Transcranial Direct Current Stimulation research line.
ECP application documentation.
Prof. Dr. Alexander Sack,
Maastricht, 21-04-2017
In this document we outline the following:




Description of Brain Stimulation Technique
Safety and Comfort
Experimental Procedures and Limitations
Additional Safety Information and Procedures
Introduction
Transcranial direct current stimulation (tDCS) is an established, safe, and comfortable
brain stimulation method for clinical and research applications, inducing temporary effects
on regional brain excitability. There are no known consistent side- or after-effects. The
most often reported noticeable effect in participants is a ‘tingling’ sensation of the skin
during stimulation, which is not uncomfortable and lasts only a few tens of seconds at the
onset of stimulation. There are industry standards of measurement parameters which will
be followed as outlined below.
Description of Brain Stimulation Technique
TDCS is a non-invasive form of transcranial electric stimulation focusing on neuromodulation rather than actual neuro-stimulation. Several applications, using the same
equipment and physical principles, are subsumed under the proposed method. These are
1) Transcranial direct current stimulation (tDCS)
2) Sinusoidal transcranial direct current stimulation (stDCS)
3) Transcranial alternating current stimulation (tACS)
4) Transcranial random-noise stimulation (tRNS)
Safety considerations and potential side effects have not been shown to be different
between these various applications, and besides the equipment they share many
characteristics in terms of experimental design, procedures, and participant comfort. We
therefore first explain the basic, common
methodology behind tDCS application,
before we outline the differences (for a
more detailed technical description of tDCS
and its specific sub-forms see Paulus et al.,
2011).
tDCS
TDCS involves a battery, connected to two
or more electrode patches (see image to
the right). One of these patches serves as
the reference electrode, the other serves
as the stimulating electrode. A low-intensity
electrical current flows between the
electrode patches. If the current flows from
the stimulating (here colored ‘red’)
electrode patch to the reference electrode
1
(‘blue’), we speak of ‘anodal stimulation’. If the current flows from the reference to the
stimulating electrode (‘blue to red’), we speak of ‘cathodal stimulation’. By changing the
baseline membrane potential of neurons underlying the stimulating electrode, these
neurons are more (in the case of anodal stimulation) or less (in the case of cathodal
stimulation) excitable than usual. This effect lasts during the stimulation period, and for
some time afterwards, depending on stimulation duration. As we will never stimulate for
periods longer than 40 mins, the maximum duration of effects (lasting excitability
modulation) will not exceed 90 to 120 minutes.
stDCS
In sinusoidal tDCS, the current flowing between the electrode patches is not constant, but
increases and decreases in intensity in a repeating sinusoidal (wave-like) pattern.
Depending on the frequency of this pattern, brain oscillations used by the brain to
communicate (measured often by electroencephalography, EEG), can be stimulated - if
the stDCS frequency is similar to the brain oscillation frequency - or inhibited - if the stDCS
frequency is different from the brain oscillation frequency. This method thus allows an
investigation of brain oscillations and their role in perception and cognition, rather than
only the role of a stimulated brain region.
tACS
In transcranial alternating current stimulation, the situation and goals are similar. The
difference is that, instead of changing current intensity with a particular frequency, the
direction of current flow (anodal versus cathodal, see above) changes back and forth with
a particular frequency. This appears to have similar effects to stDCS, although probably
stronger. Therefore, tACS is often used instead of stDCS.
tRNS
In transcranial random noise stimulation, the current flow direction and current intensity
also changes over time, yet not in any fixed frequency. Rather, the frequency of the
changing current intensity/direction varies randomly over time. This is a way to disturb the
ongoing neuronal processing by disrupting not one brain oscillation frequency band in a
specific brain region, but al. Therefore, it becomes more difficult for the region to engage in
organized spatiotemporal activities. This thus creates somehow an online, direct ‘virtual
lesion’ of the stimulated brain region.
