STORAGE: RETAINING INFORMATION

*Fun Facts* *The current world record for memorizing digits of pi is held by Chao Lu of China, who memorized 67,890 digits! *Dominic O’Brien of Great Britain memorized 54 decks of cards, totaling 2,808 cards - a world record! *Ben Pridmore of Great Britain, memorized 96 historical dates in 5 minutes. He also set the world record of memorizing a single shuffled deck of cards in 26 seconds.

Sensory Memory Iconic Memory: a momentary sensory memory of visual stimuli; a photographic or picture-image memory lasting no more than a few tenths of a second; we all have a fleeting photographic memory *for a few tenths of a second, our eyes register an exact representation of a scene & we can recall any part of it in amazing detail…but it clears quickly from our visual screen as new images are coming in… Echoic Memory: a momentary sensory memory of auditory stimuli; if attention is elsewhere, sounds & words can still be recalled within 3 or 4 seconds *ie: attention strays in class to the weekend, teacher asks “What did I just say?” you can recover the teacher’s last few words for about 3-4sec.

Working/Short-Term Memory What are the duration & capacity of short-term & of long-term memory? Short term memory is limited not only in duration but also in capacity, typically storing about seven bits of info (+/- 2) George Miller (1956) enshrined this recall capacity as the Magical Number Seven, plus or minus two Both kids & adults have short-term recall for roughly as many words as they can speak in 2s *At any given moment, we can consciously process only a very limited amount of info.

Long-Term Memory Even though our capacity for storing long-term memories is limitless, memory is not a recording of events. Stored memories are interfered with by attention issues, prior knowledge & memory decay…BUT old memories are not replaced by new memories! *Psychologist Rajan Mahadevan could repeat 50 random digits backward; given a block of 10 digits from the first 30,000 or so digits of pi, Rajan, after a few moments of mental searching would pick up the series from there…firing #s like a machine gun. -He says it is not a genetic gift, anyone could learn to do it…{his dad memorized Shakespeare’s complete works!!! }

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How does the brain store our memories? Psychologist Karl Lashley (1950) demonstrated that memories do not reside in single, specific locations. -He trained rats to find a way out of the maze then cut out pieces of cortexes & retested their memory -No matter which small brain section he removed, rats retained at least a partial memory of how to navigate maze

…Storing Memories (cont’d) Synaptic Changes: -Contemporary memory researchers have searched for a memory trace – the quest to understand the physical basis of memory – for how info becomes incarnated in matter – has sparked study of the synaptic meeting places where neurons communicate with one another via their NT messengers. -We do know that experience modifies brain’s neural networks; increased activity = new neural connections forming or strengthened

…cont’d So far…the only evidence to confirm a physical basis for memory is long-term potentiation (LTP): an increase in a synapse’s firing potential after brief, rapid stimulation. -In experiments, rapidly stimulating certain memory-circuit connections has increased their sensitivity for hours or even weeks… *Evidence that LTP is a physical basis for memory: 1.Drugs that block LTP interfere with learning (Lynch & Stabuli, 1991) 2.Mutant mice engineered to lack an enzyme needed for LTP can’t learn their way out of a maze (Silva et al., 1992) 3.Rats given drug that enhances LTP will learn a maze with ½ the usual number of mistakes (Service, 1994) 4.Injecting rats with a chemical that blocks the preservation of LTP erases recent learning (Pastalkova et al., 2006)

So What? Memory-biology explorers have helped to develop & test memory-boosting drugs; target market = Alzheimer’s patients, mild cognitive impairment that becomes Alzheimer’s, and others who’d like to stop progression of age-related memory loss. One approach…developing drugs that boost production of protein CREB which might lead to increased production of proteins that help reshape synapses & consolidate STM into LTM. {sea slugs, mice & fruit flies w/ enhanced CREB have shown enhanced memories} Another approach…developing drugs that boost glutamate, a NT that enhances synaptic communication (LTP).

Stress Hormones & Memory When excited/stressed, emotion-triggered stress hormones make more glucose energy available to fuel brain activity, signaling the brain that something important has happened. The amygdala (two emotion-processing clusters in limbic Sx) boosts activity & avail. Proteins in the brain’s memory forming areas Result? Arousal can sear certain events into brain. “Stronger emotional experiences make for stronger, more reliable memories)

Flashbulb Memory: a clear memory of an emotionally significant moment/event. -i.e.:first kiss, whereabouts when learning of friend’s death, 9/11… -It’s as if your brain says, “Capture this!” -Usually extremely accurate…unless people relive, rehearse & discuss the memory & then misinformation can seep into them. -Limits to stress-enhanced remembering: when prolonged (abuse/combat) stress acts corrodes neural connections & shrinks the hippocampus (vital for laying down new memories). -Sudden stress hormones may also block older memories…mind goes blank when making class presentation

Ok…now your turn… Turn to your text pg Start reading at Storing Implicit & Explicit Memories & STOP after you’ve read to the middle of pg.274. Take READING NOTES!!!! {amnesia, H.M., implicit/explicit memory, hippocampus, cerebellum}