Diagram of the experimental design for chronic and acute recordings (Rec). The abducens nucleus (ABD) contains motoneurons (Mn) that innervate the lateral rectus muscle (LR) and internuclear neurons (Int) whose axons contact the contralateral medial rectus muscle (MR) innervating motoneurons of the oculomotor nucleus (OCM). Bipolar stimulating electrodes were implanted in the VIth nerve (St.1) and in the medial longitudinal fascicle (MLF; St.2); in some experiments, additional stimulation electrodes were implanted in the semicircular canals (St.3 and St.4). Inputs to ABD are illustrated: EBN and IBN, reticular excitatory and inhibitory burst neurons, respectively; PHN, prepositus hypoglossi nucleus; MVN, medial vestibular nucleus. The subscripts i and c indicate ipsilateral and contralateral, respectively, to the recorded ABD. Modified from [36].