Imitation of hand and tool actions is effector-independent

Following the theoretical notion that tools often extend one’s body, in the present study, we investigated whether imitation of hand or tool actions is modulated by effector-specific information. Subjects performed grasping actions toward an object with either a handheld tool or their right hand. Actions were initiated in response to pictures representing a grip at an object that could be congruent or incongruent with the required action (grip-type congruency). Importantly, actions could be cued by means of a tool cue, a hand cue, and a symbolic cue (effector-type congruency). For both hand and tool actions, an action congruency effect was observed, reflected in faster reaction times if the observed grip type was congruent with the required movement. However, neither hand actions nor tool actions were differentially affected by the effector represented in the picture (i.e., when performing a tool action, the action congruency effect was similar for tool cues and hand cues). This finding suggests that imitation of hand and tool actions is effector-independent and thereby supports generalist rather than specialist theories of imitation

Gender differences in patients with dizziness and unsteadiness regarding self-perceived disability, anxiety, depression, and its associations

BACKGROUND: It is known that anxiety and depression influence the level of disability experienced by persons with vertigo, dizziness or unsteadiness. Because higher prevalence rates of disabling dizziness have been found in women and some studies reported a higher level of psychiatric distress in female patients our primary aim was to explore whether women and men with vertigo, dizziness or unsteadiness differ regarding self-perceived disability, anxiety and depression. Secondly we planned to investigate the associations between disabling dizziness and anxiety and depression. METHOD: Patients were recruited from a tertiary centre for vertigo and balance disorders. Participants rated their global disability as mild, moderate or severe. They filled out the Dizziness Handicap Inventory and the two subscales of the Hospital Anxiety Depression Scale (HADS). The HADS was analysed 1) by calculating the median values, 2) by estimating the prevalence rates of abnormal anxiety/depression based on recommended cut-off criteria. Mann-Whitney U-tests, Chi-square statistics and odds ratios (OR) were calculated to compare the observations in both genders. Significance values were adjusted with respect to multiple comparisons. RESULTS: Two-hundred and two patients (124 women) mean age (standard deviation) of 49.7 (13.5) years participated. Both genders did not differ significantly in the mean level of self-perceived disability, anxiety, depression and symptom severity. There was a tendency of a higher prevalence of abnormal anxiety and depression in men (23.7%; 28.9%) compared to women (14.5%; 15.3%). Patients with abnormal depression felt themselves 2.75 (95% CI: 1.31-5.78) times more severely disabled by dizziness and unsteadiness than patients without depression. In men the OR was 8.2 (2.35-28.4). In women chi-square statistic was not significant. The ORs (95% CI) of abnormal anxiety and severe disability were 4.2 (1.9-8.9) in the whole sample, 8.7 (2.5-30.3) in men, and not significant in women. CONCLUSIONS: In men with vertigo, dizziness or unsteadiness emotional distress and its association with self-perceived disability should not be underestimated. Longitudinal surveys with specific pre-defined co-variables of self-perceived disability, anxiety and depression are needed to clarify the influence of gender on disability, anxiety and depression in patients with vertigo, dizziness or unsteadiness

Visual attention and action: How cueing, direct mapping, and social interactions drive orienting

Despite considerable interest in both action perception and social attention over the last 2 decades, there has been surprisingly little investigation concerning how the manual actions of other humans orient visual attention. The present review draws together studies that have measured the orienting of attention, following observation of another’s goal-directed action. Our review proposes that, in line with the literature on eye gaze, action is a particularly strong orienting cue for the visual system. However, we additionally suggest that action may orient visual attention using mechanisms, which gaze direction does not (i.e., neural direct mapping and corepresentation). Finally, we review the implications of these gaze-independent mechanisms for the study of attention to action. We suggest that our understanding of attention to action may benefit from being studied in the context of joint action paradigms, where the role of higher level action goals and social factors can be investigated