Lecture 5 - Classical Conditioning Flashcards
dishabituation
resets things: ok, I should re-pay attention to things
Spontaneous Recovery
rat habituates but then a few days later in will start to jump and then re-habituate
Sensitization
is an increase in an organism’s behavioral response due to an arousing or noxious stimulus.
• Noxious (painful) stimuli work better for sensitization.
• It generalizes to a number
of stimuli. (greater response to any stimuli presented after)
• It can develop with a single stimulus presentation (but
more is stronger)
____ stimuli work better for sensitization.
____ stimuli work better for habituation.
noxious
innocuous
A neighbor’s alarm goes off next door on weekday
mornings at 5:30 am. It isn’t particularly loud and you
gradually are able to ignore it over time. However, on
Monday’s it always wakes you up. What best describes
your response?
Spontaneous recovery
Dual Process Theory (Groves & Thompson, 1970)
suggests that habituation and sensitization reflect
activation of two different (but related) systems:
- habituation system: A low-threshold reflex pathway that weakens with repeated (mild) stimulation.
- sensitization system: A high-threshold “state system” that, when activated by a noxious stimulus, increases global responses.
- larger change that affects the sensory neurons and the motor neurons
- like an emotional response: anger: affects everything you do
Eric Kandel
explored the habituation and sensitization responses in sea
hares (Aplysia californica)
sea hares
ex of Biological basis for habituation & sensitization
• Sea hares only have about 20,000 neurons and some simple reflexive responses (e.g. gill withdrawal).
- could see when it would habituate and when it would sensitize: he could map it out
• Found that habituation could be explained by synaptic depression: a reduction of synaptic transmission between sensory and motor neurons (connection between the sensory and motor neurons weakens).
• Sensitization is caused by increased activity from modulatory interneurons.
- really strong stimulus comes in, release a lot of neurotransmitter, Gills retract
Classical conditioning is an example of
associative learning
what being learned in classical conditioning?
common misconception
associating two different events, things, stimuli
responses are behaviors
actual learning is the unconditioned stimulus and the conditioned stimulus
Unconditioned stimulus (US):
triggers something that has a natural response (the releasor)
something that triggers a natural, reflex or response.
ex: food
Unconditioned response (UR):
The natural response to the US.
ex: salvating
conditioned stimulus
Something that is neutral and doesn’t trigger an automatic response.
ex: the bell
conditioned response
The learned response in which the CS
predicts the US.
ex: to salvate when hearing a bell (he’s really “thinking” about food)
conditioned stimulus precedes the
unconditioned stimulus
Appetitive conditioning:
Learning to predict something that satisfies a desire or appetite.
- Food is the unconditioned stimulus. It naturally produces the salivation unconditioned response. This does not need to be trained.
- The bell is a neutral stimulus and initially doesn’t produce a response.
- During training, the bell repeatedly precedes the food. With this associative pairing, the bell becomes a conditioned stimulus.
- After training, the bell (CS) will trigger the salivation response. When salivation occur as a result of the CS (without the presence of actual food), it is called a conditioned response (CR).
- Anticipation of food (US)
- (Doesn’t actually need awareness)
In aversive conditioning
you learn to avoid or minimize the effect of an expected unpleasant event.
aversive conditioning –>
eyeblink conditioning
- The eyeblink reflex is an UR to a puff of air (US).
- If you pair the airpuff with a tone (CS), the animal (or human) will learn that the tone predicts the airpuff (US).
- After training, the tone (CS) will cause an eyeblink (CR)
(also the little Albert experiment)
Classical conditioning typically builds gradually over many trials.
you have to have repeated pairings of the conditioned stimulus and unconditioned stimulus
For the conditioning to be successful, the CS must
reliably predict the US. That is, the CS must be an informative cue (useful cue to know how to adapt or respond to its environment)
extinction
After successful training, if you present the CS (tone) without the US (airpuff), the CR (eyeblink) will fade.
conditioned response goes away because the conditioned stimuli has no value anymore
blocking
If you add a second CS (e.g. light) and present it simultaneously with the tone CS, only the initially trained
tone CS will produce the CR.
the light isn’t giving you anymore predictive information than the tone
event is already paired
If the CS causes a CR because it predicts the US, which of the following should we expect to happen?
The CR should start to happen before the US.
if the cue (conditioned stimulus) is predicting the US, then the CR should precede the US
Both extinction and blocking suggest that
the CS produces a CR as a means of preparing for the US.
• The US (airpuff) always produces the UR (eyeblink). If you suspect the US is coming (cued by CS), then you will blink
sooner (CR).
- The CR will start to occur BEFORE the US.
- The CS allows the body to PREPARE for (or adapt to) the US.
(behaviors are measures, stimuli are learned)
The earliest models assumed that the CS takes the place of
the US. However, this substitution model was too simplistic.
• The CS generally never attains the same strength as the US.
• **The CR doesn’t always match the US.
–> CR is training you to prepare for the US
The CR doesn’t always match the US.
Obal (1966)
− showed that administering the drug dinitrophenol (US) caused an increase in oxygen consumption and increased temperature (UR).
− The body wants to maintain homeostasis, so will counteract the effects of the drug.
− The syringe is a cue for the drug (CS), so when a placebo is administered, the CR is a decrease in oxygen consumption and decrease in body temperature.
− In this framework, the CR is the opposite of the UR and is
ADAPTIVE.
The compensatory response model uses this adaptive
role to explain drug tolerance.
• Needles, smells, and settings act as the CS during drug use. They predict the arrival of the drug, so the body prepares to counteract the effects (CR).
• It had been observed that heroin overdoses often occur in unusual settings (Gutierrez-Cebollada et al., 1994).
- > 50% of heroin addicts admitted to the hospital for overdoses had taken their last dose in an unusual location (no CS).
- Other addicts admitted for reasons unrelated to the drug took their last dose in the usual location.
- The setting (CS) had increased tolerance (CR) to the heroin (US).
- It has been suggested that overcoming drug addictions might involve extinguishing the CR to drug paraphernalia (CS).
(also use extinction)
Thompson (1986)
Biological model for classical conditioning
• discovered that damage in the cerebellum could
permanently prevent new classically conditioned responses and eliminate old responses:
- This was based on patients for cerebellar lesions.
- Single cell recordings from the cerebellum have helped establish how classical conditioning is developed and retained.
what part of the brain is important for associative learning?
the cerebellum!
The CS -> US association seems to be implemented in two areas of the cerebellum:
- In the interpositus nucleus, activity increases after the CS and is correlated with the CR, before the US.
- Purkinje cells are inhibited after the CS and before the US.
CS predicts
US
the conditioning trace, the association, is developed and RETAINED in
the cerebellum
lesions in the cerebellum?
ppl can lose previous condition and are unable to achieve new classical conditioning
