***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: CONTEXT Cannabis sativa use can impair verbal learning , provoke acute psychosis , and increase the risk of schizophrenia . It is unclear where C. sativa acts in the human brain to modulate verbal learning and to induce psychotic symptoms . OBJECTIVES To investigate the effects of 2 main psychoactive constituents of C. sativa , Delta9-tetrahydrocannabinol ( Delta9-THC ) and cannabidiol , on regional brain function during verbal paired associate learning . DESIGN Subjects were studied on 3 separate occasions using a block design functional magnetic resonance imaging paradigm while performing a verbal paired associate learning task . Each imaging session was preceded by the ingestion of Delta9-THC ( 10 mg ) , cannabidiol ( 600 mg ) , or placebo in a double-blind , r and omized , placebo-controlled , repeated- measures , within-subject design . SETTING University research center . PARTICIPANTS Fifteen healthy , native English-speaking , right-h and ed men of white race/ethnicity who had used C. sativa 15 times or less and had minimal exposure to other illicit drugs in their lifetime . MAIN OUTCOME MEASURES Regional brain activation ( blood oxygen level-dependent response ) , performance in a verbal learning task , and objective and subjective ratings of psychotic symptoms , anxiety , intoxication , and sedation . RESULTS Delta9-Tetrahydrocannabinol increased psychotic symptoms and levels of anxiety , intoxication , and sedation , whereas no significant effect was noted on these parameters following administration of cannabidiol .  Performance in the verbal learning task was not significantly modulated by either drug . Administration of Delta9-THC augmented activation in the parahippocampal gyrus during blocks 2 and 3 such that the normal linear decrement in activation across repeated encoding blocks was no longer evident . Delta9-Tetrahydrocannabinol also attenuated the normal time-dependent change in ventrostriatal activation during retrieval of word pairs , which was directly correlated with concurrently induced psychotic symptoms . In contrast , administration of cannabidiol had no such effect . CONCLUSION The modulation of mediotemporal and ventrostriatal function by Delta9-THC may underlie the effects of C. sativa on verbal learning and psychotic symptoms , respectively 
    Output:
    
Limited research carried out in humans tends to support the evidence that chronic cannabis use reduces levels of glutamate-derived metabolites in both cortical and subcortical brain areas .
Research in animals tends to consistently suggest that Δ9-THC depresses glutamate synaptic transmission via CB1 receptor activation , affecting glutamate release , inhibiting receptors and transporters function , reducing enzyme activity , and disrupting glutamate synaptic plasticity after prolonged exposure