Optic nerve, tectal lobe, and midbrain tract lesions do not simply disturb spatial representation signals. These lesions also affect movement characteristics.

Optic nerve lesions change two-dimensional displacement and rotation at some spatial locations, while leaving response accuracy unaffected.

Tectal lobe lesions also change two-dimensional displacement and rotation, with the additional effect of attenuating turn amplitudes within the damaged visual hemifield.

Descending midbrain tract lesions alter the characteristics of movement variability in frontal responses. Responses achieving a given turn amplitude following this lesion look different than responses of similar amplitude prior to the lesion.