Nuero Unit 4

Learning

A lasting change in behavior or knowledge that results from experience, practice, or exposure.

Memory

The ability to encode, store, and retrieve information based on past experiences.

Memory trace

The physical or biochemical representation of a memory stored in the brain.

Acquisition

The initial stage of learning in which new information is first encoded.

Retrieval

The process of accessing stored memories.

Consolidation

The process by which fragile new memories become stable and long-lasting.

Reconsolidation

The re-stabilization of a memory after it has been recalled and temporarily destabilized.

Declarative memory

Conscious, explicit memories of facts and events ('knowing that').

Explicit memory

Memory requiring conscious retrieval.

Non-declarative memory

Memory expressed unconsciously through behavior ('knowing how').

Implicit memory

Memory expressed without awareness or intention.

Procedural memory

Skills and habits stored in long-term memory.

Semantic memory

Knowledge of facts, concepts, and general world knowledge.

Episodic memory

Personal, autobiographical memories tied to a specific time and place.

Autobiographical memory

Memory for one's own life events.

Skill learning

Acquiring the ability to perform tasks that require practice (e.g., riding a bike).

Priming

Exposure to a stimulus that influences response to a later stimulus without conscious awareness.

Conditioning

Learning associations between events.

Immediate memory

Very short holding of sensory events for fractions of a second.

Sensory memory

Temporary memory systems that hold sensory information.

Working memory

Short-term memory that holds information briefly for manipulation and immediate use.

Short-term memory

Storage lasting seconds to minutes, used for temporary information retention.

Long-term memory

Memory stored for days, years, or a lifetime.

Attention

Cognitive focus that enhances encoding into working memory.

Rehearsal

Repetition of information to maintain it in memory or consolidate it.

Encoding

The initial learning of information.

Storage

Keeping information in the brain over time.

Retrieval failure

Inability to access stored information.

Interference

Disruption of memory retrieval by competing information.

Neuroplasticity

The brain's ability to reorganize and change its connections and structure.

Synaptic plasticity

Long-term changes in the strength of synaptic connections.

Amnesia

Loss of memory ability.

Retrograde amnesia

Loss of memories formed before an injury.

Anterograde amnesia

Inability to form new long-term memories after an injury.

Patient H.M.

Patient who underwent bilateral hippocampal removal and developed severe anterograde amnesia.

Bilateral temporal lobectomy

Surgical removal of both medial temporal lobes.

Hippocampal removal

Loss of hippocampal structures necessary for forming new declarative memories.

Intact procedural memory

Preservation of skill learning despite memory deficits.

Mirror-tracing task

A task in which H.M. showed procedural learning despite no conscious recollection.

Patient K.C.

Individual with loss of episodic memory but intact semantic memory.

Episodic amnesia

Inability to recall personal past experiences.

Semantic memory preservation

Retention of general knowledge despite episodic memory loss.

Patient J.K.

Individual with basal ganglia dysfunction and impaired procedural memory.

Basal ganglia dysfunction

Damage affecting habit and motor learning.

Procedural memory impairment

Inability to perform learned habits.

Korsakoff’s syndrome

Memory disorder linked to thiamine deficiency from alcoholism.

Thiamine deficiency

Lack of vitamin B1 impairing metabolism in neurons.

Chronic alcoholism

Long-term alcohol abuse causing nutritional deficits.

Confabulation

Unintentional fabrication of stories to fill memory gaps.

Frontal cortex atrophy

Degeneration of frontal lobe associated with Korsakoff’s.

Diencephalon damage

Injury to thalamus/hypothalamus contributing to memory problems.

Hippocampus

Brain structure essential for forming declarative memories.

CA1 region

Area critical for LTP expression and memory consolidation.

CA3 region

Area important for pattern completion and memory retrieval.

Dentate gyrus

Region involved in forming new memories and pattern separation.

Schaffer collaterals

Axons connecting CA3 to CA1 neurons and often used to study LTP.

Hippocampal place cells

Neurons that fire when an animal is in a specific location.

Spatial representation

Mental mapping of surroundings.

Cognitive map

Internal representation of spatial environment.

Environmental mapping

Hippocampal encoding of surroundings.

Context memory

Memory of the setting in which an event occurred.

Spatial navigation

Ability to move through an environment using memory.

Long-term potentiation (LTP)

Long-lasting increase in synaptic strength following high-frequency stimulation.

High-frequency stimulation

Rapid firing that induces LTP.

Tetanic stimulation

Burst of electrical activity used to induce LTP.

EPSP

Excitatory postsynaptic potential; depolarization of postsynaptic neuron.

Synaptic strengthening

Persistent increase in synaptic efficiency.

Hebbian learning

Theory stating synapses strengthen when pre- and postsynaptic neurons fire together.

Co-activation

Simultaneous firing of neurons required for LTP.

Cells that fire together wire together

Common summary of Hebbian learning.

Glutamate

Main excitatory neurotransmitter involved in LTP.

AMPA receptors

Receptors allowing Na+ entry and depolarization.

NMDA receptors

Receptors requiring depolarization to permit Ca2+ entry.

Mg²⁺ block

Magnesium ion that normally blocks the NMDA receptor channel.

Postsynaptic depolarization

Voltage change required to remove Mg²⁺ block.

Ca²⁺ influx

Entry of calcium that triggers molecular changes for LTP.

Calmodulin

Calcium-binding protein activating downstream pathways.

CaMKII

Kinase essential for LTP induction.

PKA

Protein kinase A; part of signaling cascade.

MAPK

Mitogen-activated protein kinase; involved in synaptic remodeling.

Protein synthesis

Creation of new proteins needed to stabilize long-term memory.

New AMPA receptor insertion

Mechanism that increases synaptic strength.

Synaptic remodeling

Structural changes in synapses to store memory.

Dendritic spine enlargement

Growth of postsynaptic spines associated with LTP.

Long-term depression (LTD)

Long-lasting weakening of synaptic strength.

Low Ca²⁺ activation

Signal that promotes LTD instead of LTP.

Protein phosphatases

Enzymes that remove phosphate groups to weaken synapses.

Synaptic weakening

Reduction in synaptic strength.

Pruning

Removal of unnecessary synaptic connections.

Circuit refinement

Tuning of neural pathways through LTP/LTD balance.

Karl Lashley

Neuroscientist who searched for the 'engram'.

Mass Action Principle

Memory loss depends on amount of cortex removed, not location.

Equipotentiality

Idea that all brain areas equally capable of storing memory.

Cortical damage

Injury affecting memory depending on extent.

Distributed memory storage

Memory stored across many brain regions.

Systems consolidation

Slow reorganization of memory across brain networks.

Dementia

Progressive decline in memory plus cognitive impairments.

Alzheimer’s disease

Most common form of dementia, involving plaques, tangles, neuron loss.

Cognitive decline

Gradual loss of mental abilities.

Senile plaques

Extracellular deposits of β-amyloid protein.