tDCS, Moral Decision-Making, fMRI

National Yang Ming Chiao Tung University Hospital

Status: Completed

Conditions: Morality

Treatments: Device: transCranial direct current stimulation

Study type: Observational

Funder types: Other

Identifiers

NCT04681391

2016B008

Details and patient eligibility

About

Morality is the social rule about appropriateness of the behavior, containing concepts of justice, fairness, and rights. Previous studies suggested that the activation of right temporoparietal junction (rTPJ) should be involved in mental state reasoning in moral cognition. Implicit moral attitude, which reflects people's fundamental beliefs about right and wrong, could be assessed by implicit association test on moral scenarios (mIAT), as indicated by the D scores. According to our previous findings, we postulate that, during moral decision-making, the high D group would have less rTPJ involvement and the low D group would have more. Here we applied tDCS, a non-invasive neuromodulation technique, to modulate cortical excitability in rTPJ.

Based on our postulation, we divided participants into high D and low D group and hypothesized that tDCS over rTPJ would modulate the behavior depending on the group. The results revealed that, in aspect of mIAT, implicit moral attitude could be modulated differently depending on the group via tDCS over rTPJ. In addition, hemodynamic response within rTPJ showed a main effect of tDCS while carrying out the helping behavior. In conclusion, these findings indicated that tDCS over rTPJ could modulate the implicit moral attitude as well as the rTPJ activity during moral action.

Enrollment: 42 patients

Sex: All

Ages: 20 to 30 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• healthy volunteers, are all ethnic Chinese, right-handed, and aged between 20 to 30 years old

Exclusion criteria

• any history of psychiatry or neurological disorders (e.g., dementia, seizures), head injury, and alcohol or substance abuse

Trial design

42 participants in 3 patient groups

anodal

Description:

For the active stimulation, which are anodal and cathodal tDCS, a constant current of 1 mA was delivered through 35 cm2 electrode for 20 minutes with fade-in and fade-out of 10 seconds, producing a current density of 0.029 mA/cm2. During anodal tDCS, the anode was placed over right temporoparietal junction, and the cathode was placed over left supraorbital area.

Treatment:

Device: transCranial direct current stimulation

cathodal

Description:

For the active stimulation, which are anodal and cathodal tDCS, a constant current of 1 mA was delivered through 35 cm2 electrode for 20 minutes with fade-in and fade-out of 10 seconds, producing a current density of 0.029 mA/cm2. During cathodal tDCS, the cathode was placed over right temporoparietal junction, and the anode was placed over left supraorbital area.

Treatment:

Device: transCranial direct current stimulation

sham (as a control condition)

Description:

same fade-in, fade-out, and current density were applied for the sham stimulation, but the duration of current-delivering only last 35 seconds.

Treatment:

Device: transCranial direct current stimulation