Episodic & Semantic Memory (Chapter 7)

PN & Functional Amnesia (Lumberjack)

- Extreme grief from his grandfather's death may have precipitated fugue. -In another case, PET scan found: Decreased glucose metabolism in MTL and medial diencephalon

o Korsakoff's disease

- Thiamine (vitamin B1) deficiency - Sometimes accompanies chronic alcohol abuse. - Patients act like they have MTL damage, but damage is to diencephalon and other structures.

How do declarative memories get stored/consolidated in the cortex? (2 theories)

1) Standard Consolidation Theory - holds that the hippocampus and related medial temporal lobe structures are required for the initial storage and retrieval of an episodic memory, but that their contribution diminishes over time until the cortex is capable of retrieving the memory without hippocampal help. This view conceptualizes an episodic memory as consisting of many components that are stored in different areas of the cortex. ➢ Explains why brain disruption usually damages recent memories but not older memories. 2) Multiple Memory Trace Theory - when an event is experienced, it can be stored as an episodic memory by an ensemble of neurons in the hippocampus and in neocortex. Each time that memory is retrieved, the retrieval itself becomes a new episodic memory. Requiring both the cortex and hippocampus every time. ➢ Explains cases of severe retrograde amnesia. Also suggests that spared memories after MTL damage are actually semantic rather than true episodic

Successful retrieval of existing memories is more likely if: 1. ? 2. ?

1. encoding and retrieval conditions match (transfer-appropriate processing), and 2. more cues are available to prompt recall.

Describe the role of the medial temporal lobes in memory storage.

Consolidation seems to depend on the medial temporal lobes (Hippocampus and surrounding cortex) Hippocampal region (in MTL) is important for new episodic memory formation Deeper processing may involve more MTL activity, producing better encoding. Evidence: o Lesions of MTL produce anterograde amnesia, the inability to consolidate declarative memories. o Hippocampus activity during learning predicts subsequent ability to remember

What type of memory? Remembering the first time you rode a bike

Declarative (explicit)

What type of memory? Remembering who is the current US president

Declarative (explicit)

Encoding? Storage/Consolidation? Retrieval?

Encoding = initial storage into memory Storage/Consolidation = maintaining the store memory Retrieval = re-activating the memory for further processing.

Explicit Learning

Learning WITH conscious effort Includes episodic and semantic memory (Declarative LTM)

Implicit Learning

Learning WITHOUT conscious effort (Non-Declarative LTM)

Semantic Memory

Memory for facts or general knowledge about the world.

(Retrieval) More cues = ??

More cues = better recall

What type of memory? Remembering how to ride a bike

Non-declarative (implicit)

Describe the role of the frontal cortex in memory storage and retrieval.

The frontal cortex may play an organizing role in declarative memories. It is important for determining which new memories are stored or forgotten, as well as for metamemory and remembering the source of information

Consolidation Period

a length in time during which new episodic and semantic memories are vulnerable and easily lost or altered; each time a memory is recalled, it may become vulnerable again until it "reconsolidated".

Functional Amnesia

a sudden, massive retrograde memory loss that seems to result from psychological causes - loss of memory for specific episodes - loss of personal identity due to severe psychological trauma

Transient Global Amnesia

is a transient (or temporary) disruption of memory not due to known causes such as a head injury or epilepsy - patients typically show severe anterograde amnesia, and usually some degree of retrograde amnesia. - often due to brief interruption of blood flow to the brain

Metamemory

knowledge or belief about one's own memory applies to both episodic & semantic memory

Episodic Memory

memory for specific autobiographical events. it includes info about the spatial and temporal contexts in which the event occurred.

False Memory

memory of an event that never actually happened.

Cryptomnesia

mistakenly remembering someone else's ideas as one's own

Retroactive Interference

new information interferes with old information

Retrieval: Transfer-Appropriate Processing Godden & Baddeley (1975)??

oProcedure: -Participants learned 2 lists of 40 words -Subjects then tested under same context or different context o Results: Same context group performed significantly better. *****Interpretation: Retrieval works best when conditions are similar to encoding conditions o Study tip: Study the way you'll be tested.

Proactive Interference

old information interferes with new information

Describe the concept of transfer-appropriate processing.

refers to the finding that retrieval is more likely to be successful if the cues available at recall are similar to those that were available at encoding. (Also called the encoding specificity effect)

Consolidation

the name given to the theoretical process of strengthening the stability of stored information

Reconsolidation

the process whereby each time an old memory is recalled or reactivated; it may become vulnerable to modification.

Interference

when 2 memories overlap in content, the strength of either or both memories may be reduced.

Memory Misattribution

when information is correctly remembered but mistakenly associated with an incorrect source

Source Amnesia

when information is correctly remembered, but the source is not remembered at all

HM - Landmark Case Study

• Anterograde Amnesia: Couldn't form new lasting memories Still intact: • Most of his memories before the surgery • Could remember new things as long as he was working/attending to the information

Describe the roles of subcortical structures in memory.

• Basal Forebrain - may help determine what the Hippocampus stores -MTL is regulated by the basal forebrain -Certain strokes can lead to basal forebrain damage, resulting in anterograde and retrograde amnesia. -Survivors may confabulate. • Diencephalon - may help guide consolidation o Both the MTL and frontal cortex are regulated by the diencephalon. o (Korsakoff's disease)

How is the Consolidation Period affected by ECT.

• ECT involves the use of electroconvulsive shock, which can severely disrupt newly formed memories. **** • In rats → were able to extend consolidation period if a shock was administered an hour or more after training (little disruption). Older memories (several hours before) were relatively stable, while recent memories (less than a min ago) were highly vulnerable to disruption. • ECT can provide temporary relief for mental illness, particularly depression.

Describe the role of the cortex in memory formation and storage. Sensory cortex? Association cortex?

• Semantic memories seem to be stored in a distributed fashion throughout the cerebral cortex. o Sensory cortex - first cortical processing center for a sense o Association cortex - links across senses

Explain how research in agnosias has provided further evidence that different types of information may be stored in different ways in a variety of cortical areas.

•Agnosia = the inability to process sensory information. Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. - Evidences that different types of info may be stored in different ways in a variety of areas • Penfield found that cortical stimulation can evoke simple sensations and complex memories. • Cortical lesions can display different kinds of agnosia. - Auditory agnosia for speech - Tactile agnosia

Why memory is better for information that relates to prior knowledge?

➢ Background knowledge dramatically enhances encoding. ➢ Study tip: Read before class! (reading after not as effective) ➢ A basic principle of memory is that new info is easier to remember if you can relate it to things you already know.

What is depth/levels of processing and how does it enhances memory?

➢ Levels-of-processing effect: the more deeply you process new info during encoding, the more likely you are to remember the info later. ➢ Craik and Tulving proposed that the more deeply you process information the better it is encoded. ➢ The more deeply you analyze something, the more likely you are to successfully encode it in memory. ➢ Brain is working harder during deep processing of information.

Encoding & Mere Exposure

➢ Mere exposure to information is not enough to guarantee memory. ➢ Study tip: Just re-reading notes/book is not enough

Describe the basic findings of research on episodic and semantic memory in nonhuman animals.

➢Non-human Episodic & Semantic memory? → →These memories are difficult to assess non-verbally, but some approaches are possible. ➢Radial arm maze indicates semantic memory in rodents: ➢Episodic memory is even more difficult to assess non-verbally. ➢Tulving has argued that episodic memories require a conscious sense of self that animals simply lack. ➢Careful testing, though, suggests other animals may have something like episodic memory. ➢Scrub jays bury worms and nuts in sand-filled ice-cube tray compartments.