Free won't : neurobiological bases of the development of intentional inhibition

Self-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs from externally driven inhibition in that it is driven by an internal thought process rather than an external stimulus that tells one to stop. The goal of this thesis was to examine the development of intentional inhibition and compare this with externally driven inhibition. In order to investigate the covert process of intentional inhibition, the research described in this thesis made use of neurobiological measures such as phasic heart rate changes and functional magnetic resonance imaging (fMRI). In addition, to learn more about self-control in context, the final empirical chapter examined intentional and externally driven inhibition in the context of relevant and irrelevant emotions.Pathways through Adolescenc

Development of response inhibition in the context of relevant versus irrelevant emotions

Pathways through Adolescenc

Free won't : neurobiological bases of the development of intentional inhibition

Self-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs from externally driven inhibition in that it is driven by an internal thought process rather than an external stimulus that tells one to stop. The goal of this thesis was to examine the development of intentional inhibition and compare this with externally driven inhibition. In order to investigate the covert process of intentional inhibition, the research described in this thesis made use of neurobiological measures such as phasic heart rate changes and functional magnetic resonance imaging (fMRI). In addition, to learn more about self-control in context, the final empirical chapter examined intentional and externally driven inhibition in the context of relevant and irrelevant emotions.</p

Immunocytochemical detection of non-histone nuclear antigens in cryo-sections of developing somatic embryos from Daucus carota L.

The distribution of non-histone nuclear antigens was studied during early somatic embryogenesis of carrot using nuclear antibodies specific for small nuclear RNPs (snRNPs), nuclear matrix proteins and nucleolar proteins. Immunofluorescence showed that in interphase cells snRNPs and nuclear matrix proteins were localized in the nucleus with a speckled pattern. Immunoelectron microscopy indicated that the snRNPs were irregularly distributed while the nuclear matrix proteins showed a distribution preferentially over the condensed chromatin. None were localized in the nucleolus. The nucleolar proteins were localized in both dense fibrillar and granular components while the fibrillar centres were devoid of gold particles. The localization of these antibodies in plant cell nuclei, in a way comparable to the patterns described in animal cells, indicates the general presence of snRNPs in all eukaryotic nuclei. It further confirms the relation of the nuclear matrix proteins to plant cell proliferation events and the possible role of the nucleolar proteins in both rRNA transcription and preribosome assembly

A Three-Year Longitudinal Functional Magnetic Resonance Imaging Study of Performance Monitoring and Test-Retest Reliability from Childhood to Early Adulthood

Previous cross-sectional functional magnetic resonance imaging studies have shown that performance monitoring functions continue to develop well into adolescence, associated with increased activation in brain regions important for cognitive control (prefrontal cortex, anterior cingulate cortex, and parietal cortex). To date, however, the development of performance monitoring has not yet been studied longitudinally, which leaves open the question whether changes can be detected within individuals over time. In the present study, human boys and girls, between ages 8 and 27 years, performed a child-friendly rule-switch task in the scanner on two occasions similar to 3.5 years apart. Change versus stability was examined using two methods: (1) repeated-measures analyses and (2) test-retest reliabilities of blood oxygenation level-dependent responses. Results showed that with increasing age, participants performed better on the task. The changes in neural activation associated with the processing of performance feedback were, however, more reliably correlated with changes in performance than with age. Test-retest reliability was at least fair to good for adults and adolescents, but poor to fair for the youngest age group. Substantially more variability was observed in the pattern and magnitude of children compared with adults, which may be interpreted as proxy for developmental change. Together, the results show that (1) change within individuals is variable, and more so for children than for adolescents and adults, and (2) performance is a better predictor for change in neural activation over time. These findings set the stage for studying developmental change in the perspective of multiple predictors, rather than solely by divisions based on age groups.Neuro Imaging Researc

Children who stutter show reduced action-related activity in the rostral cingulate zone

Pathways through Adolescenc