tokens: ( RS ) - 1 - aminoindan - 1 , 5 - dicarboxylic acid ( AIDA ; 0 . 5 - 15 microg / 0 . 5 microl ) , a potent and selective mGluR1 antagonist , or ( 2R , 4R ) - 4 - aminopyrrolidine - 2 , 4 - dicarboxylate ( 2R , 4R - APDC ; 7 . 5 - 15 microg / 0 . 5 microl ) , a selective group II agonist , was injected bilaterally into the striatum of haloperidol - treated animals .