Component process model of memory

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Component process model of memory

• Why am I reviewing this article?
• Students need to learn to read articles in the
  primary literature
• article integrates much of what we have been
  discussing

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Component process model of memory

• General assumptions of model
• Moscovitch believes that memory is not unitary
  but depends upon the operation of different
  independent components
• this model distinguishes between modules and
  central systems

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Component process model of memory

• General assumptions of model
• this model postulates that the same modules
  mediate implicit domain-specific perceptual tests
  of knowledge and perceptual repetition priming
  tests
• e.g., prosopagnosics who respond differentially
  to familiar versus unfamiliar faces on implicit
  tests show normal repetition priming effects
• e.g., dyslexics who have an intact word-form
  system show preserved repetition priming effects
  

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Component process model of memory

• Overview of model
• 4 components
• nonfrontal neocortical component made up of
  perceptual and semantic modules that mediate
  performance on item-specific implicit memory
  tests
• basal-ganglia component that mediates performance
  on sensorimotor tests of memory

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Component process model of memory

• Overview of model
• 4 components
• medial-temporal/hippocampal component that
  mediates explicit memory tests that are
  cue/dependent or associative
• central-system frontal-lobe component that works
  with memory and mediates performance on
  strategic explicit tests

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Component process model of memory

• Modules and central systems
• modules are computational devices that have
  propositional content and specify three criteria
• domain specificity
• information encapsulation
• shallow output

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Component process model of memory

• domain specificity
• information that a module processes is restricted
• implies that it should be possible to damage this
  system selectively both functionally and
  neuroanatomically

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Component process model of memory

• information encapsulation
• processing operations of the system are not
  accessible to higher level functions
• it is difficult for higher level functions to
  modify the processing by the system
• implies that it should be possible for modular
  functions to process information effectively even
  when there is general intellectual decline (e.g.,
  AD)

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Component process model of memory

• shallow output
• output has no meaning other than that assigned to
  it
• e.g., a person with an associative agnosia is
  quite capable of drawing a viewed object, but
  cannot name the object, describe its function
  etc.
• Sirigu (1991) reported a patient FB with an
  associative agnosia could appropriately
  manipulate unidentified objects whose function
  could not be described

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Component process model of memory

• Examples of modules
• word form recognition system
• face-recognition system
• phonological-word-form system

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Component process model of memory

• Central systems
• central systems integrate information from
  different dissimilar domains
• the processing carried out by central systems can
  be influenced by other processes
• the information may be accessible to
  consciousness
• the output of central systems is meaningful

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Component process model of memory

• Moscovitch next classifies memory tests using the
  conceptual framework just presented
• caveat -- no test is process pure (Jacoby, 1991)
• see Table 1 in your article

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Component process model of memory

• Implicit tests
• item specific perceptual, conceptual
• procedural sensorimotor, ordered/rule-based
• Explicit tests
• Associative
• Strategic

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Component process model of memory

• Implicit tests item specific, perceptual
• e.g., identification of fragmented words or
  pictures
• hypothesized process
• when stimulus presented, it is processed by
  cortical presemantic modules that transform the
  stimulus into presemantic structural
  representation
• this output is then delivered to central system
  structures for semantic interpretation

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Component process model of memory

• Implicit tests item specific, perceptual
• the modules that processed the stimulus and the
  central structures that interpreted the stimulus
  are modified by the stimulus leaving a perceptual
  and semantic record
• reactivation of this record is the basis of
  perceptual and conceptual priming effects
  respectively

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Component process model of memory

• Implicit tests item specific, perceptual
• anatomical localization
• perceptual modules are in the posterior neocortex
• evidence (negative)
• amnesics show normal perceptual priming
• damage is in the medial temporal lobes and
  related structures in the diencephalon

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Component process model of memory

• Implicit tests item specific, perceptual
• evidence (positive)
• apperceptive versus associative agnosics
• apperceptive agnosics have relatively intact
  sensory processes (e.g., colour, acuity, motion)
• however, they cannot form a percept of the object
• for example, they are unable to recognize, copy,
  or match simple shapes

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Component process model of memory

• Implicit tests item specific, perceptual
• evidence (positive)
• apperceptive versus associative visual agnosics
• associative agnosics can copy, recognize, and
  match objects, but are unable to recognize the
  identity of an object
• apperceptive agnosics tend to have damage in the
  bilateral regions of the occipital lobes
• associative agnosics tend to have damage in the
  ventral regions in the anterior temporal lobes

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Component process model of memory

• Conceptual repetition effects and semantic
  records
• in conceptual repetition tests, the target item
  is not repeated at test
• the target is elicited by a semantic cue (e.g., a
  related word or question)
• e.g., generate exemplars of category cues

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Component process model of memory

• Conceptual repetition effects and semantic
  records
• this model postulates that conceptual repetition
  effects are mediated by central systems, which
  interpret the output from a perceptual module,
  and store a semantic record of their activity
• model predicts that modality and format should
  not affect conceptual repetition effects, but
  that levels of processing should
• these predictions have been confirmed

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Component process model of memory

• The hippocampal component A module for episodic,
  associative memory
• conscious recollection of episodes in which the
  cue is sufficient for retrieval (e.g., simple
  recognition and cued recall)

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Component process model of memory

• The hippocampal component A module for episodic,
  associative memory
• hippocampal structure consists of a circuit
  consisting of hippocampus, parahippocampal
  gyrus, entorhinal cortex, perirhinal cortex,
  mammilary bodies, dorsomedial nucleus of the
  thalamus, the cingulate cortex, and the fornix
• amnesia is associated with bilateral damage of
  these structures

