PSY 215 Lecture 13 Topic: Mechanisms of Learning and Memory Chapter 13, section 13.2 Corrections: No corrections Announcements: Question # 37 was thrown out on the last test because it was confusing the way it was worded. The average of this test was close to the average of exam one. Also, exams are set up in order according to our sections in class. Lecture Notes: OUTLINE: 1 Circuit 3 Types of learning o Non-Associative Habituation Sensitization o Associative Definitions: Learning: A change in behavior based on an experience Memory: The Nervous Systems ability to store and retrieve learned effects of experiences. These are both critical for survival Writtenby:AshleeMottler(ashleemottler@yahoo.com)
How do we study? Animal studies Dysfunction (Unintended results of surgery) Ex. Used in class was H.M. who suffered from Epilepsy and underwent brain surgery. They cut him bilaterally, along medial temporal lobes causing memory loss. Natural Experiments Donald Hebb studies interpret the saying Neurons that wire together, fire together. He says that using the synapses strengthen them. Some synapses can be referred to as Hebbian Synapses. Eric Kandel studied the sea slug what changes occurred with what processes. Aplysia: (The sea slug) The Aplysia has no brain or spinal cord It contains one simple circuit Involves the three types of behavior (Taken from slide in class) Gill- Where the water and oxygen come into the Aplysia Siphon- Where the water is released from With drawl Reflex- If touched (gill or siphon) the Aplysia recoils to protect itself. Non Associative Behaviors: Habituation- A decrease in response to a repeated stimulus. Also known as learned inhibition Reduction of effectiveness of synaptic connections Synaptic depression Long term habituation: This occurs if you habituate everyday for days or weeks; the response will eventually stay low. The key is the longer training period. Writtenby:AshleeMottler(ashleemottler@yahoo.com)
o WHY? It occurs with the changes made in the synapses and neurons. This is hard to do because you need to build new proteins to break down/build up the synapses. Habituation Circuit: (From slide in class) It begins at the Siphon, which is connected to a sensory neuron, which then synapses with a motor neuron, ending with that connection to the gill. When you tough the Siphon or Gill, gently it activates the sensory neuron which then creates a weak EPSP due to less NT s (glutamate) being released. Sensitization: Gentle stimulation creates a decrease in response but while touching the Siphon or Gill, you add a zap to the tail, the response is then increased. * The second added stimulus is called Noxious Stimulus- A harmful or painful stimuli It has the same circuit as Habituation, BUT we added the Facilitating Interneuron (FIN) and the Excitatory Interneuron. The zap to the tail of the Aplysia comes through the Facilitating Interneuron Writtenby:AshleeMottler(ashleemottler@yahoo.com)
The Facilitated Interneuron signals the other neurons, Serotonin is released at the presynaptic receptors, blocking the potassium, which causes more NT s to be released, resulting in a greater effect of the motor neuron Known as the enhanced connection We briefly started to introduce the other type of Learning, known as Associative Learning- This is associating two things together (Stimuli) to change response of a stimuli. Example: Pavlov and his dog He wanted to train his dog to respond to a bell when paired with food. He was interested in the salvation of the dog during this study US- Unconditioned stimulus (Food) UR- Unconditioned response (Saliva) *These are both unlearned, innate behaviors CS- Conditioned stimuli (Bell) CR- Conditioned response (Saliva) Writtenby:AshleeMottler(ashleemottler@yahoo.com)
His study: Pavlov would ring the bell, while presenting food, over and over again. Eventually the idea is that he conditioned the dog to salivate without the food but just due to the ringing of the bell. As we were leaving off, we said that the Aplysia with drawl reflex can be classically conditioned. (Taken from www.ivanpavlov.com) For more information: Visit www.ivanpavlov.com for a history of Ivan Pavlov and more information on how he conducted the study with his dogs. Visit www.sumanasinc.com/webcontent/.../sensitization.html to view a video slide show of the changing process in Aplysia Sensitization. Writtenby:AshleeMottler(ashleemottler@yahoo.com)
Real Life Examples: Scientist today say that learning new things and stimulating the brain is what keeps the changes occurring. Learning new things strengthens areas of the brain, like synapses and neurons. They basically say use it or lose it, generally speaking interpreting that our memories should be stimulated with new experiences and learning, even into older age. (www.fi.edu/learn/brain/exercise.html) Writtenby:AshleeMottler(ashleemottler@yahoo.com)