8A: Memory disorders Flashcards
Memory
an organisms mental ability to store, retain and recall info
-Encoding or registration: attend to or maintain current sensory or internal info
-Storage: create permanent record of encoded info
-Retrieval or recall: bring back stored information in response to some cue
Short-term (working) memory
limited, active, transient traces of experiences that happened in the very recent past (no longer than a few seconds ago). It’s the “RAM” of human memory. Lasts about 2 second without rehearsal, but can be maintained with
rehearsal. Visual working memory is limited to about 3-4 objects.
Baddeley and Hitch model
a short-term/working memory model with three main components – the visuospatial sketchpad, which stores visuospatial
information, the phonological loop, which stores auditory information, and the
central executive, which performs operations on things stored in the sketchpad or
loop
dual-task paradigms
If two tasks can be completed with as much
efficiency (as quickly and easily) as one, they are likely to be drawing on
independent mental resources, e.g., auditory and visual tasks in working
memory can be done simultaneously, while two auditory or two visual
tasks show interference with each other.
Long-term memory
relatively permanent traces of experiences that happened more than 18-30 sec ago. It’s the “hard drive” of human memory.
Declarative/explicit memory
long-term memory that can be consciously
declared (facts)
Semantic memory
a type of declarative long term memory involving factual knowledge independent of time and place
Episodic memory
a type of declarative long term memory involving theoretical knowledge of a specific moment in time and place
Procedural/implicit memory
long-term memory involving memory for
procedures, skills, and actions; thought to be encoded by cerebellum and basal
ganglia
Amnesia
memory loss with the inability to imagine the future, which can be caused by
brain trauma, infection, surgery, or psychological factors
Temporally graded amnesia
In this type of amnesia, information acquired in
the distant past (remote memory) is spared relative to more recent memory. For
example, a 50-year-old patient with recent amnesia from head trauma might
maintain normal memories of his life until he was about 40, but might have
memory issues affecting years 41-50, with worsening memory closer to the time
of the amnesia-causing injury at 50. Thus the extent of the amnesia differs (i.e., is
graded) over time
Non-graded/temporally ungraded amnesia
In this type of amnesia,
information about a specific time frame of a patient’s life is abruptly missing with
no gradual change in memory quality at the ends of that time frame. A patient
may feel like a block of time is just missing, or may have an abrupt onset of
memory loss following an injury time point with subsequent anterograde amnesia
Anterograde amnesia
memory loss where new events are not stored in long term memory (patient examples are H.M., Clive Wearing, and N.A.). H.M. has a small
amount of temporally graded retrograde amnesia, as well, affecting the time right before
his surgery.
Hippocampus
a “curly”, sea-horse-shaped structure in the medial temporal lobe, one on each side, which is very important in episodic memory and spatial navigation; patient H.M. had bilateral hippocampal structures plus some surrounding tissue removed in an attempt to treat his seizures.
Medial temporal lobe
the middle, inner section of the temporal lobe where much of the limbic system resides