VESTIBULAR COMPENSATION IN THE LAMPREY

VESTIBULAR compensation, i.e. recovery after unilateral labyrinthectom y (UL) in the lamprey (a lower vertebrate, Cyclostome), as well as dif ferent means of promoting the compensation, is described. UL results i n a loss of equilibrium and rotation during swimming which is compensa ted in about 60 days. The deficit can, however, be immediately abolish ed by applying asymmetrical tonic visual or vestibular input (electric al stimulation of the optic or vestibular nerve, illumination of one e ye, removal of one eye). In addition, asymmetrical visual input promot es plastic changes underlying the vestibular compensation. The compens ation is discussed in relation to the neuronal network responsible for postural control in the lamprey and identified in our previous studie s.