L5 - EDA Flashcards
What are the advantages of using EDA?
- EDA directly reflects sympathetic activity (unlike heart rate or blood pressure)
- Discriminability (easy to detect when a response has occured)
- Influenced primarily by activation of behavioral inhibition system (e.g. passive avoidance), which cannot be easily picked up by cardiovascular measures
- Individual differences in EDA are reliably associated with psychopathological states
- Low cost; practical solution
What are the disadvantages of using EDA?
- Slow Response Time (SCR latency is 1–3 seconds; tonic shifts in SCL take a similar time to manifest) -> Not suitable for tracking rapid processes or real-time analysis of complex cognitive events.
- Multiple Influences: EDA is influenced by many processes (e.g., attention, affect, significance) and is not specific to a single type of event.
- May need complementary measures for a complete picture of ANS activity.
- Control condition is very important
Give 4 examples of discrete stimuli infliction methods in studies
- Guilty Knowledge Test (GKT)
- Famous Faces Recognition Paradigm
- Discrimination Classical Conditioning
- Preparedness and Fear-Relevant Stimuli
Brain Mechanisms in SCR Conditioning - roles of brain zones
Amygdala: Essential for creating conditioned SCRs (learning to associate signals with fear).
Hippocampus: Necessary for understanding and consciously explaining the relationship between the signal and the outcome.
Orienting Response is
The orienting response (OR), also called orienting reflex, is an organism’s immediate response to a change in its environment, when that change is not sudden enough to elicit the startle (испуг) reflex.
Orienting Responses and Stimulus Significance
- Subjects orient more to significant stimuli (e.g., correct GKT answers, famous faces, or CS+ signals).
- SCR sensitivity extends to significant stimuli even when the significance is not consciously processed.
What are the most useful electrodermal measures in the context of continuous stimuli?
SCL and frequency of NS-SCRs, because they can be measured on an ongoing basis over relatively long periods of time.
What happens to skin conductance level (SCL) and the frequency of non-specific skin conductance responses (NS-SCRs) when anticipating or performing a task (continuous stimuli)?
The anticipation and performance of practically any task will increase both SCL and the frequency of NS-SCRs, at least initially (tonic EDA). SCL increases in every type of task (external/internal).
Typically, SCL increased about one μS above resting level during anticipation and then increased another one or two μS during performance of the task (Ms = microsiemens)
What were the main findings of Munro et al. (1988) regarding SCL and NS-SCR frequency during the vigilance task?
Munro et al. (1988) found large initial increases in SCL and NS-SCR frequency during the task, followed by a gradual decline as the task progressed.
What physiological response is reliably increased by strong emotions?
Strong emotions reliably increase tonic electrodermal activity (EDA).
How fear, anger and disgust reflected on skin conductance based on studies?
Fear caused greater increases in SCL, while anger led to greater increases in NS-SCR frequency and diastolic blood pressure.
Levenson & Gross (1993): Used films to elicit emotions like disgust for over a minute.
SCL increased more when subjects were told to suppress their emotions than when they simply watched the films or reappraised them objectively.
In stressful tasks what does increased autonomic arousal can reflect?
Increased autonomic arousal can reflect:
Effortful attention and resource allocation.
Stressful challenges that induce emotional arousal.
What were the findings in 42 hours of psychotherapy and married couples studies in relation to EDA?
Psychoteraphy:
- NS-SCR frequency was inversely related to therapist permissiveness.
- High EDA reflected patient anxiety and resistance to perceived threats of punishment.
Marital conflict discussions:
- Distressed couples showed greater physiological linkage (correlation between spouses’ physiological responses) than satisfied couples.
- Higher physiological arousal (including SCL) was associated with declining marital satisfaction over three years.
High-EE vs. Low-EE Relatives: what is EE and what were the findings in the study in relation to patients with schizophrenia?
Expressed Emotion (EE) - Describes the critical, hostile, or emotionally overinvolved attitudes of family members.
High-EE environments correlate with higher relapse rates in schizophrenia patients.
NS-SCR frequency was similar during rest without relatives.
Patients with high-EE relatives showed significantly higher NS-SCRs when relatives were present.
Supports the hypothesis that autonomic arousal mediates stress from high-EE relatives, increasing relapse risk.
Describe Vicious Cycle of Stress and Relapse in relation to patients with schizophrenia.
Continuous exposure to high-EE relatives:
1. Causes autonomic hyperarousal, leading to deteriorated behavior in patients.
2. This worsens the social environment, creating a feedback loop of stress and behavioral decline.
3. Breaking the cycle (e.g., removal from the high-EE environment) is critical to prevent relapse.
Explain Electrodermal Lability
Individual differences in the rate of NS-SCRs and the rate of SCR habituation have been used to define a trait called “electrodermal lability”
Who are labiles and stables? How they perform?
