Developmental trajectory of object recognition memory in infant rhesus macaques with and without neonatal hippocampal lesions

• Type of Material: Article
• Authors: Alyson Zeamer, Thomas Jefferson University; Eric Heuer, Emory University; Jocelyne Bachevalier, Emory University
• Language: English
• Date: 2010-07-07
• Publisher: Lippincott, Williams & Wilkins
• Publication Version: Final Published Version
• Copyright Statement: © 2010 the authors.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1523/JNEUROSCI.0022-10.2010
• Title of Journal or Parent Work: Journal of Neuroscience Nursing
• ISSN: 0888-0395
• Volume: 30
• Issue: 27
• Start Page: 9157
• End Page: 9166
• Grant/Funding Information: This work was supported by grants from the National Institute of Mental Health (MH-58846), the Yerkes Base Grant NIH RR00165, and the Center for Behavioral Neuroscience Grant NSF IBN-9876754.
• Keywords: Discrimination Learning; Neuropsychological Tests; Age Factors; Female; Male; Recognition (Psychology); Brain Injuries; Pattern Recognition, Visual; Photic Stimulation; Macaca mulatta; Analysis of Variance; Hippocampus; Reaction Time; Magnetic Resonance Imaging; Animals, Newborn; Brain Mapping; Animals
• Research Categories: Psychology, Developmental; Biology, Neuroscience

Abstract

To examine the developmental trajectory of object recognition memory and its neural substrate, 10-12-d-old monkeys (Macaca mulatta) receivedshamoperationsorneurotoxichippocampallesionsandweretestedattheagesof1.5, 6,and18monthsonthevisualpaired-comparison task using delays of 10, 30, 60, and 120 s. In sham-operated controls, incidental recognition memory was present at 1.5 months, became more robust at 6 months, and was delay-dependent by 18 months of age, suggesting that the brain structures mediating these early developing recognition abilities may undergo significant modifications after 6 months of age in monkeys. A similar developmental progression was also observed in animals with neonatal hippocampal lesions, although the delay-dependent effect at 18 months was significantly more pronounced after the neonatal hippocampal lesions, suggesting that with maturation animals with neonatal hippocampal lesions grow into a recognitionmemory deficit. These findings suggest not only that the medial temporal cortical areas, known to mediate incidental recognition memory processes in adulthood, could support these processes in early infancy even when long delays are used, but also that later in development, after reaching functional maturity, the hippocampus begins to interact with the medial temporal cortical areas to mediate this function.