NCT06197529

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

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 18 (actual)
• Sponsor: Aalborg University · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

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.

Detailed description

Randomized, cross-over study of four sessions

Conditions

• Healthy

Interventions

Type	Name	Description
OTHER	Homeostatic Plasticity	Anodal tDCS S1/M1
DRUG	Topical alone (Capsaicin 8% Patch)	4x4 patch
OTHER	Placebo Patch	4x4 patch
OTHER	Homeostatic Plasticity (Sham)	sham Homeostatic Plasticity protocol over S1

Timeline

• Start date: 2023-11-21
• Primary completion: 2024-03-04
• Completion: 2024-03-04
• First posted: 2024-01-09
• Last updated: 2024-05-16

Locations

1 site across 1 country: Denmark