Learning and Memory Flashcards
Stages of Memory: Encoding
Step 1: A subset of sensory information that enters sensory buffers is encoded and placed into short-term memory
Short-term memory (AKA working memory)
Can temporarily hold and manipulate information
- Limited capacity
- Short duration
- Active maintenance
Pre-frontal cortex
Command Center for STM
Dorsolateral PFC
Manipulating and controlling information
Ventrolateral PFC
Maintaining and retrieving information
Episodic Memories- encoding
Def. memory of specific events or experiences
Do not require multiple presentations for effective encoding
Semantic Memories- encoding
Def. general knowledge and facts
Typically do require multiple presentations for effective encoding
Stages of memory: Consolidation
Step 2: Short-term memory is transferred into long-term storage
What region of the brain plays a significant role in the early stages of consolidation?
Hippocampus
Stages of memory: Retrieval
Step 3: Stored information is used
Engram
The physical basis of a memory in the brain, aka where is memory stored
Stages of memory: Reconsolidation
Step 4: Reactivated memory becomes sensitive (vulnerable state where memory can be labile to modification)
Declarative memory
Things you know that you can tell others
Nondeclarative (procedural) memory
Things you know that you can show by doing
Ex. Skill of mirror tracing
Where in the brain is responsible for our declarative memories?
Medial temporal lobe
What are declarative memories broken into?
Episodic and Semantic
Episodic memory
Memories of events, episodes in your life
Semantic memory
Memories of facts, what is the capital of Maine
Retrograde amnesia
Loss of memories before a traumatic event
Anterograde amnesia
Inability to form new memories
Patient HM
Anterograde amnesia
Patient NA
Anterograde amnesia, damage to both mamillary bodies: Suggests that the medial temporal lobe and the midline diencephalic
region are normally parts of a
larger memory system
Korsakoff’s syndrome
Anterograde amnesia for
declarative memories caused by
lack of thiamine—seen in
chronic alcoholism
Confabulate
fill in a gap in memory with a falsification which they accept as true
Patient KC
Personal episodic memory was not intact, while semantic memory was intact
Nondeclarative Memories Overview
- Skill learning
- Priming
- Classical conditioning
- Nonassociative learning
- Spatial memory
Anatomy:
The parts that are NOT medial temporal
Skill learning
Learning to perform a challenging task through repetition
(Sensorimotor, Perceptual, and Cognitive are impaired by damage to the basal ganglia)
Priming brain region
Neocortex
Perceptual priming
Visual form of words: reduced activity in the bilateral occipitotemporal cortex.
Conceptual priming
Words meaning: Reduced activity in the left frontal cortex.
Spatial memory parts of the brain
Hippocampus and cortex. Damage to hippocampus will affect navigation.
Place cells: hippocampus
Become active when an animal is moving towards a particular location
Grid cells: Medial Entorhinal Cortex
Fire when an animal crosses an intersection point
Nonassociative learning
Reflex pathways
What is the sea slug, Aplysia, used to study?
Plastic synaptic changes in neural circuits.
The advantages of working
with Aplysia:
- Fewer nerve cells
- Can create detailed circuit
maps for particular behaviors - Little variation between
individuals
What are Aplysia capable of ?
Nonassociative learning: a single stimulus is presented once or repeated.
Habituation
decreased response to repeated presentations of a stimulus
Dishabituation
restoration of response amplitude after habituation
Sensitization
prior strong stimulation increases response to most stimuli
Habituation in Aplysia
Stimulus to the siphon causes gill
retraction, with repeated stimuli, it
retracts less. This short-term
habituation results from less
transmitter being released by the
sensory neuron.
Habituation
Fewer molecules released, so less transmission
Neurodegeneration
The progressive atrophy and loss of
function of neurons, which is present in
neurodegenerative diseases such as
Alzheimer’s disease and Parkinson’s
disease.
Dementia
A general term for loss of memory, language, problem-solving and other
thinking abilities that are severe enough to interfere with daily life.
Risk factors of Dementia
- Biological factors
- Behavioral factors: smoking, poor diet, lack of exercise, etc.
- Environmental factors
- Socioeconomic factors: Poverty, lack of access to healthcare, education, or employment
opportunities. - Psychological factors: Stress, trauma, mental health disorders, or personality traits.
- Occupational factors: Workplace hazards, exposure to dangerous materials, etc.
- Medical history: Personal or family history of certain diseases or conditions.
Non-modifiable Risk Factors
These are risk factors that cannot be changed or controlled.
Modifiable Risk Factors
These are risk factors that can be changed or controlled through interventions.
Protective Factors
Characteristics that reduce the likelihood of experiencing negative outcomes or developing certain conditions.
Mild Cognitive Impairment
A condition that involves slight but
noticeable changes in a person’s
cognitive abilities, such as memory,
thinking, and judgment. Does not interfere with activities of daily living.
MCI is known as a risk factor for __________
Dementia
Vascular Dementia
Vascular dementia is the second
most common type of dementia. It
is caused by reduced blood flow
that damages brain tissue and
impairs cognitive function.
Atherosclerosis
- The inside of your arteries (contains oxygen- rich blood) gets clogged up with a substance called plaque.
- As plaque builds up, it narrows your arteries and makes it harder for blood to flow smoothly.
- This can lead to serious problems like chest pain (angina), shortness of breath, heart attacks, or strokes
(Risk factor)
What about on imaging?
- Cortical atrophy
- White Matter Hyperintensities
(tissue damage due to small
vessel disease, ischemia, or
chronic hypoperfusion) - Widening of the sulci (grooves)
and enlargement of the
ventricles. - Infarct lesions
Lewy Body Dementia
Characterized by the presence of
abnormal protein deposits called
Lewy bodies. It accounts for about
10-25% of all dementia cases and
is often associated with motor
symptoms such as tremors and
stiffness. Affects the brains chemical messengers.
Frontotemporal
Dementia
A group of disorders that primarily
affect the frontal and temporal
lobes of the brain. It is
characterized by changes in
behavior and personality, as well
as language problems and
difficulty with movement.
*A family history of FTD is the
only known risk for these
diseases. Abnormal amounts of tau or TDP-43 proteins inside the neurons.
Alzheimer’s disease
a progressive neurodegenerative disorder that primarily affects the brain, leading to a gradual decline in cognitive function, memory, and ability to perform daily activities. Abnormal deposits of proteins form amyloid plaques.
Neurobiological changes:
There is a progressive loss of
cholinergic neurons in the
basal forebrain
What two structures have been the study of cognitive decline
Amyloid & Tau
Early-onset familial
Alzheimer disease
- A rare form of AD that affects
individuals younger than age 65. - Caused by a genetic mutation that is
passed down in an autosomal
dominant pattern - Caused by mutations in one of three
genes: amyloid precursor protein (APP),
presenilin 1 (PSEN1), or presenilin 2
(PSEN2)
Mixed Dementia
Mixed dementia refers to the
presence of more than one type of
dementia in the same person. It is
common for individuals with
dementia to have both
Alzheimer’s disease and vascular
dementia, for example.
Scenario 3: Mr. Carter, a 72-year-old retired musician, has
been experiencing vivid dreams and hallucinations for several
months. He often sees colorful patterns and shapes, especially
when he wakes up during the night. Mr. Carter has also
noticed changes in his walking, with episodes of stiffness and
shuffling gait. His family has observed fluctuations in his level
of alertness and cognition, with periods of confusion
alternating with moments of clarity.
* Imaging Findings: PET scans show evidence of reduced
dopamine transporter uptake.
Lewy Body Dementia
