Exam 3 Flashcards
How does the brain determine whether to express the inhibitory (extinction) or excitatory (fear) memory?
Renewal
Renewal
a return of conditioned fear that occurs when an extinguished CS is tested in a different context than the one in which extinction training occured
ABA renewal
through the contextual conditioning mechanism, context A has become aversive. This favors the expression of the excitatory fear memory over the inhibitory extinction memory
ABC renewal
because it is novel, context C has an ambiguous relationship with both memories. In this situation, the animal defaults to the expression of the excitatory fear memory
Post-traumatic stress disorder (PTSD)
debilitating/pathological fear memory resulting from a particular ‘index trauma’
PTSD sufferers show deficits in what kind of learning?
extinction learning
Exposure therapy
an extinction-based therapeutic intervention for PTSD and other disorders of fear and anxiety in which the patient is brought into contact with fear-evoking stimuli in a ‘safe’ environment
Active Avoidance Behavior
animals learn that behavior performed during the CS prevents the US from being delivered
Two Factor theory
1st Factor: learned fear acquired through Pavlovian processes
2nd Factor: Instrumental behavior that occurs when a response causes fear reduction
problem with the two-factor theory
if an animal is given too many tone shock pairings, it will never acquire avoidance even when it is free to do so
Learned Helplessness
The acquired belief that “nothing one does matters”
result of learned helplessness
opportunities to maximize benefit or minimize harm will be ignored
Objective helplessness
when the probability of an important outcome is just as likely in the presence and absence of an action
Subjective Helplessness
the expectation that outcomes encountered in the future will occur independently of your actions
Yoke Control Design
subjects are paired so that one, the master, controls what happens to both itself and its partner, the yoke
What was the result of the 3-way yoke design experiment for the shocked yokes?
they lost weight and developed gastric lesions (ulcers)
dorsal raphe nucleus
major serotonin-producing nucleus in the brain stem
mPFC implements the effects of control by inhibiting ___________ neurons
serotonin
SSRIs are a major treatment for _______
depression
dorsal striatum (DS)
a region crucial for the initiation of voluntary motion
major symptoms of Parkinson’s disease
akinesia (difficulty initiating motion), bradykinesia (slowness of motion), and resting tremor
S-R association memory
-If the outcome of a response is ‘satisfying’, the connection between the stimulus (S) and response (R) will be strengthened, making the response more likely to occur
-If the outcome of a response is ‘annoying’, the connection between the stimulus (S) and response (R) will be weakened, making the response less likely to reoccur
Skinner used what terms instead of ‘satisfaction’ and ‘annoyance’?
reinforcement and punishment
positive reinforcement
when behavior becomes more frequent in results in the addition of an appetitive stimulus (something the animal will seek out and consume)
Negative reinforcement
when behavior becomes more frequent because it results in the removal of an aversive stimulus (something the animal will reduce contact with or avoid)
punishment
when behavior becomes less frequent because of its results (can be positive, the addition of an aversive stimulus, the removal of an appetitive stimulus)
what was the purpose of the skinner box?
to demonstrate principles such as the shaping of successive approximations
Stimulus-Outcome (S-O) associations
the learned relationship between a previously neutral stimulus and a motivational relevant outcome that allows the outcome to be expected when the stimulus is presented
Pavolovian memory type
stimulus outcome (S-O) associations
Stimulus-response (S-R) associations
a strengthened relationship between stimulus and a behavioral response
Action-Outcome (A-O) associations
a learned relationship between an action and an outcome that makes the changes the likelihood of the action in the future
Instrumental Memory examples
Stimulus-response (S-R) associations and Action-Outcome (A-O) associations
Devaluation procedure
- Rat learns to press lever for food
- food is either paired with a sickening chemical or overfed + LiCl injection OR is given too much food
- Test if rat will press lever for food
If memory S-R, Yes! messing with food value won’t effect the association
If memory A-O, No! The animal learns that the reinforcer no longer has the same value
what is the most powerful positive reinforcer?
