| dc.description.abstract | Animal studies have suggested that iron deficiency negatively affects dopamine (DA) synthesis and reuptake, which in turn negatively affects memory and cognition. However, the literature on the possible relationships among iron deficiency, DA dysregulation, and deficits in memory and cognition in humans is sparse. This study was intended to assess whether the pattern electroretinogram (pattern ERG) could be used as an indirect measure of DA in college-age women and to assess the extent to which the features of the pattern ERG were related to measures of iron levels and measures of cognition. For the pattern ERG to be useful as an indirect measure of dopamine in the context of iron deficiency, at least two things need to be true. First, the features of the pattern ERG should be sensitive to variations in blood measures of iron. Second, the features of the pattern ERG need to be related to other measures that have been suggested as indirect measures of DA, such as blink rate. It is known that DA is present in the retina, and because the pattern ERG measures retinal activity, it has been used in a variety of contexts to assess dopaminergic functioning. The pattern ERG was measured in a total of 21 iron deficient non-anemic (IDNA) and 21 iron sufficient (IS) women, who also performed a contrast detection and probabilistic selection task, both with concurrent electroencephalography (EEG). In addition, both their spontaneous and task-related blink rates were measured. The implicit times of the two features of the pattern ERG—the A- and B- waves –were significantly longer for the IDNA than for the IS women. Both the amplitudes and implicit times of the A- and B-waves were significantly correlated with levels of serum ferritin (sFt). However, only the amplitude of the A-wave was correlated with spontaneous blink rate. IDNA women had higher contrast detection thresholds and lower levels of accuracy in the probabilistic selection task than did the IS women. Finally, there was evidence that the implicit times of the ERG features, as proxy measures of DA, mediated the relationship between iron levels and accuracy levels. The results suggest the utility of the pattern ERG in testing the hypothesis that iron deficiency affects DA levels in humans and that this may be on the mechanisms by which iron deficiency negatively affects cognition. | en_US |
