Long-term Potentiation Flashcards
Neuroplasticity
Ability of neurons and neural circuits to be remodeled by events
Structural Synaptic Plasticity
- New synapses form
- Reorganization of synaptic connections
Physiological Synaptic Plasticity
- Increase in neurotransmitter release
- Increase surface area (more receptors expressed)
- Modulated by neuromodulators
Environmental Enrichment
Multi-sensory experiences drive synaptic change
- Higher order dendritic branching
- Greater neuroplasticity
Habituation
Decreased response to repeated stimulus
- Short-term: less neurotransmitters released
- Long-term: retraction of synaptic terminals
Dishabituation
Restoration of response amplitude after habituation
Sensitization
Prior strong stimulation increases response for subsequent stimulus
Hebbian Principles
“Neurons that wire together fire together”
- Connection between presynaptic and postsynaptic neuron strengthens with repeated activation
Long-term Potentiation
Stable and enduring increase in effectiveness of synapses
- Long term change in potential of neuron to fire
LTP Steps (AMPA & NMDA)
-
Glutamate binds to AMPA receptors
- Flow of Na+ ions
- Increase in Membrane Potential -
Mg2+ block driven out of NMDA receptors
- Flow of Ca+ into cell
LTP Steps (Role of Ca+)
-
Ca2+ activates CaMKII
- More AMPA receptors on postsynaptic membrane
- More AMPA stored in vesicles
- Increases synaptic sensitivity to glutamate -
CAMKII activates CREB
- Modifies DNA expression to code for proteins to structurally change synapse -
CREB activates retrograde messenger (NO)
-Diffuses into presynaptic membrane
- Increase in neurotransmitter release
Dopamine signaling
- Can result in glutamate release
- Makes LTP more achievable
Neurogenesis
- Occurs in Dentate Gyrus of Hippocampus
Environmental Cues & Neurogenesis
Success:
- Exercise
- Environmental Enrichment
Impediments:
- Stress
