CH 12 LEARNING AND MEMORY FINAL EXAM STUDY GUIDE Learning Relatively long lasting change in an organism s behavior or thought as a result of experience Types of Learning Non associative learning involves change in the magnitude of response to environmental events Habituation Sensitization Classical conditioning Instrumental conditioning Associative learning involves a connection between two elements or events Habituation Decrease in strength or occurrence of behavior after repeated exposure to stimulus Sensitization Experience of one startling stimulus heightens responding to subsequent stimuli Learning with Aplysia Invertebrate learning offers a simpler system in which to isolate neurobiological correlates of learning Simple nervous system 20 000 neurons Neuronal development hard wired Identifiable individual neurons The gill withdrawal reflex occurs when touching the siphon produces a retraction of the gill Sensitization in Aplysia Shocking the head or tail results in an enhanced gill withdrawal reflex following siphon touch Serotonin interneuron release promotes enhanced glutamate sensory neuron release Control Aplysia have 1300 axon terminals on sensory neurons Aplysia experiencing sensitization have 2800 terminals Aplysia experiencing habituation have 800 terminals Classical Conditioning An unconditioned stimulus US is a biologically relevant stimulus An unconditioned response UR is an unlearned reaction to the US A conditioned stimulus CS is an initially neutral stimulus that acquires the ability to signal important biological events A conditioned response CR is a learned reaction to the CS Interpositus cell activity PP LTP dependent increase in neuronal firing across trials NMDA receptor activation leads to changes in synaptic efficacy i e AMPA receptors which gate sodium are inserted LTP or removed LTD from the terminal LTP dependent increase in neuronal firing across trials Neuronal activity in IP corresponds to generation of eyeblink CR suggesting IP neurons drive the behavioral response Purkinje cell activity Sole output from cerebellar cortex Inhibitory releases GABA onto IP neurons Decrease in firing rate due to LTD IP excitation generates CR Purkinje cell disinhibition enables proper timing of blink CR Extinction of Eyeblink CR Not simple unlearning New opposing response acquired Learned response is unexpressed Spontaneous Recovery CR recovers with passage of time Renewal CR is context specific Reinstatement US reminder reinstates CR Autistics show facilitatory learning in this paradigm Engram Physical representation of learned information in the brain Karl Lashley incorrectly concluded that all parts of the cortex make an equal contribution to memory formation Eyeblink Conditioning the Engram Pons CS or inferior olive US can be stimulated in place of physical stimulus The Interpositus nucleus is the brain structure that is sufficient for the CS US learning 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 Working Memory Active and temporary representation of information that is maintained for short periods of time Different systems maintain phonological and spatial visual information Central Executive Monitors and manipulates WM information Baddeley s Working Memory Model Central Executive Prefrontal Cortex plays key role in WM Attention Places long term memories into WM Damage results in Dysexective Syndrome Perseveration persist in using old rule despite repeated feedback indicating it no longer holds Long Term Memory Declarative or Explicit Memory memories for facts or events Non Declarative or Implicit Memory memories for skills habits and emotions 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 Profound anterograde amnesia able to retain information for only short periods of time Personality unchanged IQ increased Memory highly dependent on attention Hippocampus and Explicit Memory Particular learning tasks in animals can be used to model human declarative memory Animal Model of Amnesia Monkeys with medial temporal lobe damage do poorly on delay non match to sample DNMS task Anatomy of the Hippocampus LTP Learning and Memory Co occur in structures involved in memory encoding and consolidation Develops rapidly Long lasting Associativity only synapses simultaneously active are strengthened Cooperativity to be sufficiently depolarized postsynaptic neuron must be stimulated at multiple synapses AP5 blocks induction of LTP and memory of water maze platform NMDA Gene Knock in Doogie NMDA receptor altered to stay open longer allowing more calcium influx more robust LTP and enhanced memory Systems Stages of Memory Systems sensory short term long term Stages encoding storage consolidation retrieval NMDA Contextual Memory Only rats pre exposed to context can associate shock with contextual representation NMDA receptors in the hippocampus particularly area CA3 are required to bind sensory and spatial features of explored environment into single conjunctive representation Retrieval of Contextual Memory Pattern Completion because the contextual memory is encoded as a single representation even a portion of original memory can reactivate entire memory Place Cells How the Hippocampus knows where it is in space The hippocampus forms a cognitive map of your current space Place cells in the hippocampus become active when the rat is in a particular place within his immediate environment Place cells fire relative to extra maze cues and as the environment moves the place field adjusts accordingly During sleep after exploration the order of hippocampal place cell firing reflects the order in which the cells fired during track running Consolidation Process of forming a physical representation of a memory storing Neural trace formed via synaptic plasticity across many neurons and brain regions Retrieval Process of accessing stored memories remembering Amnesia Hippocampal damage results in retrograde amnesia indicating it takes years for memories to be fully consolidated Retrograde Amnesia cant remember the past Anterograde Amnesia cant form new memories Standard