Lecture: Memory
Learning goal: You can reproduce and apply the general taxonomy of memory systems (classification into different forms and timeline of
processing).
Answer:
Timeline of processing:
• Sensory memory: Very brief storage (milliseconds to seconds); high capacity but rapidly decays.
• Working memory: Limited capacity (~7 items), short duration (seconds); active manipulation of information.
• Long-term memory: Unlimited capacity and long duration; relatively stable over time.
Flow: Sensory input → sensory memory → (attention) → working memory → (encoding/consolidation) → long-term memory
Types of long-term memory:
• Declarative (explicit):
o Semantic memory (facts, concepts; not tied to specific events)
o Episodic memory (events, time and place-specific) → Mediated by the medial temporal lobe (including hippocampus)
• Non-declarative (implicit):
o Procedural memory (skills/habits): striatum, motor cortex, cerebellum
o Priming: sensory neocortex
o Classical/operant conditioning: amygdala, cerebellum
o Non-associative learning (habituation, sensitization): reflex pathways
Learning goal: You can describe the processes of memory (e.g. encoding, consolidation and retrieval)
Answer:
• Encoding: Transfer of attended sensory input into a memory trace; involves linking new info to existing knowledge.
→ Hippocampus and medial temporal lobe active during successful encoding.
• Storage: Maintenance of memory traces over time in neural circuits.
→ Long-term storage believed to shift from hippocampus to distributed cortical areas.
• Consolidation: Stabilizing memory traces; occurs at:
o Synaptic level: Minutes to hours; involves LTP (e.g. CA1 in hippocampus)
o Systems level: Days to years; involves reorganization of brain regions (e.g. hippocampus to cortex shift)
• Retrieval: Accessing stored information. → Involves hippocampus for recent memories and cortex for older ones.
• Reconsolidation: Retrieved memories become labile again and must be re-stabilized.
Learning goal: You can reproduce how memory can be affected after damage to the medial temporal lobe.
Answer:
Patient H.M. (bilateral hippocampal lesions):
• Severe anterograde amnesia (can’t form new declarative memories)
• Mild retrograde amnesia (difficulty retrieving recent memories)
Patient K.F. (left parietal damage):
• Impaired working memory but preserved long-term memory → Shows a double dissociation between working and long-term memory.
Learning goal: You can reproduce the input and output areas of the hippocampus, as well as the subareas and connections in the hippocampus.
Answer:
• Input: From neocortex, including multimodal sensory and spatial information.
• Pathway through hippocampus: Entorhinal cortex → Dentate Gyrus → CA3 → CA1
• Output: Via fornix to cortical and subcortical areas.
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, Learning goal: You can explain the role of the cortex and hippocampus in encoding, storage and retrieval.
Answer:
Hippocampus:
• Critical for encoding and retrieval of new episodic memories
• Plays a temporary role in memory storage (see standard consolidation theory)
Neocortex:
• Long-term storage of consolidated memories
• Involved in semantic memory and remote episodic memory
• Role in priming and skill learning
Learning goal: You can explain standard consolidation theory and knows what observations and results support standard consolidation theory.
Answer:
Theory:
• Hippocampus initially binds elements of a memory
• Over time, through replay, retrieval, and emotional tagging, memories become independent of the hippocampus and stored in cortex.
Supporting observations:
• H.M.: Temporal gradient in retrograde amnesia → older memories more intact than recent ones.
• Fear conditioning in rats:
o Removal of hippocampus shortly after learning → impaired freezing
o Removal after 14 or 28 days → freezing intact → memory had consolidated in cortex
Learning goal: You can describe the properties of the cells we use for orientation in space and navigation.
Answer: All these together form a cognitive map used for spatial memory and navigation (O’Keefe & Moser)
• Place cells (hippocampus): Fire when in a specific location (place field) → Discovered by John O'Keefe
• Grid cells (entorhinal cortex): Fire in a hexagonal grid pattern across space
• Head direction cells: Fire when head is facing a specific direction
• Boundary cells: Fire in relation to environmental boundaries
• Speed cells: Firing rate correlates with movement speed
Learning goal: You can describe the discussed forms of non-declarative memory.
Answer:
• Habituation: Decreased response to repeated stimulus (e.g. ignoring a ticking clock)
• Sensitization: Increased response to repeated stimulus (e.g. louder response to a repeated loud noise)
• Priming: Faster or more accurate response to a stimulus due to prior exposure (unconscious)
• Classical conditioning: Association between two stimuli (e.g. bell → food → salivation)
• Operant conditioning: Behavior shaped by reinforcement or punishment
• Procedural memory: Skills and habits (e.g. riding a bike)
Learning goal: You can reproduce brain regions are involved in the different forms of non-declarative memory
Answer:
Form of Memory: Brain Region(s):
Habituation/Sensitization Reflex pathways
Priming Neocortex (sensory-specific areas)
Procedural (skills) Basal ganglia, motor cortex, cerebellum
Classical Conditioning Cerebellum (skeletal responses), Amygdala (emotional responses)
Operant Conditioning Striatum (for habits), frontal cortex
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Learning goal: You can reproduce and apply the general taxonomy of memory systems (classification into different forms and timeline of
processing).
