d. The reflexive eye movements were mediated by the superior colliculi , a pair of nuclei in the in the white matter of the mid brain.
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The corpora quadrigemina is part of the midbrain. The name means four bodies , a reference to two pairs of nuclei in the white matter. These nuclei, which display as two pairs of spherical protuberances, are the superior colliculi and the inferior colliculi. They integrate sensory inputs and motor outputs that are related to orientation. The superior colliculi are concerned with visual inputs and control our gaze as we follow objects with our eyes--voluntarily or involuntarily. The other pair , the inferior colliculi, are concerned with auditory stimuli. When, in a startle reflex, one turns one's head in the direction of an unanticipated sound, that response is mediated by the pair of inferior colliculi nuclei.