The Effect of tDCS on Emotion Recognition and EEG

Purpose and Importance of the Project: Emotion recognition, which is defined as the process of interpreting an individual's emotional state by looking at their facial expressions, is important in maintaining social relations and communication in a healthy way. Difficulties in emotion recognition can be seen in various neurodevelopmental or psychiatric disorders. The ventromedial prefrontal cortex (vmPFC) is one of the regions that is important in the function of emotion recognition from facial expressions. Transcranial Direct Current Stimulation (tDCS) is a non-invasive, painless method of brain stimulation that provides either excitatory or inhibitory effects on different parts of the brain. When the literature is examined, it is seen that studies on the effectiveness of tDCS on emotion recognition are limited and stimulation is generally applied to the right or left dorsolateral prefrontal cortex areas in these studies. On the other hand, no study has been found examining the effect of stimulation of the ventromedial prefrontal cortex on emotion recognition. In this study, it is aimed to investigate the effect of anodal stimulation of the ventromedial prefrontal cortex, which is significantly related to emotion recognition skills, on emotion recognition and EEG oscillations.

Methods: It is an experimental, randomised controlled trial. The data will be collected with the convenience sampling method from healthy and volunteer participants. The matched-group design method will be used. As a result of the power analysis, it was determined that the current study should be done with at least 34 participants. In the study, it is aimed to include a total of 60 participants in the experimental (tDCS) and control (sham) groups. Measurement instruments are "Informed Voluntary Consent Form"; "Demographic Information Form"; "Edinburgh Hand Preference Survey"; "Beck Depression Scale"; "Amsterdam Dynamic Facial Expression Set - Bath Intensity Variations (ADFES-BIV)"; "Mind-Reading Test"; EEG and tDCS devices. Participants will be subjected to the emotion recognition task before and after the tDCS. In addition, resting state EEG recordings will be taken before and after the tDCS from 34 participants.

Measurement instruments:

* Informed Voluntary Consent Form
* Demographic Information Form
* Edinburgh Hand Preference Survey
* Beck Depression Scale
* Amsterdam Dynamic Facial Expression Set - Bath Intensity Variations (ADFES-BIV)
* Reading the Mind in the Eyes Test
* EEG and tDCS devices

Statistics:

The findings obtained from experimental and control groups the pretest-posttest of the emotion recognition and resting state EEG measurement will be evaluated with Repeated Measures Analysis of Variance (within and between groups) (or Friedman Analysis, which is its non-parametric counterpart). For all tests applied to the variables, the significance value will be accepted as p\<0.05.

Eligibility Criteria:
Inclusion Criteria:

* Being between the ages of 18-40,
* Having a score of 17 or less on the Beck Depression Inventory

Exclusion Criteria:

* Having a history of serious neurological and psychiatric illness,
* Currently taking medication that alters the cortical excitability level,
* Having visual defects that cannot be corrected with glasses,
* Left hand dominant,
* Use of intracranial metal objects, implanted stimulating devices or pacemakers