Safety and Comfort
Safety
tDCS and its various applications have been pioneered and applied in human volunteers
as early as about 1800 (Paulus et al., 2011). The method should, theoretically, not have
any adverse effects, since it merely affects the membrane potentials of brain cells. These
membrane potentials are also changed by the brain itself and constitute how the brain
communicates. TDCS uses the same bio-physiological principles, but controlled ‘from the
outside’ by the experimenter. Therefore, no damage, permanent changes, or – generally
speaking – theoretical risk of any kind to the brain can occur using this method.
Due to electrical stimulation of the skin, participants with various forms of skin diseases
(e.g. Psoriasis, Eczema) could experience irritation of the skin during and/or after
stimulation. This would not lead to lasting discomfort or damage, yet participants with skin
damage or diseases or other types of complaints will not be tested in our lab. A screening
form (see below) will include exclusion criteria to ensure this. Furthermore, electrodes are
covered by saline-solution-soaked sponges in order to avoid any electrochemical reactions
at the electrode-tissue-interface (for further explanation see Nitsche et al., 2008).
Aside from the theoretical considerations regarding safety issues using tDCS, it is
important to consider the practical experiences made in the field. Since the inception of
tDCS, hundreds if not thousands of participants were tested, and recent reviews have
taken inventory of the side effects and participant experiences. For instance, Poreisz and
colleagues (2007) systematically summarized the side effects of 567 tDCS sessions over
motor and non-motor cortical areas (occipital, temporal, parietal) including 102 participants
(75.5% healthy participants, 8.8% migraine patients, 5.9% post-stroke patients and 9.8%
tinnitus patients). During tDCS a mild tingling sensation was the most commonly reported
side effect (70.6%), moderate fatigue was felt by 35.3% of the participants, whereas a light
itching sensation under the stimulation electrodes occurred in 30.4% of cases. After tDCS
headache (11.8%), nausea (2.9%) and insomnia (0.98%) were reported, but fairly
infrequently. Even when assuming that all these reports of side effects were directly
related to the brain stimulation experiment, they seem to be mild, rare, and temporary. As
Nitsche and colleagues (2008) point out, tDCS is a non-invasive brain stimulation method
“with no serious side effects, except for a slight itching under
the electrode, and seldom-occurring headache, fatigue, and nausea” (page reference) as
long as the applied currents do not exceed a maximum stimulation intensity of 2
milliampere (mA) and the stimulation duration 1 hour – the framework in which also we will
operate (see below). Based on the application of tDCS on approximately 2000 – 3000
participants from all over the world, no side effects other than mentioned were ever
reported.
Comfort
Also in terms of comfort, tDCS has few side effects. The occasionally reported ‘tingling’ of
the skin at stimulation onset is generally not considered unpleasant, is mild, and
automatically fades after a few tens of seconds, even if the stimulation continues for
minutes up to tens of minutes. In fact, tDCS procedures are suitable to ‘single-blind’ or
even ‘double-blind’ experiments, because a control condition is often implemented as
follows: in the control (sham stimulation) condition, the brain stimulation procedure is
started the same way as in the experimental (real stimulation) condition. Yet, after 30
seconds, the device is turned off, and because the tingling sensation (if at all present) will
already have receded, participants do not notice that their brains are not stimulated. This is
how little subjective impact the methodology has on the volunteers.
Experimental Procedures and Limitations
Prior to the Experiment
Even though up to this day there are no known risk factors to tDCS, we will take the safest
possible route and, therefore, screen participants for risk factors to other brain stimulation
methods employed in our lab (i.e. Transcranial magnetic stimulation, TMS). To ensure
maximum safety and minimization of all types of risk, we will employ the same procedures
with regards to 1) participant screening, 2) participant treatment, and 3) certification of
experimenters as we do for TMS.
1) Participant screening
3
In the appendix to the ECP proposal at hand, our participant screening form is provided.
The exclusion criteria we apply are overly strict for tDCS, yet we implement them,
nevertheless, to allow for one consistent participant base for both TMS and tDCS
experiments. Briefly, participants will be excluded if they:
- have any (substantial history of) skin disease or irritation.
