Abstract
Purpose: The cerebellum is involved in a wide number of integrative
functions, but its role in pain experience and in the nociceptive information processing
is poorly understood. In healthy volunteers we evaluated the effects of transcranial
cerebellar direct current stimulation (tcDCS) by studying the changes in the perceptive
threshold, pain intensity at given stimulation intensities (VAS:0-10) and laser evoked
potentials (LEPs) variables (N1 and N2/P2 amplitudes and latencies).
Methods: Fifteen subjects were studied before and after anodal, cathodal and
sham tcDCS. LEPs were obtained using a neodymium:yttrium–aluminium–perovskite (Nd:YAP)
laser and recorded from the dorsum of the left hand. VAS was evaluated by delivering laser
pulses at two different intensities, respectively two and three times the perceptive
threshold.
Results: Cathodal polarization dampened significantly the perceptive
threshold and increased the VAS score, while the anodal one had opposite effects. Cathodal
tcDCS increased significantly the N1 and N2/P2 amplitudes and decreased their latencies,
whereas anodal tcDCS elicited opposite effects. Motor thresholds assessed through
transcranial magnetic stimulation were not affected by cerebellar stimulation.
Conclusions: tcDCS modulates pain perception and its cortical correlates.
Since it is effective on both N1 and N2/P2 components, we speculate that the cerebellum
engagement in pain processing modulates the activity of both somatosensory and cingulate
cortices. Present findings prompt investigation of the cerebellar direct current
polarization as a possible novel and safe therapeutic tool in chronic pain patients.
