Transcript Ch-28-+-29-Localisation-of-Memory-+

Localisation of memory
Memory – encoding, storage
and retrieval
Unit 3
Behaviour, Populations and
Environment
Learning Outcomes
• To learn about the limbic system in relation
to memory storage
• To examine the process of memory –
encoding, storage and retrieval
• To compare the differences between long
and short-term memory and how memory
is transferred from STM to LTM
• To find out what causes Alzheimer’s
disease at a molecular level
Limbic System
Declarative and Procedural
memories
Declarative
Procedural
• Cerebellum
• Temporal lobes
• Limbic system
Motor skills
e.g. knowing how to
swim
Recall of general facts
e.g. identifying familiar objects
Mental skills
Recall of personal facts
e.g. past experiences
e.g. knowing how
to read a book
Neuronal level
• Most procedural skills are not easily
forgotten
• Many declarative memories are retained
on long-tern or permanent basis
• Thus, memory is the result of a long-term
change affecting neurones
Memory circuit
• Each memory is held by a group pf
neurones arranged to form a specific
memory circuit
• Each memory can be retrieved by an
impulse going through specific memory
circuit
• Interaction between different memory
circuits occurs which results in one kind of
memory often awakening another kind
Molecular basis of memory
• Memory requires changes at neurone level
• Requires release of certain
neurotransmitters at synapses
• The more often an impulse passes
through the circuit, the more change that
the memory is retained long-term
Memory
• 3 stages in memorising facts and
experiences:
• encoding
• storage
• retrieval
Encoding
• Majority of information received by brain is acoustic coding (sound).
Some is also visual or semantic (meaning)
E.g. a phone number: we usually see it (visual), rehearse it
(acoustic) and may place a meaning to it (semantic)
• Easier to remember items organised into groups or use mnemonics
to remember long numbers and lists of names
E.g. twit twoo (PIN 2820)
E.g. OILRIG
E.g. Richard of York gave battle in vain
E.g. tackidy (TKD)
• To remember a number with >7 digits, can “chunk” them
e.g. 01667 – code for Nairn (in LTM)
453 – semi-sequenced
700 – 7 hundred
Retrieval
• Easier to retrieve facts and experiences if
we are in the same situation as we were
when it was encoded. As this rarely
happens, we rely on contextual cues
(smell, sound, sight, person etc) to “jog”
our memory. Can use visualisation
techniques e.g. posters for organic
molecules
Short-term memory
• Used when reading. Allows us to remember
words for a few seconds so we understand a
sentence
• Has very limited capacity – approx 7 items so
lists longer than approx 8 items almost
impossible to remember without specialised
techniques
• Is constantly bombarded by new information so
when extra information added, other items are
displaced
Long-term memory
• To retain info for any length of time, it must
be transferred to LTM – long term memory
Serial position effect
• Test 1
• Test 2
Serial position effect
• Can remember objects at start of a series
as there has been time for rehearsal so it
is transferred to LTM.
• Can remember objects at end due to
objects still being in STM
• Objects in the middle can’t be recalled as
they have been displaced before rehearsal
can take place
Alzheimer’s Disease
• afflicting 24 million people worldwide.
• a degenerative and terminal disease for which
there is currently no known cure
• early stages- short-term memory loss (often
initially thought to be caused by aging or stress
by sufferer)
• later symptoms - confusion, anger, mood
swings, language breakdown, long-term memory
loss, and general withdrawal of the sufferer as
senses decline.
• Gradual loss of minor then major bodily
functions until death occurs