Stabilization of the gaze in chameleons: visual and vestibular reflexes |
| |
Authors: | M Bennis A Sansonetti H Gioanni |
| |
Institution: | Département de Biologie, Faculté des Sciences, Université Cadi Ayyad, Marrakech, Maroc. |
| |
Abstract: | Some visual, vestibular and proprioceptive reflexes which contribute to gaze (head + eye) stabilization were quantified in the chameleon. All the reflexes were analysed in the horizontal plane, and the visual reflexes were also studied in the vertical plane. In restrained-head animals, both the optokinetic nystagmus (OKN) and the vestibulo-ocular reflex (VOR) had low gains. In free-head animals, the head (opto-collic or vestibulo-collic reflex) and eye (OKN or VOR) responses added their effects, thus improving gaze stabilization, especially during vestibular stimulation. Cervical stimulation provoked both a cervico-ocular reflex (COR) in the compensatory direction and a large number of saccades. The saccadic response was especially marked in the presence of patterned visual surroundings. |
| |
Keywords: | |
|
|