Figure 1.
Anterolateral cordotomy induces marked deficits in canonical lamina I-spinothalamic tract modalities but not in psychophysical affective touch metrics. (A) The organization of the lamina I-spinothalamic pathway. (B) Schematic showing the anterolateral cordotomy procedure. Radiofrequency lesions are given through the cordotomy electrode within the anterolateral funiculus. (C) Exemplar T2 weighted axial magnetic resonance image at the cervical-level C2 showing a lesion in the right anterolateral funiculus. (D) Bar charts showing that temperature detection, clinical pain, and cowhage-induced itch are all largely abolished by contralateral spinothalamic tract lesioning, data are presented as mean and standard error; post-cordotomy values are expressed as a percentage of pre-cordotomy function; significant differences (Related-Samples Wilcoxon Signed Rank Test) are marked with asterisks and show ****P < .0005. However, ratings of the pleasantness of gentle stroking touch show an inverted U-shaped curve that is unchanged by cordotomy (E) (Group data shown as mean and standard error. The lines of best fit with 95% confidence intervals are shown. The vertical dotted line indicates the position of a velocity of 1 cm s−1 on the logarithmic scale).