Anti-nociception induced by high-intensity electrical brain stimulation

Abstract

A universal, and possibly one of the most frequent symptomatic motives to explore professional medical attention, is pain. Pain is defined as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage” by The International Association for the Study of Pain. Additionally, over the years, local field potential (LFP) has grown in interest for many researchers. The LFP is known to demonstrate the activity of neurons around the recording electrode in a localized area, and can be subdivided into 5 frequency bands of delta (0.1 – 3 Hz), theta (3 – 7 Hz), alpha (7 – 12 Hz), beta (12 – 30 Hz), and gamma (30 – 100 Hz). Known as a seizure-inducing stimulation, a higher intensity of stimulation is the principal application of electroconvulsive therapy (ECT). For many decades, ECT has been used as a treatment in individuals with critical mood and psychotic disorders who have shown a resistance to previous treatments used. ECT has also been revealed to be effective for chronic pain. The purpose of this study is to determine the effect of ECT on LFP activities from various brain regions responding to nociceptive stimuli in anesthetized animals as well as assessing the formalin-induced behavioral activity with ECT treatment in freely-moving animals. The hypothesis is that ECT will suppress pain, as indicated by suppressing the LFP power by activation of the descending inhibitory system, and by reduction of formalin-behavior response. In the present study, LFPs will be recorded simultaneously from the contralateral anterior cingulate cortex (ACC), ventral tegmental area (VTA), and bilateral central amygdala (left and right CeA). In this study, there are two specific aims: (1) To determine the effect of ECT on the reduction of formalin-induced LFP power in anesthetized animals, and (2) to assess the formalin-induced behavioral activity with ECT treatment in freely-moving animals. This study revealed that (1) ECT has a trend of a brief suppressive effect on formalin-induced LFP power when administered after formalin injection, and (2) in behavioral testing, ECT administration produced significant pain-relief results in comparison to the control group. In conclusion, the results from this study demonstrates ECT stimulation yielding anti-nociceptive properties.