Towards a resolution of conflicting models of illusory contour processing in humans.

Despite myriad studies, neurophysiologic mechanisms mediating illusory contour (IC) sensitivity remain controversial. Among the competing models one favors feed-forward effects within lower-tier cortices (V1/V2). Another situates IC sensitivity first within higher-tier cortices, principally lateral-occipital cortices (LOC), with later feedback effects in V1/V2. Still others postulate that LOC are sensitive to salient regions demarcated by the inducing stimuli, whereas V1/V2 effects specifically support IC sensitivity. We resolved these discordances by using misaligned line gratings, oriented either horizontally or vertically, to induce ICs. Line orientation provides an established assay of V1/V2 modulations independently of IC presence, and gratings lack salient regions. Electrical neuroimaging analyses of visual evoked potentials (VEPs) disambiguated the relative timing and localization of IC sensitivity with respect to that for grating orientation. Millisecond-by-millisecond analyses of VEPs and distributed source estimations revealed a main effect of grating orientation beginning at 65 ms post-stimulus onset within the calcarine sulcus that was followed by a main effect of IC presence beginning at 85 ms post-stimulus onset within the LOC. There was no evidence for differential processing of ICs as a function of the orientation of the grating. These results support models wherein IC sensitivity occurs first within the LOC.

Karyotypic variation between wood mouse species: banded chromosomes of Apodemus alpicola and A-microps

The banding pattern (G-, C-, AgNOR-staining) was described in karyotypes of Apodemus alpicola Heinrich, 1952 and A. microps Kratochvil et Rosicky, 1952 collected from the Alps and central Europe, Distinct differences between the two species were revealed in the distribution of C-heterochromatic regions in autosomes and the sex chromosomes, and the distribution of nucleolar organizer regions (NORs). Extensive variation in the distribution pattern of C-heterochromatin and NORs obviously exists among the wood mice of the subgenus Sylvaemus, and individual species can be distinguished according to a specific variation pattern. However, it seems premature to designate individual karyotypic forms as separate species, because the extent of overall geographical interpopulation variation is still not sufficiently known.

A post-processing pipeline to reconstruct the developing fetal brain using low-resolution MRI

Introduction. Development of the fetal brain surfacewith concomitant gyrification is one of the majormaturational processes of the human brain. Firstdelineated by postmortem studies or by ultrasound, MRIhas recently become a powerful tool for studying in vivothe structural correlates of brain maturation. However,the quantitative measurement of fetal brain developmentis a major challenge because of the movement of the fetusinside the amniotic cavity, the poor spatial resolution,the partial volume effect and the changing appearance ofthe developing brain. Today extensive efforts are made todeal with the âeurooepost-acquisitionâeuro reconstruction ofhigh-resolution 3D fetal volumes based on severalacquisitions with lower resolution (Rousseau, F., 2006;Jiang, S., 2007). We here propose a framework devoted tothe segmentation of the basal ganglia, the gray-whitetissue segmentation, and in turn the 3D corticalreconstruction of the fetal brain. Method. Prenatal MRimaging was performed with a 1-T system (GE MedicalSystems, Milwaukee) using single shot fast spin echo(ssFSE) sequences in fetuses aged from 29 to 32gestational weeks (slice thickness 5.4mm, in planespatial resolution 1.09mm). For each fetus, 6 axialvolumes shifted by 1 mm were acquired (about 1 min pervolume). First, each volume is manually segmented toextract fetal brain from surrounding fetal and maternaltissues. Inhomogeneity intensity correction and linearintensity normalization are then performed. A highspatial resolution image of isotropic voxel size of 1.09mm is created for each fetus as previously published byothers (Rousseau, F., 2006). B-splines are used for thescattered data interpolation (Lee, 1997). Then, basalganglia segmentation is performed on this superreconstructed volume using active contour framework witha Level Set implementation (Bach Cuadra, M., 2010). Oncebasal ganglia are removed from the image, brain tissuesegmentation is performed (Bach Cuadra, M., 2009). Theresulting white matter image is then binarized andfurther given as an input in the Freesurfer software(http://surfer.nmr.mgh.harvard.edu/) to provide accuratethree-dimensional reconstructions of the fetal brain.Results. High-resolution images of the cerebral fetalbrain, as obtained from the low-resolution acquired MRI,are presented for 4 subjects of age ranging from 29 to 32GA. An example is depicted in Figure 1. Accuracy in theautomated basal ganglia segmentation is compared withmanual segmentation using measurement of Dice similarity(DSI), with values above 0.7 considering to be a verygood agreement. In our sample we observed DSI valuesbetween 0.785 and 0.856. We further show the results ofgray-white matter segmentation overlaid on thehigh-resolution gray-scale images. The results arevisually checked for accuracy using the same principlesas commonly accepted in adult neuroimaging. Preliminary3D cortical reconstructions of the fetal brain are shownin Figure 2. Conclusion. We hereby present a completepipeline for the automated extraction of accuratethree-dimensional cortical surface of the fetal brain.These results are preliminary but promising, with theultimate goal to provide âeurooemovieâeuro of the normal gyraldevelopment. In turn, a precise knowledge of the normalfetal brain development will allow the quantification ofsubtle and early but clinically relevant deviations.Moreover, a precise understanding of the gyraldevelopment process may help to build hypotheses tounderstand the pathogenesis of several neurodevelopmentalconditions in which gyrification have been shown to bealtered (e.g. schizophrenia, autismâeuro¦). References.Rousseau, F. (2006), 'Registration-Based Approach forReconstruction of High-Resolution In Utero Fetal MR Brainimages', IEEE Transactions on Medical Imaging, vol. 13,no. 9, pp. 1072-1081. Jiang, S. (2007), 'MRI of MovingSubjects Using Multislice Snapshot Images With VolumeReconstruction (SVR): Application to Fetal, Neonatal, andAdult Brain Studies', IEEE Transactions on MedicalImaging, vol. 26, no. 7, pp. 967-980. Lee, S. (1997),'Scattered data interpolation with multilevel B-splines',IEEE Transactions on Visualization and Computer Graphics,vol. 3, no. 3, pp. 228-244. Bach Cuadra, M. (2010),'Central and Cortical Gray Mater Segmentation of MagneticResonance Images of the Fetal Brain', ISMRM Conference.Bach Cuadra, M. (2009), 'Brain tissue segmentation offetal MR images', MICCAI.

