Multitasking: multiple, domain-specific cognitive functions in a virtual environment

Multitasking among three or more different tasks is a ubiquitous requirement of everyday cognition, yet rarely is it addressed in research on healthy adults who have had no specific training in multitasking skills. Participants completed a set of diverse subtasks within a simulated shopping mall and office environment, the Edinburgh Virtual Errands Test (EVET). The aim was to investigate how different cognitive functions, such as planning, retrospective and prospective memory, and visuospatial and verbal working memory, contribute to everyday multitasking. Subtasks were chosen to be diverse, and predictions were derived from a statistical model of everyday multitasking impairments associated with frontal-lobe lesions (Burgess, Veitch, de Lacy Costello, & Shallice, 2000b). Multiple regression indicated significant independent contributions from measures of retrospective memory, visuospatial working memory, and online planning, but not from independent measures of prospective memory or verbal working memory. Structural equation modelling showed that the best fit to the data arose from three underlying constructs, with Memory and Planning having a weak link, but with both having a strong directional pathway to an Intent construct that reflected implementation of intentions. Participants who followed their preprepared plan achieved higher scores than those who altered their plan during multitask performance. This was true regardless of whether the plan was efficient or poor. These results substantially develop and extend the Burgess et al. (2000b) model to healthy adults and yield new insight into the poorly understood area of everyday multitasking. The findings also point to the utility of using virtual environments for investigating this form of complex human cognition

Pancreatic cancer genomics

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with the worst prognosis among all solid tumors [1]. Although surgical resection offers the only hope for cure, it is possible in only 20% of patients that present with local disease [2]. Indeed, most patients are diagnosed at an advanced stage, when the disease is inoperable. Whether dismal prognosis is a result of late diagnosis or early dissemination to distant organ is still a debate. Systemic chemotherapy provides temporary benefits in controlling advanced disease and prolonging survival in the adjuvant setting but this happens in a small proportion of patients. Several factors are supposed to contribute variably to the intrinsic chemotherapic resistance of pancreatic cancer and include: (i) the presence of a dense stromal component (termed desmoplastic reaction) that significantly reduces drug delivery [3]; (ii) the transformation of epithelial cells into a mesenchymal phenotype (referred to as epithelial to mesenchymal transition, EMT) [4]; and (iii) the presence of pancreatic cancer stem cells [5]. To complicate our understanding of chemoresistance, there is the marked molecular heterogeneity among primary tumors and metastatic deposits (discussed in details below) [6]. \ua9 2013 Springer Science+Business Media Dordrecht. All rights are reserved