Learning, Memory, and Synaptic Plasticity
How experience changes the brain
Plasticity across scales
Learning modifies synapses, dendritic structure, intrinsic excitability, and large-scale network dynamics. At the cellular level, long-term potentiation and depression are canonical mechanisms, while at the system level memory depends on interaction among hippocampus, neocortex, amygdala, and striatum.
Long-term potentiation is best defined as:
LTP is a durable enhancement of synaptic efficacy following specific patterns of activity.
Correct answer: A persistent increase in synaptic strength after activity
What is an engram?
The term refers to the substrate of memory representation.
Correct answer: A physical or functional trace of memory storage in neural tissue.
Systems consolidation
Over time, some memories become less dependent on the hippocampus and more distributed across cortical networks. This process is shaped by replay, sleep, reactivation, and ongoing schema integration.
Memory systems
Declarative memory
- Facts and events
- Strong hippocampal and medial temporal lobe involvement
Procedural memory
- Skills and habits
- Strong basal ganglia and cerebellar contributions
Plasticity is not always beneficial
Maladaptive plasticity can contribute to chronic pain, addiction, dystonia, and pathological fear learning.
Why is sleep often linked to memory consolidation?
Sleep is not passive; it participates in systems-level memory processing.
Correct answer: Because replay and reactivation during sleep can stabilize and reorganize memory traces.
Which structure is most associated with initial formation of declarative memories?
The hippocampus is crucial for forming new declarative memories.
Correct answer: Hippocampus