TEMPORAL ORDER MEMORY ABILITIES IN INDIVIDUALS WITH DOWN OR WILLIAMS SYNDROME, AND TYPICALLY DEVELOPING CHILDREN

Temporal order memory enables the encoding, maintenance and retrieval of the temporal structure of events. However, different types of temporal order memory may rely on dissociable neural systems, and the developmental trajectories and specific brain regions that subserve them remain poorly understood. Here, we aimed to characterize temporal order memory abilities in individuals with Down (DS) or Williams (WS) syndrome and typically developing (TD) children, focusing on two theoretically distinct forms of temporal coding: temporal distance (which event occurred first) and relative temporal order (the precise order of events). Individuals with DS (n=25), WS (n=25) and TD children (n=25) completed novel behavioral tasks developed with this multiple memory systems framework in mind. Temporal distance memory was assessed using a Primacy/Recency task. Relative temporal order memory was assessed using a What‑Where‑When task. TD children served both as a mental age-matched comparison group for individuals with DS or WS, as well as an experimental group in which to describe the typical development of different temporal order memory abilities. We will present data on (1) between group differences in performance for each temporal order memory task; and (2) within-group differences between different temporal order memory tasks. In TD children, we predict age‑related improvements varying by task, supporting our hypothesis that temporal order memory is composed of distinct processes with distinct developmental trajectories. In individuals with DS or WS, we predict different performance between tasks, supporting our hypothesis that distinct types of temporal order memory are supported by dissociable neural systems.