20 research outputs found
On the Functional Significance of the P1 and N1 Effects to Illusory Figures in the Notch Mode of Presentation
The processing of Kanizsa figures have classically been studied by flashing the full âpacmenâ inducers at stimulus onset. A recent study, however, has shown that it is advantageous to present illusory figures in the ânotchâ mode of presentation, that is by leaving the round inducers on screen at all times and by removing the inward-oriented notches delineating the illusory figure at stimulus onset. Indeed, using the notch mode of presentation, novel P1and N1 effects have been found when comparing visual potentials (VEPs) evoked by an illusory figure and the VEPs to a control figure whose onset corresponds to the removal of outward-oriented notches, which prevents their integration into one delineated form. In Experiment 1, we replicated these findings, the illusory figure was found to evoke a larger P1 and a smaller N1 than its control. In Experiment 2, real grey squares were placed over the notches so that one condition, that with inward-oriented notches, shows a large central grey square and the other condition, that with outward-oriented notches, shows four unconnected smaller grey squares. In response to these ârealâ figures, no P1 effect was found but a N1 effect comparable to the one obtained with illusory figures was observed. Taken together, these results suggest that the P1 effect observed with illusory figures is likely specific to the processing of the illusory features of the figures. Conversely, the fact that the N1 effect was also obtained with real figures indicates that this effect may be due to more global processes related to depth segmentation or surface/object perception
Prenatal DHA Supplementation and Infant Attention
BackgroundâResults of randomized trials on the effects of prenatal docosahexaenoic acid
(DHA) on infant cognition are mixed, but most trials have used global standardized outcomes,
which may not be sensitive to effects of DHA on specific cognitive domains.
MethodsâWomen were randomized to 600 mg/d DHA or a placebo for the last two trimesters of
pregnancy. Infants of these mothers were then followed on tests of visual habituation at 4, 6, and 9
months of age.
ResultsâDHA supplementation did not affect look duration or habituation parameters but
infants of supplemented mothers maintained high levels of sustained attention (SA) across the first
year; SA declined for the placebo group. The supplemented group also showed significantly
reduced attrition on habituation tasks, especially at 6 and 9 months.
ConclusionâThe findings support with the suggestion that prenatal DHA may positively affect
infantsâ attention and regulation of state