Background & Aims
Learning to avoid harm is crucial for survival, with pain-related stimuli capturing attention and eliciting anticipatory responses [1,2]. Tonic painful injuries may result in altered spatial perception and distinct responses to looming threats [3]; however, little is known about the neural processes underlying pain anticipation after injury. This study investigates neurophysiological anticipatory responses to pain-related cues in the presence and absence of tonic pain.
Methods
Using a novel multisensory approach, twenty-six healthy participants viewed a dynamic forest scene with a head-mounted display. Animated cues differentiated by colour were followed by an audio-visual stimulus looming towards the left or right side of the body or the ground. During conditioning, left and right looming objects were accompanied by electrical pain stimuli on the corresponding forearm. During extinction, pressure cuffs were inflated to deliver lateralized tonic pain to the upper arm, and phasic electrical pain was not delivered. EEG power spectral changes (event-related desynchronisation and synchronisation, ERD/ERS) [4,5] following the cue were monitored alongside virtual-reality eye-tracking data. Linear mixed-effects models assessed differences in eye-tracking and EEG alpha-band power spectra for pain-predictive versus neutral cues during conditioning and extinction, and for pain-predictive cues congruent versus incongruent to tonic pain during extinction.
Results
Distinct neurophysiological responses emerged during conditioning, with augmented central and parietal alpha ERD following pain-related versus neutral cues. Additionally, looming objects following pain-related versus neutral cues were accompanied by greater pupil diameter. Tonic pain laterality influenced cortical activation changes during extinction, with stronger parietal and occipital alpha ERD for congruent versus incongruent pain-related cues. This effect did not modulate pupil responses. Combined, these findings suggest changes in attention and sensorimotor activation during phasic pain anticipation. Additionally, heightened spatial attention and sensory processing are preserved during extinction when previously pain-predictive cues are congruent with tonic pain location.
Conclusions
In conclusion, our study unveils enhanced anticipatory responses to pain-predictive cues, as indicated by pupil diameter dilation and cortical oscillatory changes in the alpha band. Tonic pain laterality exhibits a top-down attentional effect on cortical oscillatory changes in the alpha band. This novel multisensory method provides insights into pain learning during tonic pain, with potential implications for understanding the transition from acute post-injury pain to chronic pain.
References
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Presenting Author
Danielle Hewitt
Poster Authors
Danielle Hewitt
PhD
Wellcome Centre for Integrative Neuroimaging, University of Oxford
Lead Author
Shuangyi Tong
BMath
University of Oxford
Lead Author
Sarah Schreiber
BSc
University of Oxford
Lead Author
Ben Seymour
BSc MB ChB PhD MRCP FRSA
University of Oxford
Lead Author
Topics
- Models: Acute Pain