Breathing and Decision-Making (ProlEx-MRI)

Breathing and Decision-Making: An fMRI Study Investigating the Link Between Slow Breathing and Risky Decision-Making

The study aims to investigate how slow breathing with prolonged exhalation (i.e., ProlEx breathing) modulates decision-making under risk in healthy participants. To do this, a short-term breathing intervention is combined with a decision-making paradigm while neural, physiological, and behavioral data are recorded.

This interventional study investigates the modulatory effect of slow breathing with prolonged exhalation (i.e., ProlEx breathing) on decision-making under risk. Using functional magnetic resonance imaging (fMRI), the researchers seek to identify brain regions influenced by the breathing intervention during the decision-making task. Sixty healthy participants will be invited to perform ProlEx breathing during a risky decision-making task. After initial preparations, each individual's spontaneous breathing rhythm will be determined (i.e., Eupnea, control condition). This step is to i) ensure a natural breathing pace for each participant and ii) incorporate cue-assisted breathing into the control condition to allow comparability across conditions. To further investigate the effect of ProlEx on sympathovagal tone, physiological measures of respiration, electrocardiogram, pulse, electrodermal activity, and pupil are acquired. During scanning, the participant will perform a decision-making task based on the paradigm by Tom et al. (2007). The breathing intervention is applied simultaneously with continuous cue-assisted breathing for both conditions (Eupnea, ProlEx) throughout the duration of the task. The experiment follows a block design with counterbalanced orders to control for confounding effects. After completion of the scans, the participants fill out additional questionnaires.

20 min divided in 3 blocks of slow, 0.1 Hz breathing (6 cycles per minute) with an inhalation-to-exhalation ratio of 2:8. Cue-assisted breathing (same across participants) and performance of a risky decision-making task (Tom et al., 2007) in the magnetic resonance imaging (MRI) scanner with simultaneous acquisition of physiological and pupil data.

20 min divided in 3 blocks of normal breathing (expected range: 0.16-0.33 Hz, i.e., 10-20 per min), Cue-assisted breathing (individually adapted) and performance of a risky decision-making task (Tom et al., 2007) in the MRI scanner with simultaneous acquisition of physiological and pupil data.

Risk propensity, i.e., the willingness to accept or reject a risky mixed gamble in an adapted paradigm based on Tom et al. (2007); assessed using response options "strongly accept", "weakly accept", "weakly reject", "strongly reject"

Low-frequency and high-frequency heart rate variability (LF-HRV and HF-HRV, respectively); assessed using an electrocardiogram (ECG) and pulse oximetry

The depression scale (self-report) will be assessed using Beck Depression Inventory (BDI) (Hautzinger et al., 1994). The questionnaire consists of 21 questions, with each item corresponding to a value ranging from 0 to 3. Higher total scores indicate more severe depressive symptoms. A total score of 0-13 is considered minimal, 14-19 mild, 20-28 moderate, and 29-63 severe.

Personality traits (self-report) will be assessed using the Big Five Inventory (BFI-10) (Rammstedt et al., 2013). The BFI-10 is a 10-item scale measuring the Big Five personality traits Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Openness. Ten items are answered on a 5-point Likert scale ranging from "strongly disagree" to "strongly agree". Scoring of the BFI-10 scales (R = item is reverse-scored): Extraversion: 1R, 5; Agreeableness: 2, 7R; Conscientiousness: 3R, 8; Neuroticism: 4R, 9; Openness to Experience: 5R, 10. Individuals who score high on the BFI-10 tend to exhibit certain qualities associated with each of the personality traits. The score can range from a minimum of 2 to a maximum of 10 points for each of the personality traits.

Impulsivity (self-report) will be assessed using the Barratt Impulsivity Scale (BIS-15) (Meule et al., 2011). This scale is a questionnaire consisting of 15 items scored from 1 to 4 with 1 = rarely / never, 2 = sometimes, 3 = often, and 4 = almost always / always. Scores range from 15 to 60, with higher scores reflecting greater impulsiveness.

