Multisensory integration and age-dependent sensitivity to body representation modification induced by the rubber hand illusion.

The aim of the present study was to compare junior and senior healthy participants for their multimodal integration capability. The instrument used for the investigation was the rubber hand illusion (RHI) where synchronous and asynchronous multimodal stimulation were applied. The study focused on assessing the rate of integration for visuo-tactile and visuo-proprioceptive stimuli. METHODS: From a large sample of right-handed volunteers, 50 senior employees (containing younger and middle age adults) and 51 senior retired (senior adults) participants were recruited. RESULTS: The between-subject analyses revealed that individuals both the junior and the senior participants responded to induction of RHI with vivid ownership and disownership experiences and a higher mislocalization error in the synchronous condition. However, the between-group analysis showed that participants in the senior group reported less vivid ownership and less vivid total RHI experiences scores compared to members of the junior group, but no mislocalization error differences were found between the groups. CONCLUSION: The results indicated that when visuo-tactile stimuli synchronously presented, the gain in multisensory integration decreased in seniors group. In contrast, in the case of visuo-proprioceptive synchronous presentation, the efficiency of multisensory integration remained unchanged across the lifespan.

Association of Gait Characteristics and Depression in Patients with Parkinson's Disease Assessed in Goal-Directed Locomotion Task.

Introduction. In the genesis of Parkinson's disease (PD) clinical phenomenology the exact nature of the association between bradykinesia and affective variables is unclear. In the present study, we analyzed the gait characteristics and level of depression in PD and healthy volunteers. Methods. Patients with PD (n = 48) and healthy controls (n = 52) were recruited for the present study. Walking speed, stride length, and cadence were compared between groups while participants completed a goal-directed locomotion task under visually controlled (VC) and visually noncontrolled conditions (VnC). Results. Significantly higher depression scores were found in PD comparing to healthy control groups. In PD, depression was associated with gait components in the VC wherein the place of the target was visible. In contrast, in healthy subjects the depression was associated with gait components in VnC wherein the location and image of the target were memorized and recalled. In patients with PD and depression, the visually deprived multitask augments the rate of cadence and diminishes stride length, while velocity remains relatively unchanged. The depression associated with gait characteristics as a comorbid affective factor in PD, and that impairs the coherence of gait pattern. Conclusion. The relationship between depression and gait parameters appears to indicate that PD not only is a neurological disease but also incorporates affective disturbances that associate with the regulation of gait characteristics.

Hearing visuo-tactile synchrony - Sound-induced proprioceptive drift in the invisible hand illusion.

The rubber hand illusion (RHI) and its variant the invisible hand illusion (IHI) are useful for investigating multisensory aspects of bodily self-consciousness. Here, we explored whether auditory conditioning during an RHI could enhance the trisensory visuo-tactile-proprioceptive interaction underlying the IHI. Our paradigm comprised of an IHI session that was followed by an RHI session and another IHI session. The IHI sessions had two parts presented in counterbalanced order. One part was conducted in silence, whereas the other part was conducted on the backdrop of metronome beats that occurred in synchrony with the brush movements used for the induction of the illusion. In a first experiment, the RHI session also involved metronome beats and was aimed at creating an associative memory between the brush stroking of a rubber hand and the sounds. An analysis of IHI sessions showed that the participants' perceived hand position drifted more towards the body-midline in the metronome relative to the silent condition without any sound-related session differences. Thus, the sounds, but not the auditory RHI conditioning, influenced the IHI. In a second experiment, the RHI session was conducted without metronome beats. This confirmed the conditioning-independent presence of sound-induced proprioceptive drift in the IHI. Together, these findings show that the influence of visuo-tactile integration on proprioceptive updating is modifiable by irrelevant auditory cues merely through the temporal correspondence between the visuo-tactile and auditory events.

Temperament and psychopathological syndromes specific susceptibility for rubber hand illusion.

The aim of this study is to explore individual capacity for self-integration, susceptibility to the Rubber Hand Illusion (RHI) and the role of temperament factors in the emergence of body schema and body image dissociation. The RHI factors, proprioceptive drift, body ownership and body disownership were assessed in 48 university students. Personality and psychiatric vulnerability were measured by the Temperament and Character Inventory (TCI-R) and the Symptom Checklist-90-R (SCL-90-R). Our study pointed to the fact that the extent of behaviourally defined proprioceptive drift was associated with temperament factors, especially with Novelty Seeking and Harm Avoidance. Further, the ownership was associated with Symptom Checklist factors, especially with elevated Interpersonal Sensitivity and vulnerability to Schizotypy and Paranoid Ideation and elevated disownership score was found in the case of elevated Schizotypy, including a depersonalisation feeling when the RHI was induced. The RHI may be considered as a conflicting situation, in which a way to cope with incongruent multimodal, visual, haptic and proprioceptive stimulation provides an opportunity to test body integration and embodiment processes in healthy participants and patients without disadvantageous outcomes. The results support and replenish the two opposite processing models of the RHI with a third, temperament-based procedural mechanism.

The neural basis of the Machiavellians' decision making in fair and unfair situations.

Although previous research has revealed a number of social, cognitive and neural components of Machiavellians' decision making processes, less attention has been given to the neural correlates of the high Mach (HM) and low Mach (LM) people's responses to situations involving risks and costs imposed by others in interpersonal relationships. In the present study, we used an fMRI technique to examine individuals as they played the Trust game in fair and unfair situations. Our results revealed that the social environment involving opportunities for exploiting others may be more demanding for Machiavellians who showed elevated brain activities in the fair condition (where the partner made a cooperative initiation) but not in the unfair condition. Regarding the specific activated brain areas in the fair condition, the HM's anterior dorsolateral prefrontal cortex (DLPFC) was responding, which is likely to be involved in the inhibition of the prepotent social-emotional response to the partner's cooperative initiative. Furthermore, we found increased activity in the HM subjects' inferior frontal gyrus (IFG), compared to LMs, that plays a crucial role in the evaluation of the signals associated with the others' social behavior, especially when the player faces a cooperative partner. Alternatively, although Machiavellians are regarded as poor mind readers, inferior frontal gyrus may be effective in anticipating their partner's subsequent decisions in the social dilemma situation.

[Critical issues of the biopsychosocial treatment of Parkinson's disease]. / A Parkinson-kór biopszichoszociális ellátásának kritikus kérdései.

This paper is a summary report on the basic questions of the biopsychosocial approach to Parkinson's disease. It deals with cognitive, affective and psychological health issues which significantly influence the outcome of the physical rehabilitation. In spite of the unchanged cognitive status, the psychological burden of the changes in the quality of life, the obstruction, the change in the affective tone, and the shrinking ability to fulfil social roles decrease the patient's quality of life. An interdisciplinary approach is best suited for mitigating these effects. Not only the patient but also his/her family and environment is seriously affected by the disease and its consequences. Treatment and rehabilitation options for increasing or maintaining the quality of life of the affected patients are diverse, and significantly depend on the features of the health care system. The authors believe that the following review emphasizing health psychological principles may contribute to the work of professionals working in clinical and rehabilitational fields and through them may increase the quality of life of patients and their family.