Michelle Y. Kibby
Throughout the years, animal research has unearthed that certain cells in the hippocampus contribute to spatial processing, which involves an animal’s recognition of its environmental layout and directionality. In order to apply this work to human children, we will identify whether hippocampal volume is related to spatial processing, including identifying which section(s) of the hippocampus seem to be more related to processing layouts versus directionality. Based on previous literature (Goodrich-Hunsaker, Hunsaker, & Kenser, 2005; McHugh, Fillenz, Lowry, Rawlins, & Bannerman, 2010), we predicted there would be a relationship between bilateral posterior and middle hippocampal regions and spatial processing, such that decreased hippocampal volume of these areas would correspond with worse spatial processing. This project includes structural magnetic resonance images (MRI) from 136 children (8-12 years old) with the neurodevelopmental disorders of Attention-Deficit/Hyperactivity Disorder (ADHD), Reading Disability (RD) and comorbid ADHD/RD, as well as typically developing controls. Analyze software was used for tracing the hippocampus on these images and for segmenting bilateral hippocampal volume into three sub regions (anterior, middle, and posterior). Spatial processing was assessed with WISC Block Design, Development Test of Visual Motor Integration (DTVMI), NEPSY Visual Attention, and NEPSY Design Fluency. Linear regressions indicated that bilateral anterior, middle, and posterior hippocampal volume were significant predictors of all measures of spatial processing except Block Design. Our results provide evidence that all regions of the hippocampus are associated with spatial processing.