take home essay - Jillian Finkelstein Brain and Behavior a...

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Jillian Finkelstein Brain and Behavior a) In order to initially form an addiction to cocaine, psychological dependence occurs from reinforcement. The reward circuit reinforces behavior through dopamenergic neurons that extend from the VTA and the BIA increasing dopamine to the NA. The drug positively reinforces student x’s behavior. Cocaine’s reinforcing euphoric effect makes its users feel powerful which is associated with taking cocaine. He will quickly learn that if he injects cocaine, he will get that appetitive stimulus. The neural basis of this positive reinforcement is the increase in the amount of dopamine in the NA. Cocaine is a potent dopamine agonist; it binds to dopamine transporter proteins and blocks the reuptake of dopamine released from the terminal buttons which prolongs the pleasant effects of the dopamine. If student X becomes physically dependent on cocaine, he will show signs of tolerance, meaning that he gradually must increase the dose of the drug over time in order to achieve the same level of euphoria, and withdrawal symptoms, meaning that if he were to stop taking cocaine he would feel the opposite effects of the drug which are very aversive. However withdrawal symptoms of cocaine are due to sensitization, not tolerance, via the down regulation of presynaptic DA transporters in the NA and striatum and sensitization or dynorphin neurons in the NA that activates more kappa opiate receptors on VTA terminals in NA, which depresses the normal dopamine release there. Student x is negatively reinforced if he takes the cocaine in order to stop the unpleasant withdrawal effects caused from trying to stop taking the drug hence reinstating the addiction. Student X will crave cocaine which is associated with increased activity in the medial prefrontal cortex. Cocaine activates the mesolimbic
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This note was uploaded on 04/09/2008 for the course PSYC 314 taught by Professor Skeen during the Spring '07 term at University of Delaware.

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take home essay - Jillian Finkelstein Brain and Behavior a...

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