Questionnaire assessing approach-avoidance behavior: "Behavioral Inhibition System/Behavioral Approach System" (BIS/BAS)

Approach-avoidance behavior (self-report) will be assessed using the Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) (Strobel et al., 2001). The BIS/BAS scale is a 24-item self-report questionnaire designed to measure two motivational systems. The behavioral inhibition system (BIS), which corresponds to the motivation to avoid aversive outcomes, has 7 items with a total score ranging from 7 to 28 points. The behavioral activation system (BAS), which corresponds to the motivation to approach goal-oriented outcomes,has 13 items with a total score ranging from 13 to 52 points. Four items act as filler items. Participants respond to each item using a 4-point Likert scale: 1 (very true for me), 2 (somewhat true for me), 3 (somewhat false for me), and 4 (very false for me). Total scores are calculated for BIS and BAS, with a higher score corresponding to higher behavioral inhibition and activation, respectively.

Self-control (self-report) will be assessed using the Brief Self-Control Scale (BSCS) (Sproesser et al., 2011). The BSCS measures trait self-control via items with a 5-point Likert scale, where 1 refers to 'not at all' and 5 to 'extremely'. Scores range from 13 to 65. Higher scores represent higher levels of self-control.

Questionnaire assessing interoceptive awareness: "Multidimensional Assessment of Interoceptive Awareness" (MAIA-2)

Interoceptive Awareness (self-report) will be assessed using the "Multidimensional Assessment of Interoceptive Awareness" (MAIA-2) (Mehling et al., 2018). The MAIA assesses multidimensional aspects of self-reported interoception and includes 37 items using a six-point Likert scale (0 never, 5 always). Higher scores equate to higher awareness of bodily sensation. The results from the MAIA-2 focus on the individual scale scores (Mehling et al., 2012).

Affect (self-report) will be assessed using the Positive and Negative Affect Scale (PANAS) (Janke et al., 2014). The PANAS is a self-report questionnaire that consists of two 10-item scales to measure both positive and negative affect. Each item is rated on a 5-point scale of 1 (not at all) to 5 (very much). Positive Affect Score: the scores on items 1, 3, 5, 9, 10, 12, 14, 16, 17, and 19. Scores can range from 10 - 50, with higher scores representing higher levels of positive affect. Negative Affect Score: Add the scores on items 2, 4, 6, 7, 8, 11, 13, 15, 18, and 20. Scores can range from 10 to 50, with lower scores representing lower levels of negative affect.

Stress (self-report) will be assessed using the Perceived Stress Questionnaire (PSQ) (Fliege et al., 2001). The PSQ a self-report questionnaire that consists of 20 items. Each item is rated on a 4-point Likert scale of 1 to 4. Total scores range from 20 to 80. Higher scores indicate greater levels of stress.

Self-efficacy (self-report) will be assessed using the General Self-Efficacy Scale (GSE) (Schwarzer et al., 1997). The GSE is a 10-item scale with a score for each item ranging from 1 to 4. Total scores range from 10 to 40. Higher scores indicate higher self-reported self-efficacy.

Trait anxiety (self-report) will be assessed using the State-Trait Anxiety Inventory (STAI-T) (Grimm et al., 2009). The State-Trait Anxiety Inventory (STAI-T) is a 20-item scale with a score for each question ranging from 0 to 3. Total scores range from 0 to 60. Higher scores indicate higher levels of anxiety.

Mental well-being (self-report) will be assessed using the Warwick-Edinburgh Mental Well-Being Scale, short version (SWEMWBS) (Lang et al., 2017). The WEMWBS is scored by summing the responses to each of the 14 items on a 1 to 5 Likert scale. Total scores can range from a minimum of 14 to a maximum of 70 points. Higher scores are associated with higher levels of mental well-being.

Inclusion Criteria: Healthy men and women Normal vision (no glasses or contact lenses required) Exclusion Criteria: Smokers Extreme athletes Extensive lung function (e.g., professional musician, abnoedivers) Excessive stress Former or current physical or psychological illness (e.g., lung diseases) Current or previous medication within 2 weeks before the appointment Left-handedness Claustrophobia Tinnitus Non-removable metal parts or implants inside or on the body (e.g., hip replacements, copper IUD) Non-removable ferromagnetic objects inside or on the body (e.g., joint replacements) Non-removable magnetic objects inside or on the body (e.g., artificial eye) Large tattoos Young (>18 years) or old (>40 years) subjects Over- or underweight (BMI <18 or >25 kg/m2) Pregnancy Abnormal circadian rhythm (e.g., during shift work) Excessive alcohol consumption Illegal drug consumption within 2 weeks before the appointment Missing consent to participate Missing consent to receive incidental findings (MRI)

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Lang, G. & Bachinger, A. Validation of the German Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) in a community-based sample of adults in Austria: a bi-factor modelling approach. J Public Health 25, 135-146 (2017)

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