Cerebral and cerebrospinal processes underlying counterirritation analgesia.

نویسندگان

  • Mathieu Piché
  • Marianne Arsenault
  • Pierre Rainville
چکیده

Pain is a complex experience involving extensive interactions between brain and spinal cord processes. Various interventions that modulate pain, such as the application of a competing noxious stimulus (counterirritation), are thought to involve cerebrospinal regulation through diffuse noxious inhibitory controls (DNICs). However, no study has yet examined the relation between brain and spinal cord activity during counterirritation analgesia in humans. This fMRI study investigates brain responses to phasic painful electrical stimulation administered to the sural nerve to evoke a spinal nociceptive response (RIII reflex) before, during and after counterirritation induced by the immersion of the left contralateral foot in cold water. Responses are compared with a control condition without counterirritation. As expected, counterirritation produced robust pain inhibition with residual analgesia persisting during the recovery period. In contrast, RIII reflex amplitude was significantly decreased by counterirritation only in a subset of subjects. Modulatory effects of counterirritation on pain perception and spinal nociception were paralleled by decreased shock-evoked activity in pain-related areas. Individual changes in shock-evoked brain activity were specifically related to analgesia in primary somatosensory cortex (SI), anterior cingulate cortex and amygdala, and to RIII modulation in supplementary motor area and orbitofrontal cortex (OFC). Moreover, sustained activation induced by the counterirritation stimulus in the OFC predicted shock-pain decrease while sustained activity in SI and the periaqueductal gray matter predicted RIII modulation. These results provide evidence for the implication of at least two partly separable neural mechanisms underlying the effects of counterirritation on pain and spinal nociception in humans.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Pregnancy and vaginal delivery in epidural analgesia in woman with cerebrospinal fluid shunt.

Hydrocephalus is a medical condition characterized by enlargement of cerebral ventricles due to abnormal cerebrospinal fluid accumulation. Hydrocephalic women with cerebrospinal fluid (CSF) shunts are now surviving to reproductive age, but still there are doubts regarding the mode of delivery, analgesia and anesthesia. Postpartal complications are more frequently described in deliveries ended b...

متن کامل

Bedside prediction of central venous catheter insertion depth.

1 Grady RE, Horlocker TT, Brown RD, the Mayo Perioperative Outcomes Group. Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: implications for regional anaesthesia. Anesth Analg 1999; 88: 388–92 2 Chater SN, Greig AJ, Sugden JC. Epidural anaesthesia in the presence of a cerebral tumour. Anaesthesia 1987; 42: 433–4 3 Hilt H, G...

متن کامل

Postpartum subdural hygroma after epidural analgesia.

THE formation of cranial subdural hematomas after lumbar puncture is a well-known complication of spinal anesthesia, although rare in young patients. Pathogenesis of this condition has been related to rupture of bridging veins joining the cerebral surface and the dura mater. The precipitating event in these cases is the continuous leakage of cerebrospinal fluid through the dural hole. More unus...

متن کامل

Penetration of intravenous hydroxyethyl starch into the cerebrospinal fluid in patients with impaired blood-brain barrier function.

UNLABELLED Hypovolemic patients with impairment of the blood-brain barrier may receive IV hydroxyethyl starch (HES) to stabilize cardiovascular function and to increase cerebral perfusion pressure. It is not known whether HES can penetrate into the cerebrospinal fluid (CSF) under those conditions. We investigated plasma and CSF levels of HES after IV infusion in patients with suspected disturba...

متن کامل

Studies on the Relief of Pain by Counterirritation.

Counterirritation has always been one of the most important methods available to physicians for the relief of pain, yet it is poorly understood and in recent years has claimed scant attention. Our purpose was to experience, study, and analyze the phenomena of counterirritation in the hope of obtaining information which would lead to the improvement of the clinical methods now in use. The extrem...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • The Journal of neuroscience : the official journal of the Society for Neuroscience

دوره 29 45  شماره 

صفحات  -

تاریخ انتشار 2009