Memory II September 24, 2009 Types of Memory The Case of Henry M (H.M.) Two Limbic Circuits Anterior Thalamus
Cingulate Gyrus Dorsomedia l Thalamus Mamillothala mic Tract Mammillary Bodies Fornix
Hippocamp us Medial (Papez) Orbitofronta l Amygdalofu gal pathways
Uncus Amygdala Lateral The Human Amnesic Syndrome Impaired new learning (anterograde amnesia), exacerbated by increasing retention delay Impaired recollection of events learned prior to
onset of amnesia (retrograde amnesia, remote memory impairment), often in temporally graded fashion Not limited to one sensory modality or type of material Normal IQ, attention span, nondeclarative forms of memory Recent/Remote Distinction Three patterns of RA Temporally-graded Temporally-limited
Decade-nonspecific Typically see both AA and RA in amnesia (no RA without AA) but there are exceptions Selective (focal) retrograde amnesia Patterns of Retrograde Amnesia Normals Amnesics
Remote Recent Temporally-Graded RA Remote Recent Temporally-Limited RA
Remote Recent Decade-Nonspecific RA Frontal/Executive Contributions to Memory Temporal ordering (time tagging) of memories Contextual aspects of memory
Source memory (memory for where information was learned) Metamemory (feeling of knowing) Intentional aspects of memory/prospective memory (remembering to remember) Theoretical Accounts of Amnesia 1. Encoding deficit
Amnesics have difficulty organizing and learning TBR information for later recall Evidence from LOP studies Can explain: AA (impairment in new learning, or recent memory)
Has difficulty explaining: shrinking RA RA at 2 weeks RA at 6 months trauma Theoretical Accounts (cont.) 2. Consolidation deficit
post-encoding deficit: difficulty in the consolidation of TBR information Huppert & Percy (1979): accelerated rates of forgetting Can explain: rapid forgetting in amnesia Cant explain: extensive RA Theoretical Accounts
(cont.) 3. Retrieval deficit Studies showing amnesics are abnormally susceptible to interference Retrieval is often aided by cuing Inconsistent performance across testing situations Indirect versus direct tests of memory Helpful in explaining some retrograde deficits
Spared Abilities in Amnesic Disorders 1. Attention span (e.g. digit span) 2. Measured intelligence 3. indirect forms of memory (nondeclarative)
Skills; skill learning (rotary pursuit, mirror tracing or reading) Priming (perceptual and conceptual) Conditioning familiarity Perceptual Priming Word-Stem Completion PAR_______ IMM_______ HOL_______
GRA_______ CHI_______ PRO_______ Word-Fragment Completion AL__GA_O_ T_B_ O G _ N E_E_A_O_ G_R___F_ Explicit and Implicit
Memory Explicit memory Conscious recall of to-be-remembered (TBR) information Supposedly measured through DIRECT tasks Implicit memory Unconscious or unintentional recollection of previously-presented material Supposedly measured through INDIRECT tasks Examples of Direct and Indirect
Tests Direct tests Free recall Recognition Indirect tests Word-stem completion Word-fragment completion Lexical decision Picture fragment identification Explicit-implicit dissociations: Systems vs. Process Debate
Systems: IM and EM represent two separate memory systems (functionally and anatomically) Process: IM & EM differ in terms of the underlying processes involved in task performance Conceptual versus perceptual processing The Systems View: Characteristics of a Memory System Class-inclusion operations
(defines a particular class, or category, of operations) Deliberate (recollection) v. Nondeliberate (familiarity) retrieval mode Remember v. know Properties and relations (describes how the system works, kinds of information the system handles, neural substrates)
Temporal/diencephalic/basal forebrain v. cortex (priming) Temporal/diencephalic/basal forebrain v. striatum (skills) Stochastic independence Convergent (double) dissociations (functional, anatomical) The Process view Direct and indirect tests tap different processes within the same memory system
Crux of the argument: processes at study match those at test for successful performance (ESP, or more broadly transferappropriate processing) Data-driven: indirect tasks (implicit) Perceptually based Modality dependent Conceptually-driven: direct tasks (explicit) Conceptually based Modality independent Process-Based Explanations of
Amnesia Systems: Amnesia disrupts the system responsible for explicit, not implicit memory Process: Amnesia represents an impairment in conceptual processing, regardless of the test type Perceptual processing is intact on both direct and indirect tests
Conceptu al Modalityindependent Meaning-dependent
(changes in meaning between study and test adversely affect performance) Based on semantic characteristics Most clinical memory tests tap this Modality-dependent
(changes in modality between study and test adversely affect performance) Meaning-independent Based on physical or sensory characteristics Not tapped by typical clinical memory tests Perceptua
