Vestibular system

The vestibular system is the sensory system that helps control movement and balance.  It uses information received from the cochlea in the inner ear.  The coclea has a semicircular canal system that provides input on rotational movements.  As you go round and round, movement of fluid within the horizontal semicircular canal corresponds to rotation of the head around a vertical axis (i.e. the neck).

The vestibulo-ocular reflex (VOR) is a reflex eye movement that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field. For example, when the head moves to the right, the eyes move to the left, and vice versa. Since slight head movements are present all the time, the VOR is very important for stabilizing vision: patients whose VOR is impaired find it difficult to read, because they cannot stabilize the eyes during small head tremors. The VOR reflex does not depend on visual input and works even in total darkness or when the eyes are closed.

Damage to this system mean that nystagmus results -  involuntary but small eye movements – that fool the reasoning system into thinking the person is asleep – it thinks it is receiving REM messages.

The start of the REM cycle occurs in the reticular formation and the signals from this organ then spread via both electrical and neurotransmitter release to the rest of the brain in order to induce a state of the body and the brain which is conducive to dreaming.  The rapid eye movements that do occur during this stage are thus a consequence of the process started in the reticular formation. 

In effect, nystagmus mimics the frequency of REM sleep, and the signal is reversed  travels to the reticular formation and the person then hallucinates or has a vision.  Once having reached the reticular formation, this organ then starts the process associated with ‘waking dreaming’ and atonia can result, which is why there may be the symptoms of epilepsy.