Neurobehavioral Approach to the Study of Memory Development: A Personal Journey

This manuscript covers my personal history on the search for the neural circuits supporting early developing memory in primates. A series of developmental neuropsychological studies is presented to follow the successive knowledge we gained over several decades on the timing of development of the hippocampus and hippocampal-dependent recognition memory functions in primates. The borrowing of an incidental recognition memory task measuring novelty preference to infer subjects' memory was central to assessing memory in young infant monkeys of only a few weeks old. Data revealed that the emergence of adult-like proficiency in visual recognition and spatial memory tasks sensitive to hippocampal dysfunction is a stepwise process. This progressive development was associated with the gradual maturation of different hippocampal intrinsic circuits (Entorhinal-CA1 and Entorhinal-Dentate Gyrus-CA fields) and their connections with other cortical structures (the perirhinal, parahippocampal, parietal, and prefrontal cortices). We also showed that a similar postnatal maturation of hippocampal-dependent memory is observed in human infants, suggesting important changes in the role of the hippocampus and medial temporal cortical areas in human memory development as well.