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NCT Number: NCT07080489

Exploring the Role of the Prefrontal Cortex in Decision-Making

The goal of this study is to examine whether high-definition transcranial direct current stimulation (HD-tDCS) can influence decision-making for emotionally valenced content in younger and older adults, with or without major depression.

The main questions are:

In healthy adults, does brain stimulation modulate how people respond to emotionally valenced content during a decision-making task? What happens in the brain during modulation? Do these effects differ between younger and older adults?

In adults with depression, does brain stimulation help shift attention towards positive content during the task? What happens in the brain? Are these effects moderated by age (younger vs. older adults)?

The investigators will compare participants who receive real stimulation to those who receive sham (placebo) stimulation.

Participants will:

Receive high-definition transcranial direct current stimulation (HD-tDCS) of the dorsolateral prefrontal cortex (DLPFC)

Perform a decision-making task involving emotionally valenced words

Complete the task while undergoing a brain scan using ultra-high field 7 Tesla magnetic resonance imaging (MRI) to measure brain activity

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Key information

Conditions

Depressive Disorder, Major Depressive Disorder Aging Behavior Behavioral Symptoms Depression Depressive Disorder Depressive Disorder, Major Healthy Volunteer Mental Disorders Mood Disorders

Age range

20 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Bern, Department of Old Age Psychiatry and Psychotherapy

Bern, 3000, Switzerland

Location status: Recruiting

Location contact

Jessica Peter, PhD

CONTACT

[email protected]

+41 58 630 89 03

About this study

This study investigates whether non-invasive brain stimulation influences decision-making in four groups: younger adults (20-40 years) and older adults (60-75 years), healthy or with mild to moderate major depression. Participants with personality disorders or psychosis will be excluded.

The study builds on evidence that the dorsolateral prefrontal cortex (DLPFC) plays a key role in evaluating emotionally-valenced material and decision-making. The investigators will examine whether modulation of this region through high-definition transcranial direct current stimulation (HD-tDCS) affects responses to emotionally valenced information. Stimulation will be administered differently across groups based on theoretical models of hemispheric function in mood regulation.

To explore the effect of stimulation at neurotransmitter level, the investigators will use ultra-high field 7 Tesla magnetic resonance spectroscopy (MRS) to measure Gamma-aminobutyric acid (GABA) / Glutamate concentrations in regions of interest at baseline and after stimulation. This allows to examine whether changes in inhibitory/excitatory neurotransmitters are linked to altered emotional processing and decision making.

By combining brain stimulation, ultra-high field neuroimaging, and spectroscopy, this study examines how changes in brain network activity and neurotransmitter levels relate to decision-making in health and disease. The inclusion of both younger and older adults allows the investigators to explore age-related differences in these processes.

This project aims to provide mechanistic insights into decision-making in health and disease and to support the development of targeted neuromodulation therapies that could modulate emotional processing.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

(Healthy):

  • Written Informed Consent
  • Age between 20-40 or 60-75 years
  • Fluent in German
  • Normal or corrected-to-normal vision
  • No color blindness
  • Right-handed
  • Non-smoker

Exclusion criteria

(Healthy):

  • History of neurological disorders
  • History of psychiatric disorders
  • Use of psychotropic medication
  • Presence of magnetizable implants
  • Alcohol or drug dependence

Inclusion criteria

(Patient):

  • Written Informed Consent
  • Diagnosed with mild to moderate depression
  • Age between 20-40 or 60-75 years
  • Fluent in German
  • Normal or corrected-to-normal vision
  • No color blindness

Exclusion criteria

(Patient):

  • Intake of benzodiazepines or antipsychotic medication
  • psychiatric disorders other than depression (e.g., psychosis, mania, personality disorders) or depression with organic cause
  • Presence of magnetizable implants
  • Alcohol or drug dependence

Treatment and study plan

Active high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/F4

Device

Participants receive anodal HD-tDCS targeting the left or right DLPFC (F3/F4).

Sham high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/F4

Device

Participants receive sham HD-tDCS targeting the left or right DLPFC (F3/F4). The device mimics the sensation of stimulation without delivering active current.

Active high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/ kathodal F4

Device

Participants receive anodal HD-tDCS targeting the left DLPFC (F3) and cathodal stimulation targeting the right DLPFC (F4).

Sham high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/ kathodal F4

Device

Participants receive sham HD-tDCS targeting the left DLPFC (F3) and right DLPFC (F4). The device mimics the sensation of stimulation without delivering active current.

Primary outcomes

  1. Blood-oxygen-level-dependent (BOLD) signal changes during task-based functional magnetic resonance imaging (fMRI)

    Time frame: During study visit; measured continuously during the 20-minute stimulation period

    Blood-oxygen-level-dependent (BOLD) signal changes will be measured using ultra-high field functional magnetic resonance imaging (fMRI) during a cognitive decision-making task designed to engage prefrontal cortex regions associated with cognitive control and decision making. Structural T1-weighted and T2-weighted images will also be acquired for anatomical localization and normalization. Primary regions of interest (ROIs) include the dorsolateral prefrontal cortex (DLPFC), subgenual anterior cingulate cortex (sgACC), amygdala, and hippocampus.

