Fig. 7.

Computational lesions These plots demonstrate the consequences of simulated lesions. The first is a lesion of all the connections between the brainstem and the extraocular muscles of the left eye. As both the plots and the simulated eyes show, this causes a paralysis of the left eye, in keeping with what we would expect. On the right, we show the consequences of a lesion to the medial longitudinal fasciculus. The images and the plot of ‘action’ show that rightward gaze occurs normally in both eyes, but that leftward gaze reveals a deficit. The right eye fails to adduct to the same degree as the left abducts, and this induces nystagmus in both eyes – primarily the left. This is known clinically as an internuclear ophthalmoplegia. Please see refer to Fig. 4 for an explanation of these plots.