- are currently (or in the last 24 hours) taking medication, or consumed (hard or soft) drugs
(max. 2 units of alcohol in the preceding 24 hours).
- currently suffer from headache or sleep deprivation.
- have (1st-degree relatives with) epilepsy or a history of seizures.
- have been diagnosed with neurological or psychiatric disorders.
2) Participant treatment
Participant will receive the ‘participant information’ as documented in the appendix, after
adaptation of this document for the experiment at hand. They will receive ample time to
review this information, will be informed about the contact information of the responsible
researcher and of an independent physician - in case they experience adverse effects or
have remaining questions after the experimental session(s). Further, they will be given the
opportunity to ask questions at any time before and during the experiment. Upon
requesting written informed consent (see appendix), the experimenter will emphasize that
participants can quit the experiment at any time without giving a reason and that in such
case they will still receive compensation for their spent time.
3) Certification of Experimenters
Only “Certified Users” will be allowed to administer non-invasive brain stimulation (TMS &
tDCS) in the laboratories at FPN and Oxfordlaan 55. User certification is granted to FPN
employees on the following basis/requirements:
- They must have followed the theoretical and practical ‘certified user course’ on noninvasive brain stimulation techniques. This consists of a seminar organized by the TMS
group of the CN department under supervision of Dr. Alexander Sack, and minimally 5
session of hands-on experience with TMS/tDCS under the supervision of an already
certified TMS/tDCS user.
- They must have demonstrated under supervision of a certified user conceptual and
practical knowledge of TMS/tDCS, and proficiency in both practical TMS/tDCS
administration and participant treatment, independently.
- For further information on the Certified User training see appendix.
The Experimental Session
1) Participant arrives in the lab: the certified user (CU) welcomes him/her
2) Participant is given the “participant information”, a standard document adapted to
the specifics of the experiment at hand. He/she is given ample time to review it.
3) After the participant red the information, the CU emphasizes relevant information in
the participant information (contact information of researchers and independent
physician), and asks if there are any remaining questions.
4) The CU demonstrates the tDCS device and electrode patches and explains the
procedure (outlined below). The CU then also explains the conditions, tasks, and
parameters of the experimental session at hand (how long will it take, what will the
participant need to do, if possible without biasing results: what is the research
question and relevance of the project?).
5) The participant fills out the ‘pre-experimental check’ form (see appendix), which is a
second participant screening form filled out in each measurement session in order
to make sure that the information given in the screening form is still relevant and no
acute changes have occurred.
6) Participant provides written informed consent.
7) The participant is seated in a chair in front of the stimulus computer. The stimulating
and reference electrode patches are dipped in a saline solution (to ensure
conductance of the direct current).
8) The electrode patches are applied to the head of the participant, the reference
electrode either on the forehead (see image above) or on a mastoid behind the
ears. The location(s) of the stimulation electrode patch(es) depend on the brain
region under investigation, and can include frontal, parietal, temporal, and occipital
regions.
9) The direct current stimulation will be administered, and the CU ensures that the
participant is comfortable.
10) The participant performs a behavioral, perceptual, or cognitive task, during and/or
after the stimulation.
11) At the end of the session, the participant will be compensated with either
‘proefpersoonpunten’ (1 point per hour of participation) or IRIS-cheques (10€ per
hour). The CU will make sure that no adverse effects were experienced, and will
encourage participants to establish contact if any adverse effects occur after the
experimental session.
12) During any tDCS session a first-aider or so-called ‘bedrijfshulpverlener’ (someone
trained in dealing with emergency situations) will always be on call.
Limitations
Additional Methodology
In the proposed research line, the tDCS procedures may be combined with the following
additional measurements;
- behavioral and psychophysical measurements
- Eyetracking measurements using the Eyelink system (this requires no hardware on the
body of the participant - only a camera positioned near the stimulus monitor - and
provides no additional strain to participants)
- EMG measurements: electrodes may be attached to muscles in the hand or wrist area to
measure muscular activity
- TMS: up to 5 pulses of TMS may be applied to stimulated or other brain regions, not
during, but potentially after the administration of tDCS to modulate cortical excitability.
