Learning and vision needs DHA

    F2 generation male rats consuming the n 3 deficient diet had only 18% of the DHA in rats consuming the n 3 adequate diet. The n 3 deficient animals made significantly more total errors in a 7 problem, 2 odor discrimination task and had longer escape latency in the Morris water maze task compared to the n 3 adequate group. (see also membrane biophysics). Rats with low levels of brain docosahexaenoic acid show impaired performance in olfactory based and spatial learning tasks. Greiner RS; Moriguchi T; Hutton A; Slotnick BM; Salem NLIPIDS 1999; 34: S239 S243.

    The a and b wave implicit times of electroretinograms of 8 wk old cats showed that animals raised in litters for which maternal diets lacked 20:4n 6 and 22:6n 3 had increased a and b wave implicit times compared with those of controls. Also, the rod outer segments and brains had lower amounts of 22:6n 3 and higher amounts of long chain n 6 polyunsaturated fatty acids compared with control animals. Maintenance of 22:6n 3 status in the nervous system seems important for optimal retinal function. Only the diets containing 22:6n 3 supported a high accumulation of docosahexaenoic acid in these tissues. Retinal and brain accretion of long chain polyunsaturated fatty acids in developing felines: The effects of corn oil based maternal diets. Pawlosky RJ; Denkins Y; Ward G; Salem N.Am J Clin Nutr 1997; 65: 465 472.

Despite a 76% lower brain DHA, n-3-deficient rats were able to acquire most simple 2-odor discrimination tasks, but were deficient in the acquisition of a 20-problem olfactory learning set. This deficit could not be attributed to changes in sensory capacity but, instead, appeared to represent a deficit in higher order learning. Catalan J, Moriguchi T, Slotnick B, Murthy M, Greiner RS, Salem N Jr. Cognitive deficits in docosahexaenoic acid-deficient rats. Behav Neurosci 2002 Dec;116(6):1022-31.

Plasma docosahexaenoic acid (DHA) and arachidonic acid (AA) were significantly higher (P < 0.001) in (DHA+AA)-supplemented monkeys compared with the control monkeys eating 2% linolenate as sole n-3 nutrient. Diet-supplemented monkeys had significantly shorter b-wave implicit times at low retinal illuminances (<-0.6 log scot td-sec). There were no significant effects of diet for visual acuity or 23 other ERG parameters measured. Apparently, supplementation with 1.0% DHA and 1.0% AA neither harms nor provides substantial benefit to the development of visual acuity or retinal function in the first four postnatal months. Jeffre BG, Mitchell DC, Hibbeln JR, Gibson RA, Chedester AL, Salem N Jr.Visual acuity and retinal function in infant monkeys fed long-chain PUFA.Lipids 2002 Sep;37(9):839-48.