title: A role for the macular carotenoids in visual motor response.
abstract: OBJECTIVE
  Lutein (L), zeaxanthin (Z), and meso-zeaxanthin are the dominant carotenoids within the central retina (there, termed macular pigment, MP). L is also the dominant carotenoid in the brain. The presence of L and Z in both motor and visual areas of the central nervous system is consistent with a role of these carotenoids in visual-motor behavior. The purpose of this study was to provide a first test of this hypothesis.
  
  
  METHODS
  Balance ability (measured via the Standing Leg Test) and simple reaction time (measured via a stimulus appearing in one of four quadrants of a computer monitor) were measured in 49 subjects (mean age = 54.8 years). Fixed and variable reaction time, and coincidence anticipation ability (estimating the arrival of the stimulus at a target location moving at four velocities) were assessed in 106 younger subjects (mean age = 23 years) using a customized device. MP optical density was measured in all subjects via customized heterochromatic flicker photometry.
  
  
  RESULTS
  MP optical density was significantly (P < 0.05) related to reaction time and to balance ability for the older subjects. Even for the younger group, MP optical density was significantly (P < 0.05) related to fixed and variable position reaction time, as well as coincidence anticipation errors, at high speed.
  
  
  CONCLUSIONS
  L and Z status has been linked to benefits in cognitive function in past research. The present results, and the selective presence of L and Z in visual and motor areas in the brain, are consistent with these carotenoids having a role in visual and motor integration.
authors.affiliation: University of Georgia, Athens, GA 30602-3013, USA; Abbott Nutrition, Columbus, OH, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Renzi
authors.forename: Emily R
authors.initials: ER
authors.lastname: Bovier
authors.forename: Billy R
authors.initials: BR
authors.lastname: Hammond
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D059031:Anticipation, Psychological; D002338:Carotenoids / Q000378:metabolism*; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D014975:Lutein / Q000378:metabolism; D008266:Macula Lutea / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000254:growth & development / Q000378:metabolism*; D004856:Postural Balance; D011597:Psychomotor Performance; D011930:Reaction Time; D024341:Xanthophylls / Q000378:metabolism; D055815:Young Adult; D065146:Zeaxanthins
chemical_list: D024341:Xanthophylls; D065146:Zeaxanthins; D002338:Carotenoids; C584722:meso-zeaxanthin; D014975:Lutein