Cort
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Sharpe is a behaviorist who was involved in CFS for quite a while but who concentrates for on cancer fatigue now. He places CFS in the 'somatoform disorders' category along with FM, IBS, etc.
Here they are asking whether there is evidence of neural dysfunction in these disorders and the answer appears to be a qualified yes. As always seems to be the case more and better research needs to be done- but its an intriguing look at the neurological basis of these disorders.
Interestingly it focused on the limbic system, which, if memory serves right, Cheney suggested was important early on. What does the Limbic system do? It regulates two systems that are involved in CFS; the endocrine system and the autonomic nervous system.
It appears to be tied to flight/fight response
This is a large rather, poorly defined system containing these structures
Here they are asking whether there is evidence of neural dysfunction in these disorders and the answer appears to be a qualified yes. As always seems to be the case more and better research needs to be done- but its an intriguing look at the neurological basis of these disorders.
Interestingly it focused on the limbic system, which, if memory serves right, Cheney suggested was important early on. What does the Limbic system do? It regulates two systems that are involved in CFS; the endocrine system and the autonomic nervous system.
It appears to be tied to flight/fight response
Paul D. MacLean, as part of his triune brain theory, hypothesized that the limbic system is older than other parts of the brain, and that it developed to manage fight or flight circuitry which is an evolutionary necessity for reptiles as well as humans. However, recent studies of the limbic system of tetrapods have challenged some long-held tenets of forebrain evolution.
This is a large rather, poorly defined system containing these structures
- Amygdala:[4][5][6] Involved in signaling the cortex of motivationally significant stimuli such as those related to reward and fear in addition to social functions such as mating.
- Hippocampus:[4][5][6] Required for the formation of long-term memories and implicated in maintenance of cognitive maps for navigation.
- Parahippocampal gyrus:[5] Plays a role in the formation of spatial memory
- Cingulate gyrus:[4][5][6] Autonomic functions regulating heart rate, blood pressure and cognitive and attentional processing
- Fornix:[4][6] carries signals from the hippocampus to the mammillary bodies and septal nuclei.
- Hypothalamus:[4][6] Regulates the autonomic nervous system via hormone production and release. Affects and regulates blood pressure, heart rate, hunger, thirst, sexual arousal, and the sleep/wake cycle
- Thalamus:[4][6] The "relay station" to the cerebral cortex.
Psychosom Med. 2011 Jan 7. [Epub ahead of print]
Can Neuroimaging Help Us to Understand and Classify Somatoform Disorders? A Systematic and Critical Review.
Browning M, Fletcher P, Sharpe M.
Department of Psychiatry (M.B.), University of Oxford, Warneford Hospital, Oxford, United Kingdom; Department of Psychiatry (P.F.), University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; and Psychological Medicine Research (M.S.), University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, United Kingdom.
Abstract
Objective: Debate about the nature of somatoform disorders and their current diagnostic classification has been stimulated by the anticipation of new editions of Diagnostic and Statistical Manual of Mental Disorders and International Statistical Classification of Diseases and Related Health Problems diagnostic classifications.
In the current paper, we review systematically the literature on the neuroimaging of somatoform disorders and related conditions with the aim of addressing two specific questions: Is there evidence of altered neural function or structure that is specifically associated with somatoform disorders?
What conclusions can we draw from these findings about the etiology of somatoform disorders? Methods: Studies reporting neuroimaging findings in patients with a somatoform disorder or a functional somatic syndrome (such as fibromyalgia) were found using Pubmed, PsycINFO, and EMBASE database searches. Reported structural and functional neuroimaging findings were then extracted to form a narrative review.
Results: A relatively mature literature on symptoms of pain and less developed literatures on conversion and fatigue symptoms were identified. The available evidence indicates that, when compared with nonclinical groups, somatoform diagnoses are associated with increased activity of limbic regions in response to painful stimuli and a generalized decrease in gray matter density; however, methodological considerations restrict the interpretation of these findings.
Conclusions: Whereas the neuroimaging literature has provided evidence about the possible mechanisms underlying somatoform disorders, this is not yet sufficient to provide a basis for classification. By adopting a wider variety of experimental designs and a more dynamic approach to diagnosis, there is every reason to be hopeful that neuroimaging data will play a significant role in future taxonomies.E]