Abstract
Changes in head movements and the behaviours of various neck muscles which were caused by unilateral vestibular stimuli were studied electro-nystagmoraphycally in rabbits. the results obtained are as follows: I) When the head is deviated on the side of a non-stimulated ear, there immediately develops an increase in the tone of the perivertebral neck muscles of the same side. in head nystagmus the bilateral superficial anterior neck muscles which operated alternately head movements are inhibited on each side play the most important role. 2) the vestibular head movements are inhibited in consequence of a marked increase of tonus in the superficial nape muscles of the stimulated side under the control of the cerebellum.