1 - Memory and Learning Flashcards
Two Major Categories of Memory?
How is it sorted?
Declarative / Non-Declarative
Sorted by:
- Type of information learned
- Anatomical systems required
Declarative Memory
Brain structure?
Type of information?
Brain: Medial Temporal lobe; diencephalon, limbic system structures
Information: Facts, Events–can be brough to conscious awareness or explicity declared
“Knowing that”
Non-declarative Memory
Brain areas?
Type of Information?
Brain: Striatum, Cerebellum, Amygdala* (each for different type)
Type of Information: Procedural skills/habits, skeletal musculature (Pavlov dog), Emotional response (fear from memory, etc)
**Requires motor-related system: basal ganglia, cerebellum
“Knowing How”
Clinical: Dissociation of declarative and non-declarative memory systems?
Depend on anatomically distinct systems
Loss of one system does not impair function of the other; those with severely impaired declarative memory can still learn new skills
“You could display new learned skills with no conscious awareness of ever having practiced”
Temporal Stages of Declarative Memory:
Consolidation
First Stage of (big picture) Processing*
Stable (long-term) memories are first processed through immediate and short-term forms
There are earlier steps to memory, (immediate, short term, etc)
Temporal Stages of Declarative Memory:
Immediate Memory
Very Brief, Very Large (theoretical) Capacity
Sensory Register, sum of all ongoing sensory input to cerebral cortex
Volatile - Rapidly lost if not processed further
Temporal Stages of Declarative Memory:
Short Term
Short duration (seconds/minutes)
Extremely small capacity (7+/-2 pieces); information at center of attention
Temporal Stages of Declarative Memory:
Long Term Memory
Very long duration (years / decades)
Very Large Capacity
Vast size, very resistant to forgetting
Formed through consolidation; repetition enhances, partially consolidated is vulnerable–head trauma, seizures, etc
What is critical for consolidation of memories to long term?
Sleep, brian reactivates at night to reinforce thi stage
Clinical: How to test short and long term memory?
Short: Digit +/- test (5-9)
Long: Recall of autobiographical information, famous faces test*
*Susceptible to confabulations; or unintentional wrong answers
Retrograde vs Anterograde Amnesia
Retro - Loss of memories which were already formed; damage to long-term memory areas
Antero - Inability to reform new memories; damage to consolidation areas
Retrograde Amnesia
Temporally Limited Retrograde Amnesia
Loss of old memories, damage to long-term memories
Temporally Limited - Short span (you forgetting getting hit by the car, but remember stuff before and after)
Anterograde Amnesia
Usually accompanied by temporally limited retrograde amnesia
What areas of the CNS do procedural memory rely on?
What areas of the CNS do declarative memory rely on
Neural systems that modulate motor function
- - -
Neural systems connected to association, high level of sensory cortical areas, and limbic cortex
Association Cortex
Declarative memory depends on neural systems connected to heteromodal association and high level sensory unimodal association (ex. fusiform gyrus) cortical areas
Dorsolateral Prefrontal Cortex (part of association cortex)
“Executive” or “Working Memory” function
Exec - direct attention, entry of information into short-term memory, use information
Working - storage in short term memory
System Summary:
Immediate Memory
Short Term
Consolidation
Long-Term Memory
Immediate Memory - High level sensory cortical; association
Short Term - High level sensory; association; dorsolateral prefrontal
Consolidation - Medial temporal lobe; related limbic structures
Long-Term Memory - High level sensory cortical; association
How are long term memories stored?
Distributed Manner
Single memory is complex collection of many different stimuli; e.g. visual aspects stored in higher order areas different than smell or taste
Long Term Memory strengthing?
What does this say about the requirements for consolidations of memory?
Strengthened by increasing synaptic connections between neurons in multiple cortical areas
Consolidation of memory requires interconnected limbic structures
How are subdivisions of the hippocampus connected?
Clinical: Damage to these connections?
In a loop
Clinical: Anterograde Amnesia
Clinical: Lesions locations (2) which can impair consolidation?
Medial Temporal Lobes
Medial Diencephalic Structures
Breaking of declarative memory system loops
Long Term Potentiation (LTP)
Long Term Depression (LTD)
Where do these occur?
Process for strengthing synapses in memory storage
Process of weakening synapes in memory storage
Declarative: Hippocampus, Neocortex
Procedural: Cerebellum, Basal Ganglia
Long Term Potentiation (LTP)
Neurotransmitter
Locations
NT: Glutamate
Locations: Spines of Pyramidal Neurons at glutamate synapses in Hippocampus and Neocortex
What type of receptors are on post synaptic membranes in LTP?
non-NMDA (AMPA, kaitnate)
NMDA glutamate
What do NMDA receptors require for gating?
What does this lead to?
Depolarization + Glutamate
Increased calcium, increased protein activation, increased NMDA receptors, increased synapses
