Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Geert Crombez x
  • Search level: All x
Clear All

Localizing pain not only requires a simple somatotopic representation of the body, but also knowledge about the limb position (i.e., proprioception), and a visual localization of the pain source in external space. Therefore, nociceptive events are remapped into a multimodal representation of the body and the space nearby (i.e., a peripersonal schema of the body). We investigated the influence of visual cues presented either in peripersonal, or in extrapersonal space on the localization of nociceptive stimuli in a temporal order judgement (TOJ) task. 24 psychology students made TOJs concerning which of two nociceptive stimuli (one applied to each hand) had been presented first (or last). A spatially non-predictive visual cue (i.e., lighting of a LED) preceded (80 ms) the nociceptive stimuli. This cue was presented randomly either on the hand of the participant (in peripersonal space), or 70 cm in front of the hand (in extrapersonal space), and either on the left or on the right side of space. Biases in spatial attention are reflected by the point of subjective simultaneity (PSS). The results revealed that TOJs were more biased towards the visual cue in peripersonal space in comparison with the visual cue in extrapersonal space. This study provides evidence for the crossmodal integration of visual and nociceptive stimuli in a peripersonal schema of the body. Future research with this paradigm will explore crossmodal attention deficits in chronic pain populations.

In: Seeing and Perceiving

Introduction: There is preliminary evidence that viewing touch or pain can modulate the experience of tactile stimulation. The aim of this study was to develop an experimental paradigm to investigate whether the observation of needle pricks to another person’s hand facilitates the detection of subtle somatic sensations. Furthermore, differences between control persons and persons reporting synaesthesia for pain (i.e., experiencing observed pain as if it is their own pain) will be examined.

Method: Synaesthetes (n=15) and controls (n=20) were presented a series of videos showing left or right hands being pricked and control videos (e.g., a sponge being pricked), whilst receiving occasionally subtle threshold sensations themselves on the hand in the same spatial location (congruent trials) or in the opposite location (incongruent trials) as the visual stimuli. Participants were asked to detect the sensory stimulus. Signal detection theory was used to compare whether sensitivity was different for both groups and both categories of visual stimuli.

Results: Overall, perceptual sensitivity (d′) was significantly higher when the visual stimuli involved a painful situation (e.g., needle pricking another’s hand) compared to the control videos, and was significantly lower in synaesthetes compared to control participants. When no sensory stimulus was administered, participants reported significantly more illusory sensations when a painful situation was depicted compared to a non-painful situation.

Discussion: This study suggests that the detection of somatic sensations can be facilitated or inhibited by observing visual stimuli. Synaesthetes were generally less sensitive, suggesting that they experience more difficulties in disentangling somatic and visual stimuli.

In: Seeing and Perceiving