| Abstract [eng] |
The dissertation investigates the effect of sex and handedness on the human prefrontal cortex hemodynamic response (HR) during the classical neuropsychological Wisconsin Card Sorting Test (WCST) by applying Functional Near-Infrared Spectroscopy (fNIRS). The dissertation consists of two distinct research projects. The first research project covers the creation of a custom fNIRS device suitable for the studies of the human adult prefrontal cortex. During the final stage, a well-known, standard cognitive task such the WCST was chosen for the validation. In the scientific community, this test was assumed to be insensitive for sex and handedness related differences due to indifferent behavioural results. However, although the behavioural outcomes of the first project were indifferent, the functional neuroimaging results showed some discrepancies. Other researchers have previously identified similar discrepancies in brain research, but the reasons for this are not fully explained. Also, it was noted that the composition of the participant by sex and handedness had not been evaluated in previous studies, although factors such have been extensively studied in neuroscience. On this basis, the second research project is focused on the study of sex and handedness effects on prefrontal cortex HR during the WCST performance. To assess whether sex-related differences in hormonal exposure, and handedness-related functional lateralisation, together with sex-related odd ratios for left-handers can profoundly reflect on functional imaging of human prefrontal cortex, the study was conducted with the most extensive study to date and most consistently regarding handedness collected group of healthy participants. The findings of the dissertation suggest that significant differences in functional neuroimaging found in healthy subjects are gender-specific. Still, not all results may be analogously associated with participants' hand preference. |
