Developmental differences in hippocampal long-axis contributions to memory precision

Memory precision varies along the hippocampal long axis in the mature brain. Yet, little is known about how developmental change in long-axis functionality influences this precision. We characterized how children and adults engage the hippocampal long axis to form precise memories. Children (7-9 years) and adults performed two tasks that encouraged an orientation to the specific details versus broader category of scenes during encoding. They then performed a recognition test with studied scenes and similar lures. Adults had more precise memories than children, in that they were better able to discriminate studied scenes from lures; yet, both age groups benefited from orienting to specifics. Examining hippocampal engagement during both tasks showed a developmental shift from posterior to anterior hippocampus during specific encoding. Subregion engagement was also differently related to memory quality in children versus adults: While posterior hippocampus supported subsequent memory across age groups, both anterior and posterior hippocampus showed developmental differences in their link to false memories. Individual differences in the source of specific encoding along the long axis revealed that premature shifts towards an adult-like profile were disadvantageous to children’s memory. Our results suggest as development unfolds, refinements to both anterior and posterior subregion functionality supports memory imprecision.