The TMS pulses can be used to directly probe excitability of a brain region. Any
application of this kind of TMS would not fall under the approval of tDCS currently under
consideration, but would fall under an approval (to be requested separately) of TMS
experimentation.
Stimuli and Tasks
Only sensory stimuli are presented to participants, before, during, or after tDCS. These
stimuli would not be emotionally disturbing, or perceptually uncomfortable. The most
ethically sensitive stimuli would potentially be still images of negative emotional
expressions on faces (e.g. to test recognition of facial expressions, including faces looking
scared, sad, disgusted or angry).
Only perceptual, cognitive, or behavioral tasks are employed that do not disturb or cause
stress to participants. Cognitive tasks will include attention paradigms and numerical
paradigms, perceptual tasks will include visual and/or auditory target detection,
5
discrimination, or subjective ratings of visibility, behavioral tasks will include motor
responses.
Stimulation Parameters
The stimulation parameters we will maintain, based on previous research, are a maximum
stimulation of 40 minutes when the stimulation intensity is 2 milliampere (mA). Stimulation
will never exceed 2 mA, and will never exceed 40 minutes.
All in all, sessions will not take longer than maximally 2.5 hours. Participants will not be
stimulated more than once every 24 hours.
If in any particular implementation of stimuli or tasks there is doubt concerning potentially
ethically sensitive aspects, a new and separate ECP application will be submitted.
Additional Safety Information and Procedures
All equipment used for tDCS is CE certified, and checked for safety by FPN
‘Instrumentatie’ minimally once per year.
Participants are screened prior to participation using the ‘brain stimulation screening form’.
Furthermore, participants are screened right before each measurement session using the
‘pre-experimental check form’.
Only Certified Users will operate equipment, or supervise the operation of equipment if the
experimenter is an aspiring Certified User in training.
At no time brain stimulation will occur without a Certified User present in the lab.
References
Nitsche, M. a, Cohen, L. G., Wassermann, E. M., Priori, A., Lang, N., Antal, A., Paulus, W.,
et al. (2008). Transcranial direct current stimulation: State of the art 2008. Brain
stimulation, 1(3), 206–23.
Paulus, W. (2011). Transcranial electrical stimulation (tES - tDCS; tRNS, tACS) methods.
Neuropsychological rehabilitation, 21(5), 602–17.
Poreisz, C., Boros, K., Antal, A., & Paulus, W. (2007). Safety aspects of transcranial direct
current stimulation concerning healthy subjects and patients. Brain research bulletin, 72(46), 208–14.
7
Transcranial Magnetic Stimulation (TMS) research line.
ECP application documentation.
Prof. Dr. Alexander Sack,
Maastricht, 21-04-2017
In this document we outline the following:




Description of Brain Stimulation Technique
Safety and Comfort
Experimental Procedures and Limitations
Additional Safety Information and Procedures
Introduction
As an appendix to our ECP application for approval of a TMS research line, we would like to
provide some important background information on the nature and use of TMS, the associated
risks, and the procedures we have designed and followed during the past 12 years to successfully
reduce these risks to an absolute minimum. FPN has been hosting Non-invasive brain stimulation
(NIBS) labs and conducting behavioral TMS studies involving human participants already since
2004. Using TMS to investigate functional layout and connectivity of the working human brain can
be considered a widely accepted approach that is used safely in many labs throughout the world,
as documented by thousands of publications. In addition, we only use standard, commercially
available, and CE approved equipment. Nonetheless, in agreement with the FPN board, already in
2005 we introduced a special series of procedures to ensure highest level of training, supervision
structure, and risk control for behavioral TMS studies, as well as studies combining TMS with fMRI
and EEG. We will outline which aspects regarding the use of TMS in healthy adults are relevant for
safety, and how we deal with these aspects to ensure maximum safety for our participants.
What is TMS?
