Visual pathways. Computer model of the visual pathways from the eyes (lower centre) to the brain (not seen). Nerve impulses from the eye pass down the optic nerves (yellow), which cross at the chiasma, to the lateral geniculate bodies (red) and medial geniculate bodies (blue) of the thalamus. Some of the nerve fibres link to the superior colliculi (orange) and inferior colliculi (yellow), which are mainly involved in initiating visual reflexes. The rest of the impulse is relayed on to the visual cortex of the brain along other nerve fibres (green and red, upper left). This model was produced at the Laboratory of Neuro Imaging (LONI), UCLA, USA.