Lecture 16. Hippocampus and Memory (1).pptx - Lecture 16...

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9-1Lecture 16Memory and AmnesiaReading: Chapter 9 Memory and Learning intextbook (pages 257-272, first half of chapter)
What is memory?
What is memory for?
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9-3Amnesia is characterized by the inability toform most new long-term memories,H.M. is the most famous studied case ofamnesiaHe participated in hundreds of studies overmore than five decadesHis amnesia esulted from a surgicalresection – a “planned” lesion – to controlhis epilepsySurgeon knew specifically which structureswere to be removedAfter his surgery, H.M. was unable to formnew long-term memoriesFor example, he could not learn thedefinition of new words even after hundredsof trials!Hippocampal damage causes amnesia, a disorder oflong-term memory
9-4Amnesia results from extensive damage tothe regions of the medial temporal lobe,including thehippocampus, so named because its shaperesembles a seahorsedentate gyrus,amygdala, andneighboring parahippocampal areathe parahippocampal, entorhinal, and perirhinalcortices.Hippocampal damage causes amnesia, adisorder of long-term memoryResection in H.M.’sbrain (right)
9-5A 3-D rendering of two hippocampi, with the subfields color-coded.Abbreviations: CA1,cornu ammonissubfield 1; CA3,cornu ammonissubfield 3; DG, dentate gyrus; SUB, subiculum.
9-6The anatomy of the hippocampus is such that informationfrom many different brain regions converges on theentorhinal cortexFrom there the information enters the hippocampus via theperforant pathwayIt travels in a unidirectional manner through the differentsubfields of the hippocampus before exitingBack to the entorhinal cortexTo other brain regions via the fornixHippocampal damage causes amnesia, adisorder of long-term memory
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9-8Amnesia can also result fromdamage to the closely relatedmidline diencephalic region,involving particularly thedorsomedial nucleus of thethalamus and themammillarybodiesof the hypothalamus.Damage to these regions canoriginate in a number of ways –for example, as occurs inKorsakoff’s disease, followingchronic alcohol abuse, orsometimes through an accident.Hippocampal damage causes amnesia, a disorderof long-term memory
9-9Amnesia is characterized by a loss of memory that is global.It occurs across modalities regardless of whetherinformation is presented in the visual, auditory,somesthetic, and even olfactory modalities.

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Term
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