Neuroanatomy correlates with the psychological changes of pain. Neuroplastic transformation appears in the reduction of gray matter volume, or shrinkage in the top-down cortical areas vital for working memory, problem solving, sequencing and discrimination of different information and cognitive modulation of pain via the descending pain modulatory tracts and control over other cortical areas involved in the emotional perception of pain. These latter areas become more active,thereby intensifying the susceptibility to negative affect associated with pain (Geha & Apkarian, 2006).An animal model of chronic neuropathic pain was associated with impairment in the firing activity of the locus coeruleus and its expression of noradrenaline in ascending and descending pathways, which plays roles in not only pain perception, but mood, anxiety,attention and concentration, the sympathetic nervous system,and the activity of the hypothalamic-pituitary-adrenal axis,which serves to mobilize an organism’s survival by the expression of cortisol in an immediate survival circumstance.
Keywords: Depression; pain; pain pathways.