8.4.2 Flashcards
How is heart rate measured in hospitals?
Heart rate is often measured using electrocardiography (ECG), which records beats per minute. It can also be measured manually by taking a pulse at the wrist.
What happens to heart rate under stress?
Heart rate increases in acutely stressed individuals and decreases in chronically stressed individuals (Schubert et al., 2009).
What is heart rate variability (HRV)?
HRV is the variation in time between heartbeats, measured in milliseconds. Higher variability occurs when relaxed, and lower variability when stressed.
How can HRV be measured?
HRV can be measured using hospital ECG machines or portable devices like smartwatches that detect blood flow and calculate the interbeat interval.
What does functional MRI (fMRI) measure?
fMRI detects brain activity by measuring changes in blood oxygenation and flow, showing neural activity levels in different brain areas.
What was the aim of Wang et al. (2005)?
To study the central circuitry of psychological stress using functional MRI (fMRI).
What was the sample size in Wang et al. (2005)?
32 participants: 25 in the experimental group and 7 in the control group.
What tasks did participants perform in the fMRI scans in Wang et al. (2005)?
- Baseline scan (no task). 2. Low-stress task: Counting backward from 1000. 3. High-stress task: Serial subtraction of 13 while being pressured. 4. Final baseline scan (no task).
What were the control group conditions in Wang et al. (2005)?
The control group had four scans of equal length, but they did not perform tasks in scans two and three.
What measures were recorded in Wang et al. (2005)?
Self-report stress scale (1-9), saliva samples, effort/frustration/task difficulty ratings, and heart rate recorded every two minutes.
What brain region showed continued activation during stress in Wang et al. (2005)?
The ventral right prefrontal cortex (RPFC) remained active during and after stress tasks.
What did Wang et al. (2005) conclude about psychological stress?
Psychological stress leads to negative emotions and increased vigilance, with the ventral RPFC playing a central role in the stress response.
How does fMRI support previous research on stress?
Findings showed RPFC activation is linked to negative emotions like fear and sadness, supporting emotional network theories.
What is a key strength of using perfusion MRI in stress research?
Perfusion MRI is non-invasive compared to PET scans, as it does not require a radioactive tracer, making it safer for participants.
Why is fMRI considered a more objective method of measuring stress?
Unlike questionnaires or observations, fMRI does not rely on self-reporting or subjective interpretation, improving reliability.
What is a limitation of fMRI in stress research?
MRI scans are expensive and time-consuming, leading to small sample sizes (e.g., 32 participants in Wang et al., 2005), reducing generalizability.
What is the main function of the prefrontal cortex in stress response?
The prefrontal cortex regulates stress responses, emotions, and vigilance, particularly the ventral right prefrontal cortex.
Why was the order of tasks controlled in Wang et al. (2005)?
To prevent contamination of the control condition by heightened emotional responses from the high-stress task.
What biological measure besides fMRI is used to assess stress?
Heart rate and HRV, measured using ECGs, smartwatches, and pulse checks.
Why does chronic stress reduce HRV?
Chronic stress decreases HRV by reducing the variation between heartbeats, indicating an overactive stress response system.
