Medial temporal lobe memory in childhood: developmental transitions

Abstract

The medial temporal lobes (MTL) support declarative memory and mature structurally and functionally during the postnatal years in humans. Although recent work has addressed the development of declarative memory in early childhood, less is known about continued development beyond this period of time. The purpose of this investigation was to explore MTL-dependent memory across middle childhood. Children (6 -10 years old) and adults completed two computerized tasks, place learning (PL) and transitive inference (TI), that each examined relational memory, as well as the flexible use of relational learning. Findings suggest that the development of relational memory precedes the development of the ability to use relational knowledge flexibly in novel situations. Implications for the development of underlying brain areas and ideas for future neuroimaging investigations are discussed.

Figure 1

Schematic illustrating the five oval stimuli for the TI task

Figure 2

Premise pairs for the TI task

Figure 3

Mean latency to locate the hidden target (seconds ±1SE) for 6, 8, 10- year olds and adults in the place learning (PL) task. Between 6 and 10 years, there is a gradual, linear decline in latency to relocate a hidden target using visual cues (relational memory). In contrast, latency to a hidden target with a subset of cues removed (flexible memory use) shows a significant shift between 8 and 10 years, with 6- and 8-year olds performing similarly and 10- year olds performing like adults.

Figure 4

Mean accuracy (±1SE) for premise and BD inference pairs in the transitive inference (TI) task. Between 6 and 10 years, there is gradual improvement in premise pair accuracy (relational memory). In contrast, BD inference pair accuracy (flexible memory use) shows a significant shift between 8 and 10 years, with 6 and 8-year olds performing similarly and 10-year olds performing like adults.