Task 5: memory
PART 1: memory and corresponding brain areas___________________________________________
Kolb, B. & Whishaw, I.Q. (2015). Fundamentals of Human Neuropsychology (7th Edition). H18
18.1: learning, memory and amnesia
Remembering is not only the revival of previous experience;
rather, remembering is an active process of reconstruction. Extra uitleg, blok 1; project:
The term gist describes the objective of reconstructing geheugenrepresentaties/geheugensporen
memory, make the point that the gist serves the adaptive bestaan op een continuüm van letterlijke,
purpose of allowing us to anticipate and respond to verbale weergave naar vage en onduidelijke
situations in the future in ways that benefit from our past ‘fuzzy’ voorstellingen (gist) die de essentiële
experiences memory does not just allow us to recreate kern behouden zonder alle details. Voorbeeld:
the past, it is prospective in allowing us to imagine or Als je een shirt uit 2 winkels met elkaar
anticipate the future and so respond adaptive the next time. vergelijkt, dan onthoudt je meestal alleen dat
Because the gist is adaptive, details are often unimportant. het shirt in de ene winkel goedkoper is dan de
As such, the shortcut nature of the gist renders it prone to andere. Je onthoudt niet de exacte prijs.
errors of commission as well as of omission. Schacter
describes such errors as the seven sins of memory.
The broadest classification of memory distinguishes
transient short-term memory for recent sensory, motor,
or cognitive information from relatively permanent long-
term memory. Conscious, long-term memories may be
explicit—events and facts that you can spontaneously
recall—and either episodic, for personal experiences
(your first day at school), or semantic, for facts (England is
in Europe). Implicit, nonconscious memories (say, riding a
bicycle) consist of learned skills, conditioned responses,
and events recalled on prompting. Emotional memory for
the affective properties of stimuli or events (your first
kiss) is vivid and has characteristics of implicit and explicit
memory (figure 18.1). The notion that we have multiple
memory systems allows for errors caused by favouring
one kind of memory over others.
Witnesses at an accident can usually give the gist of what they observed. They can note the
temporal and spatial sequence of the action, identify the participants, and note the
autobiographical framework of how they became an observer. Yet when quizzed on the
details, the fallibility of memory becomes apparent. Each observer may recall details not
remembered by others. In addition, recollection can be distorted. Observers can be primed
(sensitized) by other witness’s stories and by photographs or videos of the occasion to
remark, “Oh yes, I remember that also,” even when the stories, photographs, or videos are
distorted.
Varieties of amnesia
Bekhterev (1900) autopsied the brain of a patient who had shown severe memory impairment and
discovered a bilateral softening in the medial temporal cortex (figure 18.3). Just a small region of
damage to the medial temporal lobes can produce severe amnesia. Other patients with bilateral
temporal cortex damage, whom Milner (1970) had described, confirmed not only the temporal lobe’s
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,role in memory but also the special contributions made by different structures within the temporal
lobes to different kinds of memory.
Childhood amnesia – forgetting common to us all is childhood (infantile) amnesia, an
inability to remember events from infancy or early childhood.
o Memory systems mature at different rates; personal memories of our early years
may be lost because the system central to storing adult episodic memory is not yet
mature.
o The brain plays an active role in deleting memories, perhaps to make room for new
ones. Investigators suggest that as new hippocampal neurons form new connections,
they participate in forming new memories, but in doing so they disrupt neural
circuits that support memories already acquired. More-permanent memories are
formed only after the acquisition of new neurons by the hippocampus slows.
Rare and common amnesias:
o Fugue state – sudden and usually transient memory loss of personal history
(occasional reports of adults who turn up far from home with no knowledge of their
former live but with skills and language intact).
o People who become amnesic for the meaning of nouns but not verbs, and vice versa,
or amnesic for recognizing animals but not amnesic for human faces
(prosopagnosic).
o Everyday amnesias – forgetting for example someone’s name or where you put your
keys. This kind of forgetting can increase with advancing- age, in so- called senior
moments.
