Learning and Memory in the Brain (1)

Vocabulary practice flashcards covering cellular mechanisms of learning and memory, environmental enrichment studies, cortical plasticity, Hebbian learning, and long-term potentiation (LTP).

Learning

The process by which experiences change the nervous system.

Memories

The structural and functional changes that take place in neural circuits as a result of learning.

Plastic Synapses

Synapses across which the strength or efficiency of communication between neurons can be dynamically altered, resulting in the strengthening or weakening of neural connections.

Cell Assemblies

Interconnected neural networks that represent experiences and memories, within which activation alters synaptic connection strength.

Synaptic Strengthening Mechanisms

Processes that increase communication efficacy across a synapse, including increased presynaptic neurotransmitter release, increased number or sensitivity of postsynaptic receptors, and reduced rates of neurotransmitter breakdown or reuptake.

Bennett et al. (1964)

A landmark study examining rats housed in standard, impoverished, and enriched conditions, showing that enriched conditions led to heavier cortices (increased cortical thickness) and greater acetylcholinesterase (AChE) activity.

Enriched Condition (EC)

An experimental housing environment providing social and sensory stimulation, which promotes thicker cortices, greater AChE activity, larger synapses, and greater dendritic complexity compared to an impoverished condition (IC).

Acetylcholinesterase (AChE)

An enzyme that breaks down acetylcholine; its heightened activity in the cerebral cortex of enriched-condition animals indicates an increase in acetylcholine release.

Diamond et al. (1975)

An empirical study demonstrating that existing synapses are larger in animals housed in an enriched condition.

Greenough (1976)

A study demonstrating that housing animals in an enriched condition produces increased dendritic branching in cortical neurons.

Globus et al. (1973)

A study reporting that enriched environmental conditions lead to a higher density of dendritic spines along neuronal branches.

Amunts et al. (1997)

A study showing experience-dependent cortical plasticity in humans, specifically demonstrating an enlarged hand representation area in the motor cortex of pianists.

Draganski et al. (2004)

A structural neuroimaging study demonstrating that learning to juggle induces significant increases in grey matter within human visual-motion processing areas.

Hebb (1949)

The theorist who postulated that the co-occurrence of firing in presynaptic and postsynaptic neurons produces physiological changes that strengthen the connection between the cells ('cells that fire together wire together').

Long-Term Potentiation (LTP)

A stable and enduring increase in the effectiveness of synaptic communication resulting from the concurrent activation of presynaptic and postsynaptic neurons.

Hippocampal Formation (HF)

The limbic brain structure where the cellular mechanisms of long-term potentiation (LTP) are most commonly investigated.

Entorhinal Cortex

The major cortical input region to the hippocampal formation, whose axons project directly along the perforant path.

Perforant Path

The axonal pathway that carries information from neurons in the entorhinal cortex to synapse onto granule cells in the dentate gyrus.

Granule Cells of the Dentate Gyrus

The target postsynaptic neurons within the hippocampal formation that receive synaptic connections from the perforant path and exhibit LTP upon high-frequency stimulation.

LTP Induction Protocol

A laboratory procedure in which a baseline response is recorded from a single pulse, followed by a brief high-frequency burst of electrical stimuli to the pathway, producing a long-lasting increase in postsynaptic responsivity to subsequent single pulses.