Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Lecture 18 (Nov 24th): LEARNING & MEMORY #1 Lecture Outline This Lecture: Psychology of Memory and Brain Areas Involved Next lecture: Neural Mechanisms for Memory 1) Psychology of Memory: Short Term Memory vs. Long Term Memory Explicit Memory vs. Implicit Memory 2) Types of Explicit and Implicit Memory (and involved brain areas/mechanisms) 4) Role of Hippocampus in Memory PSYCHOLOGY of Memory Some Memory Terms: Encoding: processing new information into a form that can be stored Storage: maintaining a memory Recall: to bring back to mind, to retrieve Recognition: to perceive something as previously known, it is “familiar” Short Term Memory (STM) vs. Long Term Memory (LTM) STM: memory for things that just happened limited storage 7 items (+/- 2) LTM: memory for things that do not currently occupy your attention; they must be recalled or recognized Permanent memories require: STM -> consolidated -> LTM LTM: Explicit Memory vs. Implicit Memory Explicit: memory for events or facts 1) Semantic memory 2) Episodic memory Implicit: memory that does not require recollection of specific events or facts, yet affects our behavior 1) Procedural Memory 2) Priming Effects 3) Conditioned Responses Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses LTM: Explicit Memory Semantic: facts that can be stated, things that you “know” Episodic: memory for events that you’ve experienced, things that you “remember” Video – Anton Ego Episodic Memory Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses LTM: Implicit Memory Procedural memory: procedures, motor skills, habits Mirror Drawing Tower of Hanoi LTM: Implicit Memory Procedural memory: procedures, motor skills, habits Mirror Drawing Tower of Hanoi Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses LTM: Implicit Memory Priming: exposure to one stimulus influences response to another stimulus LTM: Implicit Memory Priming: exposure to one stimulus influences response to another stimulus DEMOS Mot_____ Str_____ Thr_____ Win_____ Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Conditioned Responses LTM: Implicit Memory Conditioned Responses A) Operant Conditioning: 1) Reinforcement-> increase the likelihood of behavior X i) positive: “if you do X, I’ll give you candy” ii) negative: “if you do X, I’ll stop hitting you” 2) Punishment -> decrease the likelihood of behavior Y i) positive: “if you do Y, I’ll hit you” ii) negative: “if you do Y, I’ll stop giving you candy” LTM: Implicit Memory Operant Conditioning LTM: Implicit Memory Conditioned Responses A) Operant Conditioning: “If you do this, I'll do that” B) Classical Conditioning: uses “natural”, automatic response “When I do this, you'll do that” Developed by Ivan Pavlov, Nobel Prize 1904 After During Before Classical Conditioning Unconditioned Unconditioned Neutral Stimulus (UCS) Response (UCR) Stimulus Neutral Stimulus Conditioned Stimulus (CS) Unconditioned Stimulus (UCS) No Conditioned Response Unconditioned Response (UCR) Conditioned Response (CR) Donald Hebb (1950s): Learning/Training is an increase in connectivity between neurons as a result of simultaneous activity in those neurons (“Hebbian” Mechanisms) (more next lecture) So, let’s use Hebbian Mechanisms to explain Pavlov’s Dog! Training Strong connection CR Classical Conditioning Psychology of Memory Memory STM LTM Explicit Episodic (events) Semantic (facts) Implicit Procedural Priming Operant Conditioned Responses Classical Role of the Hippocampus in Memory Human Hippocampal Damage -> Memory Loss (“Amnesia”) -But what types of memory loss? Role of the Hippocampus in Memory Control Patient HM Patient EP Patient HM: surgical removal of hippocampus and some surrounding structures (like amygdala) Patient EP: medial temporal lobe damage caused by viral encephalitis (including all of hippocampus) (Corkin et al., 1997; Stefanacci et al., 2000) Role of the Hippocampus in Memory Symptoms following Hippocampal damage: Video: Patient EP Memory Tests Role of the Hippocampus in Memory Symptoms following Hippocampal damage: -Cognitive ability? Intact (except for memory) -STM? Intact -LTM? -Implicit memory? Intact Role of the Hippocampus in Memory Symptoms following Hippocampal damage: -Cognitive ability? Mostly intact (except for memory) -STM? Intact -LTM? -Implicit memory? Intact -Explicit memory? IMPAIRED % Recall control time of diagnosis patient Year Role of the Hippocampus in Memory Symptoms following Hippocampal damage: -Cognitive ability? Mostly intact (except for memory) -STM? Intact -LTM? -Implicit memory? Intact -Explicit memory? IMPAIRED Two Additional Classifications of Memory -Anterograde Memory: memories formed after the injury IMPAIRED -Retrograde Memory: memories formed prior to injury PARTIALLY IMPAIRED (can remember OLD memories) Role of the Hippocampus in Memory So what does this say about the function of the hippocampus? -Involved with explicit LTM -NOT where memories are stored (partial retrograde amnesia –> OLD memories intact) -NOT always necessary for recall (partial retrograde amnesia -> can recall OLD memories) -Involved with encoding or consolidation? Seems so! (can explain both anterograde amnesia and partial retrograde amnesia) BRAIN INJURY retrograde anterograde consolidation TIME The Role of the Hippocampus in Spatial Memory Water Maze Task Hippocampal Lesions in Rats: - Lose ability to learn new platform locations in the watermaze (suggests hippocampus is necessary to form new spatial memories) -Lose all memory for platform locations formed before hippocampal damage – complete retrograde amnesia (suggests that this is where the spatial memory is stored) Other Evidence that Rat Hippocampus is Involved in Spatial Learning “Place Cells” in Hippocampus have spatial receptive fields based on sensory cues in room (O’Keefe & Dostrovsky, 1971) The Role of the Hippocampus in Spatial Memory What about the human hippocampus? Video: Patient EP tested on memory of childhood neighborhood Spatial memory in the hippocampus is CONTROVERSIAL! NEXT LECTURE: NEURAL MECHANISMS: Long Term Potentiation Long Term Depression