PSY 315 Lecture 13 (3/7/2011) (Learning & Memory Mechanics) Dr. Achtman PSY 215

Transcription

1 PSY 215 Lecture 13 Topic: Learning & Memory- Mechanics Chapter 13.2, pages Announcements: Question #37 was removed from Exam 2 and all students will receive an additional point. Average grade on Exam 2 was 37/49, highest grade was 47/49 Lecture Notes: Definitions: Learning: A change in behavior based on experience. *Experience can be something you read, were told, did, etc.* Memory: The nervous systems ability to store and retrieve the learned facts of experience. Both of these are essential for survival because it allows you to learn from past mistakes. How is memory studied? Animal studies Dysfunction: Usually the unintended results of surgery. - For example the case of HM. Parts of HM s brain were removed bilaterally from the medial temporal lobes, resulting in major memory loss. Natural exceptions: Disease and aging. Donald Hebb (1950): Neurons that fire together, wire together. Meaning each time an action potential comes down the axon to the pre-synaptic terminal to the post synaptic terminal, that connection becomes stronger. Eric Kendel (1960): Won the 2000 Nobel Prize. Did substantial research on Aplysia. Aplysia: A marine invertebrate related to the common slug. While they do not have a brain or a spinal cord their neuron chemistry, principles of an action potential, and neurotransmitters are the same. Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 1 of 7

2 Three types of learning: Nonassociative: Single stimulus that changes things Habituation: A decrease in response to stimulus that is presented repeatedly without resulting in any changes in other stimuli. Sensitization: An increase in response to mild stimuli as a result of exposure to more intense stimuli. Associative Learning: Associating two stimuli together, changing the response to one of the stimuli. Classical conditioning. Examples: - If something horrible happened every time someone said boo you would freak out whenever you hear the word boo. - Pavlov s Dog: US, UR, CS, CR. The U stands for unconditioned, the S stands for Stimuli, the R stands for Repsonse and the C stands for conditioned US = Food, UR = Drool, CS = Bell, CR = Drool *Picture taken from slide* Aplysia have a withdrawal reflex. If you touch a siphon or gill it will retract to protect itself. If you repeatedly touch the siphon the apylsia will decrease its response over time and eventually not withdraw, this is an example of habituation. Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 2 of 7

3 slide* *Take from (a) is an example of habituation. Notice that the response (on the left of the graft) decreases the larger the stimulus number (bottom) gets. (b) is an example of sensitization. A sudden electrical shock is given to the tail of the apylsia (this is a noxious stimulus), this puts the apylsia on alert and so the next time it receives even just a light touch it will provide a greater response. This is example of Sensitizaion is charted above in example (b). Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 3 of 7

4 *Taken from slide* The above is a picture of the circuit in apylsia: 1) Siphon is touched 2) Sends signal to sensory neuron 3) Talks to motor neuron 4) Gill retracts If the siphon is repeatedly touched the sensory neuron is still sends signal but less neurotransmitters are released so the response decreases. This is Learned inhibition: Reduced effectiveness in synaptic connections. *This is sometimes called synaptic depression* typically only lasts a short time. If you want to achieve long term habituation then the training period needs to be as long as the term of inhibition. In order to make those synapse changes, breaking down the actual synapse, you need protein. During sensitization facilitating inter neurons release serotonin at pre-synaptic receptors, which blocks k+ and prolongs the release of neurotransmitters. Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 4 of 7

5 Summary: Simple circuit: o Habituations (depressed connections) o Sensitization (enhanced connections) They are short term but CAN be long term. Requires proteins in order to break down or build new synapses. Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 5 of 7

6 Associative learning: The pairing of two stimuli. This changes the response to one of the stimuli. An example s classical conditioning (Pavlov s dog). The aplysia s withdrawal reflex can be classical conditioned. For more information: This website contains a simply article which reviews the types of learning and how it is important in development: To check your basic understanding of habituation and sensitization take this simple quiz Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 6 of 7

7 Real-life example: The ability to learn, to gain from experience, allows one to adapt to and cope with variable environments. This is from the above website, and reminds us how crucial and yet unappreciated the simple ability to learn from small events so you don t make the same mistake twice. Such as The last time I sped down French Rd, the policeman that hides there pulled me over. Now when I turn onto French I will remember to observe the speed limit. Also, habituation has allowed me to save stress and nerves every night I leave work. The first few days the chefs would jump out at me as I walked to my car after closing my bar and COMPLETELY scared the daylights out of me. However, after repeating this on a weekly basis, it no longer fazes me. Written by:{jessica Jarvis}, {JJarvis0@naz.edu} Page 7 of 7