The homeostatic homunculus: rethinking deprivation-triggered reorganisation

Muret, Dollyane; Makin, Tamar R.

doi:10.1016/j.conb.2020.08.008

Cited by 40 publications

(41 citation statements)

References 61 publications

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“…akin to other studies reporting neural correlates of decreased motor control (18). It could also result from homeostatic plasticity mechanisms, aimed at stabilising brain activity in presence of abrupt input changes (43). This interpretation is supported by the reduced inter-body part distances found in the SMA.…”

Section: Discussionmentioning

confidence: 89%

Robotic hand augmentation drives changes in neural body representation

et al. 2021

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Humans have long been fascinated by the opportunities afforded through augmentation. This vision not only depends on technological innovations but also critically relies on our brain’s ability to learn, adapt, and interface with augmentation devices. Here, we investigated whether successful motor augmentation with an extra robotic thumb can be achieved and what its implications are on the neural representation and function of the biological hand. Able-bodied participants were trained to use an extra robotic thumb (called the Third Thumb) over 5 days, including both lab-based and unstructured daily use. We challenged participants to complete normally bimanual tasks using only the augmented hand and examined their ability to develop hand-robot interactions. Participants were tested on a variety of behavioral and brain imaging tests, designed to interrogate the augmented hand’s representation before and after the training. Training improved Third Thumb motor control, dexterity, and hand-robot coordination, even when cognitive load was increased or when vision was occluded. It also resulted in increased sense of embodiment over the Third Thumb. Consequently, augmentation influenced key aspects of hand representation and motor control. Third Thumb usage weakened natural kinematic synergies of the biological hand. Furthermore, brain decoding revealed a mild collapse of the augmented hand’s motor representation after training, even while the Third Thumb was not worn. Together, our findings demonstrate that motor augmentation can be readily achieved, with potential for flexible use, reduced cognitive reliance, and increased sense of embodiment. Yet, augmentation may incur changes to the biological hand representation. Such neurocognitive consequences are crucial for successful implementation of future augmentation technologies.

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Section: Discussionmentioning

confidence: 89%

Robotic hand augmentation drives changes in neural body representation

et al. 2021

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“…neuropathic pain). There are two main factors involved in the development of CoRe: 1) structural changes of neuronal networks and connections linked to anatomical rewiring of axons and dendrites, and 2) functional changes linked to activitydependent plasticity and/or homeostatic plasticity (Muret and Makin, 2020). Since our results were obtained in a narrow time window (from minutes to few hours after deprivation), the possibility of structural and/or anatomical changes is limited.…”

Section: Sensory Deprivation Affects the Generation Of Gamma Oscillatmentioning

confidence: 96%

“…Since our results were obtained in a narrow time window (from minutes to few hours after deprivation), the possibility of structural and/or anatomical changes is limited. On the contrary, we consider that the observed neuronal network alterations in a specific layer will depend on the importance of lacking the preferred connectivity (thalamocortical or corticocortical), the inhibitory neuronal composition and how the network integrates secondary/non-preferential and weak connections (as described in Muret and Makin, 2020). Then, immediate functional changes described in our results point to an initiation of homeostatic processes intended to compensate input deprivation by rebalancing excitation:inhibition as it has been described in other sensory systems (Keck et al, 2013;Barnes et al, 2017;Teichert et al, 2017), which can be followed in the long-term by a process of activity-dependent plasticity.…”

Section: Sensory Deprivation Affects the Generation Of Gamma Oscillatmentioning

confidence: 99%

Cortical layer-specific modulation of neuronal activity after sensory deprivation due to spinal cord injury

Zaforas

Rosa

Alonso-Calviño

et al. 2020

Preprint

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SummaryCortical areas have the capacity of large-scale reorganization following sensory deprivation. However, it remains unclear whether this is a unique process that homogenously affects the entire deprived region or it is suitable to changes depending on local circuitries across layers. By using in vivo electrophysiology to record neuronal activity simultaneously across cortical depth, we showed that sensory deprivation due to spinal cord injury induces layer-specific changes in both spontaneous and evoked-activity. While supragranular layers specifically increased gamma oscillations and the ability to initiate up-states during spontaneous activity, infragranular layers displayed increased, faster and delayed evoked-responses to sensory stimulation. Therefore, sensory deprivation immediately modifies local circuitries allowing supragranular layers to better integrate spontaneous corticocortical information to maintain column excitability, and infragranular layers to better integrate evoked-sensory inputs to preserve subcortical outputs. These layer-specific changes may guide long-term alterations in excitability and plasticity associated to network rearrangements and the appearance of sensory pathologies associated with spinal cord injury.

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“…This is consistent with the idea that the missing-hand area may be recruited to support increased representation of alternative intact body parts. However, changes to cortical map boundaries (i.e., remapping), as measured through fMRI, do not necessarily entail changed representational content and readout [3]. As such, the observed remapping may not subserve a functional role.…”

Section: Introductionmentioning

confidence: 99%

“…While sensory deprivation has long been known to trigger changes to cortical maps in sensory and motor cortex, e.g. due to blindness [1], deafness [2] or arm malformation [3], there is an ongoing debate on their functional relevance. For example, using fMRI, we have previously reported that the deprived sensorimotor hand territory of individuals born without a hand shows increased activity evoked by movements of the lips, feet and residual arm, when compared to two-handed controls [4,5].…”

Section: Introductionmentioning

confidence: 99%