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Designer Drugs and the Brain15Other drugs, like GHB and Rohypnol®, can interact directlywith the neurotransmitter receptors to either enhance or blockthe effects of the brain’s own neurotransmitters. Still otherdrugs can alter the metabolic breakdown or clearance ofcertain neurotransmitters after they are released from thesynaptic terminal, thereby altering how long the neurotransmitteraffects the activity of other nearby neurons.The brain has numerous regions that are specialized for particularfunctions (see Table 1.1, Figure 1.3a, and Figure 1.3b). Theeffect a particular drug has on a person’s thinking or behaviormay depend on which region it is acting upon.Table 1.1 Brain Regions and FunctionsREGIONFrontal cortexMotor cortexSensory cortexVisual cortexCerebellumBrainstemHypothalamusLimbic system*FUNCTIONInvolved in planning, thinking, anddecision-makingControls movement of the face,arms, and legsInvolved in perception of touchProcesses sight and visionControls motor coordination, balanceControls basic bodily functions likechewing, swallowing, heart rate, andbreathingControls metabolism, sleep, eating,and drinkingControls emotions, memory, andmotivation*Note: The limbic system is made up of several brain structures,including the hippocampus, amygdala, and basal forebrain(Figure 1.3b).