title: Remembering the dynamic changes in pain intensity and unpleasantness: a psychophysical study.
abstract: This study investigated the short-term memory of dynamic changes in acute pain using psychophysical methods. Pain intensity or unpleasantness induced by painful contact-heat stimuli of 8, 9, or 10s was rated continuously during the stimulus or after a 14-s delay using an electronic visual analog scale in 10 healthy volunteers. Because the continuous visual analog scale time courses contained large amounts of redundant information, a principal component analysis was applied to characterize the main features inherent to both the concurrent rating and retrospective evaluations. Three components explained about 90% of the total variance across all trials and subjects, with the first component reflecting the global perceptual profile, and the second and third components explaining finer perceptual aspects (eg, changes in slope at onset and offset and shifts in peak latency). We postulate that these 3 principal components may provide some information about the structure of the mental representations of what one perceives, stores, and remembers during the course of few seconds. Analysis performed on the components confirmed significant memory distortions and revealed that the discriminative information about pain dimensions in concurrent ratings was partly or completely lost in retrospective ratings. Importantly, our results highlight individual differences affecting these memory processes. These results provide further evidence of the important transformations underlying the processing of pain in explicit memory and raise fundamental questions about the conversion of dynamic nociceptive signals into a mental representation of pain in perception and memory.
authors: Department of Neurosciences, Université de Montréal, Montréal, Quebec, Canada Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Montréal, Quebec, Canada Centre de recherche de l'Institut universitaire de gériatrie de Montréal, Université de Montréal, Montreal, Quebec, Canada SafeBridge Consultants Inc., Mountain View, CA, USA Google Inc., Mountain View, CA, USA Department of Stomatology, Faculté de médecine dentaire, Université de Montréal, Montréal, Quebec, Canada.
authors: Mina
authors: M
authors: Khoshnejad
authors: Marie C
authors: MC
authors: Fortin
authors: Farzan
authors: F
authors: Rohani
authors: Gary H
authors: GH
authors: Duncan
authors: Pierre
authors: P
authors: Rainville
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D010146:Pain / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement / Q000379:methods / Q000523:psychology*; D058748:Pain Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012189:Retrospective Studies; D055815:Young Adult
keywords: Individual differences; Memory psychophysics; Pain dimensions; Principal component analysis; Segmentation