5. The Significance of the Non-specific Thalamic Nucleus in Pain

Keiji SANO, Masumi YOSHIOKA, Motohide OGASHIWA, Buichi ISHIJIMA, Chihiro OHYE, Hiroaki SEKINO, Yoshiaki MAYANAGI
1966 Neurologia medico-chirurgica  
normal. Case 2) A 25-year-old woman suffering from central pain of unknown origin was subjected to destruction of CM and Pf. In this case sensations of touch, pain and temperature were almost lost before operation. After operation all the other modalities of sensations completely recovered and the pain disappeared. According to these results, it may be supposed that there are somatotopic arrangements in CM as well as in specific thalamic nuclei. 5. This report is based mainly on clinical
more » ... of stereotaxic destruction of the posterior half of the internal medullary lamina of the thalamus (thalamolaminotomy) and experiments on cats. In patients with intractable pain, electrical stimulation of the inferior and medial portion of the posterior half of the internal medullary lamina, namely the area comprising the parvo-cellular portion of the centre median, the parafascicular nucleus, the nucleus limitans and other intralaminar nuclei, causes a marked increase of spontaneous pain, of which patients are complaining, irrespective of the side of stimulation, and at the same time, when stimulation is stronger, elicits diffuse burning pain on the side contralateral to the side of stimulation. Low frequency stimulation of the area produces a peculiar pattern of evoked potentials obtained from the scalp. Destruction of the area results in remarkable alleviation of pain with practically no sensory impairment. It is proved in cats that the C fibers and the slow A delta fibers are densely distributed in the internal medullary lamina. The latter, however, not only is the terminal of the so-called paleo-spinothalamic fibers, but is exerting a strong facilitatory influence on the specific sensory thalamic nucleus and the somato-sensory cortex. The therapeutic effects of the thalamolaminotomy may be explained by these two facts: namely, (1) by destruction of the thalamic terminal of the C fibers and the slow A delta fibers which are concerned with intractable pain in most cases (without injuring the specific sensory A delta fiber system); (2) by destruction of the facilitatory mechanism for the specific somato-sensory system. -280-
doi:10.2176/nmc.8.280 fatcat:gppnxiircvforeqnuxm3lsk2pu