Mesencephalic Chronic Electrodes in Pain Patients

Abstract

Early components of lemniscal potentials after contralateral median nerve or mechanical stimulus are due to lemniscal pathways, whereas later components, after 70 msec appearing bilaterally and at higher stimulus intensities probably express extralemniscal activity. Evoked potentials in the central gray matter show much smaller amplitudes compared with somatosensory cortical evoked potentials (SSEP). The strongest component is a negative wave after 70–100 msec. Longer conditioning stimulation of the lemniscal system inhibits late components in the median nerve evoked cortical potentials. On the contrary, stimulation of the nonspecific periaqueductal gray matter produces inhibition of early components of cortical SSEP together with facilitation of late components.

The Spread of Somatosensory-Evoked Potentials Within the Nervous System

“…lb, e, f). These data were sim ilar to other authors' results but there are some controversial points [1][2][3][5][6][7][8]. We conclude that the thalamic first positive deflection must have been of medial lemniscal origin and the first negative wave was attributable to synaptic potentials of thalamic relay neurons [7].…”

“…Very few direct recordings have been carried out from the human cortex and subcortical structures on pa tients with chronic deep electrodes. Direct recordings from the thala mus [1][2][3][5][6][7][8] and the cortex [2,4] have been discussed but failed to provide definite results and conclusions.…”

Inhibition of stimulated dopamine release and hemodynamic response in the brain through electrical stimulation of rat forepaw

“…Before interpreting our results in the context of acupuncture, it is instructive to examine the prior literature on the stimulation of the median nerve. There is a large body of evidence suggesting that electrical stimulation of the median nerve can lead to pre-synaptic inhibition in the muscle [32]. This inhibition can also extend to the motor cortex and hence decrease motor input to the basal ganglia, and has been found to be abnormal in diseases with primary dopamine deficiencies such as Parkinson's disease [3].…”

Rizotomia percutânea por radiofreqüência no tratamento das algias ororrinofaringofaciais resultantes de tumores malignos

“…A ressecção cortical das áreas de projeções sensitivas da face 50,62,77 não é mais empregada para o tratamento da dor. A estimulação elétrica do grupamento nuclear talâmico posterior foi pouco aplicada no tratamento da dor facial e os resultados proporcionados foram controversos 54,90 .…”