Textbook Notes (362,896)
Canada (158,081)
Psychology (860)
PSY 324 (20)

Week 9 - Learning and Memory

4 Pages
Unlock Document

Ryerson University
PSY 324
Ayesha Khan

Week 9 Learning and MemoryDecember12111244 PMThe Nature of LearningLearning refers to the process by which experiences change our nervous system and hence our behaviour We refer to these changes as memoriesLearning can take at least four basic forms perceptual learning stimulusresponse learning motor learning and relational learningPerceptual learningis the ability to learn to recognize stimuli that have been perceived before The primary function of this type of learning is the ability to identify and categorize objects and situationsPerceptual learning seems to be accomplished primarily by changes in the visual association cortex learning to recognize complex auditory stimuli involves changes in the auditory association cortex etcStimulusresponse learning is the ability to learn to perform a particular behavior when a particular stimulus is present Involves the establishment of connections between circuits involved in perception and those involved in movementThe behaviour could be an automatic response such as a defensive reflex or it could be a complicated series of movementsIncludes two major categories of learning that psychologists have studied extensivelyClassical conditioningis a form of learning in which an unimportant stimulus acquires the properties of an important one It involves an association between two stimuli Example Unconditional response puff of air towards an eye causes it to closeUnconditional stimulus the stimulus that produces the unconditional response puff of airConditional stimulus a tone introduced before the puff of air After several tones and puffs the eye closes before the puff is even administeredConditional response eye blink in response to the toneDonald Hebb proposed a rule that might explain how neurons are changed by experience in a way that would cause changes in behaviour The Hebb rule says that if a synapse repeatedly becomes active at about the same time that the postsynaptic neuron fires changes will take place in the structure or chemistry of the synapse that will strengthen it Instrumental conditioning also called operant conditioning Whereas classical conditioning involves automatic speciestypical responses instrumental conditioning involves behaviours that have been learned and involves an association between a response and a stimulus It permits and organism to adjust its behaviour according to the consequences of that behaviour When a behaviour is followed by favorable consequences the behaviour tends to occur more frequentlyFavourable consequences are referred to as reinforcing stimuli and unfavorable consequences are referred to as punishing stimuliMotor learningis actually a component of stimulusresponse learning It is the establishment of changes within the motor systems of the brain but it cannot occur without sensory guidance from the environmentDiffers from other forms of learning primarily in the degree to which new forms of behaviour are learned the more novel the behaviour the more neural circuits in the motor systems must be modifiedThe three forms of learning described so far consist primarily of changes in one sensory system between one sensory system and the motor system or in the motor system but obviously learning is more complex than that Relational learning involves learning the relationships among individual stimuli Synaptic Plasticity LongTerm Potentiation and LongTerm DepressionInduction of LongTerm PotentiationElectrical stimulation of circuits within the hippocampal formation can lead to longterm synaptic changes that seem to be among those responsible for learningLongterm potentiation is a longterm increase in the excitability of a neuron to a particular synaptic input caused by repeated highfrequency activity of that input AnatomyThe hippocampal formation is a specialized region of the limbic cortex located in the temporal lobeHas a characteristic 3D appearanceMany experiments have demonstrated that longterm potentiation in hippocampal slices can follow the Hebb rule That is when weak and strong synapses to a single neuron are stimulated at approximately the same time the weak synapse becomes strengthened This phenomenon is called associative longterm potentiation because it is produced by the association in time between the activity of the two sets of stimuliRole of NMDA ReceptorsNMDA receptor a specialized ionotropic glutamate receptor that controls a calcium channel that is normally blocked by Mg2 ions involved in longterm potentiationThe entry of calcium ions through the ion channels controlled by NMDA receptors is an essential step in longterm potentiation The drug that blocks NMDA receptors blocks the establishment of LTP These results indicate that the activation of NMDA receptors is necessary for the first step in the process of events that establishes LTP the entry of calcium into dendritic spinesMechanisms of Synaptic PlasticityResearch indicates that strengthening of an individual synapse appears to be accomplished by insertion of additional AMPA receptors into the postsynaptic membrane of the dendritic spine in addition to NMDA AMPA receptors control sodium channels thus when they are activated by glutamate they produce EPSPs in the membrane of the dendritic spine Therefore with more AMPA receptors present the release of glutamate by the terminal button causes a larger excitatory postsynaptic potential In other words the synapse becomes strongerCaMKII is an enzymethat allows the entry of calcium into the dendritic spine It is inactive until a calcium binds to it and activates itIt plays a critical role in LTPTwo other changes that accompany LTP are alteration of synaptic structure and production of newBiological Psychology Page 1
More Less

Related notes for PSY 324

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.