BOLD responses to itch in the human spinal cord

Area of Science:

• Neuroscience
• Sensory Physiology
• Medical Imaging

Background:

• Itch is a common symptom with diverse causes, but its central nervous system representation, particularly in the human spinal cord, remains poorly understood.
• Knowledge of neuronal correlates of itch in the human spinal cord is limited, hindering a complete understanding of itch perception.

Purpose of the Study:

• To identify itch-related neural activity in the cervical spinal cord of healthy volunteers.
• To investigate the neuronal basis of itch perception noninvasively using high-resolution functional magnetic resonance imaging (fMRI).

Main Methods:

• Histamine-induced itch was studied on the radial forearm in healthy volunteers.
• Itch intensity was modulated using non-noxious cooling, with control sessions without histamine.
• High-resolution functional magnetic resonance imaging (fMRI) was employed to detect neural activity in the cervical spinal cord.

Main Results:

• Non-noxious cooling of histamine-treated skin significantly increased itch perception compared to cooling non-treated skin.
• Itch perception was associated with neural activation in the dorsal horn of the spinal cord.
• This activation was observed at the C5-C6 spinal segment transition, ipsilateral to the stimulated side.

Conclusions:

• Itch-related neural activity can be noninvasively assessed in the human spinal cord.
• The findings suggest a specific spinal cord location for processing itch signals.
• This research provides a foundation for further investigation into the neurobiology of itch.