As implied by the name, transcranial magnetic stimulation involves the application of a magnetic
field to the scalp, which then pervades into the underlying tissue, including the brain. TMS has the
potential to very briefly and very locally disrupt cortical processing. In psychological research, TMS
is typically used in association with psychophysical testing, to assess the involvement of certain
brain areas in certain behavioral tasks. It thus complements purely observational brain imaging
methods such as fMRI and EEG, by allowing for a top-down experimental manipulation of brain
activation. In addition to psychological research, TMS is now also widely used for clinical treatment
of various conditions, most notably depression. Although there is some confusion on whether TMS
should be considered an invasive or noninvasive procedure, leading neuroscience text books all
agree in classifying TMS as noninvasive (e.g. Breedlove, Rozenzweig, & Watson, 2007;
Gazzaniga, Ivry, & Mangun, 2002).
A single TMS pulse has been shown to affect cortical processing underlying perception,
cognition, and behaviour, for a very brief period of time. Generally single pulses affect behaviour
for only milliseconds. However, TMS can be applied in various manners which have other effects
on the brain. Event-related TMS refers to the application of one or several pulses at a point in time
relative to an event, typically the presentation of a sensory stimulus. Since this application of TMS
only has a brief effect, this allows for temporal probing of the relevance of a brain region during
task execution, by varying the onset of TMS with regard to stimulus onset. Repetitive TMS (rTMS)
involves the application of many TMS pulses for a certain duration, at a certain frequency.
Repetitive TMS effects on cortical processing outlast the period of actual stimulation, with effects
after stimulation lasting maximally as long as the duration of preceding repetitive TMS stimulation.
Based on the frequency of stimulation, rTMS can have an inhibitory or excitatory effect on neuronal
activation. A special case of rTMS is patterned TMS, in which many TMS pulses are administered
in nested rhythms to have even longer lasting after-effects. For example, a widely used pattern is
continuous theta burst stimulation (cTBS); 5-pulse 20Hz trains repeated at a 5Hz frequency for
only 40 seconds, resulting in a 45-60 min. inhibitory effect (Huang et al., 2005).
Safety and Comfort
Safety
TMS with human volunteers was established in 1985 (Barker et al., 1985). Since then, thousands
of experiments, in neuroscientific, psychological, or therapeutic settings, have been performed and
reported. The method should, theoretically, not have lasting adverse effects, since the magnetic
pulses affect the membrane potentials of brain cells, leading to action potentials, a process quite
natural to the brain. Repetitive TMS likely employs natural mechanisms of short-term learning,
such as long-term potentiation (for high-frequency rTMS) and long-term depression (for lowfrequency TMS). rTMS effects, while outlasting the period of stimulation, are widely accepted to be
reversible, temporary, and safe. In the short-term, there can be negative side effects if safety
procedures are not adhered to. Participants at risk for seizures could experience a seizure during
repetitive TMS. Early pioneering work with TMS recorded the parameters at which such seizures
were induced, and based on this safety guidelines have been established (Wasserman et al.,
1998; Rossi et al., 2009). Currently, the risk to get a seizure during a TMS treatment is lower than
0.003%. In general, seizures do not appear to be a risk for participants not already predisposed.
One strict exclusion criterion in participant screening is therefore a history of epilepsy in the
participant or in relatives of the participant.
By adhering to these guidelines, our lab at FPN has since 2004 not had a single case of
induced seizure. Other adverse side effects of TMS that have been reported include syncope,
head-aches, dizziness, and hearing damage. Hearing damage is easily prevented by supplying
participants with ear plugs when necessary. The other potential side effects are rare, mild, and
temporary. They have not been reported in our lab since 2004.
Comfort
TMS in principle is painless. There is a somatosensory experience, due to the contraction of
muscles on the scalp underlying the TMS coil. This has been described as a little bird pecking on
the skull, or tapping the scalp with a pen. It is rarely described as painful. To ensure participant
comfort, we consistently and systematically inquire whether participants are uncomfortable or find
the stimulation painful. As the somatosensory experience increases in intensity with higher
magnetic field strength, intensity is raised in steps from a low level, all the time checking with
participants whether they find the stimulation tolerable. Of course, participants are informed that
they can quit the experiment at any time, for any reason, without the need for justification and with
full reimbursement as agreed prior to participation.
