An MRI study of the corpus callosum in monkeys: Developmental trajectories and effects of neonatal hippocampal and amygdala lesions

• Type of Material: Article
• Authors: Christa Payne, Emory University; Laetitia Cirilli, Emory University; Jocelyne Bachevalier, Emory University
• Language: English
• Date: 2017-05-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Wiley Periodicals, Inc.
• Final Published Version (URL): http://dx.doi.org/10.1002/dev.21514
• Title of Journal or Parent Work: Developmental Psychobiology
• ISSN: 0012-1630
• Volume: 59
• Issue: 4
• Start Page: 495
• End Page: 506
• Grant/Funding Information: Supported by grants MH-58846 and HD 3547 to JB, Autism Speaks Mentor-Based Predoctoral Fellowship; Grant number: 1657; Yerkes Base Grant NIH 00165, currently supported by the Office of Research Infrastructure Programs/OD P51OD11132; Center for Behavioral Neuroscience grant NSF IBN-9876754.
• Keywords: Psychology; PREFRONTAL CORTEX; neuroimaging; AUTISM SPECTRUM DISORDER; Science & Technology; INFANT RHESUS MACAQUES; WILLIAMS-SYNDROME; commissure; FRONTAL AREAS; Macaca mulatta; structural; neurodevelopment; BRAIN-DEVELOPMENT; WORKING-MEMORY; rhesus macaque; Social Sciences; nonhuman primate; Developmental Biology; MACACA-MULATTA; SEX-DIFFERENCES; ADULT MACAQUES; volumetric; Life Sciences & Biomedicine
• Research Categories: Psychology, Developmental; Biology, Neuroscience

Abstract

This study provides the first characterization of early developmental trajectories of corpus callosum (CC) segments in rhesus macaques using noninvasive MRI techniques and assesses long-term effects of neonatal amygdala or hippocampal lesions on CC morphometry. In Experiment 1, 10 monkeys (5 males) were scanned at 1 week—2 years of age; eight additional infants (4 males) were scanned once at 1–4 weeks of age. The first 8 months showed marked growth across all segments, with sustained, albeit slower, growth through 24 months. Males and females had comparable patterns of CC maturation overall, but exhibited slight differences in the anterior and posterior segments, with greater increases in the isthmus for males and greater increases in the rostrum for females. The developmental changes are likely a consequence of varying degrees of axonal myelination, redirection, and pruning. In Experiment 2, animals with neonatal lesions of the amygdala (n = 6; 3 males) or hippocampus (n = 6; 4 males) were scanned at 1.5 years post-surgery and compared to scans of six control animals from Experiment 1. Whereas amygdala damage yielded larger rostral and posterior body segments, hippocampal damage yielded larger rostrum and isthmus. These differences demonstrate that early perturbations to one medial temporal lobe structure may produce extensive and long-lasting repercussions in other brain areas. The current findings emphasize the complexity of neural circuitry putatively subserving neurodevelopmental disorders such as autism spectrum disorder and Williams syndrome, which are each characterized by malformations and dysfunction of complex neural networks that include regions of the medial temporal lobe.