Detecting cell assemblies in large neuronal populations

Recent progress in the technology for single unit recordings has given the neuroscientific community theopportunity to record the spiking activity of large neuronal populations. At the same pace, statistical andmathematical tools were developed to deal with high-dimensional datasets typical of such recordings.A major line of research investigates the functional role of subsets of neurons with significant co-firingbehavior: the Hebbian cell assemblies. Here we review three linear methods for the detection of cellassemblies in large neuronal populations that rely on principal and independent component analysis.Based on their performance in spike train simulations, we propose a modified framework that incorpo-rates multiple features of these previous methods. We apply the new framework to actual single unitrecordings and show the existence of cell assemblies in the rat hippocampus, which typically oscillate attheta frequencies and couple to different phases of the underlying field rhythm

A organização do processo de projeto de arquitetura no meio profissional: uma análise da produção em escritórios

This paper examines, through case studies, the organization of the production process of architectural projects in architecture offices in the city of Natal, specifically in relation to building projects. The specifics of the design process in architecture, the production of the project in a professional field in Natal, are studied in light of theories of design and its production process. The survey, in its different phases, was conducted between March 2010 and September 2012 and aimed to identify, understand, and analyze comparatively, by mapping the design process, the organization of production of building projects in two offices in Natal, checking as well the relationships of their agents during the process. The project was based on desk research and exploration, adopting, for both, data collection tools such as forms, questionnaires, and interviews. With the specific aim of mapping the design process, we adopted a technique that allows obtaining the information directly from employee agents involved in the production process. The technique consisted of registering information by completing daily, during or at the end of the workday, an individual virtual agenda, in which all agent collaborators described the tasks performed. The data collected allowed for the identification of the organizational structure of the office, its hierarchy, the responsibilities of agents, as well as the tasks performed by them during the two months of monitoring at each office. The research findings were based on analyses of data collected in the two offices and on comparative studies between the results of these analyses. The end result was a diagnostic evaluation that considered the level of organization and elaborated this perspective, as well as proposed solutions aimed at improving both the organization of the process and the relationships between the agents under the lens analyzed