  2. GABA concentration (baseline)

    Time frame: During study visit; during a 9-minute magnetic resonance spectroscopy (MRS) session performed up to 10 minutes prior to the 20-minute stimulation period

    Magnetic resonance spectroscopy (MRS) will be used to measure Gamma-aminobutyric acid (GABA) concentrations in regions of interest at baseline. The goal is to examine stimulation-related neutransmitter changes.

  3. GABA concentration (after stimulation)

    Time frame: During study visit; within 1 minute after the 20-minute stimulation period, during a 9-minute MRS scan

    Magnetic resonance spectroscopy (MRS) will be used to measure Gamma-aminobutyric acid (GABA) concentrations in regions of interest after HD-tDCS. The goal is to examine stimulation-related neutransmitter changes.

  4. Glutamate concentration (baseline)

    Time frame: During study visit; during a 9-minute magnetic resonance spectroscopy (MRS) session performed up to 10 minutes prior to the 20-minute stimulation period

    Magnetic resonance spectroscopy (MRS) will be used to measure Glutamate concentrations in regions of interest at baseline. The goal is to examine stimulation-related neutransmitter changes.

  5. Glutamate concentration (after stimulation)

    Time frame: During study visit; within 1 minute after the 20-minute stimulation period, during a 9-minute MRS scan

    Magnetic resonance spectroscopy (MRS) will be used to measure Glutamate concentrations in regions of interest after HD-tDCS. The goal is to examine stimulation-related neutransmitter changes.

Secondary outcomes

  1. Positive Affect measured by PANAS (baseline)

    Time frame: During study visit; at baseline, up to two hours before the 20-minute stimulation period

    Positive Affect will be assessed using the Positive Affect subscale of the Positive and Negative Affect Schedule (PANAS). This subscale includes 10 items reflecting positive emotions. Each item is rated on a 5-point Likert scale. The sum score ranges from 10 to 50, with higher scores indicating greater levels of positive affect.

  2. Negative Affect measured by PANAS (baseline)

    Time frame: During study visit; at baseline, up to two hours before the 20-minute stimulation period

    Negative Affect will be assessed using the Negative Affect subscale of the Positive and Negative Affect Schedule (PANAS). This subscale includes 10 items reflecting negative emotions. Each item is rated on a 5-point Likert scale. The sum score ranges from 10 to 50, with higher scores indicating greater levels of negative affect.

  3. Positive Affect measured by PANAS (after stimulation)

    Time frame: During study visit; after stimulation, up to 1 hour

    Positive Affect will be assessed using the Positive Affect subscale of the Positive and Negative Affect Schedule (PANAS). This subscale includes 10 items reflecting positive emotions. Each item is rated on a 5-point Likert scale. The sum score ranges from 10 to 50, with higher scores indicating greater levels of positive affect.

  4. Negative Affect measured by PANAS (after stimulation)

    Time frame: During study visit; after stimulation, up to 1 hour

    Negative Affect will be assessed using the Negative Affect subscale of the Positive and Negative Affect Schedule (PANAS). This subscale includes 10 items reflecting negative emotions. Each item is rated on a 5-point Likert scale. The sum score ranges from 10 to 50, with higher scores indicating greater levels of negative affect.

  5. Storytelling (baseline)

    Time frame: During study visit; at baseline, up to two hours before the 20-minute stimulation period

    Participants will be asked to verbally recall one positive and one negative autobiographical memory. Verbal responses will be audio recorded and analyzed using automated speech analysis. The analysis will be performed by ki:elements, an external provider specialized in speech analysis.

  6. Storytelling (after stimulation)

    Time frame: During study visit; after stimulation, up to 1 hour

    Participants will be asked to verbally recall one positive and one negative autobiographical memory. Verbal responses will be audio recorded and analyzed using automated speech analysis. The analysis will be performed by ki:elements, an external provider specialized in speech analysis.

Other outcomes

  1. Verbal intelligence measured by Wortschatztest (WST)

    Time frame: During study visit; at baseline, up to two hours before the 20-minute stimulation period

    The Wortschatztest (WST) is a standardized test assessing verbal intelligence by measuring vocabulary knowledge in German. It is administered to account for participants' baseline language ability, helping to control for individual differences in German word knowledge that may affect performance in the decision-making task. The maximum possible score is 42, with higher scores indicating better vocabulary knowledge.

  2. Number of (participants with) adverse effects

    Time frame: During study visit; after stimulation, up to 1 hour

    Participants report adverse effects using the Adverse Effects Questionnaire. They indicate the presence and severity of possible adverse effects related to transcranial direct current stimulation (tDCS), including headache, neck pain, scalp pain, tingling, itching, burning, drowsiness, and concentration difficulties. Severity is rated on a scale from none, mild, moderate, to strong. Participants also report the perceived duration of each sensation and whether they attribute it to the stimulation. Open responses for any additional sensations are collected.

Study contacts

Contact information is provided by the study sponsor or research team.

Maya D Yilmaz, M.Sc.

CONTACT

[email protected]

+41 58 630 79 62

Sponsors and collaborators

Lead sponsor

University of Bern

Other

Collaborators

  • ki:elements

Registry information

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jul 23, 2025
Registry last updated
Jul 23, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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