Habituation to repeated painful and non-painful cutaneous stimuli: a quantitative psychophysical study

Abstract

Repeated stimuli elicit progressively smaller responses and elevated sensory and/or pain thresholds (habituation). The present experiments were designed to determine the rate of habituation of perceptual responses to supraliminal painful and non-painful cutaneous stimuli. Changes in the perceived intensity of electrical stimuli applied to the digital nerves of the index finger were determined by a matching procedure in which subjects set the current applied to the index finger of one hand to match the perceived intensity of a stimulus train (5 pulses at 20 Hz) applied to the other index finger. Twenty-five volunteers took part in 7 experiments in which both non-painful (2.5 times the sensory threshold Ts) and painful (1.2 times the pain threshold Tp) stimulus trains were presented. Subjects were required to match the stimuli at 30 s intervals over a period of 7.5 min. The percentage change in matching current (Y) was fitted by the function Y = -20.7*[1-exp(-0.56*t)] for both painful and non-painful stimuli repeated at 2 Hz. Responses recovered completely within 2 min of cessation of the stimulation. The degree of habituation increased or decreased with the rate of stimulus presentation. These results did not depend on changes in afferent fibre recruitment or fatigue because the afferent volley on the median nerve remained constant throughout the period of stimulation. Thus perceptual responses to the perceived intensity of supraliminal painful and non-painful stimuli delivered to the index finger habituate to the same extent, and the extent of the habituation is a function of the frequency of presentation of the stimulus.

Visually Induced Analgesia: Seeing the Body Reduces Pain

“…Additional correction of ocular artifacts was performed using blind source separation with independent components analysis (Jung et al, 2000) on epoched data. To reduce effects of pain habituation (Ernst et al, 1986;Milne et al, 1991;Valeriani et al, 2003), the first 10 trials of the experiment were eliminated, and counterbalance order was included as a between-subjects factor in ANOVAs to exclude variance attributable to habituation (supplemental data, available at www.jneurosci.org as supplemental material).…”

tDCS Modulation of Visually Induced Analgesia

“…Therefore, cathodal stimulation of the occipital and centro-parietal cortices did not modulate pain levels differently from sham. There was a significant pain reduction in the poststimulation session in comparison with the prestimulation session, independently of the tDCS session, possibly because of nociceptor habituation (Milne, Kay, & Irwin, 1991).…”

Introducing the reflex probability maps in the quantification of nociceptive withdrawal reflex receptive fields in humans

“…Constant stimulation intensity throughout the experiment causes decreasing pain intensity sensation with time, probably due to habituation of subjective pain perception to repetitive stimulation (Thompson and Spencer, 1966;Milne et al, 1991). This becomes an issue when the subjective pain ratings are used to determine the initial reflex stimulation parameters or when they become the quantifiable outcome variable in human surrogate pain models.…”