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2/13/2017 Outline • Types of long-term memory Long-Term Memory (LTM) – Implicit / Explicit • How do we store? • What do we store? • How durable is the store? Explicit Memory Semantic memory – not tied to specific time or place Implicit Memory Episodic memory – tied to specific events My first ride on a roller-coaster! Date of signing of US Constitution My best friend’s middle name My worst break-up Capitol of New York? • Often a procedure • Does not require conscious recognition • Conscious thought may interfere • Can measure changes in reaction / performance My favorite birthday party Outline How are memories stored? • Types of long-term memory • Physical Location? • Synapse Strength? – Implicit / Explicit • How do we store? • What do we store? • How durable is the store? 1 2/13/2017 How are memories stored? • Physical Location? • Instead, errors in learning increased with amount of cortex lesioned • Lashley (1950) – Trained rats on various tasks – Then lesioned rat cortices in an attempt to find out where those behavioral memories were stored – Couldn’t find them in a single place How are memories stored? (Definitions for Prev. slide*) • Physical Location? • Engram – The package of information that makes up a memory – the bound representation of experienced events, including: perceptual and conceptual fragments, • Lashley (1950) – “It is not possible to demonstrate the isolated localization of a memory trace anywhere within the nervous system. Limited regions may be essential for learning or retention of a particular activity, but within such regions the parts are functionally equivalent. The engram is represented throughout the region.” self-generated thoughts, contextual details, etc… • Trace – a pointer to the memory for retrieval (*Will not test on these) How are memories stored? How are memories stored? • Physical Location? • Physical Location? • Synapse Strength? • Lashley (1950) – “every instance of recall requires the activity of literally millions of neurons. The same neurons which retain the memory traces of one experience must also participate in countless other activities.” • Recall Hebbian Learning? – Cells that fire together wire together • Changing synaptic potential stores information 2 2/13/2017 Hebb 1949 Classical Conditioning • Classic work of cognitive neuroscience • Lays out Hebb’s hypotheses on learning Whtvr… Response is physiological and subconscious Physiology of Mind (Structuralism) Hebb 1949 • Wilhelm Wundt (1832-1920) • Each neuron has tons of connections • Cells fire in networks • Some cells will be linked in groups • These “assemblies” may “reverberate” • Sensation does not differ from ideation • “Blue is and remains blue” (whether sensed or imagined) Image and dates: https://en.wikipedia.org/wiki/Wilhelm_Wundt Hebb 1949 • Even simple assemblies might reverberate for… half a second? • Reverb = short term memory? • Leads to continued firing / wiring = learning? Hebb 1949 3 2/13/2017 However, in vivo… However, in vivo… • We can try and record out of cells during a task • Do we see lasting reverb? • Record out of MT in awake monkey • Monkey sees motion sample • Delay • Monkey responds “same/different” to test stimulus Tania Pasternak, PhD University of Rochester Professor, Neurobiology & Anatomy, Brain & Cognitive Sciences, Center for Visual Science Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task. Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003 However, in vivo… • Activity drops off almost immediately • Poor evidence of local reverb Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task. Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003 Bisley, J.W., Zaksas, D., Droll, J.A., & Pasternak, T. (2004). Activity of Neurons in Cortical Area MT During a Memory for Motion Task. Journal of Neurophysiology. Jan 2004, 91 (1) 286-300; DOI:10.1152/jn.00870.2003 Frontal Areas? • Perhaps activity is maintained in other areas? • Working memory suggests frontal areas… Curtis, C. E., Rao, V. Y., & D'Esposito, M. (2004). Maintenance of spatial and motor codes during oculomotor delayed response tasks. Journal of Neuroscience, 24(16), 3944-3952. Brain activation? Frontal Areas? • Curtis & D’Esposito (2003) • Dorsolateral Prefrontal Cortex (DLPFC) • Propose 4 major areas for working memory: • Perhaps activity is maintained in other areas? • Working memory suggests frontal areas… • Similar human fMRI task – (P) Parietal areas • Stores information for location of objects – (F) Frontal Eye-Fields • Visuospatial buffer – Stim – Delay – Respond (match / non-match) – (B) Broca’s Area • Phonological buffer – (D) DLPFC • Central Executive Curtis, C. E., Rao, V. Y., & D'Esposito, M. (2004). Maintenance of spatial and motor codes during oculomotor delayed response tasks. Journal of Neuroscience, 24(16), 3944-3952. 