Static Oculomotor Reactions, Counter-rolling

Ocular counter-rolling (CR) is induced when the head is tilted from side to side in the coronal plane. The eyes tort or roll to oppose the head movement in an attempt to maintain the original angle of the retina in space. CR against 5º of head and body tilt is barely recognizable, and maximum of about 5-7º of CR is induced by head and body tilts of from 45º to 90º. Thus, CR against head and body tilt is small and does not adequately compensate for the retinal displacement caused by lateral head positions. In both humans and monkeys, CR is the same whether the head is tilted on the neck or the head and body are tilted together. It is also essentially the same whether subjects are in light or in darkness. This indicates that activity, which induces CR, must come mainly from the labyrinths, and cervical, visual, or somato-sensory afferents contribute little to its production.