Chapter 12: Learning and Memory

Pavlov’s unconditioned stimulus (meat) automatically elicits an …

unconditioned response (dog salivates)

Operant Conditioning

an individual’s response is followed by a reinforcement or punishment 

Reinforcement

an event that increases the future probability of the response

Punishment

an event that suppresses the frequency of the response

What was Karl Lashley searching for?

The engram - the physical representation of what has been learned (ex: a connection between two brain areas)

What did Karl Lashley do with rats?

Trained rats on mazes and brightness discrimination tasks (memory tasks) and made cuts between two brain areas or removed part of the brain

What was the finding from Karl Lashley’s rats?

Learning and memory does not depend on a single cortical connection or area

What are Lashley’s two principles?

Equipotentiality and Mass Action

Equipotentiality

all parts of the cortex contribute equally to complex behaviors like learning

Mass Action

the cortex works as a whole, and the more cortex the better

What was Lashley’s mistake?

He assumed that all memory types were the same and the cortical area was the best place to search for an engram

What did Thompson et al. (1986) do in their classical conditioning experiment?

They paired a tone with an air puff to the eye until rabbits blinked to the tone.

What brain area showed changes during conditioning and is necessary for learning the eyeblink response?

The lateral interpositus nucleus (LIP) of the cerebellum

What happened when the lateral interpositus nucleus (LIP) was cooled or drugged?

Rabbits did not learn; when effects wore off, they learned at the same rate as new rabbits → LIP must be active for learning.

What happened when Thompson suppressed the red nucleus?

Rabbits showed no response during training, but once normal activity returned they immediately showed learned blinking to the tone.

What did Thompson’s suppression of the red nucleus tell us about it?

it is required for performance

What did Thompson’s suppression of the lateral interpositus nucleus (LIP) tell us about it?

it is required for learning

What areas are active during classical conditioning of the eye blink?

The cerebellum, red nucleus, and other areas

What happens if the cerebellum is damaged?

Impaired at eye-blink conditioning, but not other learning types

What does cerebellum-specific learning impairment suggest?

Learning is distributed across different brain locations depending of the type of memory needed

What are the key characteristics of short-term memory according to Hebb?

Holds events that just occurred, limited capacity, information is lost permanently if forgotten, and only rehearsal transfers it into long-term memory. Hints do not help retrieve it.

How many items can you remember in short-term memory?

approximately 7 unrelated items (why phone #s are 7 digits long)

What are the main features of long-term memory?

Stores events from previous times, not permanently lost and can be recovered with hints, has extremely large capacity, and new learning does not require forgetting old information.

What is consolidation in memory?

The process of converting short-term memory into long-term memory

What role does working memory play in consolidation?

Working memory retains information long enough for it to be consolidated into long-term storage

How did researchers attempt to study memory consolidation (how memories become long term), and what did they discover?

They tried using electric shocks to wipe out memories, hoping to see a difference between short-term and long-term memory loss. Instead, the shocks erased both, and in some cases the lost memories came back when the person was reminded — meaning the memories weren’t completely gone

How do human memory studies challenge the STM/LTM distinction?

We can recall events days old that will still soon be forgotten, suggesting memory is not just strictly short-term vs long-term

What happens genetically when we learn?

Learning activates genes that enhance memory and a gene that produces PP1 (Protein Phosphatase 1).

What is the function of PP1 in memory?

PP1 interferes with memory retention by inactivating learning-related genes, helping us forget trivial experiences

How do masses vs distributed practice affect PP1 and memory?

PP1 accumulates during massed practice (cramming) → worse memory.

PP1 declines during spaced practice → better retention

How does spacing and attention affect whether memories consolidate?

If learning is spaced out and attended to, learning genes outweigh PP1 → memory stores.
If rushed or unfocused, PP1 wins → memory lost.

Is consolidation is fast or slow, and how does age of memory matter?

Consolidation is gradual. Older memories become more firmly implanted and are easier to recall.

