Modulation of SI and ACC response to noxious and non‐noxious electrical stimuli after the spared nerve injury model of neuropathic pain

Abstract

Background The current knowledge on the role of SI and ACC in acute pain processing and how these contribute to the development of chronic pain is limited. Our objective was to investigate differences in and modulation of intracortical responses from SI and ACC in response to different intensities of peripheral presumed noxious and non‐noxious stimuli in the acute time frame of a peripheral nerve injury in rats. Methods We applied non‐noxious and noxious electrical stimulation pulses through a cuff electrode placed around the sciatic nerve and measured the cortical responses (six electrodes in each cortical area) before and after the spared nerve injury model. Results We found that the peak response correlated with the stimulation intensity and that SI and ACC differed in both amplitude and latency of cortical response. The cortical response to both noxious and non‐noxious stimulation showed a trend towards faster processing of non‐noxious stimuli in ACC and increased cortical processing of non‐noxious stimuli in SI after SNI. Conclusions We found different responses in SI and ACC to different intensity electrical stimulations based on two features and changes in these features following peripheral nerve injury. We believe that these features may be able to assist to track cortical changes during the chronification of pain in future animal studies. Significance This study showed distinct cortical processing of noxious and non‐noxious peripheral stimuli in SI and ACC. The processing latency in ACC and accumulated spiking activity in SI appeared to be modulated by peripheral nerve injury, which elaborated on the function of these two areas in the processing of nociception.

Interfacing the Pig Cortex - Towards a Translational Large Animal Model of LTP-Like Pain

“…Moreover, due to the extended features of the stereotaxic frame like multi-micromanipulator compatibility, multi-electrode recording can be explored in future experiments with large animals in which multiple cortical regions can be recorded simultaneously. These areas could be the ACC, S1 and the PFC, which are known for their role in pain processing (Luo & Wang, 2009), (Tøttrup et al, 2021), (Cardoso-Cruz et al, 2013).…”