A guinea pig study has found that newborn guinea pigs subjected to moderate vitamin C deficiency had 30% fewer hippocampal neurons and markedly worse spatial memory than guinea pigs given a normal diet. For several reasons the neonatal brain is thought to be particularly vulnerable to even a slight lowering of the vitamin C level. Vitamin C deficiency is very common in some parts of the world, and even in wealthy nations occurs in an estimated 5-10% of the adult population.
(2009). Vitamin C deficiency in early postnatal life impairs spatial memory and reduces the number of hippocampal neurons in guinea pigs.
Am J Clin Nutr. 90(3), 540 - 546.