Lenz FA, Casey KL, Jones EG, Willis WD, eds. The Human Pain System: Experimental and Clinical Perspectives. Cambridge 2010, 648 pages, $140.00.
This textbook covers the field of pain system in human there are several chapters that cover pain pathways in anterolateral system in the spine, the organization of the central pain pathways as it pertains to physiology of spine and brainstem projections, and supra spinal pain related structures. Pain modulatory systems, mechanism and manifestations of chronic pain, and functional implications of treatment of chronic pain. There are two chapters that are of particular interest for imaging brain function of acute pain and chronic pain. This would be of interest to radiologists.
The fifth chapter covers the topic of acute pain. It begins with early demonstration of local cortical blood volume increase during electrical stimulation of a sensory nerve. The investigators observed changes in brain volume in dogs and rabbits, which were related to changes in systemic arterial pressure and venous pressure. There is a brief discussion of in vivo optical imaging, describing the time course and extent of local vascular events following a stimulus that excites the bioelectrical responses of neurons. These experiments were conducted on rodents; the investigators observed increase in regional cerebral blood volume and flow, and changes in oxygenated and deoxygenated hemoglobin following whisker stimulation. The changes in oxygenation of hemoglobin or blood oxygenation level dependent (BOLD) signal changes on functional magnetic resonance imaging and its principles are described in detail and in a brief discussion on the analysis of functional imaging data. The spinal, thalamic, and cortical structures and principal connecting pathways that participate in mediating pain are described. Functional imaging of acute pain on healthy humans using noxious heat or innocuous cool stimuli show activation of thalamus, superior frontal gyrus, dorsal anterior cingulated cortex, posterior cingulated cortex, supplemental motor area, and middle frontal gyrus. There is lengthy discussion of how these active regions are interconnected to sense and mediate the acute pain stimulus.
The eighth chapter covers the topic of chronic pain; authors discuss relevance of pain-related changes in the resting (default) brain in a group of patients with chronic back pain when compared to healthy controls. During fMRI, patient and control performed a visuo-motor tracking task. It was shown that the anti-correlated BOLD activity in the medial prefrontal cortex for the control subjects but it was absent in the chronic back pain patients.
This book provides useful resource to neuroscientists who are studying pain mechanisms such as neuropathic pain, spontaneous ongoing pain, back pain, headache, and fibromyalgia. It does cover imaging strategies using PET and fMRI, which would be beneficial to basic scientists to develop treatment strategies based on differences in default brain condition, chronic pain patients, and normal controls.
