Volition and “free will”

Philosophers have debated the “free will” for centuries, yet it is only in recent years that voluntary actions have become an object of investigation for cognitive neuroscience. This review begins by attempting a definition of volition (i.e., the mental state associated specifically with voluntary actions) that could be relevant for cognitive neuroscience. We then review the neuropsychology of volition. Alterations in voluntary behaviour in neurological and psychiatric patients first suggested the possibility that specific cognitive processes of volition have specific bases in the brain. These findings counter traditional dogmas that human volition is somehow ineffable, and instead suggest that voluntary actions depend on specific brain circuitry that is accessible to scientific investigation.The second part of the review focuses on the experimental psychology of volition. A number of studies have combined a systematic manipulation of experimental conditions, and recording of brain processes associated with voluntary action. We argue that this combination is most likely to identify the brain processes specifically associated with volition, and we therefore review these studies systematically. For example, several studies link the Readiness Potential of the EEG to preparatory conscious preplanning of actions. Further, a meta-analysis of neuroimaging studies (PET/ fMRI) reveals a distinctive pattern of activations for choosing one among many possible actions - a key element of volition. The medial frontal cortex appears to make a key contribution to both these biomarkers of volition.

Xylan utilisation promotes adaptation of Bifidobacterium pseudocatenulatum to the human gastrointestinal tract

Dietary carbohydrates impact the composition of the human gut microbiota. However, the relationship between carbohydrate availability for individual bacteria and their growth in the intestinal environment remains unclear. Here, we show that the availability of long-chain xylans (LCX), one of the most abundant dietary fibres in the human diet, promotes the growth of Bifidobacterium pseudocatenulatum in the adult human gut. Genomic and phenotypic analyses revealed that the availability of LCX-derived oligosaccharides is a fundamental feature of B. pseudocatenulatum, and that some but not all strains possessing the endo-1,4-β-xylanase (BpXyn10A) gene grow on LCX by cleaving the xylose backbone. The BpXyn10A gene, likely acquired by horizontal transfer, was incorporated into the gene cluster for LCX-derived oligosaccharide utilisation. Co-culturing with xylanolytic Bacteroides spp. demonstrated that LCX-utilising strains are more competitive than LCX non-utilising strains even when LCX-derived oligosaccharides were supplied. In LCX-rich dietary interventions in adult humans, levels of endogenous B. pseudocatenulatum increased only when BpXyn10A was detected, indicating that LCX availability is a fitness determinant in the human gut. Our findings highlight the enhanced intestinal adaptability of bifidobacteria via polysaccharide utilisation, and provide a cornerstone for systematic manipulation of the intestinal microbiota through dietary intervention using key enzymes that degrade polysaccharide as biomarkers.

Clubfeet and congenital constriction band syndrome

Background Clubfeet and constriction band syndrome is a very rare non-idiopathic condition. Treatment is often difficult and the recurrence deformity rate is high. The purpose of this study was to assess the effectiveness of Ponseti method in the treatment of congenital constriction band syndrome accompanied by clubfoot deformity and lymphedema. Case presentation We are presenting an interesting case of bilateral clubfeet and congenital circumferential constriction band syndrome in the lower limb. Ponseti method of correcting the congenital clubfoot deformity was applied. Constriction band release is accomplished by two stages completely excising the fibrous band and multiple two-stage Z-plasties on the right calf. Conclusion The results of this study indicate that the Ponseti method of gentle, systematic manipulation and weekly cast changes is an effective treatment of non-idiopathic clubfoot distal to congenital amniotic constriction band.

Clubfeet and congenital constriction band syndrome - Case report

Background: Clubfeet and constriction band syndrome is a very rare non-idiopathic condition. Treatment is often difficult and the recurrence deformity rate is high. The purpose of this study was to assess the effectiveness of Ponseti method in the treatment of congenital constriction band syndrome accompanied by clubfoot deformity and lymphedema. Case presentation: We are presenting an interesting case of bilateral clubfeet and congenital circumferential constriction band syndrome in the lower limb. Ponseti method of correcting the congenital clubfoot deformity was applied. Constriction band release is accomplished by two stages completely excising the fibrous band and multiple two-stage Z-plasties on the right calf. Conclusion: The results of this study indicate that the Ponseti method of gentle, systematic manipulation and weekly cast changes is an effective treatment of non idiopathic clubfoot distal to congenital amniotic constriction band.