For some people, memory disorders of aging can become incapacitating, as
happens in Alzheimer’s disease, characterized by the extensive loss of past
memories and accompanied by neuronal loss that begins in the medial
temporal lobe and then extends to other brain areas.
Antegrograde and retrograde amnesia (figure 18.4)
Memory of amnesic patients consists of 2 parts: anterograde and retrograde
amnesia.
Anterograde amnesia – inability to acquire new memories.
o Anterograde refers to the future with repespect to the time at
which person incurred brain damage.
Retrograde amnesia – loss of memories that were accessible unable to
access old memories.
o Retrograde signifies that memory loss extends back in time relative
to the time of brain inury.
Time- dependent retrograde amnesia – the injury’s severity determines
how far back in time the amnesia extends.
o For example, after a head trauma, a transient loss of consciousness
followed by a short period of confusion and retrograde amnesia is
typical. The retrograde extent of the amnesia (the period of
personal history it covers, extending from the present to the more-
distant past) generally shrinks with the passage of time, often
leaving a residual amnesia of only a few seconds to a minute for
events immediately preceding the injury.
Three theories of amnesia
System consolidation theory (Squire & Bayley, 2007) – the hippocampus
consolidates new memories making memories permanent. When
consolidation is complete, the memories are stored elsewhere in the brain,
in the neocortex. This theory explains why older memories tend to survive
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, cases of hippocampal damage (memories are stored elsewhere). whereas more-recent
memories are likely to be lost (still in hippocampus).
o If damage is limited to the hippocampus, retrograde amnesia may extend back for
only a few years because only recently acquired memories remain there. As more of
the temporal lobe, a region where longer-term memories are stored, is affected,
retrograde amnesia can extend back for one to two decades or longer.
Multiple- trace theory (Nadel & Moscovitch, 1997)
o In any learning event memories of many types are encoded in parallel in different
brain locations.
autobiographic memory depends on the hippocampus and frontal lobes;
factual semantic memory depends on temporal-lobe structures; and general
semantic memory, on the remaining cortical areas.
o Memories change throughout a person’s life with retrieval
o Different kinds of memory, being stored in different locations, are differentially
susceptible to brain injury.
Reconsolidation theory (Tronson & Taylor, 2007) - Each time a memory is used, it is
reconsolidated: the memory reenters a labile phase and is then restored as a new memory.
Each use of memory is associated with a new phase of storage, resulting in many different
traces for the same event. memory for an accident consists of multiple traces, one for
each time the accident is recalled
o Reconsolidation complicates the study of amnesia because spontaneous recall and
even investigating a subject’s memory will change the memory that is the object of
investigation.
18.2: Long- term explicit memory
Explicit memory for events and facts is conscious and intentional and consists of personal
experiences, or episodic memories (what you did last night) and fact-based semantic memories
(2x2=4). Both types of explicit memory depend on conceptually driven top-down processing, in
which a person reorganizes the data to store it.
Episodic memory
Episodic (autobiographic) memory – memory of life experiences centered on the person himself.
Recalling personal events or experiences.
The function of autobiographical memory is providing us with a sense of continuity. This autonoetic
awareness, or self- knowledge, allows us to bind together awareness of our self as continuous entity
through time. Autonoetic awareness further allows us to travel in subjective time, either into the
past or into the future.
Patients with hippocampal and frontal cortical injury often lose self-knowledge and have real
difficulty in daily living resulting from a deficit of behavioural self-regulation and the ability to
profit from past experience in making future decisions . Tulving proposes that “time travel” is
a memory ability that characterizes humans but not nonhuman animals and depends on
maturation and so will not be found in babies and young children.
Depends on the medial- temporal-lobe-ventral-prefrontal- lobe memory system .
Semantic memory
Semantic memory – knowledge about the world, all non- autobiographical knowledge. It includes the
ability to recognize family, friends, and acquaintances (bekenden); information learned in school,
such as specialized vocabularies and reading, writing, and mathematics; and knowledge of historical
events and of historical and literary figures.
Depends on the temporal- and frontal-lobe regions adjacent to the neural regions that
subserve episodic memory.
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