Supporting Cognitive Control Training With tDCS

University Hospital Tuebingen173 enrolled

Overview

Cognitive control (CC) is an important prerequisite for goal-directed behaviour and often associated with dysfunctional prefrontal activity within the cortex. This can be ameliorated by non-invasive brain stimulation. In this randomised single-blind study we compare effects of transcranial direct current stimulation (tDCS) on CC in healthy subjects. The study includes 162 subjects who undergo a two-week (six sessions) training of cognitive control (adaptive paced auditory serial addition task, PASAT) supported by tDCS. Subjects are randomised to receive either concurrent anodal, cathodal, or sham tDCS with an intensity of 1 mA or 2 mA of their left (F3) or right (F4) PFC, resulting in eight stimulation groups. Stimulation effects on performance changes are compared to a sham control group.Changes in Affective state are measured by the positive and negative affect schedule (PANAS), possible transfer effects are assessed by the Eriksen Flanker task. Stability of effects is measured up to three months after the last intervention.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

173

Conditions

Cognitive Control

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 40 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy subjects * Right-handed (assessed by Edinburgh Handedness Inventory) * No other concurrent brain stimulation during participation * Proficient in German (min. CEFR level B) * Ability to strictly adhere to study timeline Exclusion Criteria: * Diagnosed neurological illnesses * Diagnosed psychiatric disorders * Achromatopsia * Metallic implants / tattoos on or near electrode sites * Consumption of tobacco to an equivalent of ten or more cigarettes per day * Prior participation in experiments involving the PASAT

Outcomes

Primary Outcomes

Cognitive performance

Changes in performance in the PASAT (as assessed by number of correct trials within each PASAT session) due to the various tDCS interventions. All eight interventions will be compared to the sham group. Cognitive performance is modified by tDCS, which is applied through a multi-channel stimulator (DC-Stimulator MC, NeuroConn GmbH, Ilmenau, Germany; software version 1.3.8; two rectangular rubber electrodes (5 x 7 cm)).

Time frame: 2 to 14 weeks

Secondary Outcomes

Affective state

Changes in affective state over the course of the experiment (assessed by the positive and negative affect schedule (PANAS) questionnaire). Scores are calculated for negative and positive affect separately, by summing up the respective answers.

Time frame: 2 weeks

Transfer effect

Transfer effects in the Eriksen Flanker task (assessed through mean reaction times). Means are calculated for congruent, incongruent, and neutral trials respectively.

Time frame: 3 weeks