4 2/13/2017 Yes! But… Complex interplay of areas? • There appears to be a role of frontal cortex in maintaining information • But that’s more like working memory • Remember – – Lashley: Memory is distributed – Lots of small changes add up? • How do the circuits change at the lower levels? Distributed Neural Networks Distributed Neural Networks • How could memory be so distributed? • Formed of multiple layers of “nodes” / neurons • Nodes/neurons in one level pass info onto nodes/neurons in the next level • Patterns of activation in level thus can cause a specific pattern of activation in the next group of nodes/neurons 5 2/13/2017 Distributed Neural Networks Distributed Neural Networks • Through learning and feedback, weights between nodes/neurons can change • This changes the information represented in the network • Example: handwritten letter detection • Online demos: http://www.mitchcrowe.com/visualizingneural-networks/ Distributed • Example with Visual Neural Retinal Networks Areas Ganglion Rods & Cells Example: handwritten Cones Inferior letter detection Temporal Areas Input V1, V2, etc… Distributed Neural Networks This IS Artificial Intelligence! • Example: handwritten letter detection Conscious Recognition Clinical Cases… • Are there parts of the brain that knock out storage to LTM? Clive Wearing BBC – Man Without a Memory Clip: https://www.youtube.com/watch?v=Vwigmktix2Y 6 2/13/2017 Also, H.M. (Henry Molaison) • 1953, Doctors try experimental surgery to relieve seizures • Remove parts of Hippocampus & Temporal lobe (function then unknown) • Post surgery, H.M. could no longer form new memories E.P. PBS - American Scientific Frontiers (2004) https://www.youtube.com/watch?v=7Grh3PeEMIg 3:10 – 11:16 H.M.’s brain online All suffered damage to Hippocampus • http://hm.brainandsociety.org/hm _web/ • Hippocampus is part of the limbic system • Located in the medial temporal lobe • Essential to moving information from WM to LTM Lesion Cellularlevel resolution Role of Hippocampus? • How does hippocampus get info from WM to LTM? • Unclear. • But, consider: – Hippocampus reactivates recent experiences during “off-line” periods (rest & sleep) (Sutherland & MacNaughton, 2000; Davidson, et al, 2009) (Will discuss more in consciousness lecture) 7 2/13/2017 Role of Hippocampus? HM – Mirror Drawing • Also note: These were formation of explicit memories • What about implicit memories? Role of Hippocampus? • Also note: These were formation of explicit memories • What about implicit memories? – At first blush, would appear that this relies on other areas… – This was the consensus for years – But… Recent re-evaluation of H.M.’s brain • 2014 -- 3D reconstruction • Shows that a sizable portion of the hippocampus remained intact (shown in green on next slide) Annese, J., Schenker-Ahmed, N. M., Bartsch, H., Maechler, P., Sheh, C., Thomas, N., ... & Klaming, R. (2014). Postmortem examination of patient HM’s brain based on histological sectioning and digital 3D reconstruction. Nature communications, 5. 8 2/13/2017 Role of Hippocampus • E.P. had more complete hippocampal damage • E.P. was NOT able to form new implicit memories • Hippocampus appears important for all types of memory encoding – (Implicit memory tasks may just require fewer resources) Outline • Types of long-term memory – Implicit / Explicit • How do we store? • What do we store? • How durable is the store? Priming & Depth of Encoding Priming & Depth of Encoding • Depth of Encoding – the more you interact with and manipulate data, the more you remember it • Jacoby & Dallas (1981) • Stage 2: participants were divided into two groups. Each received one task: • Jacoby & Dallas (1981) – Recognition • Stage 1: Three types of questions followed by word – Perception – Q1: Constituent letters of words (Physical features) • Does the word have the letter L? – Q2: Rhyme question (Phonemic features) • Does the word rhyme with book? – Q3: Meaning question (Semantic features) • Is the word an animal? (Did this word appear in stage 1?) (Try to read a word that is flashed briefly on the screen) What kind of Memory are these? 9 2/13/2017 Jacoby and Dallas (1981) • Recognition memory increased with Level of Processing • For the perceptual group, words that appeared in stage 1 were read faster, no level of processing trend. • (Perceptual memory fairly independent of recall.) How do we get things out of memory? • When we learn, we make connections between the material we’re learning, and what we already know • These connections can serve as retrieval paths Example: Retrieval Cues Neural Networks, Levels of Processing • Q: Why does attention to meaning (e.g., deep processing) lead to better recall? • A: When the meaning of an item is attended to, many more memory links are provided to that item so retrieval is easier. Memory as Associative Network • Like a Neural Network at the Concept / Category level – A “node” for each piece of information – links between nodes that are “associated” – when one node is activated, it spreads activation to all nodes it’s linked to – if an node receives input from multiple nodes, it will be “more active” = easier to reach threshold for remembering Memory as Associative Network What is the capital of South Dakota? hint: it’s also a man’s name! 10 2/13/2017 Memory as Associative Network • context-dependent learning – Godden & Baddeley (1975) Context-Dependent Learning Divers under water and divers on land learned a list of 36 words aurally then ½ of them switched environments, and wrote down as many words from the lists as possible in 2 min. Context-Dependent Learning Context-Dependent Learning • Context-reinstatement: improved memory performance when tested in the same context that was in place during learning – Context influences how you think about the information Recall from Spreading Activation State-Dependent Learning • Activating one concept leads to activation of related concepts • # of connections: more access points • Emotion can also provide a learning context: Think of arrows as two-way access paths 11 2/13/2017 Outline • Types of long-term memory – Implicit / Explicit • How do we store? • What do we store? • How durable is the store? Familiarity Familiarity • Without looking at one, • Try to draw a US penny from memory • Examples of what people draw Baddeley (1999), based on Rubin, D. C., & Kontis, T. C. (1983). A schema for common cents. Memory & Cognition, 11(4), 335-341. Familiarity False Memories Actual Coins from that year Participant Average (Mode) Rubin, D. C., & Kontis, T. C. (1983). A schema for common cents. Memory & Cognition, 11(4), 335-341. 