Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording
Transcranial alternating current stimulation (tACS) has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of diff...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2016-03-01
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| Series: | Frontiers in Human Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnhum.2016.00135/full |
| _version_ | 1811341205401763840 |
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| author | James eDowsett Christoph S Herrmann |
| author_facet | James eDowsett Christoph S Herrmann |
| author_sort | James eDowsett |
| collection | DOAJ |
| description | Transcranial alternating current stimulation (tACS) has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG) recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01). In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique. |
| first_indexed | 2024-04-13T18:53:19Z |
| format | Article |
| id | doaj.art-15d0f427e7da4c8bb7eedc48bce5f231 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-04-13T18:53:19Z |
| publishDate | 2016-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-15d0f427e7da4c8bb7eedc48bce5f2312022-12-22T02:34:20ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612016-03-011010.3389/fnhum.2016.00135183032Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recordingJames eDowsett0Christoph S Herrmann1LMUOldenburg UniversityTranscranial alternating current stimulation (tACS) has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG) recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01). In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.http://journal.frontiersin.org/Journal/10.3389/fnhum.2016.00135/fullEEGoscillationsalphaTACsSawtooth |
| spellingShingle | James eDowsett Christoph S Herrmann Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording Frontiers in Human Neuroscience EEG oscillations alpha TACs Sawtooth |
| title | Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording |
| title_full | Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording |
| title_fullStr | Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording |
| title_full_unstemmed | Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording |
| title_short | Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording |
| title_sort | transcranial alternating current stimulation with sawtooth waves simultaneous stimulation and eeg recording |
| topic | EEG oscillations alpha TACs Sawtooth |
| url | http://journal.frontiersin.org/Journal/10.3389/fnhum.2016.00135/full |
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