Memory and its Disorders: Amnesias

Vocabulary practice flashcards covering memory stages, working memory components, neural substrates of declarative memory, clinical amnesias, neuropsychological assessments, and consolidation theory based on Introduction to Neuropsychology lecture notes.

Memory

A cognitive system for encoding, storing, and retrieving information; operates as a dynamic process where retrieval depends on cues, context, and previous learning.

Encoding

The initial memory stage involving the processing of incoming information, which can occur intentionally (effortful learning) or incidentally.

Storage

The memory process of maintaining information over time through consolidation and dynamic neural representations.

Retrieval

The process of accessing stored memory representations, which is demonstrated primarily through recall or recognition.

Encoding Specificity Principle (Tulving)

A memory principle proposing that retrieval is most successful when the cues and context present during retrieval match those present during encoding.

Proust Effect

The vivid and involuntary retrieval of autobiographical memories triggered by sensory cues, such as smells or tastes.

Atkinson-Shiffrin Model

A modal model of memory describing information as progressing sequentially through three distinct stores: sensory memory, short-term memory, and long-term memory.

Sensory Memory

A high-capacity, modality-specific memory store that retains brief sensory impressions to allow further perceptual processing.

Iconic Memory

Visual sensory memory that retains brief visual impressions for approximately $200\text{--}500\,\text{ms}$.

Echoic Memory

Auditory sensory memory that holds acoustic information for approximately $2\text{--}4\,\text{sec}$.

Short-Term Memory (STM)

A temporary store that maintains attended information with limited capacity and duration; rehearsal aids retention, but repetition alone does not guarantee long-term learning.

Miller's "Magic Number"

The recognized capacity limit of short-term memory, defined as $7 \pm 2$ chunks of information.

Chunking

The process of grouping individual pieces of information into larger, meaningful cognitive units to maximize short-term memory capacity.

Baddeley & Hitch Working Memory Model

A multi-component, limited-capacity system for temporarily maintaining and manipulating information, composed of the central executive, phonological loop, visuospatial sketchpad, and episodic buffer.

Central Executive

The component of working memory responsible for attentional control, coordination of subordinate systems, and resource allocation.

Phonological Loop

The working memory slave system specialized for maintaining and manipulating verbal and auditory information.

Visuospatial Sketchpad

The working memory subsystem responsible for retaining and manipulating visual images and spatial relationships.

Episodic Buffer

A working memory component that integrates information across multiple sensory modalities into cohesive episodes and acts as a bridge between working memory and long-term memory.

Long-Term Memory (LTM)

A large-capacity, relatively enduring storage system containing knowledge, experiences, and procedural abilities over extended periods.

Declarative (Explicit) Memory

The long-term memory category involving conscious, intentional recollection of facts, events, and propositions.

Episodic Memory

A declarative memory system that stores personally experienced events and episodes bound to a specific spatial and temporal context.

Semantic Memory

A declarative memory system comprising decontextualized factual knowledge, language concepts, and understanding of the world.

Non-Declarative (Implicit) Memory

A long-term memory system wherein previous experience facilitates performance and behavior without conscious or intentional recollection.

Procedural Memory

A non-declarative memory subcategory that governs the acquisition and automated execution of motor skills, cognitive habits, and actions.

Case of H.M. (1953)

A historical patient who received bilateral medial temporal lobe surgery (resecting hippocampus, parahippocampal structures, and part of the amygdala) for epilepsy, causing profound anterograde amnesia with preserved working memory and intact procedural skill learning.

Mirror-Drawing Task

A motor-learning task requiring an individual to trace a star outline seen only through a mirror; used to demonstrate that patient H.M. showed normal motor learning across sessions despite having no conscious memory of practicing.

Amnesia

A selective disturbance of memory that cannot be explained solely by global cognitive decline or an altered state of consciousness.

Anterograde Amnesia

A profound impairment in the ability to form and consolidate new lasting declarative memories following brain injury or disease onset.

Retrograde Amnesia

The loss of or difficulty retrieving episodic or semantic memories that were acquired prior to the onset of brain pathology or injury.

Ribot's Law

The principle of temporally graded retrograde amnesia stating that older, remote memories are relatively better preserved than memories acquired shortly before brain injury.

Medial Temporal Lobe (MTL)

A neural region essential for declarative memory formation, containing the hippocampus, entorhinal cortex, perirhinal cortex, and parahippocampal cortex.

Binding

A hippocampal function that integrates and links disparate sensory, temporal, and spatial elements of an event into a unified memory representation.

Relational Memory

A hippocampal-dependent form of memory that establishes and represents relationships among people, places, objects, and events.

Papez Circuit

An interconnected subcortical and limbic network—including the mammillary bodies and anterior thalamic nuclei—that supports memory consolidation and episodic recollection.

Source Monitoring

A prefrontal cortex-mediated process of evaluating and attributing the origin and context of a retrieved memory trace.

Standard Consolidation Theory

A neurobiological model postulating that newly formed memories rely on the hippocampus and gradually reorganize over time into stable, direct connections between cortical areas, a process supported by sleep and rehearsal.

Rey Auditory Verbal Learning Test (RAVLT)

A neuropsychological test assessing verbal learning curves over five trials, susceptibility to interference from an alternate list, delayed recall, and recognition.

Rey-Osterrieth Complex Figure Test

A visual memory assessment evaluating visuospatial construction and memory retention by having a patient copy an intricate geometric figure and reproduce it in immediate and delayed recall.

HERA Model (Hemispheric Encoding/Retrieval Asymmetry)

A neurofunctional framework stating that the left prefrontal cortex is more heavily involved in memory encoding and semantic retrieval, whereas the right prefrontal cortex is more involved in episodic retrieval.

Semantic Association Test

A cognitive assessment evaluating the retrieval of conceptual knowledge and relationships between representations, such as matching a target image (e.g., pyramids) with a semantically related option (palm tree vs. pine tree).

Korsakoff Syndrome

A severe amnestic condition caused by thiamine (vitamin $B_1$) deficiency linked to chronic alcohol misuse, featuring damage to diencephalic circuits (mammillary bodies, thalamus), severe anterograde amnesia, variable retrograde amnesia, and confabulation.

Confabulation

The unintentional fabrication or distortion of autobiographical and contextual memories produced without any deliberate intent to deceive, often seen in frontal and diencephalic pathology.

Autobiographical Memory Interview (AMI)

A structured assessment measuring retrograde memory loss across distinct life periods by probing personal episodic events and personal semantic information.

Intrusive Memories

Involuntary, emotionally intense, bottom-up recollections that can feel vividly present, arising when high stress or threat causes fragmented encoding and weak prefrontal top-down control.