Conditioning and Learning Exam 2 Study Guide Exam Date 17 July 2012 Chapter 7 Making Memories Conceptual Issues and Methodologies 1 1 LTP and Memory Review In studies of synaptic plasticity the stimulus that modified synapses was high frequency electrical stimulation Memories however are established as a result of a behavioral experience a behaving organism interacting with its environment assumed to produce changes in synaptic strength in regions of the brain that store the experience How is the info contained in a behavioral experience encoded and stored in the brain difficult to answer this requires a discussion of some important conceptual and methodological issues If the synapse is the fundamental storage unit in the brain and studies of LTP have produced a complete understanding of how synapses are modified which they have not why not argue that we already know how memories are made BECAUSE preparation so info acquired by studying LTP comes from highly artificial The experience used to induce LTP is a low intensity high frequency electrical event that bypasses all the sensory inputs that normally bring info about the environment into the brain LTP electrically induced in tissue slices or in the brain does not represent a behavioral experience Knowledge gained from the studies of LTP is best viewed as a fundamental source of hypotheses about how the brain makes memories Test Objectives 1 1 LTP does not represent a behavioral experience What good is it then 1 1 LTP is a source of hypotheses about how the brain makes memories 1 2 Learning is altering the strength pattern of communication between certain populations of neurons whereas Memory is the preservation of the altered pattern of communication 1 3 For example NMDA Receptors are important for initi ating Learning whereas Protein Synthesis is impor tant for preserving the Memory 1 2 Behavior and Memory Memories are the product of behaving organisms inter acting with their environments behavioral experience Memory is a concept that explains why our experi ences at one point in time can influence our behavioral responses at a later point in time No one has EVER directly observed a memory in the brain All experimental investigations of memory require a training phase to establish a memory and a test phase to detect the memory The existence of a memory trace is inferred when the training experience influences behavior Thus test behavior can be thought of as the window to the memory trace Learning and Memory from a Behavioral perspective Learning A change in the capacity for behavior due to particular kinds of experience Memory The change in capacity persists Test Objectives 1 2 Learning And Memory From A Behavioral Perspective 1 4 At the behavioral level Learning and Memory are concepts used to explain why how experi ences at one time point can influence behavior at a later time point 1 5 Learning is a change in the CAPACITY for behavior as a result of certain KINDS of experience 1 6 Memory is when the change in CAPACITY for behavior persists for a period of time 1 7 Behavior is only a window on the neural processes of learning and memory 1 3 The Learning Performance Distinction 1 Learning without change in performance latent learning episodic memory change in CAPACITY for behavior 2 Behavior change from experience that is NOT learning sensory adaptation motor fatigue also motivational changes developmental changes injury due to PARTICULAR KINDS of experience Traditional types of learning that fit the bill Associative two events Pavlovian classical stimulus stimulus Instrumental operant response outcome Non associative one event Habituation and Sensitization Behavior is determined by multiple factors Memory is only ONE factor among many BUT remember not all learning fits so easily into these traditional categories of con ditioning Examples Imprinting Observational social learning Latent learning episodic memory Insight Why is this so important To study memory we can munication Damage a particular region of the brain circuit breaking Inject drugs into the brain that are designed to influence some aspect of neural com Modify the DNA to increase or decrease the production of some protein or molecule Any of these treatments in principle could influence behavior by affecting some component process other than memory Thus this possibility must be ruled out by other experiments con trol groups How do we distinguish Storage failure vs Retrieval failure at the Behavioral level Memories can be disrupted for 2 reasons Storage failure amnesia is permanent Hm Memory traces can differ on at least three dimensions duration state and vulnerability to disruption Retrieval failure amnesia is temporary Extinction Drug Addiction Alzheimer s 1 2 Test Objectives 1 3 Conceptual Issues The Learning Performance Distinction 1 8 In a nutshell There are many factors besides learning than influence behavior 1 9 Whenever an experimental manipulation is used to disrupt or enhance processes of learning and memory we must always be mindful that there are many factors other than learning and memory that can influence behavior 1 10 Moreover when a memory failure is observed how can we distinguish between a stor age failure true amnesia and a retrieval failure extinction 1 4 Dimensions of Memory Traces BEHAVIORAL dimensions of memory traces Dimensions of Memory Traces Memories in the active state are more vulnerable to disruption than memories that have become inactive Memories become resistant to disruption as they age Consolidation By 19th century it was recognized that older memories were more resistant to disrup tion than new memories Ribot s Law People who suffered head injury often cannot remember the events that oc curred just prior to the injury but can remember episodes that occurred earlier How to study this phenomenon Electroconvulsive Shock Therapy 1937 Cerletti and Bini applied electrical current across the brain to treat severe psy chiatric disorder now called electroconvulsive ECS therapy This development came to the experimental study of memory when it was discovered from clinical reports that the patients who received ECS had IM PAIRED SHORT TERM BUT NOT LONG TERM MEMORY Carl Duncan 1949 first person to use ECS to experimentally induce amnesia in ani mals found that when ECS was administered within a minute after training it pro duced amnesia but it DID NOT produce amnesia an hour or so after training As memory aged it became resistant to