Abstract
The neural substrates underlying multisensory visuohaptic object recognition have been studied extensively in adults, yet are only beginning to be explored in children. Brain regions implicated in visuohaptic object processing include the lateral occipital complex (LOC) and the intraparietal sulcus (IPS). Although a few studies have investigated functional connectivity between the visuohaptic dorsal and ventral streams in adults, the development of this connectivity for supporting recognition remains unknown. In the present study, three groups of participants (4 to 5.5 year olds, 7 to 8.5 year olds, and adults) were tested using BOLD fMRI during a block design comprising visual and haptic exploration of real objects and textures. To examine the development of task-dependent functional connectivity between the LOC and the IPS and other neural substrates, general psychophysiological interaction (gPPI) methods of analysis were implemented. Results indicated stronger connectivity (correlation strength) between the LOC seed region-of-interest (ROI) and the IPS in 4 to 5.5 year olds than in the older two groups for haptics. Similarly, the IPS seed region showed a stronger functional connection to the LOC for haptics in 4 to 5.5 year olds than in 7 to 8.5 year olds or adults; the 7 to 8.5 year olds and adults indicated comparable correlation strengths overall. Additionally, the correlations between the LOC seed ROI and aspects of the IPS for vision were weaker in adults than in either group of children. These findings show decreases in bi-directional functional connectivity strength between the LOC and the IPS with increasing age, suggesting that development involves gradual uncoupling of dorsal and ventral stream visuohaptic processing centers. Critically, there appears to be a transitional period between 4 and 8 years of age during which functional connectivity plateaus for haptics, but continues to develop for vision.
Meeting abstract presented at VSS 2014