What evidence supports that older memories are stronger than newer ones?

Older adults showed greatest MRI activation to 1990s celebrities.
People showed more temporal lobe activity for places visited within 2 years vs 7 days ago.

How do emotions affect memory consolidation?

Emotional experiences strengthen consolidation by increasing cortisol and epinephrine

What brain structures are activated by emotional arousal and how does this boost memory?

Epinephrine → stimulates vagus nerve → activates amygdala.
Cortisol → stimulates hippocampus.
Both enhance memory storage.

What happens to memory when stress becomes prolonged?

Excess cortisol impairs memory instead of strengthening it

What does the amygdala damage reveal about emotional memory?

Emotional arousal no longer enhances memory; patients don’t remember emotionally charged words better

What is working memory?

A system where we actively process information, and through this processing/attention, store it into long-term memory

What are the three components to working memory?

visualospatial sketchpad, phonological loop, and central executive

Visualospatial Sketchpad

Stores visual information

Phonological loop

stored auditory information independent of visual memory

Central executive

directs attention toward one stimulus or another

Why was working memory proposed as an updated alternative to just STM and LTM?

Because memory processing is more complex than simply short-term vs long-term — we store information by actively working with or attending to it

What does the working memory model suggest about how the brain processes information?

Different types of information are handled by different brain systems — like vision and hearing — and other sensory components likely exist (touch, taste, smell) but haven’t been identified yet.

What brain area appears to store working memories according to Baddeley and Hitch?

The prefrontal cortex

When does the prefrontal cortex show high activity?

During delayed response tasks in humans and other mammals

What types of tasks also activate the prefrontal cortex?

Tasks that require different responses to signals given only after a delay

How is the prefrontal cortex activation related to performance?

Stronger activation = better performance

What is amnesia? Who is the most famous case?

Memory loss, most famous patient is H.M.

What happened to H.M. and what functions remained intact?

His hippocampus was removed. His IQ and language abilities remained intact

What type of retrograde amnesia did H.M. have?

Moderate retrograde amnesia for events 1-3 years before surgery

What type of anterograde amnesia did H.M. experience?

He could not form new memories after the operation

What type of memory could H.M. still learn slowly over time?

New facts (e.g., floor plan of his home over years).

What type of memory was impaired in H.M. (declarative or procedural)?

Declarative memory impaired (cannot state memories in words).

What type of memory remained intact with H.M.?

Procedural memory (motor learning)

Which type of memory was better in H.M.: explicit or implicit?

Implicit memory was better — experiences influenced behavior even without conscious recall.
Example: He preferred people who were kind to him.

Once memories are consolidated where are they housed?

the cortex, not the hippocampus

If consolidated memories are stored in the cortex, what role does the hippocampus appear to play?

It plays a critical role in forming new declarative and explicit memories

What type of memory shows especially strong evidence of hippocampal involvement?

Spatial memory

What evidence supports the hippocampus’ role in spatial memory in humans?

• Taxi drivers have larger hippocampi than non-drivers
• More years driving = larger hippocampus
• Their hippocampi activate more when answering taxi-route (spatial) questions than non-spatial ones

What happens to spatial memory after hippocampal damage in humans?

Difficulty with tasks like finding one’s way from place to place

What is an example of spatial memory impairment in animals after hippocampal damage?

Rats with hippocampal damage forget where the hidden platform is in murky water

What causes Korsakoff’s Syndrome?

Long-term thiamine (vitamin B1) deficiency that leads to brain damage

Why is thiamine important for the brain?

It is needed to metabolize glucose (the brain’s fuel)

What brain areas are especially affected by thiamine deficiency in Korsakoff’s Syndrome?

The hippocampus and thalamus, plus axons projecting to the prefrontal cortex

Who most commonly develops Korsakoff’s Syndrome and why?

Chronic alcoholics, because long-term alcohol use leads to thiamine deficiency

What are the major symptoms of Korsakoff’s Syndrome?

