title: Decoupling between the hand territory and the default mode network after bilateral arm transplantation: four-year follow-up case study.
abstract: Several studies have suggested both a local and network reorganization of the sensorimotor system following amputation. Transplantation of a new limb results in a new shifting of cortical activity in the local territory of the transplanted limb. However, there is a lack of information about the reversibility of the abnormalities at the network level. The objective of this study was to characterize the functional connectivity changes between the cortical territory of the new hand and two intrinsic network of interest: the sensorimotor network (SMN) and the default mode network (DMN) of one patient whom received bilateral forearm transplants. Using resting-state fMRI these two networks were identified across four different time points, starting four months after the transplantation surgery and during three consecutive years while the patient underwent physical rehabilitation. The topology of the SMN was disrupted at the first acquisition and over the years returned to its canonical pattern. Analysis of the DMN showed the normal topology with no significant changes across acquisitions. Functional connectivity between the missing hand's cortical territory and the SMN increased over time. Accordingly, functional connectivity between the missing hand's cortical territory and the DMN became anticorrelated over time. Our results suggest that after transplantation a new reorganization occurs at the network level, supporting the idea that extreme behavioral changes can affect not only the local rewiring but also the intrinsic network organization in neurologically healthy subjects. Overall this study provides new insight on the complex dynamics of brain organization.
authors.affiliation: CONACYT - Instituto de Neuroetologia, Universidad Veracruzana, Av. Luis Cartelazo Ayala s/n, Col. Industrial Ánimas, Xalapa, Veracruz, Mexico. crhernandezca@conacyt.mx.|The Brain and Mind Institute, Western University, London, Canada. crhernandezca@conacyt.mx.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Hernandez-Castillo
authors.affiliation: The Brain and Mind Institute, Western University, London, Canada.
authors.forename: Jörn
authors.initials: J
authors.lastname: Diedrichsen
authors.affiliation: Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suarez", Ciudad de México, Mexico.
authors.forename: Erika
authors.initials: E
authors.lastname: Aguilar-Castañeda
authors.affiliation: Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Ciudad de México, Mexico.
authors.forename: Martin
authors.initials: M
authors.lastname: Iglesias
mesh_terms: D001132:Arm / Q000503:physiopathology / Q000637:transplantation*; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D012046:Rehabilitation; D012146:Rest
keywords: Default mode network; Hand; Motor network; Resting state; Transplantation