Activity-dependent developmental plasticity of gaze-stabilizing reflexes
Gaze-stabilizing eye movements during head/body motion derive from sensory-motor transformations and locomotor efference copies. The neuronal circuitries underlying these reflexive motor reactions are formed during embryogenesis and are functionally tuned after birth/hatching. Using Xenopus laevis, we investigate rules and requirements for the ontogenetic establishment of the respective brainstem and cerebellar circuits. The hypothesis is that the orthogonal arrangement of semicircular canals and locomotor efference copies form intrinsic reference frames that are used to align other motion-activated sensory inputs. Manipulation of semicircular canal formation or removal and re-transplantation of inner ears during embryogenesis will reveal the role of activity-dependent sorting of spatio-temporally adequate connections through Hebbian plasticity.