The relationship between attention networks and individual differences in visual mental imagery vividness - An EEG study.

Previous research has established a strong link between attention and visual mental imagery, but it's remained uncertain whether attention networks influence individual differences in the vividness of visual mental imagery. In our study, we examined 140 participants, assessing the vividness of imagery using the Vividness of Visual Imagery Questionnaire in both eyes-open and eyes-closed conditions. We employed the Attention Network Test, coupled with EEG recording, to characterize three attention sub-networks: alerting, orienting, and executive control. To pinpoint the specific attentional networks associated with the vividness of visual mental imagery, we utilized latent profile analysis to categorize participants into distinct subgroups. Additionally, we constructed a regression mixture model to explore how attention networks predict different latent categories of visual imagery vividness. Our findings revealed that the efficiency of the alerting network, as indicated by the N1 component, demonstrated a positive correlation with the vividness of visual imagery. This electrophysiological evidence underscores the role of the alerting network in shaping individual differences in the vividness of visual mental imagery.

Can the fistula arm be used to lift heavy items? Six-pound dumbbells versus handgrip exercise in a 6-month follow-up secondary analysis of a randomized controlled trial.

INTRODUCTION: Patients with arteriovenous fistulas are advised to avoid carrying heavy objects draped over the fistula arm. Awareness gradually leads to overprotection and a reduction in the use of the fistula arm. However, restricting motion in the fistula arm leads to decreased quality of life and diminished muscle strength. The current safety recommendations regarding lifting heavy items with the fistula arm are primarily based on experience. Few studies have provided evidence clarifying the scope of safe activity and the influence of load bearing on the continued patency of arteriovenous fistulas. METHODS: This prospective observation was based on a long-term follow-up study in which 86 hemodialysis recipients with arteriovenous fistulas were randomized into either a dumbbell group or a handgrip group. The dumbbell group exercised with 6-lb dumbbells, while the handgrip group squeezed rubber balls. Postintervention primary patency and adverse events at the 6-month follow-up were analyzed. RESULTS: No significant difference in postintervention primary patency was observed between the dumbbell group and the handgrip group at 6 months (97.4% vs 95.0%). There were two participants with high-flow fistulas in the dumbbell group and three in the handgrip group, with no significant difference between the two groups (5.3% vs 7.5%). In both groups, there were no other adverse events reported regarding cardiac failure, aneurysm, puncture site hematoma, or hemorrhage. CONCLUSION: Hemodialysis patients can safely use their fistula arm to lift objects weighing less than 6 lb, which encourages increased motion and helps preserve the functionality of the fistula arm.

Expression and function of myelin-associated proteins and their common receptor NgR on oligodendrocyte progenitor cells.

Nogo-A, oligodendrocyte myelin glycoprotein (OMgp) and myelin-associated glycoprotein (MAG) are known as myelin-associated proteins that inhibit axon growth by binding a common receptor, the Nogo66 receptor (NgR). In the CNS, Nogo-A, OMgp and MAG are predominantly expressed by oligodendrocytes. As our previous study revealed that oligodendrocyte progenitor cells (OPCs) did not inhibit neurite outgrowth, it is not clear whether these myelin-associated proteins are expressed in OPCs, and what functions they perform if they are expressed in OPCs. In the present study, with OPCs induced from neural precursor cells (NPCs) derived from rat embryonic spinal cord, and oligodendrocytes differentiated from OPCs, we have observed the expression patterns of Nogo-A, OMgp, MAG and NgR in NPCs, OPCs and oligodendrocytes by immunostaining and western blot assay. We found that Nogo-A could be detected in all tested cells; OMgp could be detected in OPCs and oligodendrocytes, but not in NPCs; MAG was only detected in oligodendrocytes; while NgR could be detected in NPCs and OPCs, but not in oligodendrocytes. These results indicated that the expression pattern of MAG and NgR in OPCs was totally different from that of oligodendrocytes, which might be one of the factors that led to the discrepancy between the two cells in promoting neurite outgrowth. By respectively blocking Nogo-A, OMgp and NgR expressed on OPCs with their corresponding antibodies, we further investigated their roles in the proliferation and differentiation of OPCs, as well as the possible signal pathways involved in. Our results showed that when OPCs were cultured under proliferation condition, blocking Nogo-A, OMgp or NgR did not affect the proliferation of OPCs, but could all significantly prolong their processes. And this effect on OPC processes might involve the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. When OPCs were cultured under differentiation condition (containing tri-iodothyronine, T3), blocking Nogo-A, OMgp or NgR could all inhibit the differentiation of OPCs, and this effect might involve the extracellular signal-regulated kinases1/2 (Erk1/2) signaling pathway. These results suggested that under proliferation environment, the functions of Nogo-A, OMgp and NgR expressed in OPCs might be to control the length of processes, thus maintaining the morphology of OPCs. While in differentiation environment, the functions of Nogo-A, OMgp and NgR expressed in OPCs turned to promote the differentiation of OPCs, thus facilitating the maturation of oligodendrocytes. And NgR, as the common receptor for Nogo-A and OMgp, might be the main molecule that mediated these functions in OPCs.