control of fingertip forces, while in certain tasks vision may also contribute to predictions of required fingertip actions. This thesis focuses on two specific aspects of the sensory control of manipulation: (i) how individual fingers are controlled for grasp stability when people restrain objects subjected to unpredictable forces tangential to the grasped surfaces, and (ii) how tactile sensors in the fingertips encode direction of fingertip forces and shape of surfaces contacted by the fingertips. When restraining objects with two fingers, subjects adjust the fingertip forces to the local friction at each digit-object interface for grasp stability. This is accomplished primarily by partitioning the tangential force between the digits in a way that reflects the local friction whereas the normal forces at the involved digits are scaled by the average friction and the total load. The neural control mechanisms in this task rely on tactile information pertaining to both the friction at each digit-object interface and the development of tangential load. Moreover, these mechanisms controlled the force application at individual digits while at the same time integrating sensory inputs from all digits involved in the task. Microneurographical recordings in awake humans shows that most SA-I, SA-II and FA-I sensors in the distal phalanx are excited when forces similar to those observed during actual manipulation are applied to the fingertip. Moreover, the direction of the fingertip force influences the impulse rates in most afferents and their responses are broadly tuned to a preferred direction. The preferred direction varies among the afferents and, accordingly, ensembles of afferents can encode the direction of fingertip forces. The local curvature of the object in contact with the fingertip also influenced the impulse rates in most afferents, providing a curvature contrast signals within the afferent populations. Marked interactions were observed in the afferents' responses to object curvature and force direction. Similar findings were obtained for the onset latency in individual afferents. Accordingly, for ensembles of afferents, the order by which individual afferents initially discharge to fingertip events effectively represents parameters of fingertip stimulation. This neural code probably represents the fastest possible code for transmission of parameters of fingertip stimuli to the CNS.
Subject headings
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Physiology (hsv//eng)
Keyword
- Physiology
- cutaneous sensibility
- tactile afferents
- fingertip force
- grasp stability
- human hand
- manipulation
- object shape
- precision grip
- sensorimotor control
- coding
- Fysiologi
- Physiology
- Fysiologi
- fysiologi
- Physiology
Publication and Content Type
- vet (subject category)
- dok (subject category)
Find in a library
- Tactile Sensory Control of Dexterous Manipulation in Humans (Search the publication in LIBRIS)
To the university's database
- 1 of 1
- Previous record
- Next record
- To hitlist
Find more in SwePub
- By the author/editor
- Birznieks, Ingva ...
- About the subject
-
- MEDICAL AND HEALTH SCIENCES
- MEDICAL AND HEAL ...
- and Basic Medicine
- and Physiology
- Parts in the series
- Umeå University ...
- By the university
- Umeå University
Search outside SwePub
- Extend your search to:
- Google Book Search
- Google Scholar
Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.
- Copyright © LIBRIS - National Library Systems
- LIBRIS.kb.se
