Location of injection sites in the IO injection group (•; n = 8) and in the IN recording group (★; n = 4). A–H, The identified sites in individual animals were transferred to a set of standardized coronal sections of the rabbit medulla, arranged in rostral-to-caudal order. The anterior–posterior distance in millimeters from the rostral pole of the IO is on the lower right side of each section. All injection sites were found within or close to the rostral part of the inferior olivary complex. Injections of NBQX at all marked sites abolished CR expression. Injection site labeled “1” yielded an immediate CR abolition after a 1.0 μl injection of either 150 or 19 μm NBQX. The site labeled 12 was the least effective because CR abolition required 3.5 μl of 150 μm NBQX injected over 35 min. DAO, Dorsal accessory inferior olive; IOM, medial inferior olive; IOPr, principal inferior olive; IOA, subnucleus A of the medial inferior olive; IOB, subnucleus B of the medial inferior olive; IOK, cap of Kooy of the medial inferior olive; Sp5N, spinal trigeminal nucleus; sp5, spinal trigeminal tract; Pr, prepositus hypoglossal nucleus; 7N, facial nucleus; icp, inferior cerebellar peduncle; MVe, medial vestibular nucleus; SolN, solitary nucleus; Amb, ambiguous nucleus; 12n, hypoglossal nerve; 10N, dorsal motor nucleus of the vagus; DCN, dorsal cochlear nucleus.