sensitisation and dual process theory Flashcards
(25 cards)
What is reflex sensitisation?
It refers to increased responsiveness to a stimulus after an aversive event.
In which types of reflexes does sensitisation mainly occur
Defensive, avoidance, orienting, and startle reflexes
How does reflex sensitisation relate to habituation?
It has the opposite effect and can undo habituation (dishabituation).
What are two key differences between sensitisation and habituation?
A: 1) Sensitisation usually occurs more quickly.
2) It is non-specific, affecting multiple reflexes, unlike habituation.
What is short-term sensitisation?
An effect that lasts from minutes to hours, often caused by a single or few aversive stimuli
What produces long-term sensitisation?
A: Repeated aversive stimuli over several days, resulting in effects that last days or weeks.
What is the dual process theory?
A theory that both habituation and sensitisation processes are activated by stimuli and interact to determine reflex strength.
According to the dual process theory, what always occurs when a stimulus is presented?
The habituation process is always engaged, regardless of the stimulus.
What determines whether the sensitisation process is engaged?
A: The aversiveness or arousal level of the stimulus.
What happens when the eliciting stimulus is non-aversive?
Habituation occurs unopposed, and reflex response decreases
What happens when the stimulus is aversive/arousing?
Both habituation and sensitisation are engaged, but sensitisation dominates, increasing the reflex response
What are the outcomes when the strength of both processes is compared?
Sensitisation > Habituation → Response increases
Habituation > Sensitisation → Response decreases
Equal strength → No change in response
What is observed in the absence of stimulation?
Neither habituation nor sensitisation is engaged.
In which organism is the gill withdrawal reflex studied?
Aplysia (a sea slug).
What elicits the gill withdrawal reflex?
A light touch or “tickle” to the siphon.
What is short-term habituation in the gill reflex?
A reduction in the gill withdrawal response after a series of closely spaced tickles.
What causes long-term habituation in the gill reflex?
Repeated sessions of stimulation over days, leading to lasting effects.
What neural change is linked to long-term habituation?
A reduced number of synaptic connections (synaptic pruning)
What is homosynaptic depression?
A decrease in synaptic strength due to repeated stimulation, causing habituation.
How is sensitisation of the gill reflex induced?
By delivering electric shocks to the tail of Aplysia
What neural changes occur in short-term sensitisation?
Increased neurotransmitter release at synapses, strengthening the reflex.
What happens during long-term sensitisation at the neural level?
There is an increase in the number of synaptic connections.
How do sensitisation and habituation affect each other?
Long-term sensitisation reverses long-term habituation; short-term sensitisation reverses short-term habituation.
What does dishabituation reverse?
Only the short-term changes caused by habituation.
