Transcript Slide 1
Long Term Memory • Function = organizes and stores info. More passive form of storage than working memory • Capacity = unlimited. Average adult = 100 billion neurons, each of which can make perhaps 5,000 to 10,000 synaptic connections with other neurons five hundred trillion to a thousand trillion synapses • Duration = thought be some to be permanent Maintenance Rehearsal Encoding Attention Sensory Input Sensory Memory Working or Short-term Memory Long-term memory Retrieval History Channel: The Brain • Start at scene 12 or 58:00 of DVD 71 • What is the function of memory? • Describe Lashly’s rat maze experiment in the 1920s. What did he discover? • What is the capacity of long-term memory? • Who is Stephen Wiltshire? What is unique about his memory? How is his brain different from a “normal” brain? • Who is Clive Wearing? What type of memory loss does he suffer from and why? How has he changed over time? Why? Types of Long-Term Memory Explicit (Declarative) knowing you know something conscious recall Implicit (Non-declarative) knowing how to do something (but not know you know) without conscious recall Semantic Episodic Procedural Facts/General Knowledge Experienced events Skills Motor/Cognitive Medial Temporal Lobe / Hippocampus / Frontal Lobe Classical Conditioning Cerebellum http://ngm.nationalgeographic.com/2007/11/memory/brain-interactive Memory Loss • Anterograde amnesia – means forward; can’t form new memories. – Effects of the accident are working forward in time and patient is unable to remember things that have happened since the accident • Retrograde amnesia – means backward; can’t remember old memories . • Hit by a car at noon on Tuesday. Patient regained consciousness Tuesday night and it is now Wednesday. Patient can’t remember the accident or anything that happened Tuesday morning before the accident. Famous Amnesic Patients • • • • • EP – herpes simplex virus chewed its way though his brain, destroying his medial temporal lobe (which contains hippocampus and amygdala) HM – surgery destroyed hippocampus to stop epileptic seizures – Surgery was effective in reducing seizures BUT, had other side effects as well – Can remember explicit memories acquired before the surgery • e.g., old addresses, normal vocabulary – Cannot form NEW explicit memories • e.g., remembering the name of someone he met 30 minutes prior • cannot name new world leaders or performers • can recognize a picture of himself from before his surgery but not from after and doesn’t recognize himself in a mirror Clive Wearing - renowned European conductor; viral encephalitis (inflammation of the brain tissue) destroyed his hippocampus. – While brain damage has totally obliterated Clive's explicit memory--his ability to remember new facts or events--his implicit memory remains intact; he still has language and musical skills, although he is not consciously aware of his ability to play music. All suffer deficits in explicit, but not implicit memory All suffer from anterograde and retrograde amnesia Explicit Memory Memories are those of which one is consciously aware. EX: I may have an explicit memory of playing a particular golf course 1. Episodic = memories are those for personally experienced events 2. Semantic = memories are for general factual knowledge Medial Temporal Lobe Hippocampus (left – trouble remembering verbal info / right – trouble recalling visual designs and locations) Frontal Lobe Implicit Memory Memories are those of which one is not conscious. EX: one may have implicit memories of how to tie one’s shoe but not be able to describe to another how to do it 1. Procedural = memories are those that relate to skills or habits. Learn how to do something, often through classical conditioning, but cannot know or declare they know. 2. Classical Conditioning Cerebellum Synaptic Changes • Release more serotonin at certain synapses when learning occurs • Glutamate enhances long-term potentiation = an increase in the release of neurotransmitters or increase in receptors sites on receiving neuron. Rapidly stimulating memory-circuit connections causes those synapses to become more efficient at transmitting signals; takes less of a signal to recall a memory. Review! Pieces of Mind: Remembering What Matters • What is the role of adrenaline in the formation of memory? How do we know? Describe the experiments with the rats and people. • What is the role of the amygdala in the formation of memory? • Stress Hormones and Memory Prolonged stress Formation Emotion Charged disrupts LTP • Moderate stress enhances LTP • When subjects are given a beta blocker to stall the activation of the SNS, the experimental group did not remember the livelier story any better than the controls remembered theirs. The drug disrupts stressenhanced memory formation and the experimental subjects did not get a boost in memory for the emotional section. • Flashbulb Memories Where you when???? Event Sympathetic Nervous System releases epinephrine (adrenaline) and norepinephrine (noradrenaline) Amygdala Hippocampus into a more alert, activated state. Something important is happening… Focus! Focus! Focus! Memory Consolidation