NSCI 222: Operant Conditioning, Shaping & PTSD

Maria takes aspirin whenever she has a headache, and the headache goes away. Over time she reaches for aspirin faster whenever a headache starts. This is an example of:

A. Positive reinforcement
B. Positive punishment
C. Negative reinforcement
D. Negative punishment

C. Negative reinforcement

A teenager breaks curfew, and their parents take away their phone for the weekend. Curfew-breaking decreases afterward. This is an example of:

A. Positive reinforcement
B. Negative reinforcement
C. Positive punishment
D. Negative punishment

D. Negative punishment

Compared with a rat on a fixed-ratio 5 (FR-5) schedule, a rat on an FR-50 schedule will most likely show:

A. Longer post-reinforcement pauses
B. Shorter post-reinforcement pauses
C. A slow, steady rate with no pauses
D. A scalloped pattern of responding

A. Longer post-reinforcement pauses

A pigeon is reinforced on a fixed-interval (FI) schedule. Which response pattern is expected?

A. A high, steady rate with no pauses
B. Slow pecking right after reinforcement that speeds up as the end of the interval approaches
C. Exactly one peck per interval, timed precisely at the end
D. A burst of rapid pecking right after reinforcement, then stopping

B. Slow pecking right after reinforcement that speeds up as the end of the interval approaches

A researcher food-deprives rats for 24 hours before a lever-pressing session, and food pellets become a more effective reinforcer. In this case, deprivation functions as a(n):

A. Abolishing operation
B. Motivating operation
C. Instinctive drift
D. Extinction procedure

B. Motivating operation

A teacher wants students to raise their hands more, but only hands out a reward on Friday for hand-raising that happened earlier in the week. Which variable of reinforcement effectiveness is weakest here?

A. Contiguity
B. Reinforcer magnitude
C. Reinforcer quality
D. Deprivation

A. Contiguity

A parent starts with a very mild scolding for a behavior and slowly makes the punishment harsher each time it happens. What is the most likely outcome?

A. The behavior stops right away because the punishment is consistent
B. The punishment turns into negative reinforcement for the child
C. The behavior persists, because starting at a weak level lets the child adapt to gradually stronger punishers
D. Punishment has no effect unless it is paired with a reward

C. The behavior persists, because starting at a weak level lets the child adapt to gradually stronger punishers

Raccoons trained to drop coins into a box for food began rubbing the coins together and dipping them as if washing food, even though this delayed their reward. This phenomenon is called:

A. Learned helplessness
B. Chaining
C. Negative punishment
D. Instinctive drift

D. Instinctive drift

A person who wants to quit a drug keeps using it mainly to escape painful withdrawal symptoms. Their continued use is being maintained mostly by:

A. Positive reinforcement
B. Negative reinforcement
C. Positive punishment
D. Shaping

B. Negative reinforcement

Dogs first exposed to shocks they cannot escape later fail to escape shocks in a shuttle box, even when escape is easy. This is best explained by:

A. Learned helplessness caused by a lack of control over the earlier stressor
B. Fear generalization caused by stress-enhanced fear learning
C. Instinctive drift
D. Extinction of the escape response

A. Learned helplessness caused by a lack of control over the earlier stressor

Shaping is best defined as:

A. Punishing incorrect responses until only the correct one remains
B. Linking already-learned behaviors into a sequence
C. Reinforcing successive approximations of a target behavior
D. Reinforcing a behavior on a variable schedule

C. Reinforcing successive approximations of a target behavior

A trainer rewards a dog for scooting a slipper. Once scooting is reliable, the trainer stops rewarding scooting and rewards only picking the slipper up in its mouth. This step illustrates:

A. Chaining
B. Extinction of all slipper-related behavior
C. Negative reinforcement
D. Differential reinforcement of successive approximations

D. Differential reinforcement of successive approximations

The dog now picks up the slipper, carries it to its owner, and releases it into the owner’s hand, with each step leading into the next. Linking these behaviors into one sequence is called:

A. Chaining
B. Instinctive drift
C. Contiguity
D. Generalization

A. Chaining

Which pair of features best characterizes PTSD as described in class?

