W2: Cardiovascular Methods Flashcards
advantageous to measure the autonomic nervous system (ANS)?
Not susceptible to self-report biases as (2)
- These measurements are of automatic and uncontrollable responses so people can not lie about their heart rate or change it
- This is useful when studying sensitive topics
Advantageous to measure to autonomic nervous system
Allows for moment-to-moment reactions and therefore (2)
- Allows to track for changes in activity
- Which allows deeper understanding of physiological processes inside the body
Advantageous of measuring ANS
as may precede conscious awanress (2)
Theory + example (2)
- Cannon-Bard Theory of emotion - physiology precedes psychology
- See bear and heart rate increases and sweat and run and after all that stuff occurs then you feel that you are scared and that’s why you are scared
Advantageous of measuring ANS
Patterns of cardiovascular activity is linked to vulnerabilities in (2)
Mental and physical health
Can be used as a risk factor for cause or progression
Measuring ANS Activity Options (4)
- Electrodermal activity (or also known as galvanic skin response)
- Cardiovascular activity
- Blood pressure
- Heart rate
Electrodermal activity (EDA) measures the response of (2)
sweat glands
Measures anxiety/stress/arousal
Electrodermal activity (EDA) measures the response of sweat glands
Mostly densely located in the
hands and soles of the feet (get very sweaty there)
EDA measures the response of sweat glands because
sympathetic activation stimulates sweat glands to overcome a stressor in the environment
Measure EDA through skin conductance which is measured by
- apply sensors to the arm which passes a small electrical current through the skin
Measuring EDA
Skin conductance assesses
The resistance to the electrical current to the skin
Measuring EDA
High and less resistance (2)
Less resistance = more sweat there and assume more sympathetic activation is going on and more anxious
High resistance = vice versa
Resistence is the opposite of
Condutance
Skin conductance is measured in
Microsiemens
The more emotionally aroused an individual is, the more the SCR (skin condutance)
amount is increased
Skin conductance is not immediate, it takes
time
It could be minutes after we stress someone out to see their sweat appear and condutance increase
Since skin condutance is not immediate
we can examine
- “Phases” of change
Since skin condutance is not immediate
we can examine phases of change and tend to average over large periods of time of skin conductance as…
- Conductance changes slowly over longer periods (minutes)
Recording skin condutance (EDA)
Procedure (2)
- Ag/Ag CL (silver) electrodes placed on the fingers or plans (these conductive to electricity)
- Prepare before applying electrodes by cleaning skin (via water or alcohol) and applying electrolyte gel (containing KCL or NaCL - salt- conductive)
Recording skin condutance (EDA)
Why apply electrolyte gel to electrode
Allows for better recording of signal
Analysing conductance
Cleaning the data with smoothing fitlers as raw data is messy as (2)
- Movement artefacts (if you move slightly then causes data to move around and shift)
- Missing data: Moving too quickly (e.g., sneezes) creates temporarily disconnection of gel and sensors
Analysing conductance
How to deal with missing data? (2)
- Replaces missing data with estimations made by software
- Use regression-bases algorithms
Cardiovascular measures
Options (4)
- Electrocardiogram (ECG)
- Respiration
- Impedance cardiography (ICG)
- Blood pressure (BP)
Electrocardiogram (ECG)
The heart produces
Electrical signals
Electrocardiogram (ECG)
Electrodes capture the
depolarisation of ventricles in the heart
ECG measures the activity of electrical signals in the heart that is represented as (2)
Points on the ECG waveform
QRS complex - R point when heart is depolarised after it pushes blood out to the rest of the body
How to compute heart rate variability
ECG
What measurements do you get from ECG? - (2)
- Heart rate (amount of R points per minute)
- Heart rate variability (average distances between R points) - large distance more advantageous of stress and switching between systems
Impedance cardiography (ICG) -(3)
Estimate changes in blood flow in the heart
- How much blood ejected during each heart beat?
- Volume of blood (stroke volume)
Impedance cardiography (ICG)
electrodes placed on torso (2)
Outer sensors send electrical current
Inner sensors detect resistance of current
ICG
As blood volume increases
Resistence increases!
