Brain research bulletin
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Brain research bulletin · Apr 2010
Increased sensitivity to supra-threshold painful stimuli in patients with multiple functional somatic symptoms (MFS).
Many patients in a variety of medical settings suffer from persistently painful bodily symptoms that are not explained by known pathophysiological mechanisms. In the most severe cases, these patients complain of multiple functional somatic symptoms (MFS). We tested the hypothesis of reduced pain threshold and pain tolerance levels in patients with MFS. ⋯ Pain tolerance scores were identical in the two groups but they correlated negatively with the number of functional somatic symptoms in MFS patients. Importantly, patients had a smaller temperature range between their pain threshold and pain tolerance scores, suggesting that they differentiate poorly within the noxious range. Minor increases in stimulus intensity of supra-threshold painful stimuli may lead to disproportionate increases in pain intensity in MFS patients, suggesting a defunct endogenous pain modulatory system.
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Brain research bulletin · Apr 2010
Cardiovascular and respiratory correlates of deep nociceptive stimulation, suggestions for analgesia, pain imagery and cognitive load as a function of hypnotizability.
Hypnotizability is a cognitive trait modulating some physiological responses to cognitive and physical stimulation also in the normal awake state and in the absence of specific suggestions. Aim of the study was the characterization of the cardiovascular correlates of deep pain induced by nociceptive pressor stimulation without (PAIN) and with (AN) suggestions for analgesia, pain imagery/perception (IM) and mental computation (MC) in not hypnotized highly (Highs) and low (Lows) hypnotizable healthy subjects of both genders. The subjective experience of pain intensity, relaxation and task related fatigue were measured through a structured interview. ⋯ On the whole, the haemodynamic response consisted of decreased systolic/mean blood pressure and maximum skin blood flow together with increased diastolic blood pressure/minimum skin blood flow in both groups during all conditions. Scarce differences were observed between Highs and Lows (in systolic blood pressure during IM and in respiratory amplitude during PAIN, AN and IM, modulated by gender). The results indicate that in not hypnotized subjects hypnotizability is not associated with relevant differences in the autonomic responses to deep pain, suggestions for analgesia, pain imagery/perception and cognitive load.
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Brain research bulletin · Apr 2010
Plasticity changes of neuronal activities in central lateral nucleus by stimulation of the anterior cingulate cortex in rat.
The medial thalamus (MT) and anterior cingulate cortex (ACC) are essential components in mediating the affective emotional-aspect of pain. Whether ACC modulates the neuron activity in MT has not been elucidated and clarifying this point will further reveal the neurobiological mechanism underlying pain related emotions. ⋯ Tetanic stimulation in the ACC increased spike activities of nociceptive-responding neurons in the CL; retrograde tracing by fluorogold in the CL showed the positive neurons are distributed bilaterally in the ACC. Taken together, we demonstrated descending modulation to nociceptive responses of CL neurons by direct projections from the ACC, which may underlie the neuronal mechanism of negative pain emotions.