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Cortical plasticity; MRI; Pain; Stroke
Abstract:
It has been proposed that cortical structural plasticity plays a crucial
role in the emergence and maintenance of chronic pain. Various dis-
tinct pain syndromes have accordingly been linked to specific pat-
terns of decreases in regional gray matter volume (GMV). However, it
is not known whether central poststroke pain (CPSP) is also asso-
ciated with cortical structural plasticity. To determine this, we em-
ployed T1-weighted magnetic resonance imaging at 3 T and voxel-
based morphometry in 45 patients suffering from chronic subcortical
sensory stroke with (n = 23) and without CPSP (n = 22), and
healthy matched controls (n = 31). CPSP patients showed decreases
in GMV in comparison to healthy controls, involving secondary som-
atosensory cortex (S2), anterior as well as posterior insular cortex,
ventrolateral prefrontal and orbitofrontal cortex, temporal cortex,
and nucleus accumbens. Comparing CPSP patients to nonpain pa-
tients revealed a similar but more restricted pattern of atrophy com-
prising S2, ventrolateral prefrontal and temporal cortex. Additionally,
GMV in the ventromedial prefrontal cortex negatively correlated to
pain intensity ratings. This shows for the first time that CPSP is ac-
companied by a unique pattern of widespread structural plasticity,
which involves the sensory-discriminative areas of insular/somato-
sensory cortex, but also expands into prefrontal cortex and ventral
striatum, where emotional aspects of pain are processed.
