Memory Overview Memory Systems Amnesia Encoding Consolidation and Retrieval What is memory Learning is a relatively permanent change in behavior that marks an increase in knowledge skills or understanding Memory is the fruit of this learning process the concrete trace of it that is left in your neural networks Atkinson Shiffrin Model of Memory Short term or Working Memory Active and temporary representation of information that is maintained for short periods of time Different systems maintain phonological and spatialvisual information Central Executive Monitors and manipulates WM information Working memory Funahashi et al 1989 Central Executive Prefrontal Cortex plays key role in WM Maintains info in WEM Places long term memories into WM PFC as the Central Executive WM Attention Cognitive flexibility Long term Memory Declarative or Explicit Memory memories for facts or events Non Declarative or Implicit Memory memories for skills habits and emotions Factual versus Autobiographical memory Semantic versus Episodic memory Knowing versus Remembering Repeated exposure can weaken Episodic Memory strengthen Semantic Memory Medial Temporal Lobes Memory Henry Gustav Molaison H M 1926 2008 Two thirds of medial temporal lobes removed in 1953 including hippocampus amygdala and surrounding cortex Medial Temporal Lobe Henry Gustav Molaison H M Two thirds of medial temporal lobe removed in 1953 including hippocampus amygdala and surrounding cortex Profound anterograde amnesia able to retain information for only short periods of time Personality unchanged IQ increased Memory highly dependent on attention Animal Model of Amnesia Monkeys with medial temporal lobe damage do poorly on delay non match to sample DNMS task Animal Model of Amnesia Monkeys with medial temporal lobe damage do poorly on delay non match to sample DNMS task Systems and Stages of Memory Systems sensory short term long term Stages encoding storage consolidation retrieval Consolidation and Retrieval Consolidation Process of forming a physical representation of a memory storing Neural trace formed via synaptic plasticity across many neurons and brain regions Strength of Memory Retrieval Process of accessing stored memories remembering STM seconds to hours LTM hours to months Long lasting up to lifetime Time RETROGRADE AMNESIA ANTEROGRADE AMNESIA Amnesia Hippocampal damage results in retrograde amnesia indicating it takes years for memories to be fully consolidated Hippocampal Consolidation Memory assessed in control and hippocampal lesioned rats 1 or 28 days following training Necessity of hippocampus diminishes across time Memory is consolidated in extra hippocampal substrate Kim Fanselow 1992 Standard Consolidation Theory Hippocampus binds many components sight sound etc of memory together As consolidation occurs memory becomes hippocampalindependent As consolidation occurs memory looses specificity or detail Memory Consolidation Similar context more fear evoking than distinct context Freezing to generalized context increases with time Wiltgren et al 2010
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