Investigation of Corticospinal Excitability Aspects of Itch and Pain

A bolus injection of hypertonic saline (7% NaCl) will be administered to the FDI muscle using a 1 mL syringe with a disposable needle (27G), and the volume of the bolus will be 0.2 mL

A small drop of histamine dihydrochloride will be applied to a previously determined area on the volar forearm, followed by a prick through the drop

This insertion is conducted by forceps using a stereo-microscope, and 30-35 spicules are gently rubbed into a 1 cm diameter skin area.

Transcranial magnetic stimulation (TMS) will be used to evoke motor-evoked potentials (MEPs) in the muscle of interest and cortical responses (TMS-evoked potentials - TEPs) in the motor cortex with a figure-eight-shaped cone coil.