Lecture 3: Learning and Memory Flashcards
What is learning?
An inferred change in an organism’s mental state which results from experience, and which influences in a relatively permanent fashion and organism’s potential for subsequent adaptive behavior
List the Order of Memory (6)
- Sensory Memory
- Attention
- Short term/Working Memory
- Encoding/Consolidation
- Long Term Memory (Explicit and Implicit)
- Retrival
Explain Sensory Memory
- 1-3 secs
- 1st exposure to sensory stimuli (ex. visual, sound, touch)
Explain Short term/Working Memory
- Connection between the hippocampus and prefrontal cortex
- Active learning w/ repetition (eg. learning a phone #)
- Stored in the hippocampus
Explain Encoding/Consolidation
Hippocampus “amplifies” memory and send to corties
Explain Long Term Memory
- 1 sec to Lifetime
- Retainment of memories from the hippocampus into different corties
- Divided into Explicit Memory (Declarative) and Implicit Memory (Procedural)
Declarative further breaks down into episodic and semantic memory
Explain Retrieval
Bringing back memories from long-term memory back into short-term/working memory
What is phylogenetic/epigenetic memory?
- A cycle duration of generations (weeks to years)
- Only useful to a species
What is behavioral memory?
- A cycle time of minutes to days
- Only useful to humans
Who was patient H.M? What were the outcomes of studying him?
- hippocampus was removed to prevent epileptic seizures
- had difficulty forming new long-term memories (anterograde amnesia)
- STM/working memory remained intact
- Suggest that the hippocampus is vital for the formation of new long-term memories
What is explicit memory?
Deliberate recall of information that one recognizes as a memory
A division of Long-term memory
Declarative
What is implicit memory?
the influence of recent experience on behavior without realizing one is using a memory
A division of Long-term memory
- A specific form of nondeclarative, such as biases
- H.M. displayed greater “implicit” than “explicit” memory
What is Declarative memory?
the ability to state a memory into words
Explicit Memory
What is episodic memory?
Ability to recall single events
A division of Declarative memory
H.M. had difficulty with episodic and declarative memory
What is semantic memory?
Definitions and symbolism
A division of Declarative memory
What is procedural (non-declarative) memory?
ability to develop motor skills = remembering or learning how to do things
Implicit Memory
H.M.’s procedural memory remained intact
What is Hebbian learning (4)?
- Cells that fire together, wire together:
- stimulation of one neuron by another enhances that connection
- Increases in effectiveness occur because of simultaneous activity in the presynaptic and postsynaptic neurons
- Such “Hebbian” synapses may be critical for many kinds of associative learning
What is habituation?
a decrease in response to a stimulus that is presented repeatedly and accompanied by no change in other stimuli
- Depends upon a change in the synpase between the sensory neurons and the motor neurons
- Sensory neurons fail to excite motor neurons as they did previously
What is sensitization?
an increase in response to a mild stimulus as a result of previous exposure to more intense stimuli
How does sensitization occur (2)?
- Serotonin released from a facilitating neuron blocks potassium channels in the presynaptic neuron.
- Prolonged release of transmitter from that neuron results in prolonged sensitization
When does long-term potentiation occur?
when one or more axons bombard a dendrite with stimulation.
Leaves the synapse “potentiated” for a period of time and the neuron is more responsive to any stimulus
What is long-term depression (LTD)?
a prolonged decrease in response at a synapse that occurs when axons have been active at a low frequency
The opposite of LTP
What are the properties of LTP (3)?
- Specificity – only synapses that have been highly active become strengthened
- Cooperativity – simultaneous stimulation by two or more axons produces LTP much more strongly than does repeated stimulation by a single axon.
- Spatial summation is more potent than temporal stimulation - Associativity – pairing a weak input with a strong input enhances later responses to the weak input.
Explain mechanism of Early LTP
- Repeated glutamate excitation of AMPA receptors
depolarizes the membrane. - The depolarization removes magnesium ions that had been blocking NMDA receptors.
- Glutamate is then able to excite the NMDA receptors, opening a channel for calcium ions to enter the neuron.
Explain the mechanism of Late LTP
Second messenger pathways also stimulate the production cytoskeletal proteins increase dendritic spines and produce new synapses
Explain Hippocampal LTP
- Entry of calcium through the NMDA channel triggers intracellular changes
- More AMPA receptors are built and dendritic branching is increased
- New synapses and dendritic spines may also be formed
These changes increase the later responsiveness of the dendrite to glutamate
Explain LTP, presynaptically
Extensive stimulation of a postsynaptic cell causes the release of a retrograde transmitter that travels back to the presynaptic cell to:
- Decrease action potential threshold
- Increase neurotransmitter release
- Expand the axons
What are 3 important functions of the hippocampus?
- Critical for declarative memory functioning (especially episodic)
- Spatial memory
- Configural learning and binding
What is the result of damage to the hippocampus?
impairs recent learning more than older learning
- The more consolidated a memory becomes, the less it depends on the hippocampus
- Also can result in amnesia
What is consolidation?
