Influence of Dopaminergic Blockade on Stress Responses, Motivation and Emotional Reactivity in Humans.

Before and after the stress test of experiment 1 we ask every participant for their perceived stress level. These data serve as an indicator of subjective stress responses. We analyze changes in subjective stress level compared to baseline measurements (76 min and 22 min before). Five minutes before the stress test starts we measure subjective anticipatory stress response and directly after the completion we measure post stressor responses and possible residual feelings of stress (16 minutes post completion).

All measurements reflect a single time series. Stress levels are obtained with visual analogue scales ranging from 0 (no stress) to 100 points (extremely stressed).

In experiment 2 which is a computer task, participants can choose between an easy task with low monetary reinforcement or a hard task with higher monetary reinforcement. "Easy" means that there is a low amount of physical or cognitive effort per trial and "hard" means that there is a higher amount of physical or cognitive effort per trial. From the tasks that are described in Reddy et al (2015) the balloon effort task (physical effort) and the deck choice task (mental effort) will be used. For both tasks our software automatically obtains the percentage of difficult trials with respect to the total number of trials. Note that only a single composite score is obtained after finishing the balloon effort task.

In experiment 2 which is a computer task, participants can choose between an easy task with low monetary reinforcement or a hard task with higher monetary reinforcement. "Easy" means that there is a low amount of physical or cognitive effort per trial and "hard" means that there is a higher amount of physical or cognitive effort per trial. From the tasks that are described in Reddy et al (2015) the balloon effort task (physical effort) and the deck choice task (mental effort) will be used. For both tasks our software automatically obtains the percentage of difficult trials with respect to the total number of trials. Note that only a single composite score is obtained after finishing the deck choice effort task.

Valence and arousal measures are collected as in Strauss et al. (2017) after presentation of IAPS pictures during experiment 3. Ratings for positive affect, negative affect and arousal ratings are obtained with a 10 point self-assessment manikin scale after the presentation of each individual picture. Note that only a single composite score for positive affect is calculated as the mean value of all evaluations following the individual pictures.

Valence and arousal measures are collected as in Strauss et al. (2017) after presentation of IAPS pictures during experiment 3. Ratings for positive affect, negative affect and arousal ratings are obtained with a 10 point self-assessment manikin scale. Note that only a single composite score for negative affect is calculated as the mean value of all evaluations following the individual pictures.

Before and at three time points after the stress test is completed of experiment 1 we take saliva cortisol samples of each participant. These samples are analysed for cortisol levels and serve as an indicator of Hypothalamic-pituitary-adrenal axis reactivity.

Cortisol levels are measured in nmol/liter.

Before, during and after the stress test of experiment 1 we use blood volume pulse measures for obtaining heart rate data and calculate heart rate change scores and heart rate variability scores (HRV). These data serve as an indicator of cardiovascular stress responses.

Heart rate changes are measured in Δ1/s. Changes in heart rate variability is normalized for heart rate change because higher HR during stress exposure could induce a mathematical bias. Data that will be obtained include the low frequency band and the high frequency / low frequency ratio. A short introduction into the topic can be found in Billmann et al (2015).

Valence and arousal measures are collected as in Strauss et al. (2017) after presentation of IAPS pictures during experiment 3. Ratings for positive affect, negative affect and arousal ratings are obtained with a 10 point self-assessment manikin scale. Note that only a single composite score for negative affect is calculated as the mean value of all evaluations following the individual pictures.