PSYC20006 Lecture Notes - Lecture 10: Executive Functions, Fear Conditioning, Explicit Memory
10 May 2018
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Lecture 10
- Principal extra-temporal connection to the MTL: three regions of the extra-temporal
brain are particularly involved in memory: Papez’s circuit, Frontal Lobes,
Diencephalon [midbrain structures]
- Papez’s Circuit (1937): James Papez proposed that a specific brain circuit was
devoted to emotional experience and expression (Papez circuit + Amygdala = Limbic
System [emotional processing system])
- Role of amygdala in memory: plays key role in supporting memory for emotionally
arousing experiences (classical fear conditioning, facilitates rich representations of
emotional experiences, facilitates memory acquisition/recall/learning of events that
has significant emotional content → child bitten by a dog afterwards will have fear of
dogs, the time of being bitten by dog had huge amount of fear going on in child,
amygdala working overtime → amygdala gauges from stress-related hormones and
neurotransmitters that facilitates the laying down of that memory, amygdala also
adds emotional richness to memories); lesions result in loss of conditioned fear and
impairment of new fear learning, reduced memory for emotionally laden events (the
child bitten by dog → if damage to amygdala → lose fear response to dog, but also
reduce emotional content of new memories that are laid down from then on)
- Papez’s circuit comprise of network of mamillary bodies [sits within hypothalamus],
fornix, anterior thalamic nuclei (ATN), cingulate gyrus, and the hippocampus
- Papez’s circuit is the actual neural connection between areas of the brain
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- Hippocampus → via fornix to cells in mammillary bodies → efferent connections to
cells of anterior thalamic nuclei → cells in cingulate cortex → close circuit and goes
back to hippocampus
- Papez’s circuit lesions: general view: lesions to components of the Papez circuit
result in declarative memory impairment (poor relational memory/encoding, difficulty
making relationships between items that were previously not semantically related in
head, looks like medial temporal lobe damage); declarative memory impairment most
reliable when hippocampus or ATN are lesioned
- Damage to brain typically occurs through stroke, tumours {discreet damage} → but
not that discreet that damages one part and not affect the other parts
- Frontal lobes: executive system, top-down management role for many other cognitive
systems; very involved in motor programming [motor and premotor cortices (posterior
FL)]
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- Direct connection from primary motor cortex → down to spinal cord → to different
parts of brain
- Consistent pattern between people how motor neurons are laid out: a lot of space
given on lateral [edge surface] to face and tongue, big chunk to hand [lot of control
over hand], foot large space, back gets little space [don’t have much control over
back in terms of motor function]
- Primary somatosensory cortex: sense of touch
- Frontal lobes: cognitive control processes e.g. problem solving, planning, monitoring,
and self-correction; set a goal → work out a way to achieve the goal → determine if
we are achieving that goal → modify steps in order to successfully achieve the goal if
not heading in the right direction, [prefrontal cortex (anterior FL)]
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-
- Premotor area: premotor planning, put together sequences of movements required to
carry out particular action
- Prefrontal area: cognitive processing aspect of frontal lobes
- Frontal lobes encourage memories to be organised structured things, filing cabinet
- Good at identifying memories we are interested in very quickly, because it has been
encoded in very structured organised way and able to access it in organised
structured way, use clues or tips from broader memory to target in and get the
answer to particular question
- Clues, embedding and relating of things to other things that happened because
frontal lobes are helping to encode that information in embedded and organised
system of memories that connect to other memories → so that there is retrieval
strategy, can identify something
- Can work out answer to question because have organised strategy to get the answer
→ that is what frontal lobes are doing
- Frontal lobes are involved in developing and implementing strategies for appropriate
memory encoding and retrieval (Simons & Spiers 2003)
- Damage to frontal lobes → problems with creating organised and structured
memories, and problem retrieving that information in organised and structured way,
trouble with remembering contextual details of memory [when, where info came
from], difficulties with chronological order of memories [can remember something but
don’t know when it happened]
- Impairment in remembering contextual details e.g. source of information,
chronological order of memories (DLPH)
- Confabulation - production of statements involving bizarre distortions of memory
[remember things that happen to you and report those things happened to you that
are grossly untrue with no intention to lie or deceive at all, own ability to self monitor
that whether this actually happened has been lost; someone can confabulate by
drawing all sorts of different things that has happened during their life and stringing
them together into one memory or may string together things they have read in fiction
books and tag them onto their lives because they know it sounds familiar but not sure
whether it happened to them or just read about it]
-
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Document Summary
Principal extra-temporal connection to the mtl: three regions of the extra-temporal brain are particularly involved in memory: papez"s circuit, frontal lobes, Papez"s circuit (1937): james papez proposed that a specific brain circuit was devoted to emotional experience and expression (papez circuit + amygdala = limbic. Papez"s circuit comprise of network of mamillary bodies [sits within hypothalamus], fornix, anterior thalamic nuclei (atn), cingulate gyrus, and the hippocampus. Papez"s circuit is the actual neural connection between areas of the brain. Hippocampus via fornix to cells in mammillary bodies efferent connections to cells of anterior thalamic nuclei cells in cingulate cortex close circuit and goes back to hippocampus. Damage to brain typically occurs through stroke, tumours {discreet damage} but not that discreet that damages one part and not affect the other parts. Frontal lobes: executive system, top-down management role for many other cognitive systems; very involved in motor programming [motor and premotor cortices (posterior.
