PSY 250 Lecture Notes - Lecture 17: Tegmentum, Heritability, Nucleus Accumbens
Garrett: Brain & Behavior, 3e
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Chapter(5:(Drugs,(Addiction,(and(Reward(
Chapter(Outline(and(Key(Terms(
!
Psychoactive(Drugs(1.
a. A!drug!is!a!substance!that!on!entering!the!body!changes!the!body!or!its!functioning!
i. An!agonist(mimics!or!enhances!the!effect!of!a!neurotransmitter!!
ii. An!antagonist!reduces!the!effects!of!a!neurotransmitter!
b. Psychoactive(drugs!have!psychological!effects!
i. Addiction!is!defined!as!a!preoccupation!with!obtaining!a!drug,!compulsive!use!of!the!
drug,!and!a!high!tendency!to!relapse!after!quitting!!
ii. Withdrawal!is!a!negative!reaction!that!occurs!when!drug!use!is!stopped,!typically!
the!opposite!of!the!drug’s!effects!
iii. Tolerance!occurs!when!increasing!amounts!of!a!drug!are!needed!to!produce!the!
same!effects!as!before!
(1) Most!is!due!to!a!reduction!in!receptors!or!their!sensitivity!
(2) Tolerance!may!occur!to!some!effects!of!a!drug!and!not!others!
c. Opiates!are!drugs!derived!from!the!opium!poppy!flower.!Opiates!may!produce!
analgesia!(pain!relief),!euphoria,!or!a!hypnotic!(sleep!inducing)!effect!
i. Types!include!opium,!morphine,!heroin!and!codeine!
ii. Crosses!the!bloodDbrain!barrier!easily!
iii. Binds!to!endogenous(opioid!or!endorphin!receptors!in!the!brain!
d. Depressants!are!drugs!that!reduce!central!nervous!system!activity!
i. Effects!include!sedative!(calming),!anxiolytic!(anxietyDreducing),!and!hypnotic!
ii. Alcohol!acts!at!several!brain!sites!to!inhibit!glutamate!release!and!increase!GABA!
release,!reducing!brain!activity!
(1) Stimulant!at!low!levels,!depressant!at!high!levels!
(2) Withdrawal!can!involve!several!disturbances,!including!delirium(tremens!
(hallucinations,!delusions,!etc.)!
(3) Fetal(Alcohol(Syndrome!(FAS)!
(a) Alcohol!passes!easily!into!a!fetus!from!a!mother’s!bloodstream!
(b) No!safe!level!has!been!established!for!alcohol!intake!during!pregnancy!
(c) FAS!is!the!leading!cause!of!intellectual!disability!in!the!western!world!
iii. Barbiturates!and!Benzodiazepines!reduce!anxiety!
(1) Barbiturates!act!on!higher!cortical!centers!that!inhibit!behavior;!they:!
(a) Increase!talkativeness!and!social!interaction,!reduce!anxiety!and!act!as!
hypnotics!in!high!doses!
(b) Inhibit!glutamate!activity,!and!enhance!activity!at!the!GABAA!receptor!
complex,!like!alcohol,!but!via!a!different!receptor!
(c) are!addictive!in!large!doses!and!potentially!fatal,!especially!when!mixed!with!
alcohol!
(2) Benzodiazepines!have!effects!similar!to!those!of!barbiturates!but!are!safer.!They!
(a) act!through!GABAA!receptors!to!suppress!activity!in!the!limbic!system!
without!increasing!chloride!influx;!
