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PreciousMossAgate7078

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McGill University

Oliver Hardt PhD

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memory systems psychology cognitive neuroscience human memory

Summary

This document discusses memory systems, including episodic, implicit, and semantic memory. It also includes case studies, like Clive Wearing and Henry Molaison (HM).

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PSYC 303 | L02 WHAT IS MEMORY? & BRIEF HISTORY Oliver Hardt PhD McGill University/Department of Psychology The University of Edinburgh/Medical School/The Patrick Wild Centre (PWC) [email protected] https://www.mcgill.ca/psychology/oliver-hardt http://patrickwildcentre.com/oliver-hardt OVERVIEW...

PSYC 303 | L02 WHAT IS MEMORY? & BRIEF HISTORY Oliver Hardt PhD McGill University/Department of Psychology The University of Edinburgh/Medical School/The Patrick Wild Centre (PWC) [email protected] https://www.mcgill.ca/psychology/oliver-hardt http://patrickwildcentre.com/oliver-hardt OVERVIEW 1. Introduction 2. Memory systems 3. Brief History of Memory Research INTRODUCTION 1 4 LIFE WITHOUT EPISODIC MEMORY THE TRAGIC CASE OF CLIVE WEARING ‣ We often realize how fundamental memory is for the human condition when it is fundamentally impaired, like in cases of amnesia, such as Clive Wearing. ‣ In 1985 herpes simplex encephalitis wasted large parts of Clive Wearing’s medial temporal lobes, including the hippocampus. 1 INTRODUCTION ‣ This severely affected his episodic memory. Episodic memory is memory for events (e.g. “Jill and I had a picnic yesterday afternoon on Mount Royal.”) ‣ Now Clive Wearing has severe retrograde and dense anterograde amnesia. ‣ Retrograde amnesia (RA) is amnesia for events prior to the onset of amnesia. Anterograde amnesia (AA) is amnesia for events after amnesia started (i.e., new events). 1 INTRODUCTION 5 6 LIFE WITHOUT EPISODIC MEMORY THE TRAGIC CASE OF CLIVE WEARING 1 INTRODUCTION 1 INTRODUCTION 7 8 LIFE WITHOUT EPISODIC MEMORY THE TRAGIC CASE OF CLIVE WEARING ‣ Since his illness, Clive Wearing is “locked into a permanent present”, his memory for ongoing events reaching no more back than 20-30 seconds, after which he forgot the preceding events and “wakes up” in the current situation. ‣ This gives him an experience of suddenly arriving into the here and now from nowhere about once or twice every minute or so, making independent life impossible. 1 INTRODUCTION ‣ He cannot follow a book or TV show because he cannot remember what he just read. ‣ Despite this significant impairment, some memory remained (relatively) intact: ‣ He knows who he is, and could give a broad outline of his life, with little detail. ‣ He recognized his second wife. ‣ He can read music and play the piano. 9 LIFE WITHOUT EPISODIC MEMORY THE CASE OF HENRY MOLAISON (or HM) 1 INTRODUCTION Henry Molaison (“HM”) 1926-2008 Bilateral hippocampectomy to treat epilepsy led to temporally graded retrograde and dense anterograde amnesia for episodic memory. Other forms of memory, however, remained unaffected (e.g., semantic memory [memory for facts], procedural memory [memory for motor sequences]). 10 LIFE WITHOUT EPISODIC MEMORY SPARED AND IMPAIRED MEMORY IN PATIENT HM Study Phase Test Phase EXPLICIT MEMORY TEST: HM IMPAIRED COMPARED TO HEALTHY CONTROLS 1 INTRODUCTION “Can you put this in a bag?” “Have you seen this during study?” IMPLICIT MEMORY TEST: HM PERFORMS SIMILAR TO HEALTHY CONTROLS “What could this be?” 11 LIFE WITHOUT EPISODIC MEMORY SPARED AND IMPAIRED MEMORY IN PATIENT HM ‣ IMPAIRED ‣ Acquisition of new episodic memory ‣ Recall of pre-amnesia onset episodic memory ‣ Acquisition of new semantic memory ‣ Recognition Memory for recent objects/places ‣ Explicit memory tasks 1 INTRODUCTION ‣ PRESERVED ‣ Pre-amnesia onset semantic memory ‣ Priming ‣ Procedural memories ‣ Conditioning ‣ Implicit memory tasks 12 WHAT THESE PATIENTS HAVE TAUGHT US MEMORY IS NOT A UNITARY SYSTEM BUT COMPOSED OF SEVERAL SYSTEMS “Explicit Memory” “Implicit Memory” “Explicit Memory”: can be intentionally retrieved. “Implicit Memory”: accessed without conscious awareness of it, revealed in performance rather than experiencing a memory. 1 INTRODUCTION Cohen & Squire 1980; Squire & Cohen 1984; Squire, Cohen & Nadel 1984; Cohen & Eichenbaum 1993; Eichenbaum & Cohen 2001; 2004 MEMORY SYSTEMS 2 14 THE MODAL MODEL (OF MEMORY) MODAL BECAUSE IT SHOWS ELEMENTS COMMON TO MODELS OF THAT TIME Environmental Input Info: Auditory, Visual, Tactile, etc. Code: Relatively faithful representations of sensory input Decay Capacity: Large but limited Sensory LOST 2 MEMORY SYSTEMS Register Duration: Most info decays within seconds and is permanently lost Serial exhaustive Attention search Rehearsal Code: acoustic, linguistic Output Capacity: Small Decay STM Duration: indefinitely, if rehearsed. if info is not continuously LOST rehearsed, then decay within 18-30 seconds Recall Rehearsal Decay, Interference Code: semantic? LTM Capacity: unlimited? LOST Atkinson & Shiffrin 1968. In Spence & Spence The psychology of learning and motivation NY: Academic Press 15 THE MODAL MODEL (OF MEMORY) MODAL BECAUSE IT SHOWS ELEMENTS COMMON TO MODELS OF THAT TIME Environmental Input ‣ Model inspired by the computer metaphor, assuming that architecture of digital computers provides a good model for human (or animal) memory. Decay LOST Sensory ‣ Model was useful because it provided a general 2 MEMORY SYSTEMS Register framework to study memory. Serial exhaustive search Attention ‣ The existence of static stores has been debated, suggesting that processes are more central to memory. Rehearsal Output Decay STM ‣ Information flow most likely bidirectional on a levels, in LOST that perceived stimuli can activate long-term memory, Recall Rehearsal which in turn influences what stimuli are attended to and processed. Decay, Interference ‣ Brain physiology underpinning memory in conflict with LTM basic assumptions of the modal model, such as discrete LOST stores for STM and LTM. Atkinson & Shiffrin 1968. In Spence & Spence The psychology of learning and motivation NY: Academic Press 16 SENSORY MEMORY ICONIC MEMORY: FUNCTION ‣ Provides brief (

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