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Memory

Process during which information is encoded, consolidated, stored, and retrieved

Long-Term Potentiation (LTP)

Long-lasting increase in synaptic strength following high-frequency (repeated, fast) stimulation of a synapse

Long-Term Potentiation (LTP)

Hebbian plasticity is supported by

NMDA Receptors

Ionotropic receptors also for glutamate

Ca2+ increases

As NMDA increases,

Magnesium (Mg2+)

Can block NMDA receptors

Long-Term Depression (LTD)

Long lasting decrease in synaptic strength following low-frequency stimulation of a synapse

Ca2+

Enter can result in removal of AMPA receptors

Learning is prevented

If LTP is prevented,

Rhinal Cortex

Structure used in object recognition

Dense Postsynaptic Membrane

Higher concentration of proteins, faster and more firmly binding of neurotransmitters

AMPA Receptors

Ionotropic receptors for glutamate (gates Na+ and K+)

Na+ increases

As AMPA increases,

Hebbian Plasticity Theory

Increase in the synaptic strength arises from the presynaptic cell’s repeated and persistent stimulation of the postsynaptic cell

Coincidence Detection

Neurons detect events that happen closely together in time and integrate the temporally close but spatially distributed input signals

Habituation

Repeated stimulation leads to reduced neurotransmitter release and a weaker response

Sensitization

strong stimulation leads to increased serotonin release and a greater response

Morris Water Maze

Rat experiment testing spatial memory

Place Cells

Neurons that fire in the hippocampus when visiting specific regions of the environment

Grid Cells

Neurons that fire in the entorhinal cortex when in a repeated, hexagonal location

Hippocampus

Where place cells fire in

Entorhinal Cortex

Where grid cells fire in

Hippocampus

Consolidates short term memory into long term memory, spatial locations

Entorhinal Cortex

Major source of neural signals to the hippocampus

Learning

Deals with how experience changes the brain; it involves neuroplasticity

Neuroplasticity

Brain’s ability to modify synaptic connections as a result of experience

Engram

Memory trace or representation in the brain of what has been learned

Equipotentially

The brain is sufficiently plastic. It has the ability to use the intact part of the brain to do what a damaged part of the brain can no longer do

Mass Action

Learning and memory are distributed across all parts of the brain; deficits are proportional to the amount of brain damage

Lashley’s Conclusion

Memories are not localized to specific areas (no engram)

Thompson’s Conclusion

Discovered the cerebellum stores the memory for Eyeblink conditioning (engram = cerebellum)

Classical Conditioning

Automatic, conditioned response is paired with specific stimuli

Eyeblink Conditioning

Example of classical conditioning researched by Thompson

Cerebellum

Mediates simple conditioning

Distributed Brain Areas

Mediates complex conditioning

Sensory Register Memory

Copy of few seconds of sensory information you’ve just sensed (large capacity)

Short-Term Memory

memory for information that lasts seconds to minutes (limited capacity)

Long-Term Memory

Permanent, enduring memory (unlimited capacity)

Consolidation

Process that stabilizes a memory trace and strengthens it into long-term storage

Explicit/Declarative Memory

Memory of information and what you know

Episodic Memory

Explicit memory of experiences and events

Semantic Memory

Explicit memory of facts and concepts

Implicit/Non-Declarative Memory

Memory of unconscious information and how you know

Amnesia

Long-term inability to retain info for longer than a few minutes

Anterograde Amnesia

Inability to form new memories after brain damage

Retrograde Amnesia

Inability to recall memories prior to brain damage

Bilateral Medial-Temporal Lobectomy (BMTL)

Removal of hippocampus, amygdala, and rhinal cortex to reduce seizure, but led to TGRA

Temporally-Graded Retrograde Amnesia (TGRA)

Inability to retrieve memories is strongest for recent events and less severe for older events