The contradictory influence of velocity: representational momentum in the tactile modality.

Representational momentum (RM) is the term used to describe a systematic mislocalization of dynamic stimuli, a forward shift; that is, an overestimation of the location of a stimulus along its anticipated trajectory. In the present study, we investigate the effect of velocity on tactile RM, because two distinct and contrasting predictions can be made, based on different theoretical accounts. According to classical accounts of RM, based on numerous visual and auditory RM studies, an increase of the forward shift with increasing target velocity is predicted. In contrast, theoretical accounts explaining spatiotemporal tactile illusions such as the tau or cutaneous rabbit effect predict a decrease of the forward shift with increasing target velocity. In three experiments reported here, a tactile experimental setup modeled on existing RM setups was implemented. Participants indicated the last location of a sequence of three tactile stimuli, which either did or did not imply motion in a consistent direction toward the elbow/wrist. Velocity was manipulated by changing the interstimulus interval as well as the duration of the stimuli. The results reveal that increasing target velocity led to a decrease and even a reversal of the forward shift, resulting in a backward shift. This result is consistent with predictions based on the evidence from tactile spatiotemporal illusions. The theoretical implications of these results for RM are discussed. NEW & NOTEWORTHY This study tests two distinct predictions concerning the influence of velocity on the localization of dynamic tactile stimuli. We demonstrate for tactile stimuli that with increasing velocity, a misperception in the direction of anticipated motion (termed "representational momentum") turns into a misperception against the direction of motion. This result is in line with predictions based on tactile spatiotemporal illusions but challenges classical theoretical accounts of representational momentum based on evidence from vision and audition.

That sounds awful! Does sound unpleasantness modulate the mismatch negativity and its habituation?

There are sounds that most people perceive as highly unpleasant, for instance, the sound of rubbing pieces of polystyrene together. Previous research showed larger physiological and neural responses for such aversive compared to neutral sounds. Hitherto, it remains unclear whether habituation, i.e., diminished responses to repeated stimulus presentation, which is typically reported for neutral sounds, occurs to the same extent for aversive stimuli. We measured the mismatch negativity (MMN) in response to rare occurrences of aversive or neutral deviant sounds within an auditory oddball sequence in 24 healthy participants, while they performed a demanding visual distractor task. Deviants occurred as single events (i.e., between two standards) or as double deviants (i.e., repeating the identical deviant sound in two consecutive trials). All deviants elicited a clear MMN, and amplitudes were larger for aversive than for neutral deviants (irrespective of their position within a deviant pair). This supports the claim of preattentive emotion evaluation during early auditory processing. In contrast to our expectations, MMN amplitudes did not show habituation, but increased in response to deviant repetition-similarly for aversive and neutral deviants. A more fine-grained analysis of individual MMN amplitudes in relation to individual arousal and valence ratings of each sound item revealed that stimulus-specific MMN amplitudes were best predicted by the interaction of deviant position and perceived arousal, but not by valence. Deviants with perceived higher arousal elicited larger MMN amplitudes only at the first deviant position, indicating that the MMN reflects preattentive processing of the emotional content of sounds.

Psychological burden of achalasia: Patients' screening rates of depression and anxiety and sex differences.

OBJECTIVE: Achalasia is associated with reduced quality of life in affected patients but research regarding the psychological burden of achalasia in terms of depression and anxiety is scarce. The current study therefore aims to investigate rates of depression and anxiety in patients with achalasia in relation to prevalence rates in the general population and to examine the extent to which achalasia-related characteristics (time since diagnosis, symptom load, achalasia-related quality of life, treatment history) predict symptoms of depression and anxiety. METHODS: Using validated screening instruments, rates of depression and anxiety were assessed in a cross-sectional survey of a sample of 993 patients with achalasia and compared to population controls stratified by age and sex. Associations between depression and anxiety and achalasia-related factors were explored using linear regression. RESULTS: Compared to population controls, screening rates of female patients with achalasia were between 3.04 (p = .004) and 7.87 (p < .001) times higher for depression and 3.10 (p < .001) times higher for anxiety, respectively. No significant differences were found for male patients with achalasia. Both achalasia-related quality of life and symptom load were independently related to impaired mental health. CONCLUSION: Women appear to be specifically affected by the psychological burden of achalasia, pointing to sex-specific or gendered experiences of the disease. In addition to symptom reduction, psychological support may prove beneficial for improving the well-being of patients with achalasia.