Beth Part 2 Flashcards
(24 cards)
Tulving
Episodic has events- easily forgotten amd better when young, affected in amnesia. Semantic has facts but not time and placed learnt, more durable as consolidated, better when old. KC had amnesia, no episodic memory but semantic fine as remembered how to change tire but not where he learnt it. Personal semantic knowledge like knew was in crash but couldn’t remember it -from others
Single vs double dissociation
KC example of single dissociation - not enough as episodic may be esp vulnerable or people may show issues in both so may not be separated
Semantic dementia
Semantic impaired but episodic fine, type of fronto temporal dementia. Loss of indertsandinf of words and objects. Damage next to hippo (fusiform and entrohinal) episodic fine e.g. can describe holiday. Graham 2000: shown pic then a set of pics W identical image within, or then shown set of different images showing the same objects e.g. red phone now blue phone. If know concept-ps could id both but when don’t they can id identical object but not diff picture
Hippo and anterior temporal lobe
Hippo has episodic but ATL has extraction of similarities between experiences to create concepts e.g. semantic memory - difference between episode and concept
Different learning systems- hippo and cortex - mclelland 95
Hippo has fast learning, binds elements of episodes, few neurones (sparse coding) so memories can be separated. Neocortex has slower learning, similar instances coded strongly for semantic learning which prevents catastrophic interference (loss of old memories when new learnt)
Squire - episodic then semantic theory /opposing tulving as separate systems
Hippo time limited so transfers to neocortex. Kim and fanselow 92: inhibition of protein synthesis to stop changes in ltp disrupts memory for 1 hour (memory leaves hippo), when given hippo lesion after 2 weeks of learning, still remember 50%, if right after remember nothing, if 28 days, remembers almost everything but not 100%.
Temporal gradients
In amnesia events are not remembered after injury, better childhood memories- same as AD graham and hodges 97. Reverse temp gradient in SD as better recent memories as still in hippo. Cormack and O’Connor 83: older memories retrieved more so rely on semantic (remember what’s said not what actually happened) older more in neocortex
Encoding
Impaired in amnesia so have impaired learning of new events, retrieval also impaired for events just before injury but not childhood as in neocortex. Over time, connections go to neo as take out unnecessary
Consolidation
REM used in consol of motor skills, Marshall 2016: electrical stim that enhances slow wave sleep boosts verbal learning in declarative memory but skill memory unchanged. Friedrich 2014: babies 9-18m who napped for 1.5hrs after learning were better at generalising word meaning beyond example as erp diff for known vs unknown words
Reactivation in humans
From the rat maze okeefe: when asleep, the hippo neurones were reactivated in the series from the actions they just did. Deikelmann 2011: ps learnt card locations and presented W odours. Odours re presented during sleep as olfactory doesn’t turn off and brain reactivates the card memory
Two challenges to episodic then semantic theory
Hippo still reencodes during retrieval (creates traces)-multiple trace theory nadel and moscovitch (hippo still used for old memories). Theory says Hippo needed to form memories but in dev amnesia bilateral hippo damage so have poor verbal and non learning but iq, wm and semantic fine just didn’t recall where/when learnt, 44% reduced hippo. So may be scale and not all transferred out of hippo- may be bc entorhinal and peri may have semantic
Dfm background and areas
Has spontaneous thoughts and episodic recollection- deactivates when doing a task. Has the angular gyrus, medial pfc, hippo and posterior cingulate. Hippo isn’t main but coupled w it- when retrieving. Christoff 2009: more activity during task when ppl said their minds wandered
Episodic vs semantic retrieval part 1
Vatansever 2021: list of words then recall paired words- activity in posterior cingulate, angular gyrus, medial pfc (dmn regions overlap W episodic). When semantic, no overlap more in ventrolateral pfc
Part 2- issues W b and W thinking
Past memories should have semantic element so maybe diff due to task demands so changed memory strength (episodic lots of practice and semantic either strongly or weakly linked word pairs) in easy- overlap W dmn but in harder none so dnm for auto retrieval (episodic and auto semantic/strong) ventro pfc for episodic and semantic when weak
Vlpfc selective encoding and retrieval aka inferioir frontal gyrus or brocas area
Bias for relevant representations. Wagner 88: see the subsequent memory effect in hipoo and vlpfc esp L hemi. See peeks here when more likely to remember info layer. Vlpfx directs attention to important parts we want to remember. In amnesia- normal vlpfc so normal encoding but won’t remember
Competing memories
Similar memory interference engages vlpfc. Proactive is old interfering w new, retro is new interfering w old. Source memory (which task got info from). 1. Is object bigger or smaller 2. Is it living or not (semantic). Ask which task did you see the item but context similar so interference. Other is choose item seen before. Vlpfc in source (controls competiition’. Used for link between objects and context m can cause false memory like look out of habit
Neural basis of interference - badre and wagner
Saw set of 4, then a probe word and say if just saw it or not. Or see probe in list in last trial (competition’) more vlpfc when competition as trying to sort memories. Low levels of vlpfc can cause false memory (think saw it)
Vlpfc damage
More false memories, worse recall than recognition (strong effects of cueing). Memories not lost as hippo fine but retrieval. Poor source memory . Confabulation: say things that could have never happened as can’t inhibit irrelevant thoughts/confuse the, and don’t detect impossible (meta cog deficit)
Kosakoff syndrome
Amnesia due to long durn alc due to b1/thiamin deficiency as neglect diet and alc reduces absorption/converting into active form. Damage to mammillary bodies, pfc. See confabulation, apathy, retrieval deficits and formation of memory but fine W cueing
Semantic retrieval
Memories have features and retrieval depends on context- if trying to link multiple contexts, use control processes. Semantic dementia have damage to anterioir temp lobe, SA damage to vlpfc and pmtg (fail same semantic tests but for diff reasons) SD breakdown of knowledge (spec then general), sa have info but can’t make links e.g. SD say animal instead of cow but sa may say zoo or rhino as related. Sa use cues,
Separating episodic and semantic memory
Ps W sa/vlpfc damage confuse episodic and semantic, false episodic memories when shower related semantic info. False semantic when linked episodic. Saw diff concepts in diff locations, asked what’s related either logical or the thing paired W say the thing paired W. Vlpfc resolves source memory contrition
Large scale network
Vlpfc makes connections w other regions, also see activation in posterior temporal region, when disrupt both using tms, disrupt retrieval or weaker associations but not stronger
Forgetting
Forgetting useful as need to control competition. Anderson: retrieval induced forgetting in paired association task. In practice: selectively practice one of two pairs. Makes remembering the other harder 78% of practised 38% not, no practice 50/50. Independent probe suppressed it. Repeated retrieval means reduced vlpfc, greater forgetting decreased pfc . More forget, less competition, less vlpfc
Repression
Og was fried now suppression (conscious, intentional and linked to ef). Cog control is stopping unwanted thoughts (think no think task) Anderson and green: see paired words, think or no think, independent or test prove, ppl don’t remember suppressed. In mri see less hipoo more pfc. Trauma leads to intrusive. Ptsd have less pfc when suppressing. Catarino asked to link doll to traumatic picture, then think or not. Ppl in car accident no ptsd shower lower memory in suppress but ptsd don’t (pfc risk factor)
