There is minimal knowledge on how cortical functions develop. I propose to characterize cortical development by measuring neural responses to visual global integration and attentional selectivity in children (6-10 year olds), adolescents (13-15 year olds) and adults (?18 year olds). Global integration is the process by which distributed features allow a pattern to be detected. It is classically thought that global integration based on form is processed by ventral visual areas while motion is processed by dorsal visual areas. Recent evidence suggests that global integration has relatively late maturation compared to tasks that only require feature detection. Moreover, evidence suggests that form and motion integration have different developmental trajectories. To examine the relationship of form and motion integration, we will measure cortical activity related to Glass pattern and coherent motion, stimuli created from copies of random dots. Although distinguishable as rotation, expansion or translation, these stimuli provide weak local orientation or direction cues, making them ideal stimuli in investigating global integration. By utilizing visually evoked potentials (VEP) coupled with magnetic resonance imaging (MRI) data, I plan to test three main hypotheses: (1) that form and motion integration are processed by separate ventral and dorsal cortical areas, (2) that form processing has a different maturation rate than motion processing, and (3) that the effects of sustained attention on global integration is different in children and adults due to immature mechanisms that govern executive control.
These studies will give us a better understanding how global form and motion integration may be related, and if this relationship changes as the visual system matures. Knowing how cortical function behaves in typical visual development may provide insight into the processes involved in atypical visual development. This information is especially important in special populations in which differences between dorsal and ventral visual functions have been found, such as in amblyopia, dyslexia, autism, Williams Syndrome and Turner Syndrome. In addition, the coupling of VEP responses to anatomical and functional MRIs is a novel technique that can be useful for investigating neural activity across typical and atypical development because participants are not subjected to long-duration fMRI scans, which can create anxiety and discomfort in young children and in people with special needs. ? ? ?
| Palomares, Melanie; Ales, Justin M; Wade, Alex R et al. (2012) Distinct effects of attention on the neural responses to form and motion processing: a SSVEP source-imaging study. J Vis 12:15 |
| Englund, Julia A; Palomares, Melanie (2012) The relationship of global form and motion detection to reading fluency. Vision Res 67:14-21 |
| Palomares, Melanie; Egeth, Howard (2010) How element visibility affects visual enumeration. Vision Res 50:2000-7 |
| Palomares, Melanie; Pettet, Mark; Vildavski, Vladimir et al. (2010) Connecting the dots: how local structure affects global integration in infants. J Cogn Neurosci 22:1557-69 |
| Pelli, Denis G; Majaj, Najib J; Raizman, Noah et al. (2009) Grouping in object recognition: the role of a Gestalt law in letter identification. Cogn Neuropsychol 26:36-49 |