A. Enhanced fear extinction and reduced freezing
B. Fear generalization and failure of fear extinction
C. Hallucinations and disorganized thinking
D. Reduced startle and complete memory loss for the event

B. Fear generalization and failure of fear extinction

In stress-enhanced fear learning (SEFL), rats get a severe shock in Context A and later a single mild shock in Context B. Compared with non-traumatized controls, the traumatized rats:

A. Explore Context B more and freeze less
B. Freeze the same amount in Context B
C. Freeze more in Context B, showing enhanced and generalized fear
D. Freeze less in Context A only

C. Freeze more in Context B, showing enhanced and generalized fear

After trauma in the SEFL model, interleukin-1β (IL-1β) was found to be elevated in the:

A. Amygdala, about 2 weeks after trauma
B. Prefrontal cortex, immediately after trauma
C. Cerebellum, about 24 hours after trauma
D. Dorsal hippocampus, about 48 hours after trauma

D. Dorsal hippocampus, about 48 hours after trauma

Giving the IL-1 receptor antagonist (IL-1RA) after trauma:

A. Blocks the inflammatory IL-1 response and prevents the development of SEFL
B. Strengthens fear memory consolidation
C. Has no effect on later fear learning
D. Prevents SEFL only if given before the trauma

A. Blocks the inflammatory IL-1 response and prevents the development of SEFL

Morphine given right after a traumatic event reduces later SEFL because it:

A. Speeds up consolidation of the fear memory
B. Reduces pain and the trauma-induced rise in IL-1β in the dorsal hippocampus
C. Acts as a positive punisher for freezing
D. Permanently erases the original trauma memory

B. Reduces pain and the trauma-induced rise in IL-1β in the dorsal hippocampus

Which statement best describes a psychoplastogen?

A. A drug that suppresses symptoms but takes weeks to act
B. An inflammatory cytokine that consolidates fear memories
C. A fast-acting compound that promotes structural and neural plasticity, regrowing dendritic connections lost in the prefrontal cortex, with long-lasting effects
D. A stimulus that reinforces behavior on a fixed-ratio schedule

C. A fast-acting compound that promotes structural and neural plasticity, regrowing dendritic connections lost in the prefrontal cortex, with long-lasting effects

In the animal model of PTSD, traumatized rats given MDMA, compared with traumatized rats not given MDMA, showed:

A. Higher hippocampal IL-1β and more freezing
B. No change in IL-1β but more freezing
C. Higher IL-1β but less freezing
D. Lower hippocampal IL-1β and little to no freezing when re-exposed to the stressor

D. Lower hippocampal IL-1β and little to no freezing when re-exposed to the stressor

What are the proteins released in the brain after a traumatic event that are seen as an inflammatory response?

A. Cytokines
B. IL-1RA
C. Dopamine
D. Neurotransmitters

A. Cytokines

What did MDMA and psychoplastogens show in PTSD treatment?

MDMA-assisted therapy lets patients revisit the trauma during re-exposure therapy without overwhelming fear, which enhances fear extinction. In rats, MDMA lowered hippocampal IL-1β and reduced freezing. Psychoplastogens act fast and last long: they promote structural and neural plasticity, regrowing dendritic connections in the PFC lost in PTSD, so they target the root cause rather than just suppressing symptoms.

What do the animal models of PTSD show about PTSD?

The three major models are predator stress, single prolonged stress, and SEFL. SEFL shows enhanced and generalized fear (a severe shock in Context A leads to more freezing to a mild shock in Context B) and a lack of extinction. IL-1β in the dorsal hippocampus about 48 hours after trauma drives consolidation; blocking it (IL-1RA, morphine, MDMA) prevents SEFL. Implication: there is an early neuroinflammatory window when intervention could prevent PTSD.

What is learned helplessness? How did it show up with the dogs (example learned in class)?

When an individual learns it has no control over a stressor, it stops trying to escape or avoid it later. Dogs given inescapable shocks later failed to escape in a shuttle box even when escape was easy, while dogs that had control learned to escape. Controllability of stress shapes future behavior.