Angela Sirigu is delighted to have Tamar Makin, from the University of Oxford, to come and give a talk on:
Adaptive and maladaptive reorganisation in amputees: Exploring the adult brain's opportunities for change
Arm amputation provides a powerful model for studying plasticity, as it results in massive input and output loss consequential to losing a hand. Amputation also leads to profound changes in behaviour, driven by individuals’ need to compensate for severe disability (adaptive behaviour). Despite this strong behavioural pressure, research on amputation has been largely restricted to deprivation-driven (and supposedly passive) brain reorganisation, with little regard for the potential interaction between deprivation and behavioural related plasticity. As a consequence, sensory deprivation is widely held to cause maladaptive plasticity, resulting in phantom pain. Using a range of neuroimaging approaches I examine the extent to which experience modulates brain structure and function in amputees and individuals with congenital hand absence. I present evidence to challenge the proposed link between cortical reorganisation and phantom pain, and instead demonstrate preservation of topographic representations of the missing (‘phantom’) hand. I will show that phantom pain is associated with maintained representation of the phantom hand as opposed to brain plasticity, with potential implications on future treatment using neuromodulation. Instead I provide new evidence that adaptive behaviour using the intact hand, residual arm or a prosthetic limb leads to extensive reorganisation, both within and beyond the sensorimotor system. In amputees, this process of adaptive plasticity occurs well beyond the traditionally conceptualised “critical period”. Based on this evidence, I suggest that plasticity in amputees is experience-dependant, and is not inherently maladaptive.
Council Room, ISC Marc Jeannerod, from 12pm.