some slides are courtesy of Dr GPSutton February 5 2015 Lecture Plan Memory definition subtypes and processes Clinical examples of memory loss patients HM amp CW What is memory loss ID: 684693
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Slide1
Memory: Introduction
Zara A. Melikyan
(some slides are courtesy of Dr. G.P.Sutton)
February 5, 2015Slide2
Lecture Plan:
Memory: definition, subtypes and processes
Clinical examples of memory loss - patients H.M. & C.W.
What is memory loss
Memory: assessment
Example of progressive memory loss - Alzheimer’s dementiaSlide3
Memory: Definition
Memory is the process in which information is:
-
encoded
- receiving, processing, combining information,
- stored - creation of permanent record of encoded information, - retrieved - calling back the stored information to use in activitySlide4
Temporal Memory Organization
Sensory Memory
- limited capacity 12 elements (G. Sperling), limited duration (hundreds of milliseconds). Registers all the sensory information.
- Iconic
- Echoic
- HapticShort-Term Memory - limited capacity (7+/-2, or 4-5 elements), limited duration (18-30 sec). Registers information to which attention is paid. Transient patterns of neuronal connection in prefrontal & temporal lobes, hippocampus essential for information consolidation from STM to LTM.
Information is rehearsed and chunked
Long-Term Memory
- close to unlimited capacity, unlimited duration. More stable and permanent changes in neuronal connections throughout the brain.Slide5
Memory Models
Atkinson-Shiffrin Model (1968)
Baddeley & Hitch Model of Working Memory (1974)Slide6
Types of Long-Term Memory
LTM
Declarative
Episodic
Semantic
Nondeclarative
(Procedural)
Skill learning
Priming
ConditioningSlide7
LTM:
Declarative vs. Nondeclarative
Declarative memory
- Memory that can be stated or described
- Capital of Italy
Nondeclarative (Procedural)
- Memory about perceptual/motor procedures
- Demonstrated via performance (not conscious recollection)
- Riding a bicycleSlide8
Declarative:
Episodic vs. Semantic
Episodic
- Detailed autobiographical memory
-15th birthday party
Semantic- Generalized declarative memory
- Facts and information acquired through learning
- Capital of ItalySlide9
Nondeclarative:
Skill Learning vs. Priming vs. Conditioning
Skill Learning
Learning how to perform a task by repeating a process
May include:
- Sensorymotor skills (mirror tracing)- Perceptual skills (reading mirror-reversed text)
- Cognitive skills (planning and problem-solving)Slide10
Nondeclarative:
Skill Learning vs. Priming vs. Conditioning
Priming
- Change in how you process a stimulus (e.g. word, picture) because you have seen it (or something similar) previously
- Does not require declarative memory (intact in H.M.)Slide11
Nondeclarative:
Skill Learning vs. Priming vs. Conditioning
Conditioning
Involves relationships between events
Associative learning
- Classical conditioning. Association is formed between two previously unrelated stimuli. Pavlov’s dogs.
-
Instrumental/operant conditioning
. Association is formed between behavior and cosenquences. Skinner box.
http://www.youtube.com/watch?v=TtfQlkGwE2USlide12
Patient 1:
Henry Gustav Molaison (1926-2008)
The case of H.M. is widely studied and published on. Played important role in cognitive neuropsychology of memory;
Suffered intractable epilepsy: partial seizures, after 16y.o. tonic-clonic seizures;
Source of epileptic discharge - left and right medial temporal lobes;
1953 (27 y.o.) bilateral medial temporal lobe resection - hippocampi, amygdalae, enthorhinal cortex, anterolateral temporal cortex. Most structures were not functional;Slide13
Patient 1:
Henry Gustav Molaison (1926-2008)
After the surgery: epilepsy is controlled, severe memory impairment:
Severe anterograde amnesia
: explicit & semantic memory;
Moderate temporary-graded retrograde amnesia: could not remember most events 1-2 years prior and some events 11 years prior to surgery;Intact: working memory, procedural memory;
At the end of life: worked crossword puzzles, able to fill in answers to cues related to pre-surgery knowledge, able to modify old memories with new information;
Resided in care institute 1953-2008. Sliced brain in UCSD.Slide14
Patient 2:
Clive Wearing (born 1938)
Accomplished British musicologist, conductor, keyboardist;
In 1985 (47y.o.) contracted Herpesviral encephalitis (Herpes simplex virus) that attacked his CNS: hippocampus (transfers STM to LTM), frontal lobes;
Profound total amnesia:
- severe anterograde amnesia (unable to form new memories, his memory lasts 7-30 seconds),
-
moderate-severe retrograde amnesia
(cannot recall aspects of past memories, knows that he has children but does not remember their names, loves his second wife),
- unable to associate memories effectively,
- unable to control emotions (labile mood) (e.g. shakes spasmodically after music stops)
Intact: procedural memory (knows how to play the piano, conduct an orchestra);
Can learn new practices and very few new facts not from episodic memory but by procedural memory (e.g. after having watched a video multiple times he is able to anticipate parts of it).