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Component process model of memory

• The hippocampal component A module for episodic,
  associative memory
• how it works
• the input modules and central system deliver
  their output to working memory
• the contents of working memory are accessible to
  consciousness
• the domain of the hippocampal component is
  consciously apprehended information (ie the
  information processed by the hippocampal
  component)

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Component process model of memory

• The hippocampal component A module for episodic,
  associative memory
• how it works
• hippocampus binds or integrates the output from
  the modules and central systems that contributed
  to the conscious experience
• the bound engram (memory trace) is encoded as a
  file entry in the hippocampal complex

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Component process model of memory

• The hippocampal component A module for episodic,
  associative memory
• how it works
• ecphory or conscious retrieval occurs when a cue
  (external or internal) automatically interacts
  with a memory trace
• encoding and retrieval (ecphoric) processes are
  automatic, obligatory, cognitively impenetrable,
  and informationally encapsulated because this
  component is modular

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How episodic memory works
Conscious Awareness
Control systems
Encoding/Ecphory
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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• frontal lobes critical in memory tests in which
  extracue strategic factors are critical
• e.g., free recall (esp. categorized FR), memory
  for temporal order

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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• prefrontal cortex is a large heterogeneous
  structure consisting of several distinct areas,
  each with its own projections to and from
  different brain regions, and with its own
  function
• e.g., dorsolateral versus orbital regions

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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• the frontal lobes postulated to play a critical
  role during encoding by
• its selection of memory strategies
• by organizing input

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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• during retrieval the frontal lobes play a
  critical role by
• organizing output from hippocampal component
• determining its temporal order
• organizing mnemonic searches

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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• e.g., What were you doing last Friday?
• Frontal lobes
• not critical for storage and retention of
  information (hippocampal)
• critical in those aspects of memory requiring
  organizational and strategic processing

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Component process model of memory

• Frontal lobes central systems and strategic
  explicit tests
• Moscovitch refers to this function as
  working-with-memory (it is theoretically close to
  the central executive of Baddeleys working
  memory model

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Component process model of memory

• Procedural implicit tests
• two general categories distinguished
• sensorimotor and ordered/rule based
• sensorimotor
• improvement of motor or sensory skills
• e.g., pursuit rotor, mirror drawing, reading
  transformed script
• ordered/rule based
• e.g., Tower of Hanoi

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Component process model of memory

• Procedural implicit tests
• sensorimotor
• basic assumption of model acquisition and
  retention of motor skills result from
  modification of structures involved in performing
  the task
• performing a task leaves behind a sensorimotor
  record
• reactivation of a sensorimotor record accounts
  for performance on implicit tests of memory

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Component process model of memory

• Procedural implicit tests
• sensorimotor
• these assumptions have at least two testable
  implications
• first, deficits should be observed in people with
  damage to sensorimotor structures no matter how
  well preserved their intellect is
• patients with amnesia should have preserved
  sensorimotor function

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Component process model of memory

• Procedural implicit tests
• sensorimotor
• studies have shown that patients with AD have
  normal pursuit rotor function (Jacobs, 1999)
• patients with amnesia have normal pursuit rotor
• patients with Huntingtons and Parkinsons
  disease have impaired pursuit rotor learning
• Rule learning
• see article

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Component process model of memory

• Implications of model
• perceptual priming is a consequence of
  reactivation of perceptual-input modules is
  supported by
• finding of modality-specific priming effects
• finding of strong format effects
• finding that levels of processing effects have
  negligible effects on perceptual tests (recall
  perceptual-input modules are presemantic)

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Component process model of memory

• Implications of model
• perceptual priming is a consequence of
  reactivation of perceptual-input modules is
  supported by
• finding that perceptual priming effects are
  little affected by dividing attention (recall
  modules are hypothesized to operate
  automatically)

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Component process model of memory

• Ignore Sections 4.2 - 4.5 inclusive

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Component process model of memory

• 4.6 The hippocampal module Implications and
  comparisons with other models
• Is hippocampally-based memory spatial, conscious
  or both?
• Nadel has proposed that the hippocampus is
  specialized for dealing with spatial information
• Moscovitch has claimed that the hippocampus binds
  together any information that is consciously
  apprehended

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Component process model of memory

• 4.6 The hippocampal module Implications and
  comparisons with other models
• note Moscovitch uses the term consciousness
  interchangeably with phenomenological awareness
• ie the individual is aware of having experienced
  a stimulus previously
• Moscovitch argues that the memory trace includes
  the contents of consciousness as well as the
  elements that make experience conscious

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Component process model of memory

• Conscious recollection, thus is a property of the
  memory trace
• Cognitive resources differential effects on
  central frontal systems and hippocampal systems
• Moscovitch postulated that dividing attention
  should have differential effects on memory tasks
  that are mediated by hippocampally versus
  frontally
• strategy select tasks known to be affected by
  frontal damage, and evaluate whether they are
  impaired by dividing attention

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Moscovitch (1992)
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• Aspects of data to note
• there is no difference between the two conditions
  on trial one
• there is a significant different on the release
  trial

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Moscovitch contd

• Aspects of data to note
• there is no difference between the two conditions
  on trial one
• there is a significant different on the release
  trial between the two conditions

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Moscovitch contd

• Moscovitch showed that letter and category
  fluency tasks were differentially influenced by
  divided attention task known to require frontal
  lobe function
• letter fluency -- generate as many words as you
  can in one minute to a given letter
• category fluency -- generate as many words as you
  can that are members of a given category

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Moscovitch contd

• Note letter fluency impaired by frontal damage
  category fluency impaired by temporal lobe damage