Experimental Procedures and Limitations
Prior to the Experiment
9
Even though up to this day there are no known risk factors to TMS, we will take the safest possible
route and, therefore, screen participants for risk factors to other brain stimulation methods
employed in our lab (i.e. Transcranial magnetic stimulation, TMS). To ensure maximum safety and
minimization of all types of risk, we will employ the same procedures with regards to 1) participant
screening, 2) participant treatment, and 3) certification of experimenters as we do for TMS.
2) Participant screening
In the appendix to the ECP proposal at hand, our participant screening form is provided. Although
this screening form has been used since the beginning of the use of TMS at our faculty, over the
years it has regularly been updated and adapted based on the most recent insights from scientific
literature. It covers all the relevant aspects of TMS safety related to individual participant
circumstances. Briefly, participants will be excluded if:
- they are currently (or in the last 24 hours) taking medication, or recently consumed drugs or >2
units of alcohol.
- they chronically suffer from headache or sleep deprivation.
- they have (1st-degree relatives with) epilepsy or a history of seizures.
- they have been diagnosed with neurological or psychiatric disorders.
3) Participant treatment
Participant will receive the ‘participant information’ as documented in the appendix, after
adaptation of this document for the experiment at hand. They will receive ample time to review this
information, will be informed about the contact information of the responsible researcher and of an
independent physician - in case they experience adverse effects or have remaining questions after
the experimental session(s). Further, they will be given the opportunity to ask questions. Upon
requesting written informed consent (see appendix), the experimenter will emphasize that
participants can quit the experiment at any time without giving a reason and that in such case they
will still receive compensation for their time.
4) Certification of Experimenters
Only “Certified Users” will be allowed to administer non-invasive brain stimulation (TMS & tDCS) in
the laboratories at FPN and Oxfordlaan 55. User certification is granted to FPN employees on the
following basis/requirements:
- They must have followed the theoretical and practical ‘certified user course’ on non-invasive brain
stimulation techniques. This consists of a seminar organized by the NIBS group of the CN
department under supervision of Prof. Dr. Alexander Sack, and minimally 10 sessions of handson experience with NIBS under the supervision of an already certified NIBS user.
- They must have demonstrated under supervision of a certified user conceptual and practical
knowledge of NIBS, and proficiency in both practical NIBS administration and participant
treatment, independently.
- For further information on the Certified User training see appendix.
The Experimental Session
13) Participant arrives in the lab: the certified user (CU) welcomes him/her
14) Participant is given the “participant information”, a standard document adapted to the
specifics of the experiment at hand. He/she is given ample time to review it.
15) After the participant has read the information, the CU emphasizes relevant information in
the participant information (contact information of researchers), and asks if there are any
remaining questions.
16) The CU explains the conditions, tasks, and parameters of the experimental session at hand
(how long will it take, what will the participant need to do, if possible without biasing results:
what is the research question and relevance of the project?) and the use of TMS in this
context (which type, how long etc.).
17) The participant fills out the ‘pre-experimental check’ form (see appendix), which is a second
participant screening form filled out in each measurement session in order to make sure
that the information given in the screening form is still relevant and no acute changes have
occurred.
18) Participant provides written informed consent.
19) The participant is seated in a chair in front of the stimulus computer. If applicable, the motor
threshold is determined by delivering several single pulses to the motor cortex, and
observing the intensity at which involuntary motor output (finger twitches) is no longer
produced. This procedure takes several minutes, and is not uncomfortable or painful. It is
also a good way for new participants to get their first acquaintance with receiving TMS.
20) The coil is positioned over the stimulation site. This site can be determined in different ways
(functional or anatomical neuronavigation, measurements on the scalp, etc.). If TMS is to
be applied for more than several minutes, the coil is often fixated in a flexible arm in a way
that is as comfortable for the participant as possible.
