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Brain and Memory
By: Pamela L. Washbourne
Neurocognitive Networks
Recent advances in basic and cognitive
neurosciences now allow a more detailed
analysis of networks
Memory and Learning can be dissociated into
several behavioral components: registration
storage (encoding), retention and retrieval
Memory can also be classified according to
modality (visual and auditory) or material
(verbal and nonverbal) that is being
processed.
Mesulam M.D.,MM.D.,M-Marsel,
Marsel, (1990), “Large Scale Neurocognitive Networks and Distributed
Processing for Attention, Language, and Memory”
Memory”, Annual Neurology, 28, 597597-613.
Cognitive Neuroscience….
…of memory is based on observations of brain
damaged patients with various kinds of memory loss,
experiments with healthy volunteers, studies using
brain imaging techniques
The fractionation of memory into component
systems and subsystems has been a major theme in
the cognitive neuroscience of memory for the past
10-15 years
Brain imaging techniques are now providing new
perspectives on various forms of memory
Schater,PH.D.,Daniel (2002), “The Cognitive Neuroscience of Memory”
Memory” Harvard University Conference,
Neurology of Behavior.
Seven Sins of Memory….
Transience: forgetting information over time
Absent-mindedness: lapses in attention that produce
forgetting
Blocking: temporary inability to retrieve information
Misattribution: confusing the source of a memory
Suggestibility: incorporating misleading information into
memory
Bias: influence of present knowledge and beliefs on
recollections of the past
Persistance: unwanted memories
Schater,PH.D.,Daniel (2002), “The Cognitive Neuroscience of Memory”
Memory” Harvard University Conference, Neurology of Behavior.
Memory Types….
Retrieval – can be declarative- the
verbal report of conscious memories
Procedural – the learning of a motor
skill
Autonomic – the visceral response
associated with the experience
Memory Systems…..
Defined as: specific neural networks
that support specific mnemonic
processes
Which brain regions mediate specific
kinds of memory functions?
Gavrielli,
Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory”
Memory”, Annu.
Annu. Rev. Psychology, 49,8749,87-115.
Evidence….
Neuroimaging studies provide evidence
about the participation of medialtemporal regions in declarative memory
Medial-temporal activations are
observed during intentional memory
retrieval and is noted to activate
during encoding of memories
Gavrielli,
Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory”
Memory”, Annu.
Annu. Rev. Psychology, 49,8749,87-115.
Regions….
Declarative memory is generally thought to reflect
an interaction between medialtemporal/diencephalic and neocortical brain regions
Medial-temporal or diencephalic lesions spare
remote memories this has encouraged the view that
the neocortex is the ultimate repository of
consolidated long-term memory
Neocortex contributes to the encoding, storage and
retrieval of declarative memories
Declaritive Memory…
Seems to dependent on the integrity of parts of the
limbic network and their interconnectivities
Noted by patients with the amnesic state can
acquire new motor skills although they may have no
conscious knowledge of having learned the skills
Of all the stages of declarative memory,
registration (short-term or immediate memory) is
the least dependent on the limbic system and most
closely associated with vigilance and concentration
*amnesic patients can have a normal concentration
span
Mesulam M.D.,MM.D.,M-Marsel,
Marsel, (1990), “Large Scale Neurocognitive Networks and Distributed Processing for
Attention, Language, and Memory”
Memory”, Annual Neurology, 28, 597597-613.
Declarative Memory….
Encompasses the acquisition, retention,
and retreival of knowledge that can be
consciously and intentionally
recollected
This includes memory for events
(episodic memory) or facts (semantic
memory)
Gavrielli,
Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory”
Memory”, Annu.
Annu. Rev. Psychology, 49,8749,87-115.
Episodic memory….
Measured by direct or explicit test of
memory, such as free recall, cued
recall, or recognition, that refer to a
prior episode
Gavrielli,
Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory”
Memory”, Annu.
Annu. Rev. Psychology, 49,8749,87-115.
Intentional retrieval…
A consistent by poorly understood activation occurs
in right frontal cortex during intentional declarative
or episodic retrieval of memory for words
This activation are unexpected because they apply
to verbal and nonverbal memories and because right
frontal lesions have modest effect on declarative
memory.
One speculative interpretation is right-frontal
retrieval activations reflect working memory
processes that guide or evaluate the products of
episodic retrieval
Nondeclarative or procedural
memory….
Encompass the acquisition, retention, and retrieval
of knowledge expressed through experience induced
changes in performance.
Measured by indirect or implicit tests where no
reference is made to that experience
Skill learning, repetition priming, and conditioning
are classes of implicit tests that often reveal
procedural memory processes dissociable from
declarative memory
Gavrielli,
Gavrielli, J.D.E. (1998), “Cognitive Neuroscience of Human Memory”
Memory”, Annu.
Annu. Rev. Psychology, 49,8749,87-115.
Memory systems….
Nyberg and Tulving discuss memory
systems as 4 major human memory
systems
Episodic, semantic, perceptual
representation (PRS), and procedural
Nyberg and Tulving,
Tulving, (1996), “Classifying Human LongLong-Term Memory: Evidence from Converging
Dissociations”
Dissociations”, European Journal of Cognitive Psychology, 8(2), 163163-183.
Dissociations …..
Nyberg & Tulving hypothesize
dissociations yielded by task
comparisons as partial evidence for
multiple memory systems
Memory processes differ with respect
to rules of operation and component
processes
4 kinds of dissociations….
1. Functional dissociations: different
values of independent variables
2. Developmental dissociations:
stages of ontological development
3. Pharmacological dissociations:
drug-induced brain states
4. Brain-damage dissociations: the
presence or absence of brain damage
Studies ……
Many studies were reviewed and it was
found to demonstrate existence of
dissociations as well as contributing to
the neuroanatomical localization of
memory functions
Localizations….
Nyberg & Tulving review suggest the two declarative systems
(episodic and semantic) seem to depend on integrity of medial
temporal lobe structures
Frontal lobe structures have been found to be critical for
both episodic and semantic memory, but different frontal
regions seem to be important for the 2 systems
Frontal regions in the left hemisphere are more involved in
semantic and right hemisphere for episodic
PET studies suggest cerebellum plays an important role in
these 2 systems
Occipital brain structures are critical for visual subsystem of
perceptual representation
Midbrain structures in procedural memory has been confirmed
by several PET studies
Findings….
Nyberg & Tulving concluded that the
survey of exisiting dissociations can be
encouraging
And these studies can play an
important role in shaping our ideas
about classifying memories
More research…
There is a lot of evidence to support
memory localization and systems which leads
the way to studying recovery and plasticity
of the brain
If memory systems are in fact located in
more than one place in the brain and is more
of a network, why can’t the brain plasticity
aid in recovery of functions?
Further research is much needed and
encourged with positive hypothesis agreed
upon.