Answer:
Timeline of processing:
• Sensory memory: Very brief storage (milliseconds to seconds); high capacity but rapidly decays.
• Working memory: Limited capacity (~7 items), short duration (seconds); active manipulation of information.
• Long-term memory: Unlimited capacity and long duration; relatively stable over time.
Flow: Sensory input → sensory memory → (attention) → working memory → (encoding/consolidation) → long-term memory
Types of long-term memory:
• Declarative (explicit):
o Semantic memory (facts, concepts; not tied to specific events)
o Episodic memory (events, time and place-specific) → Mediated by the medial temporal lobe (including hippocampus)
• Non-declarative (implicit):
o Procedural memory (skills/habits): striatum, motor cortex, cerebellum
o Priming: sensory neocortex
o Classical/operant conditioning: amygdala, cerebellum
o Non-associative learning (habituation, sensitization): reflex pathways
Learning goal: You can describe the processes of memory (e.g. encoding, consolidation and retrieval)
Answer:
• Encoding: Transfer of attended sensory input into a memory trace; involves linking new info to existing knowledge.
→ Hippocampus and medial temporal lobe active during successful encoding.
• Storage: Maintenance of memory traces over time in neural circuits.
→ Long-term storage believed to shift from hippocampus to distributed cortical areas.
• Consolidation: Stabilizing memory traces; occurs at:
o Synaptic level: Minutes to hours; involves LTP (e.g. CA1 in hippocampus)
o Systems level: Days to years; involves reorganization of brain regions (e.g. hippocampus to cortex shift)
• Retrieval: Accessing stored information. → Involves hippocampus for recent memories and cortex for older ones.
• Reconsolidation: Retrieved memories become labile again and must be re-stabilized.
Learning goal: You can reproduce how memory can be affected after damage to the medial temporal lobe.
Answer:
Patient H.M. (bilateral hippocampal lesions):
• Severe anterograde amnesia (can’t form new declarative memories)
• Mild retrograde amnesia (difficulty retrieving recent memories)
Patient K.F. (left parietal damage):
• Impaired working memory but preserved long-term memory → Shows a double dissociation between working and long-term memory.
Learning goal: You can reproduce the input and output areas of the hippocampus, as well as the subareas and connections in the hippocampus.
Answer:
• Input: From neocortex, including multimodal sensory and spatial information.
• Pathway through hippocampus: Entorhinal cortex → Dentate Gyrus → CA3 → CA1
• Output: Via fornix to cortical and subcortical areas.
1|Page
, Learning goal: You can explain the role of the cortex and hippocampus in encoding, storage and retrieval.
Answer:
Hippocampus:
• Critical for encoding and retrieval of new episodic memories
• Plays a temporary role in memory storage (see standard consolidation theory)
Neocortex:
• Long-term storage of consolidated memories
• Involved in semantic memory and remote episodic memory
• Role in priming and skill learning
Learning goal: You can explain standard consolidation theory and knows what observations and results support standard consolidation theory.
Answer:
Theory:
• Hippocampus initially binds elements of a memory
• Over time, through replay, retrieval, and emotional tagging, memories become independent of the hippocampus and stored in cortex.
Supporting observations:
• H.M.: Temporal gradient in retrograde amnesia → older memories more intact than recent ones.
• Fear conditioning in rats:
o Removal of hippocampus shortly after learning → impaired freezing
o Removal after 14 or 28 days → freezing intact → memory had consolidated in cortex
Learning goal: You can describe the properties of the cells we use for orientation in space and navigation.
Answer: All these together form a cognitive map used for spatial memory and navigation (O’Keefe & Moser)
• Place cells (hippocampus): Fire when in a specific location (place field) → Discovered by John O'Keefe
• Grid cells (entorhinal cortex): Fire in a hexagonal grid pattern across space
• Head direction cells: Fire when head is facing a specific direction
• Boundary cells: Fire in relation to environmental boundaries
• Speed cells: Firing rate correlates with movement speed
Learning goal: You can describe the discussed forms of non-declarative memory.
Answer:
• Habituation: Decreased response to repeated stimulus (e.g. ignoring a ticking clock)
• Sensitization: Increased response to repeated stimulus (e.g. louder response to a repeated loud noise)
• Priming: Faster or more accurate response to a stimulus due to prior exposure (unconscious)
• Classical conditioning: Association between two stimuli (e.g. bell → food → salivation)
• Operant conditioning: Behavior shaped by reinforcement or punishment
• Procedural memory: Skills and habits (e.g. riding a bike)
Learning goal: You can reproduce brain regions are involved in the different forms of non-declarative memory
Answer:
Form of Memory: Brain Region(s):
Habituation/Sensitization Reflex pathways
Priming Neocortex (sensory-specific areas)
Procedural (skills) Basal ganglia, motor cortex, cerebellum
Classical Conditioning Cerebellum (skeletal responses), Amygdala (emotional responses)
Operant Conditioning Striatum (for habits), frontal cortex
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