Brain Systems for Memory (The Remembering Brain) Flashcards
what type of deficit is amnesia?
specific memory
verbal behaviour can index what?
non-conscious memory (can prime via previous exposure to words, as the lexical have been activated)
why is memory important?
- critical for everything about cognition
- learning from experience shapes thought and behaviour in an adaptive way (so they are more adaptive)
- perception / attention
- underpins conscious and unconscious decisions
- central to personal identity
- allows language and culture (we share memories with one another - shared experiences create a shared culture and shared identity)
- practical importance of memory failures (i.e. they aid us in learning from our mistakes - and support independent living i.e. for those with Alzheimers)
perception
an interaction between sensory input and stored knowledge
attention
driven by memory (i.e. cocktail party effect - change of attention based on the importance of someone else’s statement / attention is guided by semantic information
who is Clive Wearing?
- conductor and musicologist who developed dense amnesia in 1985 following encephalitis
- STM -> can retain about 20 seconds
- capacity to play piano not affected by his brain trauma
- his language, knowledge of general information and speech fluency is preserved (semantic knowledge intact)
- can retain sentences when he’s processing and then everything else is void
- he has some understanding in which he has a brain injury
Who is Patient HM (Henry Molaison)
- bilateral medial temporal (lesion) lobectomy to treat epilepsy in 1953
- removed hippocampus in both hemispheres
- epilepsy cured but unexpected consequences for memory
- virtually all anterior hippocampus and surrounding cortex removed, plus amygdala
- some posterior hippocampus remains
what were some issues with HM? Like when we assessed his memory problems what happened?
- no memory for things that happened since operation -> dense anterograde amnesia
- some forgetting of events that happened 11 years before surgery (yet childhood memories preserved) -> retrograde amnesia
where does the hippocampus lie?
temporal lobe
where does hippocampus lobe lie?
all the way from the anterior to the posterior
-> right next door to the amygdala
what is the hippocampus output bundle called and what does it do?
fornix -> projects to the millimary body -> sends information via the thalamus back to the cortex in a loop
how did know HM had dense anterograde amnesia
Read the same magazines; watched the same movies; did the same jigsaws repeatedly; ate lunch several times in a row; unable to learn his way around the hospital
anterograde amnesia
affecting memories that are affected since the brain injury
retrograde amnesia
affects memories formed before the brain injuries take place
why was retrograde amnesia not complete?
could still remember childhood memories and they were preserved
what does HM suggest about the hippocampus?
crucial for new learning and for storing recently-formed memories but not for older memories i.e. childhood memories
what happened as HM aged?
his rooting of time/age got more and more inaccurate
what was HM’s amnesia caused by?
surgical resection of hippocampus -> very specific
what are some other causes of amnesia that also produces damage to bilateral medial temporal lobe
- Anoxia (e.g., heart attack; carbon monoxide poisoning) [hippocampus] -> lack of oxygen reaching the brain
- Patient RB – anoxia following heart surgery [almost entirely in a specific cell field in the hippocampus] (Zola Morgan et al., 1986)
- Head injury [hippocampus, thalamus, frontal lobes]
- Patient KC (Rosenbaum et al., 2005)
- Herpes simplex encephalitis [hippocampus and anterior temporal cortex]
- Clive Wearing, Patient EP (Insausti et al., 2013)
- Korsakoff’s syndrome [mammillary bodies] - Vitamin B deficiency
- [Alzheimer’s disease]
why can patients with amnesia vary?
some injuries are not as specific -> so they cause damage to other structures
* patients with amnesia show a variety of different symptoms dependent on what is damaged
Where is the Hippocampus
within medial temporal lobe
Fornix
major output bundle of hippocampus
Mammillary bodies
gateway from hippocampus (fornix) to thalamus (and then back to the cortex- but mammillary bodies do’t do this)
Thalamus
receives and feeds back to the cortex
-> in a corticothalamic loop (pass info between the thalamus and the cortex
Episodic Memory
Event Memory
Semantic Memory
Factual, Conceptual Knowledge
what can we argue about different types of memory
they use different brain systems
STM
short information in your mind
-> if you keep thinking about it - you can keep it in your head (rehearsal) and people with amnesia can do that (STM is preserved)