Decoupling between the hand territory and the default mode network after bilateral arm transplantation: four-year follow-up case study.
Carlos R Hernandez-Castillo, Jörn Diedrichsen, Erika Aguilar-Castañeda, Martin Iglesias
Brain Imaging and Behavior February 1, 2018 DOI: 10.1007/s11682-017-9683-1 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case study Case report Peer reviewed |
|---|---|
| Sample size | 1 |
| Population | One patient who received bilateral forearm transplants |
| Duration | Four time points starting four months after transplantation and during three consecutive years |
| Measures | resting-state fMRI |
| Topics | Default mode network |
| Keywords | Arm Brain Neural pathways Humans Magnetic resonance imaging Rehabilitation Follow-up studies Neuronal plasticity Middle aged Male Functional laterality Transplantation Hand Resting state Motor network |
| Key findings | In one bilateral forearm transplant recipient, the sensorimotor network was disrupted four months after surgery and returned to its typical topology over three years of rehabilitation, while the default mode network remained normal. Connectivity between the transplanted hands' cortical territory and the sensorimotor network increased over time and became anticorrelated with the default mode network, which the authors argue suggests network-level reorganization after transplantation. |
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.
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