The primate chair offers also the possibility to test separately the left hand from the right hand, as needed to assess hand dominance for instance. Finally, in monkeys, the assessment of manual performance was not restricted to a single or very few time points, but it was

monitored in daily sessions over several weeks or months. Overall, the results confirmed our hypothesis that hand preference in M. fascicularis is variable across manual tasks and individuals (Table ​(Table1).1). Furthermore, the hand preference in monkeys did not systematically correspond to the hand dominance in the modified Brinkman board task (four out of eight monkeys: see Table ​Table1).1). In contrast, human subjects are Inhibitors,research,lifescience,medical more lateralized and the correspondence between hand preference and hand dominance was systematic in the vast majority of cases (one exception out of 20 subjects: see Table ​Table11).

As expected, our results related to hand preference show that left-handers are not a mirror image of right-handers, at least based on the questionnaire (Fig. Inhibitors,research,lifescience,medical ​(Fig.7B).7B). Right-handers are clearly more lateralized, as laterality scores (absolute values) were significantly larger in right-handers than in left-handers. In monkeys, based on the three tasks they performed (Fig. ​(Fig.7A),7A), only one animal exhibited a consistent lateralization (Mk-TH: right-hander), whereas Inhibitors,research,lifescience,medical in the others, the preferred hand was largely task dependent. The part of the present study focused on human subjects, in spite of a relatively limited sample of subjects (n = 20, comprising 10 men and 10 women distributed in 10 right-handers and 10 left-handers based on their self-assessment) revealed some interesting Inhibitors,research,lifescience,medical differences. First, the questionnaire data showed that left-handers are less lateralized than right-handers (Fig. ​(Fig.7B),7B), as previously reported (see e.g., Kastner-Koller et al. 2007) and in line with our hypothesis (see Introduction and Inhibitors,research,lifescience,medical Methods).

However, this lateralization click here difference between self-declared left- and right-handers reflected by the questionnaire was not found for the two bimanual tasks tested here: as shown in Table ​Table1,1, there was a comparable number of hand preference deviations in each group (four right hand deviations ADAMTS5 in the left-handers and five left hand deviations in the right-handers). Second, in the context of hand dominance assessment based on the modified Brinkman board task, right-handers performed significantly better than left-handers, in the 10 trials conducted for each subject during the unique behavioral session. Whether this difference would be maintained along multiple sessions conducted at subsequent days remains an open question. Third, women performed significantly better than men in the modified Brinkman board task, as reflected by a higher total score.