Direction of attentional focus in prosthetic training: Current practice and potential for improving motor learning in individuals with lower limb loss.

OBJECTIVE: Adopting an external focus of attention has been shown to benefit motor performance and learning. However, the potential of optimizing attentional focus for improving prosthetic motor skills in lower limb prosthesis (LLP) users has not been examined. In this study, we investigated the frequency and direction of attentional focus embedded in the verbal instructions in a clinical prosthetic training setting. METHODS: Twenty-one adult LLP users (8 female, 13 male; 85% at K3 level; mean age = 50.5) were recruited from prosthetic clinics in the Southern Nevada region. Verbal interactions between LLP users and their prosthetists (mean experience = 10 years, range = 4-21 years) during prosthetic training were recorded. Recordings were analyzed to categorize the direction of attentional focus embedded in the instructional and feedback statements as internal, external, mixed, or unfocused. We also explored whether LLP users' age, time since amputation, and perceived mobility were associated with the proportion of attentional focus statements they received. RESULTS: We recorded a total of 20 training sessions, yielding 904 statements of instruction from 338 minutes of training. Overall, one verbal interaction occurred every 22.1 seconds. Among the statements, 64% were internal, 9% external, 3% mixed, and 25% unfocused. Regression analysis revealed that female, older, and higher functioning LLP users were significantly more likely to receive internally-focused instructions (p = 0.006, 0.035, and 0.024, respectively). CONCLUSIONS: Our results demonstrated that verbal instructions and feedback are frequently provided to LLP users during prosthetic training. Most verbal interactions are focused internally on the LLP users' body movements and not externally on the movement effects. IMPACT STATEMENT: While more research is needed to explore how motor learning principles may be applied to improve LLP user outcomes, clinicians should consider adopting the best available scientific evidence during treatment. Overreliance on internally-focused instructions as observed in the current study may hinder prosthetic skill learning.

Different transcriptional responses by the CRISPRa system in distinct types of heterochromatin in Drosophila melanogaster.

Transcription factors (TFs) activate gene expression by binding to elements close to promoters or enhancers. Some TFs can bind to heterochromatic regions to initiate gene activation, suggesting that if a TF is able to bind to any type of heterochromatin, it can activate transcription. To investigate this possibility, we used the CRISPRa system based on dCas9-VPR as an artificial TF in Drosophila. dCas9-VPR was targeted to the TAHRE telomeric element, an example of constitutive heterochromatin, and to promoters and enhancers of the HOX Ultrabithorax (Ubx) and Sex Combs Reduced (Scr) genes in the context of facultative heterochromatin. dCas9-VPR robustly activated TAHRE transcription, showing that although this element is heterochromatic, dCas9-VPR was sufficient to activate its expression. In the case of HOX gene promoters, although Polycomb complexes epigenetically silence these genes, both were ectopically activated. When the artificial TF was directed to enhancers, we found that the expression pattern was different compared to the effect on the promoters. In the case of the Scr upstream enhancer, dCas9-VPR activated the gene ectopically but with less expressivity; however, ectopic activation also occurred in different cells. In the case of the bxI enhancer located in the third intron of Ubx, the presence of dCas9-VPR is capable of increasing transcription initiation while simultaneously blocking transcription elongation, generating a lack of functional phenotype. Our results show that CRISPRa system is able to activate transcription in any type of heterochromatin; nevertheless, its effect on transcription is subject to the intrinsic characteristics of each gene or regulatory element.

The transcriptional stress response and its implications in cancer treatment.

Cancer cells require high levels of transcription to survive and maintain their cancerous phenotype. For several years, global transcription inhibitors have been used in the treatment of cancer. However, recent advances in understanding the functioning of the basal transcription machinery and the discovery of new drugs that affect the components of this machinery have generated a new boom in the use of this type of drugs to treat cancer. Inhibiting transcription at the global level in the cell generates a stress situation in which the cancer cell responds by overexpressing hundreds of genes in response to this transcriptional stress. Many of these over-transcribed genes encode factors that may be involved in the selection of cells resistant to the treatment and with a greater degree of malignancy. In this study, we reviewed various examples of substances that inhibit global transcription, as well as their targets, that have a high potential to be used against cancer. We also analysed what kinds of genes are overexpressed in the response to transcriptional stress by different substances and finally we discuss what types of studies are necessary to understand this type of stress response to have more tools to fight cancer.