title: Cerebello-thalamo-cerebral connections in pediatric brain tumor patients: impact on working memory.
abstract: Brain tumors are the leading cause of death and disability from childhood disease in developed countries. Pediatric posterior fossa tumors are often effectively controlled with a combination of surgery, radiation, and chemotherapy, depending on tumor type. White matter injury following resection of tumor and radiation treatment is associated with cognitive declines, including working memory deficits. We investigated how brain injury following treatment for posterior fossa tumors results in deficits in working memory. We used diffusion tensor imaging and probabilistic tractography to examine the structural integrity of cerebello-thalamo-cerebral tracts in patients and healthy children. We also compared working memory outcome in patients versus controls, and related this function to integrity of cerebello-thalamo-cerebral tracts. Bilateral cerebello-thalamo-cerebral tracts were delineated in all participants. Patients treated with a combination of surgery and radiation had lower mean anisotropy and higher mean radial diffusivity within the cerebellar regions of the cerebello-thalamo-cerebral tract compared to patients treated with surgery only and healthy controls. Poorer working memory scores were observed for the cranial radiation group relative to controls. Reduced anisotropy and higher radial diffusivity within the entire cerebello-thalamo-cerebral pathway predicted lower working memory. Our finding that working memory function is related to the integrity of cerebello-thalamo-cerebral connections is a novel contribution to the understanding of cerebral-cerebellar communication. Identifying differences in the structural integrity of white matter for specific pathways is an essential step in attempting to localize the effects of posterior fossa tumors and their treatment methods.
authors.affiliation: Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Law
authors.forename: Eric
authors.initials: E
authors.lastname: Bouffet
authors.forename: Suzanne
authors.initials: S
authors.lastname: Laughlin
authors.forename: Normand
authors.initials: N
authors.lastname: Laperriere
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Brière
authors.forename: Douglas
authors.initials: D
authors.lastname: Strother
authors.forename: Dina
authors.initials: D
authors.lastname: McConnell
authors.forename: Juliette
authors.initials: J
authors.lastname: Hukin
authors.forename: Christopher
authors.initials: C
authors.lastname: Fryer
authors.forename: Conrad
authors.initials: C
authors.lastname: Rockel
authors.forename: Jolynn
authors.initials: J
authors.lastname: Dickson
authors.forename: Donald
authors.initials: D
authors.lastname: Mabbott
mesh_terms: D016880:Anisotropy; D002531:Cerebellum / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D002648:Child; D003131:Combined Modality Therapy; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D015192:Infratentorial Neoplasms / Q000532:radiotherapy / Q000601:surgery; D008297:Male; D008569:Memory Disorders / Q000209:etiology* / Q000473:pathology; D008570:Memory, Short-Term / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011832:Radiation Injuries / Q000473:pathology*; D011878:Radiotherapy / Q000009:adverse effects; D013788:Thalamus / Q000033:anatomy & histology / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects