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Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols
There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was rep...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285376/ https://www.ncbi.nlm.nih.gov/pubmed/28203151 http://dx.doi.org/10.3389/fnhum.2017.00023 |
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author | Beyer, Linda Batsikadze, Giorgi Timmann, Dagmar Gerwig, Marcus |
author_facet | Beyer, Linda Batsikadze, Giorgi Timmann, Dagmar Gerwig, Marcus |
author_sort | Beyer, Linda |
collection | PubMed |
description | There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based on individual anatomy may also play role. Likewise cerebellar tDCS during extinction did not modulate extinction or reacquisition. Further studies are needed in larger subject populations to determine parameters of stimulation and learning paradigms yielding robust cerebellar tDCS effects. |
format | Online Article Text |
id | pubmed-5285376 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-52853762017-02-15 Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols Beyer, Linda Batsikadze, Giorgi Timmann, Dagmar Gerwig, Marcus Front Hum Neurosci Neuroscience There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based on individual anatomy may also play role. Likewise cerebellar tDCS during extinction did not modulate extinction or reacquisition. Further studies are needed in larger subject populations to determine parameters of stimulation and learning paradigms yielding robust cerebellar tDCS effects. Frontiers Media S.A. 2017-02-01 /pmc/articles/PMC5285376/ /pubmed/28203151 http://dx.doi.org/10.3389/fnhum.2017.00023 Text en Copyright © 2017 Beyer, Batsikadze, Timmann and Gerwig. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution and reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Neuroscience Beyer, Linda Batsikadze, Giorgi Timmann, Dagmar Gerwig, Marcus Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title | Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title_full | Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title_fullStr | Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title_full_unstemmed | Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title_short | Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols |
title_sort | cerebellar tdcs effects on conditioned eyeblinks using different electrode placements and stimulation protocols |
topic | Neuroscience |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285376/ https://www.ncbi.nlm.nih.gov/pubmed/28203151 http://dx.doi.org/10.3389/fnhum.2017.00023 |
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