l Characteristics of Conceptual and Perceptual tests Memory System Process Declarative
Stem completion, perceptual identification DataDriven (perceptual ) Conceptual ly-Driven (conceptual )
Nondeclarati ve Free recall, cued recall, recognition (from Roediger, 1990) Memory System
Process Declarative DataDriven Graphemic cued recall (perceptual ) Conceptual ly-Driven
Free recall, cued recall, recognition (conceptual ) (from Roediger, 1990) Nondeclarati ve Stem completion, perceptual
identification Category exemplar generation, general knowledge test Blaxton, 1985 (Exp. 2) Modality effect in data-driven, but not conceptuallydriven tasks
Generate: at learning were given tin C _ _ _ _ _ and generated copper No Context: at learning, were given XXX-COPPER SS BRAIN DIAGRAM ModalityNonspecific Representations (conceptual)
Au d Vis ModalitySpecific Representatio ns Synthesis Current data is favorable for both system and process views
Multiple forms of memory are represented by a distributed memory system Fractionated memory impairments possible with subtotal damage to memory system Two-Process Theory (Mandler, Jacoby) Recollection: a controlled process in which there is conscious retrieval of a prior learning episode
Familiarity: an automatic process in which the results of prior exposure or processing lead to a feeling of familiarity or perceptual fluency Recollection/Familiarity Diana, Yonelinas, & Rangrath, 2007, Trends in Cog Sci Process Dissociation Procedure
Opposing recollection and familiarity Inclusion vs. exclusion test Derive formulae to calculate recollection and familiarity from performance data Many manipulations (e.g., age, dividing attention) affect recollection but not familiarity A
B C Problems with ProcessDissociation Assumes independence of recollection and familiarity; however R and F are often correlated Seriousness of this problem depends upon mode of retrieval/instructions
Generate-recognize (first word that comes to mind): R & F not independent Direct retrieval (use cue for retrieval): Remember-Know Two subjective states of remembering Seem to be relatively independent Many variables affect remembering but not knowing ERPs distinguish R vs. K words
irrespective of study history Lorazepam reduces remembering and leaves knowing intact Functional Neuroimaging of Memory Allows evaluation of in vivo memory performance Allows evaluation of extended networks of memory Some techniques allow real-time assessment
Functional Imaging of Explicit Memory HERA (hemispheric encodingretrieval asymmetry) model Encoding preferentially associated with LDLPFC activation Retrieval preferentially associated with RDLPFC activation But theres also materialspecificity
Functional Imaging of Explicit Memory 2 Prefrontal, MTL responses greater during learning if items eventually remembered Hemispheric asymmetries in material (verbal vs. nonverbal) TP differentiated from FP Hippocampus active during encoding, less so during retrieval
Functional Imaging of Perceptual Priming Multiple Trace Theory Previous studies suggest hippocampus important in laying down a new memory but becomes less important over time MTT suggests, in contrast to standard model, that hippocampus is always involved in retrieval of autobiographical memories, however old
Cabeza & St. Jacques, 2007 Dissociations of forms of memory Selective impairment in STM with preserved LTM Impairment in semantic memory with relatively preserved episodic memory (e.g., semantic dementia) Selective retrograde amnesia
Selective impairments in skill learning and priming Five Memory Systems (Schacter et al., 1994, 2000) Working Memory
Episodic Memory Semantic Memory Perceptual Representation System Procedural Memory Metamemory Thinking about thinking Allows control of retrieval RJR (recall-judge-recognize)/FOK paradigm Theories (all explain some data) Target retrievability hypothesis
Cue familiarity hypothesis e.g. CHARM (monitoring/control prior to retrieval) Accessibility heuristic (e.g. speed of access) Metamemory: Sample findings Tip-of-the-tongue phenomenon Can recall phonemic information, number of syllables, gender of speaker, etc. Strongest evidence for accessibility hypothesis Retrieval Latency
Game show paradigm: FOK or actual retrieval by fast fingers. Responses faster in FOK than in retrieval. Favor cue-familiarity hypothesis. Knowing not Judgments about what is not known are made accurately and very quickly. Appears to be positively marked and immediately accessible. Dissociation between FOK and recognition Seen in some forms of amnesia (e.g., Korsakoff
patients) but not in others. May be attributable to Reconstructive Memory Reconstructive vs. reproductive Paradigms Post-event manipulations Minsinformation acceptance Associated phenomena Own bias Hindsight bias
Clinical implications: self report
