An example of<unk>  over a photograph over the span of just two seconds.<unk>  includes the voluntary or involuntary<unk>  of the<unk> s, helping in acquiring, fixating and tracking visual stimuli. A special type of<unk> , rapid<unk> , occurs during REM sleep. The<unk> s are the visual organs of the human body, and move using a system of six muscles. The retina, a specialised type of tissue containing photoreceptors, senses light. These specialised cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as vision in the visual cortex. Primates and many other vertebrates use three types of voluntary<unk>  to track objects of interest: smooth pursuit, vergence shifts and saccades. These types of<unk> s appear to be initiated by a small cortical region in the brain's frontal lobe. This is corroborated by removal of the frontal lobe. In this case, the reflexes (such as reflex shifting the<unk> s to a moving light) are intact, though the voluntary control is obliterated.
Eye movement
Color vision
Visual perception
Sense of smell
Acoustic reflex
Vision
Visual field
Thermoregulation