The aim is to specify the role of the vlPFC in the control of social emotional behavior. We will combine transcranial direct current stimulation (tDCS) and a modified version of the joystick affective AAT involving posturography (to assess postural…
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Source
Brief title
Condition
- Other condition
Synonym
Health condition
na
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Reaction time and responses, made by the participant, will be used to test
whether anodal tDCS of the vlPFC compared with the control tDCS conditions will
decrease the instrumental biases evoked by the emotional faces. Furthermore,
postural sway will be used to test whether anodal tDCS of the vlPFC compared
with the other tDCS conditions will decrease reduction of postural sway evoked
by negative emotional faces (as a measure of an automatic emotional response).
Secondary outcome
Enhanced freeze has been shown to be associated with anxiety, whereas decreased
emotional influences on instrumental approach-avoidance biases have been found
to be associated with instrumental aggression. To account for the effects of
individual differences, subjective questionnaires will be administered to
assess the individual differences in anxiety, aggression, and attentional
control. Data of a non-social version of the task, in terms of reation time and
responses, made by the participant, will be used to test whether offline tDCS
of the vlPFC will decrease the instrumental biases evoked by the non-social
emotional stimuli.
Background summary
A number of studies have employed the joystick affective approach-avoidance
task (AAT) for studying control of social emotional behavior. Using this
paradigm, it has been shown that reaction times are longer during approach of
negative and avoidance of positive facial expressions (affect-incongruent),
compared with the reaction times during the approach of positive and the
avoidance of negative facial expressions (affect-congruent), referred to as the
congruency-effect. This effect is due to the requirement to override the
automatic emotional responses in the affect-incongruent condition. There is
causal evidence that the vlPFC is crucial for overriding such automatic
emotional responses. However, it remains unknown whether the vlPFC exerts its
effect by inhibiting the emotional responses themselves in the
affect-incongruent context, or by regulating their influence (i.e. transfer) on
goal-driven (instrumental) behavior during performance of affect-incongruent
trials, or even both.
Study objective
The aim is to specify the role of the vlPFC in the control of social emotional
behavior. We will combine transcranial direct current stimulation (tDCS) and a
modified version of the joystick affective AAT involving posturography (to
assess postural control), which allows us to disentangle automatic emotional
responses and instrumental responses. The primary objective is to causally test
whether the vlPFC is involved in the control of social emotional behavior, by
inhibiting emotional responses and/or by regulating the transfer of emotional
responses onto instrumental behavior.
Study design
This involves an experimental between-subject design. Participants will receive
one of the three tDCS conditions and perform a modified version of the joystick
affective AAT involving posturography.
Intervention
Participants will receive one of the following three interventions:
1. Anodal tDCS of the vlPFC (experimental condition)
2. Cathodal tDCS of the vlPFC (to control for polarity)
3. Sham tDCS (to control for stimulation)
Study burden and risks
Participants will not directly benefit from their participation in the study,
except for a compensatory (financial) incentive. Transcranial current
stimulation (tCS) is a widely used non-invasive brain stimulation technique,
applying weak direct/alternating currents (tDCS/tACS) via conductive
rubber/sponge electrodes to the scalp. These weak currents can slightly shift
the neurons* membrane potential and thereby increase or decrease spontaneous
neuronal activity in the stimulated cortex, but (unlike TMS) they do not evoke
action potentials. During the stimulation, participants may transiently
experience light tingling, itching or burning sensations on the skin underlying
the electrodes, which can be unpleasant. The most common side effects are a
light transient headache and a feeling of fatigue. In the current study,
healthy participants will be stimulated with a protocol that is considered safe
with respect to the latest published safety guidelines. All subjects are
screened for their relevant medical history and other tCS safety aspects (e.g.
metal parts in the head, skin allergies). In summary, because the risk is
negligible and the burden associated with participation can be considered
minimal, we do not expect serious adverse events during the project.
Kapittelweg 29
Nijmegen 6525 EN
NL
Kapittelweg 29
Nijmegen 6525 EN
NL
Listed location countries
Age
Inclusion criteria
Only healthy, competent, women (18-35 years) with normal or corrected-to-normal vision will be included.
Exclusion criteria
• Serious head trauma or brain surgery
• Large or ferromagnetic metal parts in the head (except for a dental wire)
• Implanted cardiac pacemaker or neurostimulator
• Pregnancy
• Skin diseases at intended electrode sites (tCS)
• Disorders of vision (i.e., deviation from *normal or corrected-to-normal vision*)
• History or current presence of any neurologic or psychiatric disease
• Any prescribed medication that can alter cortical excitability (e.g. antiepileptics, tricyclic anti-depressives or benzodiazepines) or can have an influence on the participant*s vigilance or cognitive performance within two weeks prior to participation
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL44618.091.13 |