Memory And Amnesia

Question 1

HM

Answer 1

Had a bilateral tea section of the temporal lobes due to severe epilepsy on both sides.

Poor navigational skills, anterograde amnesia, strong iq, strong procedural memory but could not report that he had done the tests. For example the mirror drawing task. Was getting better at it despite not remembering ever doing it.

Question 2

What about HM’s surgery now?

Answer 2

We would never take out this much tissue now - especially not bilaterally. But his case allows us to understand what structures aid in long term memory etc.

Question 3

Explicit or declarative memory

Answer 3

Autobiographical or episodic memory

• singular events a person recalls
• life experiences
• autoneotic awareness of time (time travel)

Semantic memory

• facts
• knowledge

Question 4

THEORIES OF EXPLICIT MEMORY STORAGE

Consolidation theory

Answer 4

Hippocampus consolidates all memories which are then stored elsewhere in the brain

Account for preservation of old memories and for forming new memories

As more damage occurs, the more old memories will be lost

Question 5

THEORIES OF EXPLOCIT MEMORY STORAGE

Multiple trace theory

Answer 5

Episodic memory remains dependent on hippocampus

Semantic memory gradually becomes independent

** parallel encoding in different systems **

Question 6

THEORIES OF EXPLICIT MEMORY STORAGE

Reconsolidation theory

Answer 6

A memory renters a liable phase when it is recalled and then restored as a new memory

Results on many different traces of the same event

Consistently re-remembering it will give it more weight in all brain regions

Question 7

THEORIES OF EXPLICIT MEMORY STORAGE

Dual-process theory

Answer 7

Hippocampus crucial only for episodic memory

Semantic memories can accrue independent of hippocampus

Question 8

Neural substrates of explicit memory

Temporal-frontal lobe neural system (refer to index card)

Answer 8

Disruption of neurotransmitters can impact memory

Question 9

ANATOMY OF THE HIPPOCAMPUS

Perforant pathway

Answer 9

Connection between the hippocampus and the posterior neocortex

Question 10

ANATOMY OF THE HIPPOCAMPUS

Fimbria-Fornix

Answer 10

Connects the hippocampus to the thalamus, frontal cortex, basal ganglia, and the hypothalamus.

Question 11

Damage to the fimbria-fornix pathway

Answer 11

Results in retrograde and anterograde amnesia

Question 12

Damage to temporal stem

Answer 12

Contributes to amnesia

Question 13

Severing of the connections between the posterior neocortex and the temporal lobe

Answer 13

May produce amnesia

Question 14

Four conclusions about hippocampal damage

Answer 14

1. Anterograde amnesia deficits are more severe
2. Episodic memories are more affected than semantic memories
3. Autobiographic memory is especially affected
4. Patients cannot time travel - hippocampus helps us predict and imagine the future

Question 15

Rhinal cortex

Answer 15

Cortex that surrounds the rhinal fissure

Includes the entorhinal and perirhinal cortex

Projects to the hippocampus

Question 16

HEMISPHERIC SPECIALIZATION

right temporal cortex

Left temporal cortex

Answer 16

Removal leads to deficits in face recognition, spatial position, and maze learning

Removal leads to deficits in recall of word lists, recall of consonant trigrams, and non-spatial associations

Question 17

Implicit memory

Answer 17

Procedural learning

Priming (stimulus sensitizes brain to later presentation of same stimulus - filling incomplete figures test)

Classical conditioning

Question 18

Implicit and explicit memory are independent of each other

Answer 18

Depth of processing effect
- if it requires deeper processing it will be a stronger memory

Study test modality shift
- learner performance depends on how the information is presented

Question 19

Basal ganglia

Answer 19

Plays role in habit and procedural learning

Question 20

Motor cortex

Answer 20

Acquisition of implicit knowledge requires reorganization of motor cortex (hand homunculi will get larger)

Question 21

Cerebellum

Answer 21

Plays a role in classical conditioning

Question 22

Development of memory:

Implicit memory

Answer 22

Implicit memory appears to be present at birth

Explicit memory more gradual

• debates about when it starts
• early ages with elicited imitation
• infantile amnesia reflects a lack of language

Question 23

Early hippocampal damage

Answer 23

Leads to poor episodic memory

• familiar surroundings or where objects are located
• appointments or events
• daily activities

Semantic memory will still be intact

• factual knowledge
• academic skills

Question 24

Short term or working memory

Answer 24

Memory of recent events and their order

Short term may differ from working

Mediated by the dorsal and ventral pathways to two regions of the frontal cortex

Question 25

Short term memory and temporal

Answer 25

If damage to these areas short term memory may be impacted

Question 26

Working memory and frontal lobe

Answer 26

Separate systems for spatial working memory and working memory for objects

Question 27

Other localizations Parietal and occipital cortex Frontal cortex

Answer 27

Injuries may produce Color amnesia, prosopagnosia, object anomia, and topographic amnesia (hard to tell if they are actually amnesias) Retrieval - left encodes semantic and episodic info and right retrieves it ** prospective memory

Question 28

Infantile amnesia Electroconvulsive therapy Transient global amnesia Restricted damage

Answer 28

Sudden onset and short course - inability to form new memories Verbs nouns or animals

Question 29

Herpes simplex encephalitis

Answer 29

Medial temporal lobe damage leads to anterograde amnesia Damage to the insula produces retrograde amnesia

Question 30

Alzheimer’s disease

Answer 30

Begins with cellular change in the medial temporal cortex and anterograde amnesia Later damage to the temporal association areas and frontal cortical areas is related to retrograde amnesia

Question 31

Korsakoff’s syndrome

Answer 31

Anterograde and retrograde, confabulation and meager content in conversation a lack of insight and apathy Caused by thiamine deficiency Damage may be on the medial thalamus mammillary bodies and general atrophy