Lec11_Pre_Notes PDF

3/22/24 Memory X.Liu PSYC5130 1 What is memory? What’s the professor’s name? What did you have for breakfast today? Yesterday? Two days ago? On your first day of 1st grade? When was the last time you went to bed before midnight? How do you drive a car? Play the piano? X.Liu PSYC5130 2 Definition… Me...

3/22/24 Memory X.Liu PSYC5130 1 What is memory? What’s the professor’s name? What did you have for breakfast today? Yesterday? Two days ago? On your first day of 1st grade? When was the last time you went to bed before midnight? How do you drive a car? Play the piano? X.Liu PSYC5130 2 Definition… Memory is the process in which information is encoded, stored, and retrieved. 3R: Registration Retention Retrieval X.Liu PSYC5130 3 1 3/22/24 Memory Types Transient (sec to min) Capacity-limited Information that guides ongoing behavior ‘permanent’ ‘unlimited’ Information that has been saved across time X.Liu PSYC5130 4 Long-term memory Declarative(explicit) l Storage and retrieval of material that is available to the conscious mind and (in humans) can be encoded in symbols and language l “I had Cheerios for breakfast Tuesday” Non-declarative(implicit) l Skills and associations unavailable to the conscious mind l Habits, skills, behaviors l Playing the piano, throwing a frisbee, tying your shoes X.Liu PSYC5130 5 Neuropsychology: Amnesia Memory loss may manifest itself in two ways: RETROGRADE amnesia – prior to trauma ANTEROGRADE amnesia – following trauma May be a mix, as below: X.Liu PSYC5130 Trauma to brain 6 2 3/22/24 Declarative memory--encoding X.Liu PSYC5130 7 H.M. Right now, I’m wondering. Have I done or said anything amiss? You see, at this moment everything looks clear to me, but what happened just before? That’s what worries me. ——H.M. You'd think it would be impossible to have a relationship with someone who didn't recognize you, but I did. ——Suzanne Corkin X.Liu PSYC5130 8 H.M. Lesion Site 1953, at age of 27, H.M. had an operation in which an 8 cm length of the MTL was bilaterally removed cortex, amygdala, anterior 2/3 of the hippocampus X.Liu PSYC5130 9 3 3/22/24 X.Liu PSYC5130 10 R.B. Another amnesic patient –Lost his memory after episode during heart bypass surgery (loss blood to brain) –Dense anterograde amnesia (similar to H.M.) –Retrograde amnesia back 1-2 years pre-surgery Upon death several years later, studied brain –MTL appeared intact! –But, careful analysis revealed that within each hippocampus (within the MTL), there were specific lesions X.Liu PSYC5130 11 R.B. X.Liu PSYC5130 12 4 3/22/24 Hippocampus X.Liu PSYC5130 13 Memory abilities X.Liu PSYC5130 14 X.Liu PSYC5130 15 5 3/22/24 Their Memories Are Not Equally Affected Retained the ability to learn procedural tasks. X.Liu PSYC5130 16 Hippocampal Profile Working memory is intact Encoding of declarative memory is impaired Storage and retrieval of declarative memory are intact Non-declarative memory is intact X.Liu PSYC5130 17 Declarative memory—storage X.Liu PSYC5130 18 6 3/22/24 Memory Consolidation X.Liu PSYC5130 19 Where in the Cortex X.Liu PSYC5130 20 X.Liu PSYC5130 Reagh & Ranganath, 2023 21 7 3/22/24 Encoding Predictions – fMRI Pattern Similarity Between Encoding and Recall X.Liu PSYC5130 Recall 22 X.Liu PSYC5130 23 AT Network Represents Person X.Liu PSYC5130 24 8 3/22/24 PM Network Represents Context X.Liu PSYC5130 25 mPFC Represents Schema X.Liu PSYC5130 26 Hippocampus represents episodes X.Liu PSYC5130 27 9 3/22/24 Storage Recent --- hippocampus Remote --- distributed in higher-order cortices X.Liu PSYC5130 28 A New Way to Understand Memory – Neural Perspective X.Liu PSYC5130 29 The Brain IS Memory Memory is located in every single synapse in the brain There are as many different kinds of memory as there X.Liu PSYC5130 are neurons and synapses… 30 10 3/22/24 Two Neural Forms of Memory: Activation vs. Synaptic Changes Activation = Neurons continue to fire action potentials, “remembering” what you were just seeing, thinking Synapses change strength (“weight”) as a result of LTP (learning): this encodes long-term memories that last even after your But when firing stops.. You forget.. activation switches to something new.. X.Liu PSYC5130 31 Major Types of Memory Activation-based (sustained neural firing) –Transient, easily lost –Very flexible: mental arithmetic, etc. Weight-based (changes in synapses) –Long