Modulations of stretch reflex by altering visuomotor contexts
Various functional modulations of the stretch reflex help to stabilize actions, but the computational mechanism behind its context-dependent tuning remains unclear. While many studies have demonstrated that motor contexts associated with the task goal cause functional modulation of the stretch refle...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2024-02-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnhum.2024.1336629/full |
| _version_ | 1827351425001193472 |
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| author | Sho Ito Sho Ito Hiroaki Gomi |
| author_facet | Sho Ito Sho Ito Hiroaki Gomi |
| author_sort | Sho Ito |
| collection | DOAJ |
| description | Various functional modulations of the stretch reflex help to stabilize actions, but the computational mechanism behind its context-dependent tuning remains unclear. While many studies have demonstrated that motor contexts associated with the task goal cause functional modulation of the stretch reflex of upper limbs, it is not well understood how visual contexts independent of the task requirements affect the stretch reflex. To explore this issue, we conducted two experiments testing 20 healthy human participants (age range 20–45, average 31.3 ± 9.0), in which visual contexts were manipulated in a visually guided reaching task. During wrist flexion movements toward a visual target, a mechanical load was applied to the wrist joint to evoke stretch reflex of wrist flexor muscle (flexor carpi radialis). The first experiment (n = 10) examined the effect of altering the visuomotor transformation on the stretch reflex that was evaluated with surface electromyogram. We found that the amplitude of the stretch reflex decreased (p = 0.024) when a rotational transformation of 90° was introduced between the hand movement and the visual cursor, whereas the amplitude did not significantly change (p = 0.26) when the rotational transformation was accompanied by a head rotation so that the configuration of visual feedback was maintained in visual coordinates. The results suggest that the stretch reflex was regulated depending on whether the visuomotor mapping had already been acquired or not. In the second experiment (n = 10), we examined how uncertainty in the visual target or hand cursor affects the stretch reflex by removing these visual stimuli. We found that the reflex amplitude was reduced by the disappearance of the hand cursor (p = 0.039), but was not affected by removal of the visual target (p = 0.27), suggesting that the visual state of the body and target contribute differently to the reflex tuning. These findings support the idea that visual updating of the body state is crucial for regulation of quick motor control driven by proprioceptive signals. |
| first_indexed | 2024-03-08T02:03:05Z |
| format | Article |
| id | doaj.art-c3542ed4f45b453cbae01a5ba7afdfb4 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-03-08T02:03:05Z |
| publishDate | 2024-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-c3542ed4f45b453cbae01a5ba7afdfb42024-02-14T04:19:20ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612024-02-011810.3389/fnhum.2024.13366291336629Modulations of stretch reflex by altering visuomotor contextsSho Ito0Sho Ito1Hiroaki Gomi2NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Atsugi, JapanSchool of Engineering, Tokyo Institute of Technology, Yokohama, JapanNTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Atsugi, JapanVarious functional modulations of the stretch reflex help to stabilize actions, but the computational mechanism behind its context-dependent tuning remains unclear. While many studies have demonstrated that motor contexts associated with the task goal cause functional modulation of the stretch reflex of upper limbs, it is not well understood how visual contexts independent of the task requirements affect the stretch reflex. To explore this issue, we conducted two experiments testing 20 healthy human participants (age range 20–45, average 31.3 ± 9.0), in which visual contexts were manipulated in a visually guided reaching task. During wrist flexion movements toward a visual target, a mechanical load was applied to the wrist joint to evoke stretch reflex of wrist flexor muscle (flexor carpi radialis). The first experiment (n = 10) examined the effect of altering the visuomotor transformation on the stretch reflex that was evaluated with surface electromyogram. We found that the amplitude of the stretch reflex decreased (p = 0.024) when a rotational transformation of 90° was introduced between the hand movement and the visual cursor, whereas the amplitude did not significantly change (p = 0.26) when the rotational transformation was accompanied by a head rotation so that the configuration of visual feedback was maintained in visual coordinates. The results suggest that the stretch reflex was regulated depending on whether the visuomotor mapping had already been acquired or not. In the second experiment (n = 10), we examined how uncertainty in the visual target or hand cursor affects the stretch reflex by removing these visual stimuli. We found that the reflex amplitude was reduced by the disappearance of the hand cursor (p = 0.039), but was not affected by removal of the visual target (p = 0.27), suggesting that the visual state of the body and target contribute differently to the reflex tuning. These findings support the idea that visual updating of the body state is crucial for regulation of quick motor control driven by proprioceptive signals.https://www.frontiersin.org/articles/10.3389/fnhum.2024.1336629/fullstretch reflexvisually guided reachingvisuomotor transformationstate estimationfeedback control |
| spellingShingle | Sho Ito Sho Ito Hiroaki Gomi Modulations of stretch reflex by altering visuomotor contexts Frontiers in Human Neuroscience stretch reflex visually guided reaching visuomotor transformation state estimation feedback control |
| title | Modulations of stretch reflex by altering visuomotor contexts |
| title_full | Modulations of stretch reflex by altering visuomotor contexts |
| title_fullStr | Modulations of stretch reflex by altering visuomotor contexts |
| title_full_unstemmed | Modulations of stretch reflex by altering visuomotor contexts |
| title_short | Modulations of stretch reflex by altering visuomotor contexts |
| title_sort | modulations of stretch reflex by altering visuomotor contexts |
| topic | stretch reflex visually guided reaching visuomotor transformation state estimation feedback control |
| url | https://www.frontiersin.org/articles/10.3389/fnhum.2024.1336629/full |
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