Differential effects of conventional transcranial direct current stimulation (tDCS) and high-definition transcranial direct current stimulation (HD-tDCS) of the cerebellum on offset analgesia

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I whakaputaina i:	bioRxiv (Jan 28, 2025)
Kaituhi matua:	O'connor, Niamh
Ētahi atu kaituhi:	Ashe, Hannah, Wragan, Max, O'flaherty, Ruairi, Deevy-Gray, Eoin, Witney, Alice G
I whakaputaina:	Cold Spring Harbor Laboratory Press
Ngā marau:	Signal processing Pain Cerebellum Information processing Latency Electrical stimulation of the brain > ESB Sensory integration Analgesia Placebos Pain perception
Urunga tuihono:	Citation/Abstract Full text outside of ProQuest
Ngā Tūtohu:	Tāpirihia he Tūtohu Kāore He Tūtohu, Me noho koe te mea tuatahi ki te tūtohu i tēnei pūkete!

Whakaahuatanga
Whakarāpopotonga:	Background: Offset analgesia (OA) describes the large decrease in perceived pain in response to a minor decrease in applied painful thermal stimulus. Here non-invasive brain stimulation (NIBS) is used to modulate the cerebellum, since the cerebellum is known to signal sensory prediction errors and implicated in pain processing. Methods: An OA protocol individualized to heat pain threshold (HPT) was applied via TSA-II (Medoc, Israel). NIBS interventions were applied prior to OA. Cathodal cerebellar transcranial direct current stimulation (tDCS) and high-definition (4X1) transcranial direct current stimulation (HD-tDCS) were applied to 46 healthy participants within a sham controlled repeated measures design to examine whether diffuse or focal stimulation differentially modulates OA. Results: OA induced hypoalgesia was robust, with 90% of responses showing a drop in perceived pain (δVAS) > 10 following the 1°C fall in temperature. This OA response was augmented following a protocol with sham and focal cathodal cerebellar stimulation on four OA parameters (OA latency, VAS minimum, VAS mean and VAS 2nd max) relative to pre-stimulation. This effect was differential to the protocol with sham and conventional tDCS where two OA metrics altered (OA duration, VAS 2nd max). Conclusion: OA enhancement via cathodal cerebellar NIBS may involve both a placebo effect and sustaining a noxious sensory prediction error. Understanding how the cerebellum is involved in OA could enhance therapies for pain patients.Competing Interest StatementThe authors have declared no competing interest.Footnotes* There are updates to the introduction, including missing references
ISSN:	2692-8205
DOI:	10.1101/2024.10.03.616281
Puna:	Biological Science Database