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The optic radiations (OR) are white matter tracts forming the posterior part of the visual ways. As an important inter-individual variability exists, atlases may be inefficient to locate the OR in a given subject. We designed a fully automatic method to delimitate the OR on a magnetic resonance imaging using tractography. On 15 healthy subjects, we evaluated the validity of our method by comparing the outputs to the Julich post-mortem histological atlas, and its reproducibility. We also evaluated its feasibility on 98 multiple sclerosis (MS) patients. We correlated different visual outcomes with the inflammatory lesions volume within the OR reconstructed with different methods (our method, atlas, TractSeg). Our method reconstructed the OR bundle in all healthy subjects (

The self-organized assembly of acentrosomal meiotic spindles has been extensively studied1 but little is known about how chromosomes segregate on these spindles. Here, we investigate two chromosome-microtubule interaction mechanisms—kinetochores and chromokinesins—during meiosis in fertilized C. elegans oocytes. We show that the conserved kinetochore protein KNL-1 directs assembly of meiotic kinetochores that orient chromosomes on the acentrosomal spindles. However, in contrast to mitosis, chromosome separation during meiotic anaphase was kinetochore-independent. The chromokinesin KLP-19 did not contribute to chromosome orientation or anaphase, but stabilized late anaphase spindles. Prior to anaphase separation, meiotic kinetochores and spindle poles disassembled along with microtubules on the poleward side of the chromosomes; during anaphase, microtubules were formed between the separating chromosomes. Functional analysis implicated a set of proteins that localize to a ring-shaped domain between the kinetochores in pre-anaphase spindle assembly and anaphase separation. Ring domain proteins are localized by the chromosomal passenger complex (CPC), whose local enrichment is patterned by recombination to control step-wise loss of meiotic cohesion2–4. Thus, meiotic segregation in C. elegans is a two-stage process where kinetochores orient chromosomes but are dispensable for their separation. We suggest that separation is instead controlled by a meiosis-specific chromosomal domain to coordinate step-wise dissolution of cohesion with chromosome segregation.

Cet article presente des strategies de codage permettant d’implanter Videe du codage avec information adjacente (ou dpc, dirty paper coding) dans le cadre du canal de diffusion avec un emetteur et des recepteurs a antennes multiples. Ce travail decrit des strategies de codage qui utilisent la connaissance du canal a l’emetteur qui s’inspirent de concepts suggeres par la theorie de l’information. La mise en œuvre complete des algorithmes de codage et de decodage nous permet d’evaluer les performances de ces strategies en termes de taux d’erreurs binaires et non pas en terme de region de debit de codage. Differents codeurs internes et externes sont compares entre eux. Enfin, nous considerons le codage dpc en tant que strategie d’acces multiple et le comparons avec l’acces multiple temporel (TDMA). Nous verrons que les resultats obtenus pour les codeurs pratiques proposes ne concordent pas toujours avec les predictions theoriques pour les codeurs optimaux.

Nat. Cell Biol. 17, 697–705 (2015); published online 13 April 2015; corrected after print 8 June 2015 In the version of this Letter originally published, the following sentence was omitted from the Acknowledgements: 'B.L. is supported by a post-doctoral fellowship from FRM (ARF20140129055).' This has been corrected in the online versions of the Letter.