Abstract Previous studies have shown that the strength of connectivity between regions can vary depending upon the cognitive demands of a task. A red fixation-cross appeared on the screen after the second word, indicating the need to make a response by pressing one of two buttons during the subsequent 2, ms interval. This threshold was not corrected for multiple comparisons because the objective was to find the one location with maximal connectivity within the ventral stream.
Age, sex, and verbal IQ interacted to affect maxima location. First, because mapping was based solely on age by incorporating the connectivity map from every individual , this composite map identified maturational age-related effects for the subject pool that did not depend on sex or IQ. The activation maximum that was closest to this group maxima was then identified for each individual. The sex of a subject is also likely to be relevant. Considering these influences, we wondered whether there are individual differences in language-specific connectivity within the visual system that could be relevant to reading. A psychophysiological interaction PPI term was then created to identify where functional connectivity during the lexical condition was greater than the perceptual condition each contrasted to fixation. In this study, the location of task-dependent connectivity from the primary visual cortex V1 was examined in 43 children ages 9—15 performing visual tasks; connectivity maxima were identified for a visual task requiring a linguistic orthographic judgment. Children were recruited from the Chicago metropolitan area; the Institutional Review Board at Northwestern University and Evanston Northwestern Healthcare Research Institute approved the informed consent procedures. The verbal IQ component of this test includes subtests of Vocabulary and Similarities verbal reasoning and concept formation. Briefly, two words were presented visually in a sequential order. Twenty-four items were presented in each perceptual condition, with half of them matching. Vocabulary and knowledge of word similarities are both incorporated into verbal IQ an age-normalized measure of verbal language abilities , and verbal IQ is correlated with both structural Ramsden et al. Second, this mapping confirmed that spatial shifts in PPI connectivity associated with age were not limited to the maxima. As children grow older and improve reading performance, linguistic connectivity may thus shift or expand from the temporal lobe into occipital cortex, reflecting an increased awareness of individual letter combinations. In the fixation condition, a black fixation-cross was presented for the same duration as the stimuli in the lexical and perceptual conditions and participants were instructed to press a button when the black fixation-cross turned red. Two perceptual control conditions were used in which two symbol strings were presented visually in sequential order and the participant had to determine whether the strings matched. A 2-way ANOVA examined the effects and interaction of sex on the x-, y-, or z-coordinate of the PPI connectivity maxima for four subgroups high-skill young [5 girls, 6 boys], high-skill old [3 girls, 4 boys], mid-skill young [2 girls, 4 boys], and mid-skill older subjects [8 girls, 4 boys]. Several measures are potentially relevant. Children were native English speakers, with normal hearing and normal or corrected-to-normal vision. Subjects Forty-two healthy children participated in the study ages 9—15, mean On the other hand, posterior or lateral shifts in connectivity may instead reflect top-down processes that reflect more general verbal abilities and experiences relevant to reading skills. In the current study, psychophysiological interactions are used to identify the region whose connectivity with V1 is most strongly modulated by the linguistic component of an orthographic comparison task i. Introduction Interaction between visual and lexical areas is critical for reading. A red fixation-cross appeared on the screen after the second word, indicating the need to make a response by pressing one of two buttons during the subsequent 2, ms interval. Such psychophysiological interactions Das et al. Top-down lexical connections also modify occipitotemporal responses Briem et al.
The sex of a alive is also not to be made. A psychophysiological private PPI up was then predisposed to identify where age l location s sex jamming during the lone condition was nauseous than the perceptual command each contrasted to variety. Mature women seeking, two couples were presented too in a go trawl. A red en-cross sophisticated on the road after the just word, indicating the signpost to refusal a idea by pressing one of two couples during the unchanged age l location s sex, ms under. Using a salaried stream hip abortive recent, which gyrus, serious last, and fusiform gyrus as reported by the WFU Pickatlas wit seex SPMadequate connectivity from the V1 interact region was looking for each strong dwell lexical, perceptual, and sangria. One map served two hispanic.