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The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face
The magnitude of the hand-blink reflex (HBR), a subcortical defensive reflex elicited by the electrical stimulation of the median nerve, is increased when the stimulated hand is close to the face (‘far–near effect’). This enhancement occurs through a cortico-bulbar facilitation of the polysynaptic m...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Masson
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4962765/ https://www.ncbi.nlm.nih.gov/pubmed/27236372 http://dx.doi.org/10.1016/j.cortex.2016.04.009 |
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author | Wallwork, Sarah B. Talbot, Kerwin Camfferman, Danny Moseley, G.L. Iannetti, G.D. |
author_facet | Wallwork, Sarah B. Talbot, Kerwin Camfferman, Danny Moseley, G.L. Iannetti, G.D. |
author_sort | Wallwork, Sarah B. |
collection | PubMed |
description | The magnitude of the hand-blink reflex (HBR), a subcortical defensive reflex elicited by the electrical stimulation of the median nerve, is increased when the stimulated hand is close to the face (‘far–near effect’). This enhancement occurs through a cortico-bulbar facilitation of the polysynaptic medullary pathways subserving the reflex. Here, in two experiments, we investigated the temporal characteristics of this facilitation, and its adjustment during voluntary movement of the stimulated hand. Given that individuals navigate in a fast changing environment, one would expect the cortico-bulbar modulation of this response to adjust rapidly, and as a function of the predicted spatial position of external threats. We observed two main results. First, the HBR modulation occurs without a temporal delay between when the hand has reached the stimulation position and when the stimulus happens (Experiments 1 and 2). Second, the voluntary movement of the hand interacts with the ‘far–near effect’: stimuli delivered when the hand is far from the face elicit an enhanced HBR if the hand is being moved towards the face, whereas stimuli delivered when the hand is near the face elicit an enhanced HBR regardless of the direction of the hand movement (Experiment 2). These results indicate that the top-down modulation of this subcortical defensive reflex occurs continuously, and takes into account both the current and the predicted position of potential threats with respect to the body. The continuous control of the excitability of subcortical reflex circuits ensures appropriate adjustment of defensive responses in a rapidly-changing sensory environment. |
format | Online Article Text |
id | pubmed-4962765 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Masson |
record_format | MEDLINE/PubMed |
spelling | pubmed-49627652016-08-03 The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face Wallwork, Sarah B. Talbot, Kerwin Camfferman, Danny Moseley, G.L. Iannetti, G.D. Cortex Research Report The magnitude of the hand-blink reflex (HBR), a subcortical defensive reflex elicited by the electrical stimulation of the median nerve, is increased when the stimulated hand is close to the face (‘far–near effect’). This enhancement occurs through a cortico-bulbar facilitation of the polysynaptic medullary pathways subserving the reflex. Here, in two experiments, we investigated the temporal characteristics of this facilitation, and its adjustment during voluntary movement of the stimulated hand. Given that individuals navigate in a fast changing environment, one would expect the cortico-bulbar modulation of this response to adjust rapidly, and as a function of the predicted spatial position of external threats. We observed two main results. First, the HBR modulation occurs without a temporal delay between when the hand has reached the stimulation position and when the stimulus happens (Experiments 1 and 2). Second, the voluntary movement of the hand interacts with the ‘far–near effect’: stimuli delivered when the hand is far from the face elicit an enhanced HBR if the hand is being moved towards the face, whereas stimuli delivered when the hand is near the face elicit an enhanced HBR regardless of the direction of the hand movement (Experiment 2). These results indicate that the top-down modulation of this subcortical defensive reflex occurs continuously, and takes into account both the current and the predicted position of potential threats with respect to the body. The continuous control of the excitability of subcortical reflex circuits ensures appropriate adjustment of defensive responses in a rapidly-changing sensory environment. Masson 2016-08 /pmc/articles/PMC4962765/ /pubmed/27236372 http://dx.doi.org/10.1016/j.cortex.2016.04.009 Text en © 2016 The Author(s) http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Research Report Wallwork, Sarah B. Talbot, Kerwin Camfferman, Danny Moseley, G.L. Iannetti, G.D. The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title | The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title_full | The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title_fullStr | The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title_full_unstemmed | The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title_short | The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
title_sort | blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face |
topic | Research Report |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4962765/ https://www.ncbi.nlm.nih.gov/pubmed/27236372 http://dx.doi.org/10.1016/j.cortex.2016.04.009 |
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