Altered brain mechanisms of emotion processing in pre-manifest Huntington's disease.

Huntington's disease is an inherited neurodegenerative disease that causes motor, cognitive and psychiatric impairment, including an early decline in ability to recognize emotional states in others. The pathophysiology underlying the earliest manifestations of the disease is not fully understood; the objective of our study was to clarify this. We used functional magnetic resonance imaging to investigate changes in brain mechanisms of emotion recognition in pre-manifest carriers of the abnormal Huntington's disease gene (subjects with pre-manifest Huntington's disease): 16 subjects with pre-manifest Huntington's disease and 14 control subjects underwent 1.5 tesla magnetic resonance scanning while viewing pictures of facial expressions from the Ekman and Friesen series. Disgust, anger and happiness were chosen as emotions of interest. Disgust is the emotion in which recognition deficits have most commonly been detected in Huntington's disease; anger is the emotion in which impaired recognition was detected in the largest behavioural study of emotion recognition in pre-manifest Huntington's disease to date; and happiness is a positive emotion to contrast with disgust and anger. Ekman facial expressions were also used to quantify emotion recognition accuracy outside the scanner and structural magnetic resonance imaging with voxel-based morphometry was used to assess the relationship between emotion recognition accuracy and regional grey matter volume. Emotion processing in pre-manifest Huntington's disease was associated with reduced neural activity for all three emotions in partially separable functional networks. Furthermore, the Huntington's disease-associated modulation of disgust and happiness processing was negatively correlated with genetic markers of pre-manifest disease progression in distributed, largely extrastriatal networks. The modulated disgust network included insulae, cingulate cortices, pre- and postcentral gyri, precunei, cunei, bilateral putamena, right pallidum, right thalamus, cerebellum, middle frontal, middle occipital, right superior and left inferior temporal gyri, and left superior parietal lobule. The modulated happiness network included postcentral gyri, left caudate, right cingulate cortex, right superior and inferior parietal lobules, and right superior frontal, middle temporal, middle occipital and precentral gyri. These effects were not driven merely by striatal dysfunction. We did not find equivalent associations between brain structure and emotion recognition, and the pre-manifest Huntington's disease cohort did not have a behavioural deficit in out-of-scanner emotion recognition relative to controls. In addition, we found increased neural activity in the pre-manifest subjects in response to all three emotions in frontal regions, predominantly in the middle frontal gyri. Overall, these findings suggest that pathophysiological effects of Huntington's disease may precede the development of overt clinical symptoms and detectable cerebral atrophy.