12 2/13/2017 Illusion of Truth Illusion of Truth… • Hasher, Goldstein, & Toppino (1977) – Participants rate repeated statements as more true than new statements • Bacon (1979) – Even hearing parts of a statement (e.g. The Statue of Liberty) lead people to rate related statements as more true (“The statue of Liberty’s arm is 46 ft long.”) Begg, I. M., Anas, A., & Farinacci, S. (1992). Dissociation of processes in belief: Source recollection, statement familiarity, and the illusion of truth. Journal of Experimental Psychology: General, 121(4), 446. 2009 2017 Illusion of Truth… • “This was the largest audience ever to witness an inauguration, period” http://time.com/4641381/donald-trump-inauguration-crowd/?xid=homepage https://www.nytimes.com/interactive/2017/01/20/us/politics/trump-inauguration-crowd.html?_r=0 http://stmedia.startribune.com/images/211Trump_Inauguration.jpg 13 2/13/2017 Non-famous Famous Faces Illusion of Truth… • Landau & Leed (2012) • Nonfamous faces paired with “famous” or “semifamous” faces • Task: Rate “Would these two people make strong business partners?” Landau, J. D., & Leed, S. A. (2012). The illusion of fame: How the nonfamous become famous. The American journal of psychology, 125(3), 351-360. Non-famous Famous Faces • Later, asked to rate individual faces on how famous • Newly familiar faces rated as more famous John C. Lilly “Reality is a matter of local custom” (1915-2001) Developed Flotation Isolation Tanks Gave LSD to dolphins & self to try and communicate Landau, J. D., & Leed, S. A. (2012). The illusion of fame: How the nonfamous become famous. The American journal of psychology, 125(3), 351-360. Photo: Thinking Allowed (1983). PBS / Thinking Allowed Productions; Quote: Lilly, JC & Gold, EJ (1996) Tanks for the Memories: Flotation Tank Talks. Gateway Constructionist Approaches of LTM Alas, the film eventually was lost, wrote Gertie, “and we all began to remember the night differently—each memory perfectly true and exactly how it happened, of course.” • Memory is not a file-drawer • Not for remembering past events Gertrude Sanford • Useful for prediction • We create reasonable accounts from limited data (1902-2000) - Dickey, Christopher (2016) https://goo.gl/PgOqWJ American Socialite / WWII Spy Painting: William Orpen, 1922 14 2/13/2017 Constructionist Approaches of LTM Greenberg (2004) • Isolated details remembered: – reasonable story created during recall to rationalize the details • General theme (only) remembered: Pearl Harbor, December 7, 1941 – detail often added to give credibility and coherence to the story • **This all happens subconsciously and we believe the recall as if it were reality. “I was listening to a baseball game on the radio when it was interrupted by an announcement of the Pearl Harbor attack.” 1941 Baseball schedule: April through September Fall 1988 two years after the incident, student “RT” Fair Trial… • If source & details are fragile… – Can we change recollection through leading questions? 24 hrs after the explosion, student “RT” Neisser & Harsch, 1992 • Participants shown films of traffic accidents • Then asked questions with varied verbs: • “About how fast were the cars going when they _____ each other?” – Contacted – Hit – Bumped – Collided – Smashed Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction […] . Journal of verbal learning and verbal behavior, 13(5), 585-589. Loftus & Palmer (1974) 45 MEAN SPEED ESTIMATE (MPH) Loftus & Palmer (1974) 40 35 30 25 VERB 15 2/13/2017 Wade, Garry, Read, & Lindsay (2002) “A picture is worth a thousand lies” Loftus (1975) • Personal Experiences can be altered, too: • Study about “headaches” (N=40) – In terms of the total number of products, how many other products have you tried? 1? 2? 3? – In terms of the total number of products, how many other products have you tried? 1? 5? 10? – Do you get headaches frequently, and, if so, how often? – Do you get headaches occasionally, and, if so, how often? Avg 3.3 Avg 5.2 • “Twenty adult confederates each recruited a family member who (1) had not taken a hot air balloon ride, (2) was at least 18 years old, and (3) had not taken a psychology class” • “The confederates each provided a selection of photographs in which the subject was 4–8 years old” Avg 2.2/wk Avg 0.7/wk Loftus, E. F. (1975). Leading questions and the eyewitness report. Cognitive psychology, 7(4), 560-572. Wade, Garry, Read, & Lindsay (2002) “A picture is worth a thousand lies” Wade, K. A., Garry, M., Read, J. D., & Lindsay, D. S. (2002). A picture is worth a thousand lies: Using false photographs to create false childhood memories. Psychonomic Bulletin & Review, 9(3), 597-603. Wade, Garry, Read, & Lindsay (2002) “A picture is worth a thousand lies” • 50% of participants recalled the balloon ride with lots of additional details Hopeless? • Overall, memory is pretty good – We can remember soooo much stuff! • But, memory is also highly malleable • Highly prone to suggestion 16