Early emergence of cortical interneuron diversity in the mouse embryo

GABAergic interneurons regulate neural circuit activity in the mammalian cerebral cortex. These cortical interneurons are structurally and functionally diverse. Here, we use single-cell transcriptomics to study the origins of this diversity in mouse. We identify distinct types of progenitor cells and newborn neurons in the ganglionic eminences, the embryonic proliferative regions that give rise to cortical interneurons. These embryonic precursors show temporally and spatially restricted transcriptional patterns that lead to different classes of interneurons in the adult cerebral cortex. Our findings suggest that shortly after the interneurons become postmitotic, their diversity is already patent in their diverse transcriptional programs, which subsequently guide further differentiation in the developing cortex

A postnatal molecular switch drives activity-dependent maturation of parvalbumin interneurons

Cortical neurons are specified during embryonic development but often acquire their mature properties at relatively late stages of postnatal development. This delay in terminal differentiation is particularly prominent for fast-spiking parvalbumin-expressing (PV +) interneurons, which play critical roles in regulating the function of the cerebral cortex. We found that the maturation of PV + interneurons is triggered by neuronal activity and mediated by the transcriptional cofactor peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α). Developmental loss of PGC-1α prevents PV + interneurons from acquiring unique structural, electrophysiological, synaptic, and metabolic features and disrupts their diversification into distinct subtypes. PGC-1α functions as a master regulator of the differentiation of PV + interneurons by directly controlling gene expression through a transcriptional complex that includes ERRγ and Mef2c transcription factors. Our results uncover a molecular switch that translates neural activity into a specific transcriptional program, promoting the maturation of PV + interneurons at the appropriate developmental stage. </p

Study of pion-proton elastic scattering in the region of the X[superscript 0] threshold

Imperial Users onl

La périurbanisation dans l'espace rural grec / Peri-urbanisation in Greak rural areas

Peri-urbanisation in Greece occurs in three major ways. First, around the two cities of Athens and Salonika with the outward spread of industry and the extension of residential zones. Second, by the progressive diffusion of activities around small and medium-sized towns. Finally, along coastal zones and in the islands, in more less discontinuous form, linked to tourism. The study of two villages in the region of Corinthia in the Peloponnese illustrates peri-urbanisation around Athens : population increase, a change in agricultural specialisation and the development of second homes.La périurbanisation en Grèce se réalise selon trois modalités principales. D'abord autour des deux grandes villes d'Athènes et Salonique par desserrement industriel et extension des zones résidentielles. Ensuite autour des villes petites et moyennes par progression diffuse. Enfin le long des littoraux et dans les îles par urbanisation plus ou moins discontinue à fonction touristique. Une étude de deux villages de la région de Corinthie dans le Péloponnèse illustre la périurbanisation autour d'Athènes : accroissement de la population, changement des spécialités agricoles, développement des résidences secondaires.Anthopoulou Théodossia, Moissidis Antonis. La périurbanisation dans l'espace rural grec / Peri-urbanisation in Greak rural areas. In: Géocarrefour, vol. 77, n°4, 2002. La Grèce aujourd'hui. pp. 359-366

Tuition fees and funding – barriers for non-traditional students? First results from the international research project Opening Universities for Lifelong Learning (OPULL)

Project OPULL – Opening Universities for Lifelong Learning – is undertaking research into ways of opening up higher education to vocationally qualified and experienced target groups in four European countries. Open university models in Germany, Denmark, Finland and the United Kingdom are being investigated in three research phases between 2009 and 2012 with the aim of identifying critical success factors for building open universities for Europe. This paper presents the first phase, in which educational systems in the participant countries have been mapped and interviews with lifelong learning experts undertaken. The current situation and perspectives in each country together with critical issues on how fees and funding influence higher education access for non-traditional students in these countries are discussed and explored through the interview evidence. The initial findings of the first phase of the project indicate that while the long-term effect of an increase in tuition fees for non-traditional students is not yet known, current evidence suggests that other factors such as the recognition of vocational and experiential learning will most likely have an impact on widening participation in higher education

Somatostatin interneurons control the timing of developmental desynchronization in cortical networks

Synchronous neuronal activity is a hallmark of the developing brain. In the mouse cerebral cortex, activity decorrelates during the second week of postnatal development, progressively acquiring the characteristic sparse pattern underlying the integration of sensory information. The maturation of inhibition seems critical for this process, but the interneurons involved in this crucial transition of network activity in the developing cortex remain unknown. Using in vivo longitudinal two-photon calcium imaging during the period that precedes the change from highly synchronous to decorrelated activity, we identify somatostatin-expressing (SST+) interneurons as critical modulators of this switch in mice. Modulation of the activity of SST+ cells accelerates or delays the decorrelation of cortical network activity, a process that involves regulating the maturation of parvalbumin-expressing (PV+) interneurons. SST+ cells critically link sensory inputs with local circuits, controlling the neural dynamics in the developing cortex while modulating the integration of other interneurons into nascent cortical circuits.<p/

Tuition fees and funding – barriers for non-traditional students? First results from the international research project Opening Universities for Lifelong Learning (OPULL)

Project OPULL – Opening Universities for Lifelong Learning – is undertaking research into ways of opening up higher education to vocationally qualified and experienced target groups in four European countries. Open university models in Germany, Denmark, Finland and the United Kingdom are being investigated in three research phases between 2009 and 2012 with the aim of identifying critical success factors for building open universities for Europe. This paper presents the first phase, in which educational systems in the participant countries have been mapped and interviews with lifelong learning experts undertaken. The current situation and perspectives in each country together with critical issues on how fees and funding influence higher education access for non-traditional students in these countries are discussed and explored through the interview evidence. The initial findings of the first phase of the project indicate that while the long-term effect of an increase in tuition fees for non-traditional students is not yet known, current evidence suggests that other factors such as the recognition of vocational and experiential learning will most likely have an impact on widening participation in higher education