Transcript Memory 1&2
Memory Ref: Banich Ch. 10, 323-363. Test 1 • Marks will be out today (noticeboard and website) Results: class average 67% • Papers will in your labs C be returned 7% C+ BB B+ AA A+ 15% 18% 16% 11% 8% 8% 8% Test 1 • Double-check the arithmetic on your paper (mistakes can happen1) • Queries about grading are welcome • Model answers will be posted late today • Did worse than you expected? Come and see me or one of the tutors NOW. Maybe we can help for next time…. Memory Ref: Banich Ch. 9, pp. 315-339, 343354, 356-361 Memory: Brain Regions • Many brain regions involved in memory • BUT one network of structures has special role: Medial Temporal System • • • • Medial temporal lobe Hippocampus Thalamus Hypothalamus (mammillary bodies) The Medial Temporal System Can see what it does by examining P's with damage • Common causes: brain injury, infection, also some degenerative diseases (Alzheimer's, Korsakoff's) HM: "He could no longer recognise the hospital staff, apart from Dr. Scoville himself, who he had known for many years; he did not remember and could not relearn the way to the bathroom, and he seemed to retain nothing of the day-to-day happenings in the hospital... A year later, HM had not yet learned the new address, nor could he be trusted to find his way home alone... He is unable to learn where objects constantly in use are kept” Two Components to Amnesia Affects facts/events both before and after illness: Retrograde amnesia: loss of things learnt before illness Before illness Onset of illness After illness Anterograde amnesia: loss of new facts/events Anterograde Amnesia Retrograde Amnesia Time Retrograde Amnesia: Features Shows "temporal gradient": Laurel: "When I came out of the coma, I thought I was 13 years old, and I was actually 26. I didn't remember I was married; I didn't remember a whole ream of things.” Retrograde Amnesia: Features Amount recalled • PZ's recall of autobiography: older newer Age of memory Retrograde Amnesia: Features Ways of Testing: • Events questionnaires with items from diff. periods e.g. What British scientist was imprisoned for telling the Russians how to make the atomic bomb? • Famous Faces Tests Retrograde Amnesia: Features Shrinks gradually with recovery over time Laurel: "Often I find myself saying things I didn't know that I knew. It's almost like a third person relaying the information, which to me is fascinating. It made me realise that all of that information is not lost. It's still there.” Medial Temporal System involved in retrieval of existing memories - at least recent ones Two Components to Amnesia Affects facts/events both before and after illness: Retrograde amnesia: loss of things learnt before illness Before illness Onset of illness After illness Anterograde amnesia: loss of new facts/events Anterograde Amnesia Retrograde Amnesia Time Anterograde Amnesia: Features • Knowledge and personal history are "frozen in time” • P may be unable to recall events from 5 HM: "… every day is alone in itself; whatever enjoyment minI’vebefore: had and whatever sorrow I’ve had. 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. Its like waking from a dream; I just don’t remember Anterograde Amnesia: Features • Not specific to any modality System deals with all info. regardless of source • Affects facts as well as event e.g. new vocab: jacuzzi, granola current affairs Deals with both Episodic and Semantic memories Anterograde Amnesia: Features • Short Term Memory not affected • Amnesics perform normally at this: Repeat the following sequence: 391785 System involved only in Long Term Memory Anterograde Amnesia: Features • Skill learning spared e.g. learning piano piece mirror tracing System does not deal with Procedural Learning, only Declarative Knowledge (Cohen et al) Anterograde Amnesia: Features • Certain types of “implicit” learning also spared: e.g. Repetition Priming Word stem completion Anterograde Amnesia: Features Repetition Priming (Gollin pictures): Anterograde Amnesia: Features Word-stem completion: Study these words e.g. motel cyclone DELAY Report first word that comes to mind: mot_______ • P will choose "motel" rather than "motorcycle” • No recollection of ever having done the task Anterograde Amnesia: Features Spared memory not limited to motor skills, but can also include cognitive tasks Some authors prefer terms Explicit vs. Implicit memory Conclusions about Medial Temporal System • Helps form new long-term memories (but not STM) • Also helps retrieve recently-acquired memories • Deals with both episodic and semantic memory Current View • Actual content of memories is distributed throughout cortex (exact area depends on type of info.) • Medial Temporal System ties together the various components of a memory • With time, rest of cortex can learn to tie together the components without going thru this system Other Systems Involved in Memory • All areas of cortex involved, because all are capable of "learning" in their own domain e.g. new skills: cerebellum word-stem completion: posterior language areas • Two Especially Important Regions Left Parietal Lobe: STM • Short term storage of verbal information e.g. digit span After a mild stroke, JK made a good physical recovery, and some months later, was able to return to his previous, demanding position as a private secretary in a large corporation. He had little difficulty resuming his former duties: he was able to remember which tasks/clients he had worked with just before his illness, and had no problem learning new tasks and remembering new clients. However, he noticed a sudden difficulty with numbers. He found himself unable to accurately record numerical information given to him verbally. Also, when dialling phone numbers, he could still deal with familiar numbers, but would repeatedly make mistakes when dialling a new number for the first time. JK underwent further neuropsychological tests which revealed that he had a digit span of only one! task Left Parietal Lobe: STM • STM helps maintain auditory-verbal information • Is one of several resources we use to maintain information temporarily • Current view: STM (or “phonological store”) a slave system of Working Frontal lobes: Working Memory Working Memory: Phonological Store • “Smart” system that keeps info. on-line while a task is performed • relies on more passive e.g.like Baddeley’s stores STM, model: as well as other storage systems Central Executive Visuospatial scratch pad Frontal lobes: Working Memory Phonological Store Central Executive Visuospatial scratch pad • Central Executive (the “smart” part of Working Memory) is located in frontal lobes Frontal lobes: Working Memory Evidence: Monkeys with prefrontal lesions: Food placed in one bowl Food No food Bowls covered Delay (1-10sec) S must choose correct bowl Frontal lobes: Source Memory • Temporal relationships between events: ? Which was most recent? Frontal lobes: Source Memory P’s can't judge temporal relationships, but can recognise previous experiences: ? Which did you see?