Medial Forebrain Bundle (MFB)
What is so special about the MFB?
it has axons of dopamine neurons that originate in the midbrain and forms synapses in places like the Nucleus Accumbens (NAcc) and the Dorsal Striatum (DS)
Increasing the intensity of the stimulation in the MFB increases:
- the reinforcing efficacy of MFB stimulation
- the amount of dopamine released in the striatum
The MFB contains the axons of _________ and _________________ neurons
dopamine and norepinephrine
what is norepinephrine related to?
wakefulness
Reward Hypothesis
dopamine release occurs following an instrumental behavior, upon delivery of the reinforcer, creating the ‘hedonic impact’ that makes the instrumental memory more likely to occur again in the future
Incentive Motivation Hypothesis
dopamine release occurs preceding an instrumental action, serving to activate that behavior. Dopamine release has nothing to do with the reward or hedonic impact of the reinforcer, once received
Positive reinforcement and prediction error
unlikely reinforcers are more surprising than likely ones, and the activity of dopamine neurons in response to an unlikely reinforcer tends to be higher
If dopamine isn’t a reward, what is?
Endogenous opiods
Why do rats press a lever for MFB stimulation?
the brain reacts as if it is getting something better than expected every time the lever is pressed
sexually dimorphic
males sing to attract females (females do not sing)
who do male birds imitate to learn their song?
their father (tutor)
critical period
a key developmental window before and after which song memorization is not possible
What is the finch’s optimal critical period?
Postnatal days 30-65
What allows the onset of the critical period?
testosterone and estradiol
the absence of testosterone ________ song learning
delays
the absence of estradiol ________ song learning
prevents
introducing estradiol prior to the critical period does what to the female finch brain?
it masculinizes it and can lead to song learning if a tutor is present
why is a tutor important in song learning?
if the finch is isolated during the typical critical period (p30-p65), song learning is still possible if the juvenile is exposed to a tutor prior to maturity at p90
The two phases of song learning
Phase 1: song memorization during the critical period
Phase 2: motor rehearsal, extends beyond the critical period
when does song crystallization occur?
at the end of motor rehearsal
mechanism of motor learning
Motor nuclei produce the song -> the sound of the song is compared to the template memorized from the tutor -> if the two differ, the instructive signal is sent to the motor nuclei in an attempt to correct the discrepancy
HVC
high vocal center
RA
robust nucleus of the acropallium
LMAN
lateral magnocellular nucleus of the anterior nidopallium
HVC projects to the RA to initiate what?
singing
what is important for the instructive signal involved in song improvement during motor rehearsal?
LMAN projections to the RA
HVC initiates the song -> patterns of activity are replicated in the RA -> if mismatch detected, LMAN activated -> LMAN introduces variability of pattern to RA, changing the song randomly -> if random change matches the template, the bird keeps it, if not, LMAN produces another change
Roles of HVC and LMAN in motor rehearsal learning
physiological arousal
an increase in the utilization of metabolic energy
the autonomic nervous system has two primary divisions:
sympathetic and parasympathetic
epinephrine is also known as
adrenaline
epinephrine is a hormone, so it goes through the
circulatory system
inhibitory avoidance example
rat enters the dark
side of the chamber and receives a
shock. Later, when placed in the light
side of the chamber, it takes far longer
to re-enter the dark side
flashbulb memories
a highly vivid snapshot in which an emotional (arousing) event has occured
what is the problem with epinephrine?
it doesn’t cross the blood brain barrier
the vagus nerve (cranial nerve 10) has what type of receptors?
epinephrine
vagus nerve -> NTS (nucleus of the solitary tract) -> LC (locus coeruleus) -> LC releases ___________ in the BLA
norepinephrine
Activation of BLA axons in the entorhinal cortex during consolidation __________ inhibitory avoidance memory
strengthens
entorhinal projects to the ____________, which is also necessary for inhibitory avoidance
hippocampus
Morris water maze
prior lesion of the amygdala has no effect on learning the morris water maze, which is dependent on the hippocampus. However, amphetamine (NE release) injected into the BLA following morris water maze facilitates memory at test
James McGaugh perspective
BLA modulates memory and doesn’t store or acquire anything
LeDoux and Faneslow perspective
BLA is required for the acquisition, consolidation, storage, retrieval, and reconsolidation of memory
