Copyright © 2004 Allyn and Bacon 1 Chapter 13 Learning and Memory: Basic Mechanisms This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease, or lending of the program.

Copyright © 2004 Allyn and Bacon 2  The Nature of Learning  Learning: The process by which experiences change our nervous system and hence our behaviors.  Perceptual learning: Learning to recognize a particular stimulus.

Copyright © 2004 Allyn and Bacon 3  The Nature of Learning  Classical conditioning: A learning procedure; when a stimulus that initially produces no particular response is followed several times by an unconditioned stimulus that produces a defensive or appetitive response.

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5  The Nature of Learning  Hebb rule: The hypothesis proposed by Donald Hebb that the cellular basis of learning involves strengthening of a synapse that is repeatedly active when the postsynaptic neuron fires.

Copyright © 2004 Allyn and Bacon 6  The Nature of Learning  Instrumental learning: A learning procedure whereby the effects of a particular behavior in a particular situation increase (reinforce) or decrease (punish) the probability of the behavior; also called operant conditioning.

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8  The Nature of Learning  Reinforcing stimulus: An appetitive stimulus that follows a particular behavior and thus makes the behavior become more frequent.  Punishing stimulus: An aversive stimulus that follows a particular behavior and thus makes the behavior become less frequent.  Motor learning: Learning to make a new response.

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10  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Long-term potentiation: A long-term increase in the excitability of a neuron to a particular synaptic input caused by repeated high-frequency activity of that input.

Copyright © 2004 Allyn and Bacon 11  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Hippocampal formation: A forebrain structure of the temporal lobe, constituting an important part of the limbic system; includes the hippocampus proper (Ammon’s horn), dentate gyrus, and subiculum.

Copyright © 2004 Allyn and Bacon 12  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Entorhinal cortex: A region of the limbic cortex that provides the major source of input to the hippocampal formation.  Granule cell: A small, granular cell; those found in the dentate gyrus send axons to the field CA3 of the hippocampus.

Copyright © 2004 Allyn and Bacon 13  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Dentate gyrus: Part of the hippocampal formation; receives inputs from the entorhinal cortex and projects to the CA3 field of the hippocampus.  Perforant path: The system of axons that travel from cells in the entorhinal cortex to the dentate gyrus of the hippocampal formation.

Copyright © 2004 Allyn and Bacon 14  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Field CA3: Part of the hippocampus; receives inputs from the dentate gyrus and projects to field CA3.  Pyramidal cell: A category of large neurons with a pyramidal shape; found in the cerebral cortex and Ammon’s horn of the hippocampal formation.

Copyright © 2004 Allyn and Bacon 15  Learning and Synaptic Plasticity  Induction of Long-Term Potentiation  Field CA1: Part of the hippocampus; receives inputs from field CA3 and projects out of the hippocampal formation via the subiculum.  Population EPSP: An evoked potential that represents the EPSPs of a population of neurons.

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23  Learning and Synaptic Plasticity  Role of NMDA Receptors  Associative long-term potentiation: A long-term potentiation in which concurrent stimulation of weak and strong synapses to a given neuron strengthens the weak one.  NMDA receptor: A specialized ionotropic glutamate receptor that controls a calcium channel that is normally blocked by Mg 2 ions; involved in long-term potentiation.

Copyright © 2004 Allyn and Bacon 24  Learning and Synaptic Plasticity  Role of NMDA Receptors  AP5: 2-Amino-5-phosphonopentanoate; a drug that blocks NMDA receptors.  AMPA receptor: An ionotropic glutamate receptor that controls a sodium channel; when it’s open, it produces EPSPs.

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29  Learning and Synaptic Plasticity  Role of NMDA Receptors  Dendritic spike: An action potential that occurs in the dendrite of some types of pyramidal cells.

Copyright © 2004 Allyn and Bacon 30  Learning and Synaptic Plasticity  Mechanisms of Synaptic Plasticity  CaM-KII: Type II calcium-calmodulin kinase, an enzyme that must be activated by calcium; may play a role in the establishment of long-term potentiation.  Nitric oxide synthase: An enzyme responsible for the production of nitric oxide.

Copyright © 2004 Allyn and Bacon 31  Learning and Synaptic Plasticity  Long-term Depression  Long-term depression: A long-term decrease in the excitability of a neuron to a particular synaptic input caused by stimulation of the terminal button while the postsynaptic membrane is hyperpolarized.

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33  Perceptual Learning  Perceptual Short-term Memory  Short-term memory: Memory for a stimulus that has just been perceived.  Delayed matching-to-sample task: A task that requires the subject to indicate which of several stimuli has just been perceived.  Paired-associate task A task that requires the subject to learn to recognize pairs of stimuli.

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36  Instrumental Conditioning and Motor Learning  Reinforcement Neural Circuits Involved in Reinforcement  Medial forebrain bundle (MFB): A fiber bundle that runs in a rostral-caudal direction through the basal forebrain and lateral hypothalamus; electrical stimulation of these axons is reinforcing.

Copyright © 2004 Allyn and Bacon 37  Instrumental Conditioning and Motor Learning  Reinforcement Neural Circuits Involved in Reinforcement  Ventral tegmental area (VTA): A group of dopaminergic neurons in the ventral midbrain whose axons form the mesolimbic and mesocortical system; plays a critical role in reinforcement.

Copyright © 2004 Allyn and Bacon 38  Instrumental Conditioning and Motor Learning  Reinforcement Neural Circuits Involved in Reinforcement  Nucleus accumbens: A nucleus of the basal forebrain near the septum; receives dopamine-secreting terminal buttons from neurons of the ventral tegmental area and is thought to be involved in reinforcement and attention.

Copyright © 2004 Allyn and Bacon 39  Instrumental Conditioning and Motor Learning  Reinforcement Detecting Reinforcing Stimuli  Conditioned reinforcer: A previously neutral stimulus that has been paired with an appetitive stimulus, which then itself becomes capable of reinforcing a response.

Copyright © 2004 Allyn and Bacon 40  Instrumental Conditioning and Motor Learning  Reinforcement Detecting Reinforcing Stimuli  Conditioned punisher: A previously neutral stimulus that has been followed by an aversive stimulus, which then itself becomes capable of punishing a response.

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