Labiles: Individuals with high NS-SCR rates and slow SCR habituation.
Stabiles: Individuals with low NS-SCR rates and fast SCR habituation.
Traits of Labiles:
1. Better performance in tasks requiring sustained attention and vigilance.
2. Stronger capacity for resource allocation in cognitive tasks.
Traits of Stabiles: Greater vigilance decrement (снижение бдительности; performance decline over time).
What are the two subgroups of schizophrenia patients based on electrodermal activity (EDA) & what characterises them?
What percentage of schizophrenia patients are non-responders, and how does this compare to healthy controls?
Non-responders and responders.
Non-responders fail to exhibit SCRs to mild stimuli, are associated with emotional withdrawal, disorganization, and negative symptoms.
Responders show heightened tonic arousal (high SCL and NS-SCR frequency) and are associated with excitement, anxiety, and manic behavior.
Non-responders make up 40-50% of schizophrenia patients compared to 10-25% in healthy controls.
What are the predictive and stable findings regarding electrodermal activity (EDA) in schizophrenia subgroups?
- Non-responders: Tend to have more severe illness and poorer adjustment.
- Responders: Hyperarousal (high EDA) is linked to impending psychotic relapse, often observed weeks before the relapse.
What are the key findings about electrodermal activity (EDA) in psychopaths, and how are they linked to emotional responses and behavior?
Key Findings:
Psychopaths have lower tonic EDA at rest and smaller SCRs to fear-related or anxiety-provoking stimuli, reflecting low arousal and deficient emotional responses.
Notable Studies:
Hare (1965): Psychopaths showed smaller SCL increases when anticipating punishment.
Emotional Stimuli: Psychopaths exhibit lower SCRs to distress cues (e.g., crying child) but respond similarly to threatening and neutral stimuli.
Developmental Links:
Adolescents with lower resting NS-SCR rates are more likely to exhibit antisocial behavior or commit crimes later in life.
How does electrodermal activity (EDA) relate to social and occupational functioning in schizophrenia?
Non-responders: Predict poor social and employment outcomes.
Responders: High SCL and NS-SCRs correlate with negative social interactions and occupational difficulties. Hyperarousal can interfere with cognitive and social functioning, creating a vicious cycle of stress and poor outcomes.
What does high EDA arousal predict in schizophrenia, and how is it linked to relapse?
High EDA arousal predicts symptomatic relapse in schizophrenia. It suggests that hyperarousal increases vulnerability to relapse, especially when exacerbated by environmental stressors.
How does blunted emotional processing in psychopaths relate to their behavior?
Psychopaths demonstrate blunted emotional responses to distressing stimuli, contributing to their antisocial and thrill-seeking behavior.
How do palm-based and wrist-based SCL measurements compare in terms of consistency and response to stress?
Palm-based SCL: Higher and more consistent across conditions; weakly affected by stress manipulations, with inter-individual differences being the dominant variance source.
Wrist-based SCL: Showed a downward drift over time and failed to capture expected increases during stress tasks.
What were the findings regarding wrist-based and palm-based ns.SCR frequency during stress and recovery?
Both palm and wrist ns.SCR frequencies increased during mental and physical stressors and decreased during recovery, reflecting sensitivity to SNS activity.
Wrist-based ns.SCR_cf (curve-fit detection method) aligned closely with palm-based measurements and outperformed ns.SCR_mat in detecting peaks during low physical activity.
What does the study reveal about the criterion validity of EDA measures with Pre-Ejection Period (PEP)?
Changes in PEP, a measure of cardiac SNS activity, correlated well with ns.SCR frequency at both palm and wrist.
Wrist-based ns.SCR_cf explained 25.5% of PEP variability.
SCL, especially wrist-based, showed weaker correlations with PEP.
What were the findings on predictive validity of wrist and palm-based EDA measures for affect changes?
Changes in ns.SCR frequency (both wrist and palm) were associated with self-reported changes in positive and negative affect during stress tasks.
Wrist-based SCL did not significantly predict affect changes.
What are the practical implications of wrist-based EDA monitoring for stress and SNS activity?
Wrist-based ns.SCR frequency is promising for ambulatory monitoring of SNS activity, particularly in real-world and large-scale studies.
Wrist-based SCL is less effective due to lower conductance levels and signal drift.
Dry electrodes on the wrist perform better under higher sweat production (e.g., during physical stress) but struggle during sedentary conditions.
What are the reasons for no EDA?
- Due to medication use, lower SNS arousal, lower density of sweat glands, neuropathy, etc.
- No direct negative effects, but could be related to individual differences in psychological factors
What is the the main neurotransmitter involved in EDA? How does it work from biological perspective?
