title: Alterations of hippocampal projections in adult macaques with neonatal hippocampal lesions: a Diffusion Tensor Imaging study.
abstract: Neuropsychological and brain imaging studies have demonstrated persistent deficits in memory functions and structural changes after neonatal neurotoxic hippocampal lesion in monkeys. However, the relevant microstructural changes in the white matter of affected brain regions following this early insult remain unknown. This study assessed white matter integrity in the main hippocampal projections of adult macaque monkeys with neonatal hippocampal lesions, using diffusion tensor imaging (DTI). Data analysis was performed using tract-based spatial statistics (TBSS) and compared with volume of interest statistics. Alterations of fractional anisotropy (FA) and diffusivity indices were observed in fornix, temporal stem, ventromedial prefrontal cortex and optical radiations. To further validate the lesion effects on the prefrontal cortex, probabilistic diffusion tractography was used to examine the integrity of the fiber connections between hippocampus and ventromedial prefrontal cortex, and alterations were found in these connections. In addition, increased radial diffusivity in the left ventromedial prefrontal cortex correlated negatively with the severity of deficits in working memory in the same monkeys. The findings revealed microstructural changes due to neonatal hippocampal lesion, and confirmed that neonatal neurotoxic hippocampal lesions resulted in significant and enduring functional alterations in the hippocampal projection system.
authors.affiliation: Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, GA, USA.
authors.forename: Christa
authors.initials: C
authors.lastname: Payne
authors.affiliation: Marcus Autism Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA.
authors.forename: Longchuan
authors.initials: L
authors.lastname: Li
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Hu
authors.affiliation: Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA. Electronic address: xzhang8@emory.edu.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, GA, USA. Electronic address: jbachev@emory.edu.
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Bachevalier
mesh_terms: D000367:Age Factors; D000818:Animals; D001927:Brain Diseases / Q000150:complications / Q000175:diagnosis* / Q000662:veterinary*; D056324:Diffusion Tensor Imaging; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D008253:Macaca mulatta; D008297:Male; D008569:Memory Disorders / Q000209:etiology; D008992:Monkey Diseases / Q000175:diagnosis*; D009413:Nerve Fibers, Myelinated / Q000473:pathology
keywords: DTI; Fornix; Hippocampus; Temporal stem; Ventromedial prefrontal cortex; White matter integrity