Effects of reward and stimulus modality on stimulus-preceding negativity.

The present study aimed to investigate the effect of reward and stimulus modality of feedback stimuli on the stimulus-preceding negativity. A time estimation task was performed, and (a) the motivational level (reward and no-reward) and (b) the stimulus modality (auditory and visual) of feedback stimuli were manipulated. The results demonstrated that the stimulus-preceding negativity was larger in the reward than in the no-reward condition, especially at the right frontal and the left occipito-temporal areas. Moreover, the stimulus-preceding negativity prior to visual feedback stimuli was larger over the occipital areas than in the auditory condition. In contrast, at the prefrontal areas, the amplitude prior to auditory feedback stimuli was larger than in the visual condition. Our results revealed that the prefeedback stimulus-preceding negativity was independently influenced by stimulus modality and motivation.

Effects of information and reward on stimulus-preceding negativity prior to feedback stimuli.

The purpose of the present study was to investigate the effects of informational and motivational level of feedback stimuli on the stimulus-preceding negativity (SPN). In the time estimation task, in which a visual stimulus was presented 3 s after a voluntary movement, (a) the information level (high information and low information) and (b) the motivation level (reward and no-reward) for feedback stimuli were manipulated. Under the high-information condition, subjects received feedback information about (1) correctness (correct or incorrect), (2) direction of error (under- or overestimate), and (3) degree of accuracy (accurate or less accurate) of their time estimation. In the low-information condition, however, they received information about the correctness only. In the reward condition, they received a monetary reward for accurate time estimations but received nothing in the no-reward condition. The results demonstrated a significant interaction of information by motivation level, showing that the SPN amplitude under the reward/high-information was larger than that in the no-reward/high-information condition. The results are discussed in terms of emotional anticipation, taking into consideration the result of self-report that subjects felt to be more motivated when they received precise information.