- Sweat glands are unique (exception): innervated by sympathetic cholinergic neurons
- Cholinergic neurons act locally at the sweat glands to stimulate sweating -> not the widespread effect PNS has
- These neurons are specific to SNS
-> PNS neurons are not involved in sweat gland activity
What is the method which is used most often today to measure EDA?
Exosomatic method is used predominantly
What does the signal strength depend on?
Signal strength depends upon the density of the eccrine sweat glands.
How is discrete stimuli applied?
To record response to change in one stimulus aspect (e.g. significance, novelty, intensity) and look at size of the response (amplitude)
What are the examples of discrete stumuli?
- Guilty Knowledge Test,
- Classical conditioning (covered by Dr. Mertens),
- Strong emotions (valence),
- Affective (high risk) decision making
What electrodermal activity components respond during the orienting response?
Both tonic SCL and phasic SCR respond in orienting response
What is orienting response size influenced by?
distance and direction
stimulus significance
novelty
stimulus intensity
What does tonic electrodermal activity (EDA) reflect during task performance (continuous stimuli) ?
Tonic EDA reflects the allocation of attentional resources associated with autonomic nervous system (ANS) arousal and stress-induced autonomic arousal.
How do tonic arousal levels respond to continuous stimuli in tasks or emotions?
Tonic arousal levels modulate (increase or decrease) during cognitive tasks or emotional responses, reflected in both non-specific skin conductance responses (nsSCR) and skin conductance level (SCL).
What neural pattern EDA lability is associated with?
EDA lability is associated with a neural pattern of widespread cortical activation and sustained hyperactivity of the sympathetic branch of the autonomic nervous system (ANS).
What is a neurophysiological signature of PTSD related to EDA?
Sustained hyperactivity of the sympathetic branch of the ANS is a neurophysiological signature of PTSD, as evidenced by elevated EDA at baseline.
How are psychological factors related to EDA lability and stability?
Hyperreactivity: More pronounced in individuals with EDA lability.
Hyporeactivity: Related to stable EDA.
What behaviors and conditions are associated with electrodermal hyporeactivity (sympathetic under-arousal)?
- Children with autism spectrum disorder (ASD) who display more externalizing behavioral problems (Baker et al., 2018).
- Antisocial behavior (Herpertz et al., 2003).
3/ Alcohol dependence/abuse (Knott & Bulmer, 1985).
4/ Children with ADHD: Reduced electrodermal response to errors related to sustained attention deficits (Redmond et al., 2004).
How is hyperreactivity linked to internalizing behavior and neuroticism?
Neuroticism: Associated with a stronger arousal response to negative emotion-eliciting pictures (e.g., fear) compared to positive ones.
According to Eysenck:
Increased reactivity of the limbic system.
Low tolerance for stress or aversive stimuli.
Research Findings:
Individuals with high neuroticism are more sensitive to negative mood induction and show greater distress following life events.
What role does autonomic hyperarousal and interoceptive cues play in Social Anxiety Disorder (SAD)?
Autonomic Hyperarousal: A key feature in cognitive models of SAD, contributing to heightened physiological responses like increased heart rate and sweating, and is used as a diagnostic criterion.
Interoceptive Cues: Individual differences in awareness of internal bodily sensations, such as heartbeat, which can amplify anxiety symptoms in SAD.
Example Research: Children with parents who have SAD exhibited heightened stress responses during a stress task, highlighting a potential familial influence.
Why should we measure more than one physiological reaction to stress?
To fully understand stress responses, we need to measure specific markers of both sympathetic (e.g., skin conductance) and parasympathetic (e.g., HRV) activity. Heart rate alone can’t tell the whole story because of how the two systems interact.
Berntson’s Autonomic Modes:
Sympathetic and parasympathetic systems can interact in different ways:
- Reciprocal mode: One system activates while the other deactivates (e.g., stress activates the sympathetic system and suppresses the parasympathetic system).
- Uncoupled mode: Both systems can act independently of each other (e.g., one activates while the other doesn’t change).
- Ceiling or floor effects: The organ’s response depends on how the two systems are interacting and if the organ is already at its maximum or minimum level of activity.
Why is NS-SCR frequency preferred for prolonged recordings of SNS activity?
NS-SCR frequency has better validity:
Construct: More closely linked to sympathetic arousal.
Criterion: Correlates with measures like PEP.
Predictive: Better reflects emotional (affective) states.
It is more suitable for long-term monitoring of the sympathetic nervous system (SNS) compared to SCL.
What are the differences between SCL and NS-SCR frequency in terms of measurement?
SCL measures between-subject differences but is less sensitive to changes within the same individual.
NS-SCR frequency is better at detecting within-subject changes over time.
Both can be measured at the palm and wrist, but palm measurements are more reliable.
NS-SCR is less affected by anatomical and thermoregulatory factors compared to SCL.
