Wouter Durnez

The anticipation of pain at a specific location of the body prioritizes tactile stimuli at that location

&NA; This study shows that the anticipation of pain at a particular location of the body prioritizes somatosensory sensations at that particular location of the body. &NA; This study investigated whether one becomes more quickly aware of innocuous somatosensory signals at locations of the body where pain is anticipated. Undergraduate students (N = 20) indicated which of 2 stimuli that were administered to each hand using a range of stimulus onset asynchronies (SOAs), was presented first. Participants were instructed that the color of a cue (1 of 2 colors) signaled the possible occurrence of pain on 1 hand (threat trials). The other color of the cue signaled that no pain would follow (control trials). Results showed that during threat trials tactile stimuli on the hand where pain was expected, were perceived earlier in time than stimuli on the “neutral” hand. These findings demonstrate that the anticipation of pain at a particular location of the body resulted in the prioritization in time of somatosensory sensations at that location, indicating biased attention towards the threatened body part. The value of this study for investigating hypervigilance for somatosensory signals in clinical populations such as patients with chronic lower back pain is discussed.

Trying to Fix a Painful Problem: The Impact of Pain Control Attempts on the Attentional Prioritization of a Threatened Body Location

UNLABELLED Motivational accounts of pain behavior and disability suggest that persisting attempts to avoid or control pain may paradoxically result in heightened attention to pain-related information. We investigated whether attempts to control pain prioritized attention to the location where pain was expected, using a tactile change detection paradigm. Thirty-seven undergraduate students had to detect changes between 2 consecutively presented patterns of tactile stimuli at various body locations. One of the locations was made threatening by occasionally administering a pain-eliciting stimulus. Half of the participants (pain control group) were encouraged to actively avoid the administering of pain by pressing a button as quickly as possible, whereas the other participants (comparison group) were not. The actual amount of painful stimuli was the same in both groups. Results showed that in the comparison group, the anticipation of pain resulted in better detection of tactile changes at the pain location than at the other locations, indicating an attentional bias for the threatened location. Crucially, the pain control group showed a similar attentional bias, but also when there was no actual presence of threat. This suggests that although threat briefly prioritized the threatened location, the goal to control pain did so in a broader, more context-driven manner. PERSPECTIVE This study investigates the impact of attempts to control pain on somatosensory processing at the pain location. It provides further insight into the motivational mechanisms of pain-related attention. It also points to the negative consequences of trying to control uncontrollable pain, such as is often the case in chronic pain.

Is attentional prioritization on a location where pain is expected modality-specific or multisensory?

Previous research suggests that anticipating pain at a particular body location prioritizes somatosensory input at that location. The present study tested whether this prioritization effect is limited to somatosensory information (modality-specific hypothesis) or generalizes to other sensory modalities (multisensory hypothesis). Thirty-four students performed tactile and visual Temporal Order Judgment (TOJ) tasks while either expecting a painful stimulus on one of the hands (threat), or expecting no pain stimulus (control). Participants judged the order of either two visual stimuli (visual condition) or two tactile stimuli (tactile condition), one on each hand. Analyses revealed that only in threat trials, participants became aware of stimuli on the threatened hand more quickly as compared to the neutral hand, replicating the prioritization effect. Of particular interest, this effect was not different between the tactile and visual conditions. This suggests that the anticipation of pain results in multisensory prioritization of information at the threatened body location.

Detection of Tactile Change on a Bodily Location Where Pain is Expected

As it is adaptive to accurately detect and localize bodily threats, it has been proposed that the brain prioritizes somatosensory input at body locations where pain is expected. To test this proposition, the detection of tactile changes on a body location was investigated to assess whether detection was facilitated by threat of pain. Healthy participants (N = 47) indicated whether two consecutive patterns of three tactile stimuli were the same or not. Stimuli could be administered at eight possible locations. In half of the trials, the same pattern was presented twice. In the other half, one stimulus location was different between the two displays. To induce bodily threat, a painful stimulus was occasionally administered to the non-dominant lower arm. Mean accuracy of tactile change detection as a function of location was analyzed using repeated-measures analysis of variance (ANOVA). Tactile changes on the threatened arm (i.e., when a tactile stimulus emerged at or disappeared from that arm), both at the exact pain location (lower arm) and at the other location (upper arm), were better detected than tactile changes on other limbs.

Attentional prioritisation of threatening information: Examining the role of the size of the attentional window

In line with most models of emotion, research has shown that threatening information receives attentional priority over neutral information. Recently, it has been suggested that the degree to which participants divide their attention across the visual field (the attentional window) may modulate the extent to which salient objects are attentionally prioritised. In the current study, participants were required to identify a target inside one of a variable number of coloured circles. One colour (Conditioned Stimulus, CS +) was fear-conditioned using an electrocutaneous stimulus at tolerance level. This search task was combined with a go/no-go task that required participants to either divide attention across the visual field to create a broad attentional window (global group), or focus their attention on the fixation point to create a narrow attentional window (local group). The results showed that only in the global group was the CS + colour prioritised over the neutral colours, indicating that a broader attentional window leads to enhanced attentional prioritisation of threat. Implications for research on attentional bias to threat are discussed.

