Visuomotor coordination in behaviour of pigeons following post-hatching monocular experience: An image analysis study

We investigated the role of visual binocular inputs during the development on visuo-motor coordination in conditioned key-pecking responses to differently sized spots. Five groups of pigeons were used: monocular control group; two early groups (retinal ablated -ERA-, and eyeball enucleated -EEE) operated in two days post-hatching; two late groups (adult pigeons, retinal ablated LRA-, and eyeball enucleated -LEE). The most substantial results occurred in early groups: the impairment of visual performance at small size spot, the loss of bill gape/spot size coordination and the permanent inaccurate reaching trajectory, particularly in the EEE group. On the contrary, late groups did not show any significant difference compared with the control group. The present data indicate that binocular interactions are crucial during the development of the visual system and, in addition, prove the differential role played by retinal and extraretinal inputs on the development of the visuomotor coordination. Once the maturation stage is accomplished (late groups) the eyes can work independently one from the other in conditioned key-pecking responses.