Behavioural species discrimination in red wood ants (Formica rufa group)

The Formica rufa group (red wood ants) currently includes six species. Nevertheless, during previous work based on molecular markers, we showed the existence of one population morphologically identified as F. lugubris, but genetically different from all other analysed populations of this species. This population could represent a cryptic species within the Swiss National Park and has been provisionally named Formica lugubris-A2. To verify our hypothesis, we conducted a behavioural test based on the ability of ants to recognize pupae of their own species when compared to those of another species. The three red wood ant species present in the Swiss National Park (F. lugubris, F. paralugubris and F. aquilonia) and the F. lugubris-A2 population were used in our study. Results indicate that the F. lugubris-A2 population differs from other F. lugubris and from all other species in the behaviour of its workers and in the way its pupae are discriminated by other species. This is in accordance with the genetic data and strengthens our hypothesis on the existence of a new cryptic red wood ant species within the Swiss National Park.

Intelligence-led crime scene processing. Part II : Intelligence and crime scene examination.

A better integration of the information conveyed by traces within intelligence-led framework would allow forensic science to participate more intensively to security assessments through forensic intelligence (part I). In this view, the collection of data by examining crime scenes is an entire part of intelligence processes. This conception frames our proposal for a model that promotes to better use knowledge available in the organisation for driving and supporting crime scene examination. The suggested model also clarifies the uncomfortable situation of crime scene examiners who must simultaneously comply with justice needs and expectations, and serve organisations that are mostly driven by broader security objectives. It also opens new perspective for forensic science and crime scene investigation, by the proposal to follow other directions than the traditional path suggested by dominant movements in these fields.

Role of prohormone convertases in pro-neuropeptide Y processing: coexpression and in vitro kinetic investigations.

Proneuropeptide Y (ProNPY) undergoes cleavage at a single dibasic site Lys38-Arg39 resulting in the formation of 1-39 amino acid NPY which is further processed successively by carboxypeptidase-like and peptidylglycine alpha-amidating monooxygenase enzymes. To investigate whether prohormone convertases are involved in ProNPY processing, a vaccinia virus derived expression system was used to coexpress recombinant ProNPY with each of the prohormone convertases PC1/3, PC2, furin, and PACE4 in Neuro2A and NIH 3T3 cell lines as regulated neuroendocrine and constitutive prototype cell lines, respectively. The analysis of processed products shows that only PC1/3 generates NPY in NIH 3T3 cells while both PC1/3 and PC2 are able to generate NPY in Neuro2A cells. The convertases furin and PACE4 are unable to process ProNPY in either cell line. Moreover, comparative in vitro cleavage of recombinant NPY precursor by the enzymes PC1/3, PC2 and furin shows that only PC1/3 and PC2 are involved in specific cleavage of the dibasic site. Kinetic studies demonstrate that PC1/3 cleaves ProNPY more efficiently than PC2. The main difference between the cleavage efficiency is observed in the Vmax values whereas no major difference is observed in Km values. In addition the cleavage by PC1/3 and PC2 of two peptides reproducing the dibasic cleavage site with different amino acid sequence lengths namely (20-49)-ProNPY and (28-43)-ProNPY was studied. These shortened ProNPY substrates, when recognized by the enzymes, are more efficiently cleaved than ProNPY itself. The shortest peptide is not cleaved by PC2 while it is by PC1/3. On the basis of these observations it is proposed, first, that the constitutive secreted NPY does not result from the cleavage carried out by ubiquitously expressed enzymes furin and PACE4; second, that PC1/3 and PC2 are not equipotent in the cleavage of ProNPY; and third, substrate peptide length might discriminate PC1/3 and PC2 processing activity.

Contribution to the conservation biology of the wood ant Formica lugubris (Hymenoptera, Formicidae) in Switzerland