DETECTION OF TACTILE CHANGE ON A BODILY LOCATION WHERE PAIN IS EXPECTED1,2

As it is adaptive to accurately detect and localize bodily threats, it has been proposed that the brain prioritizes somatosensory input at body locations where pain is expected. To test this proposition, the detection of tactile changes on a body location was investigated to assess whether detection was facilitated by threat of pain. Healthy participants (N = 47) indicated whether two consecutive patterns of three tactile stimuli were the same or not. Stimuli could be administered at eight possible locations. In half of the trials, the same pattern was presented twice. In the other half, one stimulus location was different between the two displays. To induce bodily threat, a painful stimulus was occasionally administered to the non-dominant lower arm. Mean accuracy of tactile change detection as a function of location was analyzed using repeated-measures analysis of variance (ANOVA). Tactile changes on the threatened arm (i.e., when a tactile stimulus emerged at or disappeared from that arm), both at the exact pain location (lower arm) and at the other location (upper arm), were better detected than tactile changes on other limbs.

Let it be? Pain control attempts critically amplify attention to somatosensory input

Recent studies have suggested that the threat of pain may redirect attention towards specific features of the pain stimulus via attentional control settings. For instance, it has been shown that anticipating pain results in attentional prioritization of the location where pain is expected. In contemporary theories on attention and pain, it has been argued that pain control motivation—e.g., attempting to avoid pain—is capable of enhancing these effects. The present study investigated if the threat of pain prioritizes attention towards somatosensory input over other sensory information, and if pursuing a pain control goal augments this effect. In a Temporal Order Judgment experiment, 41 participants were presented with visuo-tactile stimulus pairs and asked to judge which stimulus they had perceived first. Half of all trials were associated with the threat of acute pain, while the other half was not. Furthermore, half of our sample was encouraged to avoid the administration of pain by means of a specified behavioral response, whereas the other half was not. In line with our hypotheses, we found the threat of pain to prioritize attention towards the somatosensory modality, i.e., participants tended to perceive the tactile stimulus as occurring earlier in time than the visual stimulus. Interestingly, in-depth analyses suggested that this effect was predominantly carried by participants who were engaged in pain control efforts. These findings support the idea that pain goals exert top–down attentional control prioritizing pain-relevant sensory information. Clinical relevance and future directions are discussed.

No Evidence for Threat-Induced Spatial Prioritization of Somatosensory Stimulation during Pain Control Using a Synchrony Judgment Paradigm

Topical research efforts on attention to pain often take a critical look at the modulatory role of top-down factors. For instance, it has been shown that the fearful expectation of pain at a location of the body directs attention towards that body part. In addition, motivated attempts to control this pain were found to modulate this prioritization effect. Such studies have often used a temporal order judgment task, requiring participants to judge the order in which two stimuli are presented by indicating which one they perceived first. As this constitutes a forced-choice response format, such studies may be subject to response bias. The aim of the current study was to address this concern. We used a ternary synchrony judgment paradigm, in which participants judged the order in which two somatosensory stimuli occurred. Critically, participants now also had the option to give a ‘simultaneous’ response when they did not perceive a difference. This way we eliminated the need for guessing, and thus reduced the risk of response bias. One location was threatened with the possibility of pain in half of the trials, as predicted by an auditory cue. Additionally, half of the participants (pain control group) were encouraged to avoid pain stimuli by executing a quick button press. The other half (comparison group) performed a similar action, albeit unrelated to the occurrence of pain. Our data did not support threat-induced spatial prioritization, nor did we find evidence that pain control attempts influenced attention in any way.

Do Not Disturb: Psychophysiological Correlates of Boredom, Flow and Frustration During VR Gaming

Since the technology behind virtual reality (VR) is evolving rapidly and the number of VR applications is growing every year, research on the user’s experience of being in the virtual environment itself and the methodologies to measure these experiences becomes highly important. In this study, we apply the methodology of measuring attentional allocation by means of a dual-task paradigm to the topic of VR gaming. The idea is to ask participants to react to oddball sounds (secondary task), pulling attention away from the primary task (the game). The behavioral (reaction time and accuracy) and neural response (P300 component) to these oddball sounds then tells us something about indirect attentional allocation to the game and possibly the experience of flow. In order to check the latter, we created experiences of boredom, flow and frustration by manipulating the mechanics of the game. In addition, we were interested in other psychophysiological correlates like brain oscillations and average heart rate and whether these differed between gaming with a regular and a VR set-up. Although we were not able to accurately induce feelings of boredom, flow and frustration and could not replicate previous studies showing increased reaction times for oddball sounds during flow, we did find a decreased P300 and more high-frequency brain oscillations in VR compared to regular gaming (indicating more attention to the game). Together, this suggests that psychophysiological measures are promising tools to quantify attentional allocation in VR, but more research is needed to clarify whether and how this translates to flow.

Observing social stimuli influences detection of subtle somatic sensations differently for pain synaesthetes and controls

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.