Thermal Stimulation Changes Diffusivity of the Spinothalamic Tract.

Area of Science:

• Neuroimaging
• Spinal Cord Research
• Pain Perception

Background:

• Functional diffusion tensor imaging (fDTI) has previously detected task-related white matter activity.
• Previous studies observed increases in fractional anisotropy (FA) during functional tasks.
• This study extends fDTI research to the spinal cord during painful stimulation.

Purpose of the Study:

• To investigate task-dependent changes in spinal cord FA during painful stimulation.
• To determine if fDTI can detect changes in white matter tracts involved in pain transmission.
• To compare activity in the spinothalamic tract with control tracts.

Main Methods:

• Twenty-three healthy males underwent diffusion-weighted imaging from C2 to T4.
• A painful thermal stimulus was applied to the left thenar eminence.
• FA values in the spinothalamic tract and corticospinal tracts were analyzed.

Main Results:

• Significant task-related decreases in FA were observed in the right spinothalamic tract (C2-C5).
• No significant changes were found in control regions (ipsilateral/contralateral corticospinal tracts).
• No changes were detected in the spinothalamic tract below the C6 dermatome input level.

Conclusions:

• fDTI can detect task-related FA changes in the spinal cord during pain.
• Decreased FA in the contralateral spinothalamic tract suggests its role in pain signal transmission.
• Findings highlight the utility of fDTI for studying pain pathways in the spinal cord.