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The opticogravic nerve: eye-level anatomic relationships within the central nervous system
1Air Surgeon, National Guard Bureau, Andrews AFB.
Aviation, Space, and Environmental Medicine
|October 1, 1993
Summary
Understanding acceleration stress requires examining the eye's role in detecting gravitational forces. This research proposes redefining the optic nerve as the "opticogravic" nerve due to its dual sensory functions.
Area of Science:
- Neuroscience
- Aerospace Medicine
- Physiology
Background:
- Central nervous system (CNS) vascular-neurologic relationships are key to understanding acceleration (+Gz) stress.
- The eye is vulnerable to compromised retinal perfusion during +Gz stress, often preceding +Gz-induced loss of consciousness (G-LOC).
Purpose of the Study:
- To investigate the neuroanatomic relationships at eye-level crucial for comprehending G-LOC.
- To identify specific CNS structures affected by ischemia that precipitate G-LOC.
Main Methods:
- Review of neuroanatomic and physiological principles related to acceleration stress.
- Theoretical consideration of the eye's sensory role in detecting gravitational forces.
Main Results:
- Cerebral perfusion is pressure-equalized by cerebrospinal fluid, protecting the brain and brainstem but not the eye.
- Compromised retinal perfusion leads to decreased visual function, a precursor to G-LOC.
Conclusions:
- The exact CNS locations causing G-LOC remain unknown.
- The eye functions as a dual sensor for vision and acceleration stress.
- Proposes redefining the second cranial nerve as the "opticogravic" nerve to reflect its expanded sensory role.