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

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.

Why Brain Science is Essential to the Success of Hand Allotransplantation

“…Consistent with animal models [3], transcranial magnetic stimulation (TMS) studies suggest that reduced levels of intrahemispheric inhibition post-injury may play a key role in M1 reorganization [28,29]. To date, there is no evidence for macroscopic changes in cortical gray matter following amputation [30,31], although thalamus volume may be decreased [30].…”

“…However, not all evidence from amputees supports this hypothesis [29,41]. A recent report presents data that pain is actually associated with preservation of function and structure within the former sensorimotor hand territory following amputation [31]; a result that questions the idea that cortical reorganization is maladaptive (cf. [42]).…”

Phantom Pain: The Role of Maladaptive Plasticity and Emotional and Cognitive Variables

“…After the loss of input, the vacated areas start to process sensory information from the adjacent nerves, and this might be perceived as phantom pain. Makin et al ( 2013 ) showed that the presence of phantom limb pain was enhanced when more input from the preserved representation of the former hand in SI was present in amputees. Although controversial (Flor et al 2013 ), there are clearly interactions between peripheral and central changes in PLP.…”

Map of the nervous system in the brain and the phantom pain

“…Mogą one być błędem interpretacyjnym faktycznego pobudzenia receptora. Badania wskazują, że ból fantomowy aktywuje te same obszary w mózgu, które odpowiedzialne są za percepcję bólu [1]. Może to powodować odczuwanie fizycznego bólu.…”