title: Thalamocortical connectivity is enhanced following functional hemispherotomy for intractable lateralized epilepsy.
abstract: Although developmental outcomes may improve following functional hemispherotomy for lateralized, catastrophic childhood epilepsy, the neuronal processes mediating these improvements are unknown. We report the case of a 14-year-old child with neurocognitive impairment who underwent functional hemispherotomy with longitudinal resting-state fMRI. Compared with preoperative fMRI, we report significantly more robust thalamo-default mode network connectivity on postoperative neuroimaging. Furthermore, we show decreased connectivity to nodes within the disconnected hemisphere, providing direct evidence that functional interactions are dependent upon structural connectivity. Since the vascular supply to these nodes remains intact, although they are disconnected from the remainder of the brain, these findings also confirm that blood-oxygen level dependent oscillations are driven primarily by neuronal activity. The current study highlights the importance of thalamocortical interactions in the understanding of neural oscillations and cognitive function, and their impairment in childhood epilepsy.
authors: Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada. Electronic address: georgem.ibrahim@utoronto.ca.
authors: George M
authors: GM
authors: Ibrahim
authors: Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Benjamin R
authors: BR
authors: Morgan
authors: Department of Psychology, Hospital For Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Mary Lou
authors: ML
authors: Smith
authors: Department of Psychology, Hospital For Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Elizabeth
authors: E
authors: Kerr
authors: Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Elizabeth
authors: E
authors: Donner
authors: Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Cristina Y
authors: CY
authors: Go
authors: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada; Neuroscience and Mental Health Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
authors: Sam
authors: S
authors: Doesburg
authors: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada; Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada; Neuroscience and Mental Health Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
authors: Margot
authors: M
authors: Taylor
authors: Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, Ontario, Canada; Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Elysa
authors: E
authors: Widjaja
authors: Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors: James T
authors: JT
authors: Rutka
authors: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada; Neuroscience and Mental Health Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
authors: O Carter
authors: OC
authors: Snead
mesh_terms: D000293:Adolescent; D002540:Cerebral Cortex; D003072:Cognition Disorders / Q000209:etiology / Q000523:psychology; D000069279:Drug Resistant Epilepsy / Q000601:surgery*; D007839:Functional Laterality; D038421:Hemispherectomy / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways; D019635:Neurosurgical Procedures / Q000379:methods*; D010100:Oxygen / Q000097:blood; D012640:Seizures / Q000601:surgery; D013788:Thalamus; D016896:Treatment Outcome
chemical_list: D010100:Oxygen
keywords: Epilepsy; Functional connectivity; Hemispherectomy; Oscillations; Peri-insular hemispherotomy; Resting-state fMRI; Thalamocortical oscillations