Neuroscience of Memory and Synaptic Plasticity

These vocabulary flashcards cover key scientists, theories, learning types, synaptic mechanisms, molecular players, and properties central to memory and synaptic plasticity as presented in the lecture notes.

Hermann Ebbinghaus

• Forgetting curve – Memory fades over time.
  
  

• Spacing effect – Spaced studying helps long-term memory.
  
  

Forgetting curve

Graph showing how memory retention declines over time without reinforcement.

Spacing effect

Improved long-term retention when learning sessions are spread out over time rather than massed together.

Georg Müller

Researcher who discovered and introduced the concept of memory consolidation.

Memory consolidation

Process by which short-term memories are stabilized into long-term storage.

Camillo Golgi

An old idea that said all brain cells (neurons) are connected together in one big network without any gaps.

Reticular theory

Discredited idea that nervous tissue is a single interconnected web without discrete cells.

Santiago Ramón y Cajal

Neuroscientist who established the neuron doctrine and argued neurons are individual cells.

Neuron doctrine

Principle that neurons are separate, discrete units communicating via specialized contacts (synapses).

Terje Lømo

Norwegian scientist who discovered long-term potentiation (LTP) in 1973.

Long-Term Potentiation (LTP)

Enduring increase in synaptic strength produced by high-frequency stimulation; model for learning and memory.

Non-associative learning

Learning where your response gets stronger or weaker to one repeated thing — either by getting used to it (habituation) or becoming more sensitive to it (sensitization).

Habituation

Progressive decrease in behavioral response to a repeated, harmless stimulus.

Sensitization

Enhanced response to a stimulus following exposure to a strong or noxious event.

Associative learning

Learning that links two stimuli or a stimulus and a response, as in classical conditioning.

Classical conditioning

Learning by connecting two things — like a sound and food — so that one starts to cause the same reaction as the other

Conditioned stimulus (CS)

Something that starts to cause a reaction after being paired with something important

Unconditioned stimulus (US)

Something that naturally causes a reaction, without any learning.

Conditioned response (CR)

Learned reaction produced by the conditioned stimulus after conditioning.

Excitatory postsynaptic potential (EPSP)

Depolarizing change in membrane potential that makes a neuron more likely to fire an action potential.

Inhibitory postsynaptic potential (IPSP)

Hyperpolarizing change in membrane potential that decreases the likelihood of neuronal firing.

Action potential

All-or-none electrical impulse that rapidly travels along an axon to transmit neural information.

Excitatory synapse

Synaptic connection that releases glutamate to generate EPSPs in the postsynaptic neuron.

Inhibitory synapse

Synaptic connection that releases GABA to generate IPSPs in the postsynaptic neuron.

Neurotransmitter life cycle

Sequence of synthesis, vesicular storage, release, receptor binding, and removal (reuptake or degradation) of a neurotransmitter.

Long-Term Depression (LTD)

Persistent weakening of synaptic strength produced by low-frequency stimulation or weak Ca²⁺ signals.

Tri-synaptic pathway

Hippocampal circuit: Entorhinal cortex → Dentate gyrus → CA3 → CA1.

High-frequency stimulation

Rapid trains of impulses that raise intracellular Ca²⁺ levels and induce LTP.

Low-frequency stimulation

Sparse impulses that cause modest Ca²⁺ entry and promote LTD.

Kinase

Enzyme activated by high Ca²⁺ that phosphorylates proteins, facilitating LTP.

Phosphatase

Enzyme activated by low Ca²⁺ that removes phosphates, contributing to LTD.

Calcium model of plasticity

Theory that the magnitude of Ca²⁺ influx determines whether a synapse undergoes LTP (high Ca²⁺) or LTD (low Ca²⁺).

AMPA receptor (AMPAR)

Ionotropic glutamate receptor; insertion into the postsynaptic membrane increases synaptic strength during LTP.

NMDA receptor (NMDAR)

Voltage- and ligand-gated glutamate receptor that admits Ca²⁺ only when glutamate is present and the membrane is depolarized; acts as a coincidence detector.

CaMKII

Calcium/calmodulin-dependent protein kinase II that is activated by Ca²⁺ and drives AMPAR insertion during LTP.

Constitutive AMPAR pathway

Continuous, basal recycling of AMPA receptors to and from the synaptic membrane.

Regulated AMPAR pathway

Activity-dependent trafficking of AMPARs, especially during LTP induction.

AMPAR endocytosis

Removal of AMPA receptors from the postsynaptic membrane during LTD, weakening the synapse.

Input specificity

Only synapses that receive stimulation undergo LTP; neighboring inactive synapses do not.

Associativity (LTP property)

Weak synaptic input can be potentiated if it occurs simultaneously with strong input to the same postsynaptic cell.

Cooperativity

Multiple weak inputs can collectively generate enough depolarization to induce LTP.

Persistence

LTP can last from hours to the entire lifetime of an organism.

Activity dependence

Induction of LTP requires coincident pre- and postsynaptic activity.

Hebb’s Law

Principle stating that “neurons that fire together wire together,” underlying synaptic strengthening.

Cajal’s memory hypothesis

Proposal that synapses are the primary sites where memories are stored.

Jerzy Konorski

Neuroscientist who, in 1948, independently proposed the idea of synaptic plasticity as a basis for learning.