Clubfeet and Constriction Band Syndrome - Case Report

Background: Clubfeet and constriction band syndrome is a very rare non-idiopathic condition. Treatment is often difficult and the recurrence deformity rate is high. The purpose of this study was to assess the effectiveness of Ponseti method in the treatment of congenital constriction band syndrome accompanied by clubfoot deformity and lymphedema. Case presentation: We are presenting an interesting case of bilateral clubfeet and congenital circumferential constriction band syndrome in the lower limb. Ponseti method of correcting the congenital clubfoot deformity was applied. Constriction band release is accomplished by two stages completely excising the fibrous band and multiple two-stage Z-plasties on the right calf. Conclusion: The results of this study indicate that the Ponseti method of gentle, systematic manipulation and weekly cast changes is an effective treatment of non idiopathic clubfoot distal to congenital amniotic constriction band.

Clubfeet and Constriction Band Syndrome - Case Report

Background: Clubfeet and constriction band syndrome is very rare nonidiopathic condition. Treatment is often difficult and the recurrence deformity rate is high. The purpose of this study was to assess the effectiveness of Ponseti method in treatment of congenital constriction band syndrome accompanied clubfoot deformity and lymphedema.Case presentation: We are presenting an interesting case of bilateral clubfeet and congenital circumferential constriction band syndrome in lower limb. Ponseti method of correcting the congenital clubfoot deformity was applied. Constriction band release is accomplished by two stage completely excising the fibrous band and multiple two stage Z-plasties on the right calf.Conclusion: The results of this study indicate that the Ponseti method of gentle, systematic manipulation and weekly cast changes is effective treatment of nonidiopathic clubfoot distal to congenital amniotic constriction band.

The Effects of Systematic Environmental Manipulation on Gait of Older Adults

Quantification of gait changes in response to altered environmental stimuli may allow for improved understanding of the mechanisms that influence gait changes and fall occurrence in older adults. This study explored how systematic manipulation of a single dimension of one’s environment affects spatiotemporal gait parameters. A total of 20 older adult participants walked at a self-selected pace in a constructed research hallway featuring a mobile wall, which allowed manipulation of the hallway width between three conditions: 1.14 m, 1.31 m, and 1.48 m. Spatiotemporal data from participants’ walks were captured using an instrumented GAITRite mat. A repeated measures ANOVA revealed older adults spent significantly more time in double support in the narrowest hallway width compared to the widest, but did not significantly alter other spatiotemporal measures. Small-scale manipulations of a single dimension of the environment led to subtle, yet in some cases significant changes in gait, suggesting that small or even imperceptible environmental changes may contribute to altered gait patterns for older adults.

Clubfeet and Constriction Band Syndrome - Case Report

Background: Clubfeet and constriction band syndrome is very rare nonidiopathic condition. Treatment is often difficult and the recurrence deformity rate is high. The purpose of this study was to assess the effectiveness of Ponseti method in treatment of congenital constriction band syndrome accompanied clubfoot deformity and lymphedema.Case presentation: We are presenting an interesting case of bilateral clubfeet and congenital circumferential constriction band syndrome in lower limb. Ponseti method of correcting the congenital clubfoot deformity was applied. Constriction band release is accomplished by two stage completely excising the fibrous band and multiple two stage Z-plasties on the right calf.Conclusion: The results of this study indicate that the Ponseti method of gentle, systematic manipulation and weekly cast changes is effective treatment of nonidiopathic clubfoot distal to congenital amniotic constriction band.

Stimulus-dependent contrast sensitivity asymmetries around the visual field

Asymmetries in visual performance at isoeccentric locations are known as performance fields. At a fixed eccentricity, visual performance is best along the horizontal, intermediate along the lower vertical, and poorest along the upper vertical meridian. These performance fields are pervasive across a range of visual tasks, including those mediated by contrast sensitivity. However, contrast performance fields have not been characterized with a systematic manipulation of stimulus spatial frequency, eccentricity, and size; three parameters that constrain contrast sensitivity. Further, individual differences in performance fields measurements have not been assessed. Here, we use an orientation discrimination task to characterize the pattern of contrast sensitivity across four isoeccentric locations along the cardinal meridians, and to examine whether and how this asymmetry pattern changes with systematic manipulation of stimulus spatial frequency (4 cpd to 8 cpd), eccentricity (4.5° to 9°), and size (3° visual angle to 6° visual angle). Our data demonstrate that contrast sensitivity is highest along the horizontal, intermediate along the lower vertical, and poorest along the upper vertical meridian. This pattern is consistent across stimulus parameter manipulations, even though they cause profound shifts in contrast sensitivity. Eccentricity-dependent decreases in contrast sensitivity can be compensated for by scaling stimulus size alone. Moreover, we find that individual variability in the strength of performance field asymmetries is consistent across conditions. This study is the first to systematically and jointly manipulate, and compare, contrast performance fields across spatial frequency, eccentricity, and size, and to address individual variability in performance fields.