This shows the types of errors made by an adult prior to and after bilateral
ophthalmic sections. The errors increase after the surgery, but notice
that the immediate effect is to produce a small increase in grasping errors.
In these cases, the bird made contact with the seed but could not hold
it in its beak. Subsequently grasp errors decline but spatial targeting
errors increase in which the bird pecked but either missed the seed or
knocked it away. The bird frequently misses the seed toward which
its peck is directed. This demonstrates that the trigeminal
input plays the important role of giving feedback about the success versus
failure of the spatial aspects of the peck. When that feedback
is attenuated or perhaps eliminated, the targeting becomes more variable.
Thus far, our sham controls do not show decreased efficiency of eating,
indicating a specific effect of deafferentation. |