Phantom pain is associated with preserved structure and function in the former hand area

TLDR

Phantom pain after arm amputation is commonly attributed to maladaptive cortical reorganization caused by loss of sensory input. The study proposes that chronic phantom pain drives cortical plasticity by maintaining local representations and disrupting inter‑regional connectivity, opposing the maladaptive model. Functional MRI shows that persistent phantom pain preserves local structural and functional organization of the former hand area while reducing inter‑regional connectivity in the primary sensorimotor cortex, challenging the notion that cortical reorganization drives phantom pain.

Abstract

Phantom pain after arm amputation is widely believed to arise from maladaptive cortical reorganization, triggered by loss of sensory input. We instead propose that chronic phantom pain experience drives plasticity by maintaining local cortical representations and disrupting inter-regional connectivity. Here we show that, while loss of sensory input is generally characterized by structural and functional degeneration in the deprived sensorimotor cortex, the experience of persistent pain is associated with preserved structure and functional organization in the former hand area. Furthermore, consistent with the isolated nature of phantom experience, phantom pain is associated with reduced inter-regional functional connectivity in the primary sensorimotor cortex. We therefore propose that contrary to the maladaptive model, cortical plasticity associated with phantom pain is driven by powerful and long-lasting subjective sensory experience, such as triggered by nociceptive or top–down inputs. Our results prompt a revisiting of the link between phantom pain and brain organization. Reorganization of the sensorimotor cortex due to loss of sensory input is implicated in phantom pain. Makin and colleagues use functional MRI to show that phantom pain experience is instead associated with maintained local functional and structural cortical representations but disrupted inter-regional connectivity.