lasting, persist over distraction, etc –Very high capacity X.Liu PSYC5130 32 STM vs. LTM X.Liu PSYC5130 33 11 3/22/24 Where is Sensory Memory? Surprise! It is just neural firing in sensory brain areas – those neurons just keep on firing away (briefly..) X.Liu PSYC5130 34 Where is Short-Term Memory? Surprise! It is neural firing in higher level brain areas that represent specific thing you’re remembering – those neurons just keep on firing away (briefly..) X.Liu PSYC5130 35 Where is Short-Term Memory? Extra surprise! And it usually requires contribution from prefrontal cortex – has extra holding power to keep those neurons firing longer! X.Liu PSYC5130 36 12 3/22/24 Where is Long-Term Memory? Surprise! It is in the relevant brain area(s) that encode the specific information! LTM is the sum total of all those synaptic weight changes! X.Liu PSYC5130 37 Organization of LTM Episodic = hippocampus Semantic = Neocortex (mostly) X.Liu PSYC5130 38 Complementary Learning Systems Episodic Semantic X.Liu PSYC5130 39 13 3/22/24 Real Life Task X.Liu PSYC5130 40 Classic Lab Task: AB-AC Learn AB paired associates: –window-reason –bicycle-garbage –... Then AC paired associates: –window-apple –bicycle-towel –… X.Liu PSYC5130 41 AB-AC Test on AB list: –Window ? –Bicycle ? And AC list: –Window ? –Bicycle ? X.Liu PSYC5130 42 14 3/22/24 Catastrophic Interference X.Liu PSYC5130 43 Hippocampal System The hippocampus plays a critical role in the rapid learning of new episodic memories. Pattern Separation: overlapping or similar inputs (representations) are transformed into less similar (sparse) representations. X.Liu PSYC5130 44 How Does Hippocampus Achieve This X.Liu PSYC5130 45 15 3/22/24 How Does Hippocampus Achieve This Cornu Ammonis (Ammon‘s Horn) X.Liu PSYC5130 46 How Does Hippocampus Achieve This X.Liu PSYC5130 47 How Does Hippocampus Achieve This X.Liu PSYC5130 48 16 3/22/24 How Does Hippocampus Achieve This X.Liu PSYC5130 Zheng, Liu, et al., 2022 49 Learning (Train) – Pattern Separation X.Liu PSYC5130 50 Memory Retrieval X.Liu PSYC5130 51 17 3/22/24 Recall (Test) – Pattern Completion X.Liu PSYC5130 52 Recall (Test) – Pattern Completion In the hippocampus, pattern completion is facilitated by the recurrent connections among CA3 neurons –Glued together during encoding –During recall, a subset of CA3 neurons can trigger recall of the reminder X.Liu PSYC5130 53 Recurrent Network X.Liu PSYC5130 54 18 3/22/24 X.Liu PSYC5130 55 Trade-off Pattern separation: The system will treat the retrieval cue like a novel stimulus and thus encode a new pattern in CA3, instead of recalling the old one. Pattern completion: The system will reactivate old memories instead of encoding new patternseparated ones for truly novel episodes. Solution: –Hippocampus is fine-tuned –Strategic influences from other brain areas X.Liu PSYC5130 56 Complementary Learning Systems Episodic Semantic X.Liu PSYC5130 57 19 3/22/24 Slow Learning Integration Event has a.66 probability of occurring: only with a slow learning rate (.005) does it converge on an accurate estimate across discrete events X.Liu PSYC5130 58 Behavior Complexity Where We Are Co Cellular/ Molecular ut mp a tio nal N os eur Systems c ie nce Cognitive Biology Psychology Levels of Analysis in Neuroscience X.Liu PSYC5130 59 Another Facilitator? X.Liu PSYC5130 60 20 3/22/24 Sleep X.Liu PSYC5130 61 Stages of Sleep EEG – Electrodes on the scalp monitor the brain’s activity – Two basic patterns of activity: Alpha activity when resting Beta activity when alert – Records sleepers to identify particular patterns of waveform activity Corresponds with different stages of sleep X.Liu PSYC5130 62 Participant in a Sleep Study X.Liu PSYC5130 63 21 3/22/24 X.Liu PSYC5130 64 A Typical Pattern of Sleep Stages During a Single Night The dark blue shading in this figure indicates REM sleep. X.Liu PSYC5130 65 Lifespan Change X.Liu PSYC5130 66 22 3/22/24 Complementary Learning Systems Episodic Semantic X.Liu PSYC5130 67 Sleep & Memory The hippocampus teaches the cortex during SWS through replay Place Cells in the Hippocampus X.Liu PSYC5130 Skaggs & McNaughton, 1996 68 Sleep & Memory The hippocampus teaches the cortex during SWS through replay During REM sleep, the cortex incorporates new memories into existing knowledge (Singha et al., 2022) X.Liu PSYC5130 69 23 3/22/24 Why Sleep is Necessary Wake Sleep X.Liu PSYC5130 70 24