Mental imagery—The cognitive maps of memory retrieval based on statistical graphs

Statistical graph is widely used to represent quantitative data in science, business, and many other fields in our daily life. To the best of our knowledge, the neural mechanisms underlying memory retrieval based on statistical graphs have not been reported yet. We investigated this issue using functional magnetic resonance imaging (fMRI). In our study, 36 normal subjects were instructed to read statistical information that was visually presented in either statistical graph or text. Then the reading stimuli disappeared, subjects were instructed to answer a question that needed to retrieval information of the content of the statistical graph or text. The direct comparison of the memory retrieval based on statistical graphs and that based on text showed that there were significantly more activated the lateral regions including ventral and dorsal pathways, as well as the parietal-temporal-occipital (PTO) association area (BA19/39); the medial regions including parahippocampal cortex (PHC) and retrosplenial complex (RSC). The results suggest that the two visual pathways and the PTO are involved in forming the imagery of statistical graphs, and the PHC and RSC are involved in the memory retrieval that played on the mental imagery of statistical graphs, in which PHC is involved in the retrieval of object-location associations and RSC is involved in orientation mechanisms. Previous studies demonstrated that spatial navigation was also composed of two similar processes: retrieval of object-location associations and orientation. We propose that memory retrieval based on statistical graphs draws on similar processing in spatial navigation that is based on the cognitive maps.