Reverberating circuits of neuronal activity strengthen memories
How is consolidation influenced by attention, the passage of time and emotions?
- Focus on stimuli (e.g. food when hungry)
- Small to moderate amounts of cortisol activate the amygdala and hippocampus and enhance storage and consolidation of recent experiences
- Prolonged stress impairs memory
What is priming?
- A previous experience makes you MORE likely to exhibit a specific behavior
- This is most commonly studied through the use of words lists
What is operant conditioning?
Responses are followed by reinforcement or punishment that alter the likelihood that the behavior will be repeated
What are reinforcers?
Operant conditioning
are events that increase the probability that the response will occur again (Rewards)
What are punishments?
Operant conditioning
events that decrease the probability that the response will occur again
What is classical conditioning?
- A conditioned stimulus (CS) is paired with an unconditioned stimulus (US) which automatically results in an unconditioned response (UR)
- After several pairings, a response can be elicitied by the CS without the US = conditioned responsed (CR)
How is the amygdala involved in learning?
fear learning
How is the parietal lobe involved in learning?
pieces information together
How is the anterior and inferior region of the temporal lobe involved in learning?
semantic memory
semantic dementia (loss of semantic memory)
How is the prefrontal cortex involved in learning?
learning about rewards and punishments
Basal ganglia, anterior cingulate cortex also involved
How are the prefrontal cortex and memory affected in the elderly?
- Declining activity of the prefrontal cortex in the elderly is associated with decreasing memory
- Sometimes, there’s increased activity; indicative of compensation for other regions in the brain
- Older people often have impairments in working memory
What are the 2 major types of amnesia?
- Anterograde amnesia
- Retrograde amnesia
What is retrograde amnesia?
the loss of memory events prior to the occurrence of the brain damage
What is anterograde amnesia?
the loss of the ability to form new memory after the brain damage
List 3 types of damage/diseases that can cause amnesia.
- Korsakoff’s syndrome
- Alzheimer’s disease
- Frontotemporal dementia
What is Korsakoff’s syndrome?
brain damage caused by prolonged thiamine (vitamin B1) deficiency
What is the result of Korsakoff’s syndrome?
- impedes the ability of the brain to metabolize glucose
- Leads to a loss of or shrinkage of neurons in the brain
- Often due to chronic alcoholism
What are the symptoms (4) of Korsakoff’s syndrome?
- apathy
- confusion
- forgetting
- confabulation = generates a false memory without the intention of deceit
What is Alzheimer’s Disease?
gradual, progressive loss of memory
Who does Alzheimer’s Disease affect?
Affects 50% of people over 85
- Early onset seems to be influenced by genes, but 99% of cases are late onset
- About half of all patients with late onset have no known relative with the disease
What are the causes (2) of Alzheimer’s Disease?
Accumulation and clumping of :
- β-amyloid protein 42 → amyloid plaques, which produce widespread atrophy of the cerebral cortex, hippocampus, and other areas.
- An abnormal form of the tau protein → tau tangles, part of the intracellular support system of neurons.
- Henry Gustav Molasion (Patient H.M.) had his hippocampus surgically removed to prevent epileptic seizures. Due to the procedure, he began experiencing difficulty with specific forms of memory. Which of the following forms of memory were affected?
I. Forming new long-term memories
II. Forming short term memories
III. Procedural memory
IV. Episodic memory
V. Declarative memory
A. I, III, IV, & V
B. II, III, & IV
C. I, II, & III
D. I, IV, & V
D. I, IV, & V
- Which of the following best describes the biochemical process of sensitization within learning pathways?
A. ↓ response due to ↓ neurotransmitter release onto motor neurons
B. ↑ response due to ↑ serotonin release which inhibits K+ channels
C. ↑ response due to ↓ serotonin release which inhibits K+ channels
D. ↓ response due to ↑ neurotransmitter release onto sensory interneurons
B. ↑ response due to ↑ serotonin release which inhibits K+ channels
- Operant conditioning is a method of learning that uses rewards and punishments to modify behavior. The removal of a stimulus to suppress a behavior is known as what?
A. Positive Reinforcement
B. Negative Reinforcement
C. Positive Punishment
D. Negative Punishment
D. Negative Punishment
- The hippocampus plays an important role in all of the following EXCEPT:
A. Contextual learning
B. Spatial memory
C. Memory consolidation
D. Non-declarative memory
D. Non-declarative memory
- A 53-year-old woman is admitted into a rehabilitation facility due to chronic alcoholism. Upon arrival, nursing staff note that the woman is very forgetful and often generates false memories without intent. Neurological exam suggests shrinkage of the neurons in the pre-frontal cortex. Which of the following is the likely diagnosis and respective cause?
A. Korsakoff syndrome; thiamine deficiency
B. Alzheimer’s disease; intracellular buildup of tau proteins
C. Frontal-temporal dementia; extracellular buildup of amyloid plaques
D. Retrograde amnesia; trauma to the pre-frontal cortex
A. Korsakoff syndrome; thiamine deficiency
