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Object recognition is ubiquitous and essential for interacting with, as well as learning about, the surrounding multisensory environment. The inputs from multiple sensory modalities converge quickly and efficiently to guide this interaction. Vision and haptics are two modalities in particular that offer redundant and complementary information regarding the geometrical (i.e., shape) properties of objects for recognition and perception. While the systems supporting visuohaptic object recognition in the brain, including the lateral occipital complex (LOC) and the intraparietal sulcus (IPS), are well-studied in adults, there is currently a paucity of research surrounding the neural development of visuohaptic processing in children. Little is known about how and when vision converges with haptics for object recognition. In this dissertation, I investigate the development of neural mechanisms involved in multisensory processing. Using functional magnetic resonance imaging (fMRI) and general psychophysiological interaction (gPPI) methods of functional connectivity analysis in children (4 to 5.5 years, 7 to 8.5 years) and adults, I examine the developmental changes of the brain regions underlying the convergence of visual and haptic object perception, the neural substrates supporting crossmodal processing, and the interactions and functional connections between visuohaptic systems and other neural regions. Results suggest that the complexity of sensory inputs impacts the development of neural substrates. The more complicated forms of multisensory and crossmodal object processing show protracted developmental trajectories as compared to the processing of simple, unimodal shapes. Additionally, the functional connections between visuohaptic areas weaken over time, which may facilitate the fine-tuning of other perceptual systems that occur later in development. Overall, the findings indicate that multisensory object recognition cannot be described as a unitary process. Rather, it is comprised of several distinct sub-processes that follow different developmental timelines throughout childhood and into adulthood. |
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