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The term gaze is frequently used in physiology to describe coordinated motion of the eyes and neck. The lateral gaze is controlled by the paramedian pontine reticular formation (PPRF). [1] The vertical gaze is controlled by the rostral interstitial nucleus of medial longitudinal fasciculus and the interstitial nucleus of Cajal. [2]
The approximate field of view of an individual human eye (measured from the fixation point, i.e., the point at which one's gaze is directed) varies by facial anatomy, but is typically 30° superior (up, limited by the brow), 45° nasal (limited by the nose), 70° inferior (down), and 100° temporal (towards the temple).
Anatomical "lines", or "reference lines," are theoretical lines drawn through anatomical structures and are used to describe anatomical location. The following reference lines are identified in Terminologia Anatomica: Anterior median line; Lateral sternal line: A vertical line corresponding to the lateral margin of the sternum.
The nucleus prepositus integrates velocity-position information for horizontal eye movements to enable eccentric gaze. [6] Tonic neurons of the nucleus (along with those of with the medial vestibular nucleus) are believed to maintain eccentric (i.e. off resting position) direction of gaze, counteracting forces pulling the eye back to its default, resting, straight-forward gazing position after ...
Humans have semicircular canals, neck muscle "stretch" receptors, and the utricle (gravity organ). Though the semicircular canals cause most of the reflexes which are responsive to acceleration, the maintaining of balance is mediated by the stretch of neck muscles and the pull of gravity on the utricle (otolith organ) of the inner ear. [2]
The vestibulocerebellum receives vestibulocerebellar fibers from the vestibular nuclei, then projects back to the vestibular nuclei to influence medial vestibulospinal tract (MVST). The MVST then projects bilaterally to cervical and upper thoracic levels of the spinal cord to control head/neck movements in order to coordinate head-eye movements.
Gaze-stabilising movement may include the vestibulo-ocular reflex and optokinetic reflex, and gaze-shifting mechanisms as saccades and pursuit movements. Vergence movement or convergence is the movement of both eyes to make sure that the image of the object being looked at falls on the corresponding spot on both retinas.
A conjugate eye movement is a movement of both eyes in the same direction to maintain binocular gaze (also referred to as “yoked” eye movement). This is in contrast to vergence eye movement, where binocular gaze is maintained by moving eyes in opposite directions, such as going “cross eyed” to view an object moving towards the face.