http://www.youtube.com/watch?v=Lu9UY8Zqg-Q&feature=related
http://www.youtube.com/watch?v=xCyvzI2aVUo&feature=relmfu
https://www.youtube.com/watch?v=9BrCBq2FY_USlide15
Memory Loss
Amnesia
, from Greek “a” - without, “mnemi" - memory
- Severe memory impairment
- Usually due to injury or disease
Retrograde amnesiaLoss of memories prior to an event. Disruption of memory consolidation
Anterograde amnesia
Inability to form new memories (e.g. H.M., C.W.)Slide16
Study of Memory
Tests:
-
Verbal
: word lists, paragraphs
- Visual: shapes, objects, scenes - Tactile, audial, memory for smellsLearning and immediate retrieval, delayed recall, recognitionRecency and Primacy EffectsSlide17
Progressive Memory Loss: Alzheimer’s Dementia
Dementia
from Latin: “de” - to depart, “mens” - mind, being out of one's mind.
General term that describes a wide range of symptoms associated with a decline in mental ability severe enough to reduce a person's ability to perform everyday activities. These symptoms:
- Are not present since birth
- Are a change from previous baseline mental function
- Last more than six months
- Not associated with a loss/alteration of consciousness
- Not due to other medical conditions (e.g. depression)
- Progressive
Dementias have different etiologies: primary - organic brain degeneration (AD), secondary (TBI, infection, intoxication, etc.).
Dementia is very wide spread due to increased life expectancy and decreased birth: 2010 worldwide 35.6 million, in 2030 65.7 million, in 2050 115.4 million;
AD 50-75% of all types of dementia;
Associated with significant cost: lost jobs for patients and caregivers, medical supplies and drugs, home modification, care, nursing homeSlide18
Progressive Memory Loss: Alzheimer’s Dementia
Alzheimer’s Dementia named after Aloysius (Alois) Alzheimer, a German psychiatrist and neuropathologist who identified the first case of the disease in 1906;
His patient Mrs. Auguste Dete, a 51 year old woman experiencing symptoms of memory loss, unusual behavioral changes, hallucinations, delusions, and impaired social functioning;
Post-mortem brain examination by Dr. Alzheimer revealed AD markers: amyloid plaques, neurofibrillary tangles, and arteriosclerotic alterations of brain matter.Slide19
Alzheimer’s Dementia: Symptoms
Symptoms worsen over time. Symptoms may vary but, at least two of the following mental functions must be significantly impaired:
Domain
Symptoms
Memory
First short-term memory: keeping track of purse, wallet, keys, paying bills, planning meals and cooking, remembering appointments, where car is parked, the route to home
Long-term memory: own biography, names and faces of family members
Abstraction, planning
Lose the ability to perform familiar tasks, plan activities, and draw simple conclusions from facts
Communication, language, comprehension
Inability to understand instructions, follow the logic of moderately complex sentences. Later: difficulty understanding own sentences, difficulty forming thoughts into words
Poor judgement
Do not recognize consequences of own actions, unable to evaluate appropriateness of behavior, level of risk. Behavior may become rude, overly friendly, aggressive. Personal hygiene may be ignored.
Impaired orientation
To time (date, time), place, person
Decreased attention, increased restlessness
Quickly begin activity, quickly loose interest/wander (safety problems)
Visual perception
Behavioral changes, psychosis
Loose interest in once-pleasurable activities, become passive, depressed (20-30%), anxious (20%). Delusions, suspicion, paranoia, hallucinations. Sleep disturbances: insomnia, sleep interruptions. Disinhibition, impulsivity, agitation, balance problems, tremor, troubles eating and swallowing, wondering and restlessness.Slide20
Thank you!