Concepts Flashcards
Law of initial value
A physiological response to a stimulus or situation depends on the prestimulus level of the system being measured
The higher the initial value,
What concepts relate to this? (2)
The smaller the increase
Ceiling effects, Magnitude of change
Baseline levels
Establishing baseline levels
Returning to baseline levels
Anticipating properties of a stimulus (to be presented) during prestimulus (baseline) period
Autonomic balance
What systems are relevant to this? (2)
A measure of autonomic functions (skin conductance, respiration, blood pressure, etc)
Sympathetic nervous system, parasympathetic nervous system
Predominance of this autonomic factor is, but
Constant for long term (tonic) level
BUT
May show changes in short term (phasic level)
“Activation” or “arousal”
Intensity of behavior
Intensity of behavior:
Activation reflected in
Level of physiological response
Related to increased activation (3)
High HR (heart rate), BP (blood pressure), muscle potentials
Yerkes and Dodson
Performance on Y axis, Tension/arousal/anxiety on X axis
Curve: low, comfort, LINE (medium), anxiety, high
On top of line: Constructive optimum tension
Reticular formation (RF) and Reticular activating system (RAS)
What is it important for?
Maintaining wakefulness and producing cortical arousal
Activation of RF in anesthetized cats shifts EEG from
High-voltage slow waves to low-voltage fast waves
High levels of RF activation leads to
Decrement in performance
Diagram:
Brainstem
Ascending cortical activation
REM/SWS switch
Diagram:
SCN
Circadian clock
Diagram:
Hypothalamus
Sleep/wake switch
Diagram:
Thalamus
Cortical activation
Sleep spindle
EEG synchronization
Stimulus-Response (SR) Specificity
Patterning of physiological responses according to the particular stimulus situation
Cognitive function tasks (2) and how it affects heart rate
Mental arithmetic: Increases HR
Attention to visual stimuli (Decreases HR)
A concept in Psychophysiology
Habituation
Initial response
Orienting response (Sokolov)
Response habituation
Subsequent responses to same stimuli are not as great
A subsequent novel stimulus
Creates a mismatch and produces an orienting response
Orienting response
The “What is it” reflex
Pavlov
In dogs, a conditioned response failed to occur when an unusual (novel) stimulus captured the attention of the animal
Orienting Responses:
In humans, a novel stimulus elicits
Increased SCL and EMG
Pupil dilation
EEG activation
Decreased HR
Vasoconstriction in limbs, vasodilation in the head
Orienting responses:
Believed to facilitate
Perception of and response to new stimulus
Orienting response to
What does it do? (2)
Novel stimuli
Habituates rapidly
Enhances perceptibility of stimuli
Defensive response
What does it do?
To intense, potentially painful stimulus
Habituates slowly
Factors producing an OR (3)
Novelty, intensity, significance
Novelty
Decreases with repeated presentations until it habituates
Intensity
Must be above threshold to capture attention
If too intense
Orienting response changes to defensive response
Concepts in Psychophysiology:
Implications
For experimental investigations
