Is Nociceptive Processing Evoked by Heat Homeostatically Regulated: A Contact-heat Evoked Potentials Study

Summary

Homeostatic plasticity is a mechanism that stabilizes neuronal activity to prevent excessive nervous system excitability. This mechanism can be investigated in humans by applying two blocks of non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS). In healthy subjects, homeostatic plasticity induction over the primary motor cortex increases the amplitude of motor-evoked potentials after the first block of excitatory tDCS, which then decreases after the second block of excitatory tDCS. However, this mechanism is impaired in chronic and experimental pain, demonstrated by an increase in excitability instead of a reversal. The role of homeostatic plasticity mechanisms in pain is yet to be unraveled, but homeostatic plasticity may hold an important role in pain development or persistence. Thus, the aim of this study is to investigate if the cortical nociceptive response reflected by contact heat stimulation (CHEPs) is regulated by homeostatic mechanisms. For this, homeostatic plasticity will be induced in both the primary motor (M1) and sensory cortices (S1). The first research question will explore if the contact heat evoked potentials are homeostatically regulated and if this regulation is occurring locally or globally in the cortex. Additionally, it will be investigated if and how capsaicin-induced nociception interacts and effects the homeostatic response as reflected by CHEPs.

Timeline

Start

2023-11-21

Primary completion

2024-03-04

Completion

2024-03-04

Publications

• Background Wittkopf PG, Larsen DB, Gregoret L, Graven-Nielsen T. Prolonged corticomotor homeostatic plasticity - Effects of different protocols and their reliability. Brain Stimul. 2021 Mar-Apr;14(2):327-329. doi: 10.1016/j.brs.2021.01.017. Epub 2021 Jan 24. No abstract available.
• Background Wittkopf PG, Larsen DB, Graven-Nielsen T. Protocols for inducing homeostatic plasticity reflected in the corticospinal excitability in healthy human participants: A systematic review and meta-analysis. Eur J Neurosci. 2021 Aug;54(4):5444-5461. doi: 10.1111/ejn.15389. Epub 2021 Jul 30.
• Background Wittkopf PG, Boye Larsen D, Gregoret L, Graven-Nielsen T. Disrupted Cortical Homeostatic Plasticity Due to Prolonged Capsaicin-induced Pain. Neuroscience. 2023 Nov 21;533:1-9. doi: 10.1016/j.neuroscience.2023.09.011. Epub 2023 Sep 27.
• Background Thapa T, Graven-Nielsen T, Schabrun SM. Aberrant plasticity in musculoskeletal pain: a failure of homeostatic control? Exp Brain Res. 2021 Apr;239(4):1317-1326. doi: 10.1007/s00221-021-06062-3. Epub 2021 Feb 26.
• Background Thapa T, Graven-Nielsen T, Chipchase LS, Schabrun SM. Disruption of cortical synaptic homeostasis in individuals with chronic low back pain. Clin Neurophysiol. 2018 May;129(5):1090-1096. doi: 10.1016/j.clinph.2018.01.060. Epub 2018 Feb 9.
• Background Lejeune N, Petrossova E, Frahm KS, Mouraux A. High-speed heating of the skin using a contact thermode elicits brain responses comparable to CO2 laser-evoked potentials. Clin Neurophysiol. 2023 Feb;146:1-9. doi: 10.1016/j.clinph.2022.11.008. Epub 2022 Nov 24.
• Background Lenoir C, Algoet M, Mouraux A. Deep continuous theta burst stimulation of the operculo-insular cortex selectively affects Adelta-fibre heat pain. J Physiol. 2018 Oct;596(19):4767-4787. doi: 10.1113/JP276359. Epub 2018 Sep 4.

Drugs

Indications

No indication recorded.