Abstracts / Brain Stimulation 7 (2014) e1ee16 e13

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An investigation into the effects of transcranial alternatingcurrent on alpha oscillations using simultaneous stimulationand EEG.James Dowsett , Christoph HerrmannExperimental Psychology Lab, Carl von Ossietzky University,Oldenburg, Germany*E-mail: james.dowsett@uni-oldenburg.de.

Transcranial alternating current stimulation (tACS) has beenshown to have frequency specific effects on the cortex and isthought to operate by interacting with ongoing neural oscil-lations(see Herrmann et al. 2013 for a review).

To date, various studies have demonstrated both online behav-ioral effects and offline changes in the electroencephalogram (EEG)and cortical excitability. However, until recently simultaneousmeasurement with EEG and tACS has not been explored due to theproblem of the resulting artifact in the EEG data.

Recently some progress has been made with the removal of thisartifact allowing the ongoing neural oscillations to be observed. Theability to observe the online effects of tACS on human neural ac-tivity is an important step towards understanding the mechanismsby which tACS aff5cts neuronal oscillations and in developingfuture applications.

Here we present results which build on previous research intothe effect of tACS on the occipital alpha rhythm (Zaehle et al. 2010,Neuling et al. 2013). tACS was administered to participants at 0.4,0.7 and 1mA (peak to peak, sine wave)with eyes open and closed.EEG was recorded from parietal electrodes before, during and afterstimulation. Three conditions were administered on separate days:stimulation at the participant’s individual alpha frequency, at 20Hzand sham.

The removal of the tACS artifact is more reliable when the fre-quency band of interest (i.e. 8-14Hz alpha) is different from thestimulation frequency. The various successes and remaining prob-lems with artifact removal are discussed here as well as the onlineand offline effects of the stimulation on the ongoing alphaoscillations.

References

Herrmann C. S., Rach S., Neuling T., Struber D. (2013). Transcranialalternating current stimulation: a review of the underlyingmechanisms and modulation of cognitive processes. Front. Hum.Neurosci. 7:279. http://dx.doi.org/10.3389/fnhum.2013.00279

Neuling, T., Rach, S., and Herrmann, C. S. (2013). Orchestratingneuronal networks: sustained after-effects of transcranial alter-nating current stimulation depend upon brain states. Front. Hum.Neurosci. 7:161. http://dx.doi.org/10.3389/fnhum.2013.00161

Zaehle, T., Rach, S., and Herrmann, C. S. (2010). Transcranial alter-nating current stimulation enhances individual alpha activity inhuman EEG. PLoS ONE 5:e13766. http://dx.doi.org/10.1371/journal.pone.0013766

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Cranial electrical stimulation (CES): Barriers to acceptance andnew advancesJanet Mindes a,*, Marc J. Dubin b, Margaret Altemus ba Center for Bioethics, Columbia University, New York, NY, USAbWeill Medical College of Cornell University, New York, NY, USA*E-mail: jm653@columbia.edu.

Cranial electrical stimulation (CES) is a non-invasive brain stim-ulation technology that uses a low intensity alternating current(AC) applied to the head through one or more electrodes. CES var-iants using a range of frequencies and other stimulation parameters

have been used clinically and in research for approximately 100years. From early human and animal studies of so-called electro-sleep and electro-analgesia, to later twentieth century andcontemporary explorations of potential usefulness of CES for mildto moderate depression, anxiety, insomnia and pain, CES deviceshave persisted, mostly outside the mainstream of psychiatric andneurological treatment. Low-powered or poor quality studies, var-ied stimulation parameters and device names, questions concern-ing the nature and extent of brain stimulation possible with CESdevices, limits to clinical and basic science investigation of CESusing proprietary devices (i.e., patented frequencies), and associa-tions with alternative medicine all have been barriers to CES beingscientifically studied and refined. This may soon change, for mul-tiple reasons: CES is very affordable and easy to use; it appears tohave a good safety profile; biomedical engineers are optimizing CESdevices; more well-designed and controlled clinical studies arebeing conducted; new CES variants targeted to individual cranialnerve aff5rents show some success in treating specific neurologicalconditions; and recent modeling and human laboratory data sug-gest CES may be particularly well suited to modulating endogenousbrain oscillations. This poster will present barriers to scientific andmainstream clinical interest in CES, and will review new de-velopments that may contribute to those barriers being lowered.

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Cranial electrical stimulation (CES): Comparison with cranialnerve stimulation, transcranial direct current stimulation andtranscranial low voltage pulsed electromagnetic fieldsJanet Mindes a,*, Marc J. Dubin b, Margaret Altemus ba Center for Bioethics, Columbia University, New York, NY, USAbWeill Medical College of Cornell University, New York, NY, USA*E-mail: jm653@columbia.edu.

Cranial electrical stimulation (CES) is a non-invasive brain stim-ulation technology that uses a low intensity alternating current(AC) applied to the head through one or more electrodes. CES var-iants using a range of frequencies and other stimulation parametershave been used clinically and in research for approximately 100years. CES has long been used to treat mild to moderate depression,anxiety, insomnia, pain, and other conditions, mostly outside themainstream of psychiatric and neurological treatment. Questionsconcerning the extent of actual brain stimulation possible with CESdevices have persisted, although recent modeling studies and somehuman data do offer evidence that brain stimulation can occur,along with cranial nerve stimulation. In recent years, new CESvariants engineered specifically to stimulate cranial nerve aff5rentshave shown some success in treating certain neurological condi-tions such as migraine headache and epilepsy. This poster willcompare and contrast contemporary CES devices with this newgeneration of low intensity electrical cranial nerve stimulators, e.g.,external trigeminal nerve stimulation (eTNS), and also with trans-cranial direct current stimulation (tDCS) and a new experimentalform of low intensity magnetic stimulation called transcranial lowvoltage pulsed electromagnetic fields (t-PEMF), with respect totheir stimulation parameters, proposed mechanisms of action,safety profiles, and the evidence for their clinical usefulness.

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Short Interval Intracortical Inhibition Attenuates PAS Plasticityin ChildrenO. Damji a,*, J. Keess b, A. Kirton b,c,d

aDepartment of Neurosciences, University of Calgary, Calgary, ABb Calgary Pediatric Stroke Program, University of Calgary, Calgary, ABcDepartment of Pediatrics and Clinical Neurosciences, University ofCalgary, Calgary, AB