What does Electrodermal Activity (EDA) refer to?
Umbrella term covering Galvanic kin Response (GSR), Skin Conductance Response (SCR), and Skin Conductance level (SCL). Refers to changes in skin’s electrical conductance influenced y sweat gland activity controlled by sympathetic nervous system.
How does skin moisture affect electrical properties in EDA?
Dry skin has higher electrical resistance and lower conductivity.; moisture skin has lower resistance and higher condtivity
which nervous system controls sweat gland activity influencing EDA?
Sympathetic nervous system controls sweat gland activity affecting EDA
Describe the exosomatic method of measuring EDA
Application of small external electrical current across the skin and measuring resistance changes
describe the endosomatic. Method of measuring EDA
measures internally generated electrical skin potentials without external electrical application.
Name the three branches of the Automatic nervous System important for Physiological regulation
- Enteric (Gut functions),
- Parasympathetic (Rest and Digest)
- Sympathetic (Fight or Flight)
What Happens during the fight or flight response relevant to EDA?
Sympathetic activation increases sweat gland activity, heart rate, respiration; sweating increases skin conductance due to eccrine glands.
What are the two main types of sweat glands and which is relevant for EDA?
- Apocrine glands (armpits/ genitalia, adrenergic innervation),
- Eccrine glands (palms/soles, cholinergic innervation).
Eccrine Glads are relevant for EDA
WHat neurotransmitters innervate eccrine sweat glands
Cholinergic fibres releasing acetylocholine innervate eccrine sweat glands.
How does EDA specifically measure sweat gland activity?
Measured changes in sweat level in eccrine sweat duct leading to changes in skin electrical conductivity, not just sweat secretion onto skin
State Ohm’s Law and its significance in EFA measurement.
Ohm’s Law: V = IR (Voltae = Current c Resistance). EDA often measures conductance (C), where Conductane = 1/Resistance; skin conductance measured in microsiemens (μS)
What is the typical voltage used in EDA measurement to avoid tissue damage?
Constant voltage typically between 0.5 and 1.0 volts is used during EDA measurement.
What type of electrodes are used for EDA and Why
Non-polarising sintered silver/silver chloride (Ag/AgCI) electrodes are used because they are chemically inert, minimising artifacts.
what are electrodes placed for EDA measurement and why?
On distal phalanges of index and middle fingers due to high eccrine gland density and minimal hair; usually on non-dominant hand
Define Skin conductance Level (SCL)
Tonic measure reflecting baseline or background skin conductance at rest, slowly changing and influenced y arousal hydration, and temperature
Define Skin Conductance Response (SCR)
Physic measure reflecting rapid, discrete changes in skin conductance influenced response to specific stimuli, characterised by latency, rise time, amplitude and recovery.
what are the Key parameters of SCR?
- Latency (delay before response
- Rise Time (time to peak)
- Amplitude (size of response
- Recovery (time to baseline)
What psychological processes is EDA correlated with?
Arousal, Attention, Emotionality, Cognition; reflects sympathetic nervous system activity.
How does EDA reflect arousal intensity?
Larger SCR amplitudes indicate higher physiological arousal regardless of emotional valence.
How is EDA related to attention and orienting reflex?
Novel or significant stimuli trigger sympathetic activation, causing eccrine sweat release and SCR; larger SCR indicates greater attentional allocation.
What i Habituationanddishabituation inEDA responses?
- Habituation: decreased SCR amplitude to repeated stimuli.
- Dishabituation : increased SCR amplitude when stimulus changes or new stimulus presented.
How does EDA reflect emotional intensity?
stronger emotions produce larger SCR amplitudes, irrespective of positive o negative valence.
Does EDA differentiate emotional valence?
No, EDA reflects intensity but not valence; responses are similar for positive and negative emotions if intensity is equal.
How does cognitive load affect EDA
Higher cognitive load increases sympathetic activation causing greater SCR amplitudes during tasks needing more mental effort.
