Somatosensory attentional modulations during pain-related movement execution.

Pain serves to protect against bodily threat, and therefore initiates protective responses such as attending toward threat-relevant information. Since pain is often exacerbated by executing movements, these motor actions may serve as cues for pain. Up to date, however, pain-related attention during movement remains largely unexplored. While it has been shown that the preparation of a pain-related movement leads to enhanced processing of somatosensory information, it is unclear how the actual execution of a movement interacts with somatosensory attention. In the current study, we examined whether somatosensory processing is enhanced at a moving body part when the movement is expected to be associated with pain. Participants were asked to execute hand movements which were occasionally followed by a pain stimulus. To measure somatosensory attention, a task-irrelevant, innocuous tactile probe was presented on either hand to evoke a somatosensory evoked potential (SEP). The results showed an elevation of the N120 SEP at the hand performing a potentially painful movement, indicating heightened attention toward tactile information at the threatened moving hand compared to the non-threatened hand. Additionally, the P200 SEP also showed enlarged responses when performing a pain-related movement compared to a no-pain-related movement. These results show that not only the anticipation, but also the execution of pain-related movements, may modulate the processing of somatosensory input, driven by attentional processes.

Factors influencing the reinforcing value of fruit and unhealthy snacks.

OBJECTIVE: The present study investigated the reinforcing value of healthy and unhealthy snack food in adolescents (n = 108, aged 14-16 years). Moderation by access to different foods, sex and the personality trait reward sensitivity is tested. METHODS: In a computerized Food Reinforcement Task, adolescents could earn portions of a healthy and an unhealthy snack following an identical progressive reinforcement schedule for both food types. Reinforcing value of food was indexed by the number of button presses for each food type. Participants were allocated randomly to two-order condition: fruit-snack versus snack-fruit. Reward sensitivity was assessed with the Dutch age-downward version of Carver and White's BIS/BAS scale. RESULTS: Results showed that the reinforcing value of an unhealthy snack is higher than that of fruit, with participants making more button presses for unhealthy snacks, M = 1280.40, SD = 1203.53, than for fruit, M = 488.04, SD = 401.45, F(1,48) = 25.37, p < 0.001. This effect is stronger in boys (ß = -1367.67) than in girls (ß = -548.61). The effect is only present in the snack-fruit condition, not in the fruit-snack condition, indicating that access to food moderates the effect of food type. There is no evidence for moderation by reward sensitivity. CONCLUSIONS: Results point to the importance of simultaneously increasing barriers to obtain unhealthy food and promoting access to healthy food in order to facilitate healthy food choices.