These two neurotransmitters have broadly distributed effects; they are found throughout the brain. Glutamate is the main excitatory neurotransmitter in the brain; it activates the nervous system and appears to be involved in learning and memory. New research suggests it is also involved with schizophrenia. In contrast, GABA is an inhibitory neurotransmitter; it calms the nervous system. GABA neurotransmitters are targeted by the benzodiazepines, antianxiety medications that also act as tranquilizers. Examples of benzodiazepines include clonazepam (Klonopin), lorazepam (Ativan), diazepam (Valium), and alprazolam (Xanax). Because of their enjoyably relaxing effect (as well as their addictive potential), these GABA-ergic medications are sometimes used as drugs of abuse.