Apathy, confusion, and amnesia

How does memory function differ in Korsakoff’s patients?

They have better implicit memory and difficulty ordering past events

What is confabulation, and how does it relate to Korsakoff’s syndrome?

Confabulation is unintentionally filling in memory gaps with guesses that are believed to be true (not purposeful lying)

What is malingering, and how is it different from confabulation?

Malingering is intentionally faking or exaggerating symptoms for external gain, unlike confabulation, which is unintentional.

What is Alzheimer’s Disease?

A severe, progressive, and insidious memory-loss disorder associated with aging

How common is Alzheimer’s Disease in older adults?

It affects about 50% of people over age 85

Which type of memory is relative better preserved in Alzheimer’s patients?

Procedural memory (they can learn new skills but don’t remember learning them)

What genetic condition guarantees development of Alzheimer’s in middle age?

Down syndrome (3 copies of chromosome 21)

Which chromosomes are linked to early-onset Alzheimer’s?

Chromosomes 14 and 1

Which chromosomes are linked to late-onset Alzheimer’s?

Chromosomes 10 and 19

What causes neural disruption in Alzheimer’s Disease?

Abnormally folded brain proteins that clump and interfere with normal neuronal activity

What are plaques in Alzheimer’s Disease?

Degenerating axons and dendrites that accumulate between neurons, disrupting synapses

What are tangles in Alzheimer’s Disease?

Degenerating structures within the soma of neurons

What abnormal protein is associated with widespread brain degeneration in Alzheimer’s?

Amyloid

What treatments can slightly slow Alzheimer’s progression?

• Elevating glucose levels

• Drugs that increase acetylcholine activity

• Diets rich in antioxidants

Why is Aplysia used to study learning?

It has few, very large neurons, making it easier to observe how neuronal activity leads to behavior changes

What idea did D.O. Hebb propose about learning at the synaptic level?

When an axon successfully stimulates a cell, it becomes even more effective at stimulating it in the future

What behavioral response in Aplysia is commonly studied?

Gill withdrawal when touched

What is habituation?

A decreased response to a repeated stimulus when no other changes occur

What causes habituation in Aplysia at the neural level?

After repeated stimulation, the sensory neuron stops increasing action potentials, reducing its stimulation of the motor neuron - due to changes in synaptic activity

What is sensitization?

An increased response to a mild stimulus after exposure to a strong/intense stimulus

How does sensitization occur in Aplysia?

A strong stimulus activates facilitating neurons, which release serotonin onto presynaptic terminals of sensory neurons, prolonging neurotransmitter release

What role do facilitating neurons play in learning?

They release serotonin when activated, strengthening synaptic activity and producing sensitization

What do habituation and sensitization in Aplysia demonstrate?

That learning results from changes in synaptic activity between neurons

What is long-term potentiation (LTP)?

learning - a burst of stimulation from axons (ex: 100 excitations per second for 1-4 seconds) onto dendrites results in those synapses being even more responsible to similar input for minutes, days, or weeks

What are the three properties of LTP?

Specificity, cooperativity, and associativity

What is specificity?

when only active synapses become strengthened

What is cooperativity?

nearly simultaneous stimulation by two or more axons results in LTP more strongly than repeated stimulation by just one

What is associativity?

pairing a weak input with a strong input enhances later response to the weak input

What is long-term depression?

forgetting - prolonged decrease in response to a synaptic input where two or more axons have been active together at 1-4 times per second - that’s not very often, so the synapse is weakened

Where does Long-Term Potentiation (LTP) occur?

Only at glutamate synapses

Which two glutamate receptors are involved in LTP?

AMPA and NMDA receptors

What does glutamate do at AMPA receptors?

Opens sodium channels, allowing Na+ to enter and depolarize the postsynaptic cell

What normally blocks NMDA receptors, and how is it removed?

Magnesium (Mg²⁺) blocks the channel; strong depolarization from AMPA activation “pops” Mg²⁺ out.