Chapter 9: The Biology of Learning and Memory

Basic History of Learning & Memory  There are 3 people I want you to know: 1. Pavolv 2. Skinner 3. Lashley

Pavlov & the Mutts 1. He was originally interested in the physiology of digestion  Started noticing that animals experienced ‘psychic salivation’ 2. From this observation came his most famous contribution to science: classical conditioning

Conditioning Simplified  The unconditioned stimulus (UCS) is the thing that evokes the unconditioned response (UCR)  UCS = food  UCR = is the natural response the animal has to the food = drooling  Pairing the conditioned stimulus (CS) and the drooling (UCR)  CS = tone  Tone + drooling  The change of the UCR to the conditioned response(CR) = animal drools in response to the tone

Skinner: Reinforcement & Punishment 1. Have you run across his name before? 2. He believed learning occurred as a result of an organism receiving reinforcing or punishing stimuli  Positive reinforcement  Negative reinforcement  Punishment

Lashley: Brilliant Failure 1. Search for the ENGRAM. 2. Focused on the cortex

How many types of memory are there?  It depends on how you are thinking about memory. 1. Short vs. Long term memory 2. Declarative vs. Procedural memory 3. Implicit vs. Explicit memory

Short and Long Term Memory 1. Short-term is used for information that has just occurred 2. Long-term is used to retain information over longer periods of time 3. Rehearsal

Modification: Working memory 1. Short-term memory was once thought as a holding pen for information 2. This is really memory that requires attention or ‘work’ 3. Delayed response

Declarative & Procedural memory 1. Declarative memory is the ability to use words to demonstrate a memory 2. Procedural memory is ‘physical skill’ memory

Implicit vs. Explicit memory 1. Explicit memory is memory that you KNOW you have and can recall whenever you want 2. Implicit memory is when information influences your behavior, with out you being aware of it.

Brain Areas Important for L & M 1. Remember Lashley’s failed search for the engram?  Cerebellum  But cortex IS important 2. The other big ‘name’ in L & M is the hippocampus.

Hippocampus and Memory  What types of memory is the hippocampus involved in?  We’re not entirely sure, but research shows: 1. Declarative memory 2. Spatial memory 3. Configural learning

Learning & Slugs 1. Cellular mechanisms of learning are studied using animals with simple nervous systems 2. Aplysia Slugs  Their nervous systems are all the same  Easy to observe learning in reflexive action

Habituation and Sensitization 1. What do you think these are?  Habituation  Sensitization is the opposite… 2. In Aplysia, you can see habituation to a touch stimulus

What about us? 1. In humans we call lasting changes in the synapse long-term potentiation (LTP)  Activity burst & senstitization

Properties of LTP 1. Specificity 2. Cooperativity 3. Associativty

Neurotransmitters & LTP 1. LTP is dependent upon activity at glutamate receptors 2. There are two kinds of receptors that are important:  AMPA  NMDA

How does LTP relate to YOUR Experience? 1. We know that drugs that block LTP prevent learning and delay or prevent the consolidation process

Learning Disabilities  There are 4 general types of learning disabilities  What are some learning disabilities that you guys know about?

Amnesia 1. Amnesia – means memory loss. There are two kinds:  Retrograde amnesia  Anterograde amnesia 2. Damage to the hippocampus can result in both kinds of amnesia

The case of H.M. 1. H.M. was a patient suffering from severe epilepsy 2. His hippocampus was removed as treatment 3. His memory was severely impaired, especially bad anterograde amnesia 4. His short-term/working memory & procedural/implicit memory abilities are somewhat intact

What H.M.’s Brain Looked Like

Korsakoff’s Syndrome 1. This syndrome results from prolonged and severe thiamine (vitamin B 1 ) deficiency  Usually the result of severe alcoholism  Causes brain damage in the hypothalamus and thalamus  can’t get into and out of the prefrontal cortex 2. Results in both kinds of amnesia, apathy, confusion 3. Confabulation is a hallmark symptom

Brain Damage from Alcoholism

Alzheimer’s Disease 1. Progressive memory loss with eventual depression, hallucinations/delusions, sleeplessness and loss of appetite 2. Caused by generation of plaques and tangles in the brain  Plaques are build up between cells caused by cell death  Tangles are caused by degradation of structures within a cell

Alzheimer’s Brains

Brain Damage or Toxicity 1. Head trauma can cause mild or severe, temporary or permanent memory loss 2. Cell death can be caused by exposure to chemicals as well  Carbon monoxide poisoning