Nerve cells in the eye require vitamin C in order to function properly -- a surprising discovery that may suggest that vitamin C is required elsewhere in the brain for its proper functioning. Henrique von Gersdorff, from Oregon Health & Science University (Oregon, USA), and colleagues report that the brain has special receptors, called GABA-type receptors, that help modulate the rapid communication between cells in the brain. GABA receptors in the brain act as an inhibitory "brake" on excitatory neurons in the brain. The researchers found that these GABA-type receptors in the retinal cells stopped functioning properly when vitamin C was removed.  Because retinal cells are a kind of very accessible brain cell, the team suggests that GABA receptors elsewhere in the brain also require vitamin C to function properly; as well, because vitamin C is a major natural antioxidant, it may be that it essentially 'preserves' the receptors and cells from premature breakdown.