21) TMS will be administered. The CU continually retains visual contact with the participant,
and ensures that he/she participant is comfortable. If TMS is applied for a longer time than
several minutes (i.e. during prolonged behavioural task execution), the CU will remain
vigilant and during short breaks verify that the participant is still comfortable and well. In
case of discomfort due to having to maintain the same position, the coil can be slightly
repositioned or temporarily removed.
22) The participant meanwhile performs a behavioral, perceptual, or cognitive task, during
and/or after the stimulation.
23) At the end of the session, the participant will be compensated with either
‘proefpersoonpunten’ (1 point per hour of participation) or VVV-cheques (10€ per hour).
The CU will make sure that no adverse effects were experienced, and will encourage
participants to establish contact if any adverse effects occur after the experimental session.
24) During any TMS session a first-aider or so-called ‘bedrijfshulpverlener’ (someone trained in
dealing with emergency situations) will at least be on call, if not physically present.
Limitations
Additional Methodology
In the proposed research line, the TMS procedures may be combined with the following additional
measurements;
- Behavioral and psychophysical measurements
- Eyetracking measurements using the Eyelink system (this requires no hardware on the body of
the participant - only a camera positioned near the stimulus monitor - and provides no additional
strain to participants)
- EMG measurements: electrodes may be attached to muscles in the hand or wrist area to
measure muscular activity
- TCDS may have been applied before single pulse TMS is used, to combine the prolonged
enhancing effects of TDCS with the focal, transient inhibition of TMS.
Stimuli and Tasks
Only perceptual (mostly visual and/or auditory) stimuli are presented to participants, before, during,
or after TMS. These stimuli are neither emotionally disturbing nor perceptually uncomfortable. The
most ethically sensitive stimuli would potentially be still images of negative emotional expressions
on faces (e.g. to test recognition of facial expressions, including faces looking scared, sad,
disgusted or angry).
Only perceptual, cognitive, or behavioral tasks are employed that do not disturb or cause stress to
participants. Cognitive tasks will include attention paradigms and numerical paradigms, perceptual
tasks will include visual and/or auditory target detection, discrimination, or subjective ratings of
visibility, behavioral tasks will include motor responses.
If in any particular implementation of stimuli or tasks there is doubt concerning potentially ethically
sensitive aspects, a new and separate ECP application will be submitted.
11
Additional Safety Information and Procedures
All equipment used for TMS is CE certified, and checked for safety by FPN ‘Instrumentatie’
minimally once per year. Only Certified Users will operate equipment, or supervise the operation of
equipment if the experimenter is an aspiring Certified User in training. At no time brain stimulation
will occur without a Certified User present in the lab.
References
Barker, A. T., Jalinous, R., & Freeston, I. L. (1985). Non-invasive magnetic stimulation of human
motor cortex. Lancet, 1(8437), 1106–1107.
Breedlove, S. M., Rozenzweig, M. R., & Watson, N. V. (2007). Biological Psychology: An
introduction to behavioral, cognitive, and clinical neuroscience (5th ed.).
Sunderland: Sinauer Associates, Inc.
Gazzaniga, M. S., Ivry, R. B., & Mangun, G. R. (2002). Cognitive Neuroscience: The
biology of the mind (2nd ed.). New York: W. W. Norton & Company.
Huang, Y. Z., Edwards, M. J., Rounis, E., Bhatia, K. P., & Rothwell, J. C. (2005). Theta burst
stimulation
of
the
human
motor
cortex.
Neuron,
45(2),
201–206.
doi:10.1016/j.neuron.2004.12.033
Rossi, S., Hallett, M., Rossini, P. M., & Pascual-Leone, A. (2009). Safety, ethical considerations,
and application guidelines for the use of transcranial magnetic stimulation in clinical
practice and research. Clinical neurophysiology : official journal of the International
Federation of Clinical Neurophysiology, 120(12), 2008–2039.
Wassermann, E. M. (1998, January). Risk and safety of repetitive transcranial magnetic
stimulation: report and suggested guidelines from the International Workshop on the Safety of
Repetitive Transcranial Magnetic Stimulation, June 5-7, 1996. Electroencephalogr Clin
Neurophysiol.
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