ICG relates to
ECG
Blood pressure (BP)
Systolic blood pressure - (2)
Peak arterial pressure
Heart is pushing blood through your system
Blood pressure (BP)
Diastolic blood pressure - (2)
Lowest arterial pressure
When the heart stopped beating - heart is refractory period before going to next heart beat
Systolic and diaolstic blood pressure
While often correlated/related, they provide
unique information
Blood pressure on graph (4)
- Blood pressure increases as blood flows into the aorta of heart
- Then max (systolic) pressure reaches at the peak
- As the aortic value closes, blood pressure falls as blood flows out of aorta of heart
- Then reaches minium (diasoltic) pressure
Systolic and diastolic - While often correlated, they provided unique information
Increased systolic, but not diastolic =
Adaptive stress response
Systolic blood pressure is how much blood you are pushing out
The pressure your blood is
being resistant against
Systolic pressure = amount of effort (2)
- Heart is beating faster - more effort to push blood through the system and working against the blood vessels
- Increase blood pressure as a result
High systolic blood pressure is more indicative of (3)
Poor health - heart worker harder than rest of the body
predicts development of heart disease
hypertension (increased arterial pressure) causes wear
Low systolic blood pressure (3)
- Heart is working cooperatively with your blood pressure
- Not much resistance to let blood pass through the system
- No pressure build up
High Systolic blood pressure predicts the development of heart disease
Hypertension (increased arterial pressure) causes wear (2)
- If you are constantly working against your blood vessels and pushing blood through restricted passages causes wear and tear and damage heart and blood vessels
Blood pressure (BP)
Mean arterial pressure (MAP)
- Ratio of systolic and diastolic pressure
- Often reported instead of diasoltic/systolic pressure
- Weighted average of systolic and diastolic pressure
- 2 parts diastolic
- 1 part systolic
Blood pressure (BP)
Diagram Mean arterial pressure (MAP)
Blood pressure
Total peripheral resistence (4)
- Ratio of blood flow vs restrictions
- Capture how much blood we are pushing through our body vs how much resistance there is to that blood flow
- A lot of blood through your heart and low resistance = body working adaptively - blood easily pass
If we believe we can overcome a stressor..
Challenged state (positive stress state)
Challenged state is where -(3)
- SAM axis is activated for short-term response to the stress
- Increased blood output and higher heart rate
- Lower blood pressure due to reduced restriction of blood flow (blood easily gets where it needs to go to make you feel relaxed)
Example of a challenged state (2)
- Well-prepared and studied for an exam
- Exam is stressful but felt like you did good
If we are unsure whether we can overcome a stressor…
Threatened state
Threatened state (2)
Physiologically what happens..?
- SAM axis is engaged (short-term response) as well as the HPA axis (long-term response)
- On a physiological level, there is little to no change in blood output due to restriction of arteries that causes high blood pressure.
Threatened state example - (3)
- Hangover for exam
- Show late for exam
- Didn’t study for exam
Vick et al. 2017
Challenge and threat states results from (2)
Evaluation of situational demands and personal resources
Both influenced by cognitive and affective (moods, feelings)
Vick et al 2017
Situations in where challenge and threat emerge from is + examples (2)
Situations defined as goal-relevant and task engaging that require cognitive or cognitive-behavioural responses
For example, delivering a speech, taking a test
Challenged vs threat in terms of resources (2)
- Resources are evaluated as equalling or exceeding situational demands, challenge motivation results
- When demands are evaluated as outweighing the resources to cope with task then threat mtoviation results
Vick et al. (2017)
Method -(3)
- 141 psychological students - male and female
- Individual participants assigned to one of two stereotype threat conditions of gender-biased or gender-fair.
- Cardiovascular response was collected continuously during the conditions while they took a quantitative comparison test to test their maths ability
Vick et al. (2017)
Findings (2)
- Women were relatively threatened during a performance when task was characterised as gender-biased whereas men were relatively challenged when they believed gender-differences in performance were expected.
- Women were relatively challenged during a performance when the task was characterised as gender-fair, whereas men were relatively threatened when they believed they were taking a non-biased test.
HRV is a index (indicator) of vagal tone and reflects the balance between
parasympathetic and sympathetic.
Sympathetic nervous system activation accelerates heart rate (HR) and decrease HRV, whereas parasympathetic nervous system decelerates HR and
increases HRV.
What cardiovascular measurements did Vick et al (2017) obtained?
impedance cardiography, electro-cardiography and continuous blood pressure equipment