Summary Among ants, wood ants are probably the most fascinating and studied species in temperate European forests. Unfortunately, due to several threats they are nowadays registered in red lists. Recent studies made in the Swiss Jura Mountains ended up in the description of a new sympatric sibling species of Formica lugubris (i.e. Formica paralugubris Seifert 1996). Because of this confusion the biology of F. lugubris is incomplete. Due to the extreme difficulties to distinguish morphologically F. lugubris from F. paralugubris we studied their cuticular hydrocarbons profiles. Irrespective of their geographic origin, we observed quantitative discrimination between species within each caste (workers, males and gynes =young alate female). Moreover, using a behavioural taxonomic approach (i.e. the pupa-carrying test) we showed that ants preferred conspecific worker pupae to those of the sibling species. These first results allowed us to consider the two species as two separate taxonomic units. To understand their coexistence, habitat distribution models were fitted with GIS predictors and factors known to influence wood ant distribution. In the Jura Mountains, although the two species share very similar habitats, they are spatially segregated. F. lugubris occurs more frequently at woodland borders than in forest interiors. We demonstrated with genetic and field data that Formica lugubris displays two different social forms in close proximity in alpine zone (e.g. unmanaged forests of the Swiss National Park). We discovered populations mostly monogynous to weakly polygynous (i.e. one to a few egg laying queens per colony) and monodomous (i.e. one nest per colony), and polygynous/polydomous populations (new nests being founded by colony budding). It is generally admitted that monogyne species disperse well in order to find suitable habitat to found new colonies whereas polygyne species have restricted dispersal and local mating within the nest. In order to compare reproductive strategies of F. lugubris and F. paralugubris (i.e. matings and dealation process) we conducted experiments with sexuals. F, lugubris gynes from monogynous/monodomous populations do not show a local strategy like the obligately polygynous F. paralugubris (i.e. early dealation even without mating, insemination without flight activity and low fat reserve). They always keep their wings, do not mate when not able to fly and have high amount of fat content revealing high survival capacities. On the other side, F, lugubris gynes from polygynous/polydomous populations have lower lipid reserves and displayed a reproductive behaviour close to the F. para lugubris one. After dispersal, wood ant gynes can either start new societies by temporary social parasitism of another species (i.e. subgenus Serviformica) or be adopted intraspecifically in an existing nest. In F. lugubris, we demonstrated that gynes from monogynous/monodomous colonies showed a high success for temporary social parasitism compare to the lower success of gynes from polygynous/polydomous colonies. However, physiological analyses suggested that only gynes from monogynous/ monodomous populations can efficiently disperse and found new nest by temporary social parasitism. Intraspecifically, gynes were accepted to a high degree in polygynous nest and in monogynous nests as long as these nests contained sexuals. In conclusion, Formica lugubris displays a social and dispersal polymorphism (mixed mating and founding system) representing a behavioural plasticity in relation to environmental and ecological conditions. Therefore, conservation measures directed toward this species should try to maintain a maximum of diversity at the habitat level. Résumé Les fourmis des bois sont probablement parmi les espèces de fourmis les plus fascinantes et les plus étudiées des forêts tempérées Européennes. Actuellement, du fait de différentes menaces, elles figurent malheureusement sur listes rouges. Plusieurs études menées au sein du Jura Suisse ont abouti à la description d'une nouvelle espèce jumelle et sympatrique de Formica lugubris (F. para- lugubris Seifert 1996). A cause de cette confusion la biologie de F lugubris est lacunaire. La distinction morphologique de F. lugubris et de F. para lugubris est si difficile que nous avons étudié leurs hydrocarbures cuticulaires. Indépendamment de l'origine géographique, nous avons observé une discrimination quantitative entre les espèces au sein de chaque caste (ouvrières, mâles et jeunes femelles ailées). De plus, à l'aide d'une approche taxonomique comportementale (le test de transport de cocons) nous avons montré que les fourmis préfèrent des cocons d'ouvrières conspécifiques à ceux de l'espèce jumelle. Ces premiers résultats nous permettent de considérer ces deux espèces comme deux unités taxonomiques distinctes et valables. Afin de comprendre leur coexistence, des modèles mathématiques ont été développés avec des données SIG et des facteurs écologiques influençant la répartition des fournis des bois. Dans le Jura, même si elles partagent des habitats fortement similaires, les deux espèces n'occupent pas les mêmes secteurs. F. lugubris est plus fréquente en lisière forestière plutôt qu'en pleine forêt. Nous avons démontré grâce à des données génétiques et de terrain que F. lugubris présente deux formes sociales au sein de la zone alpine (forêts protégées du Parc National Suisse). D'autre part, nous avons découvert des populations monogynes à faiblement polygynes (une à quelques reines pondeuses par colonie) et monodomes (colonies composées d'une seule fourmilière), et des populations polygynes/polydomes (les nouveaux nids étant produit par bourgeonnement). Généralement, les espèces monogynes dispersent sur de grandes distances et peuvent coloniser des habitats favorables à la fondation de nouvelles colonies alors que les espèces polygynes possèdent une dispersion limitée avec des accouplements à l'intérieur des nids. Afin de comparer les stratégies de reproduction de F. lugubris et de F. paralugubris (accouplements et perte des ailes) nous avons mené des expériences avec les sexués. Les jeunes femelles ailées de F. lugubris issues de populations monogynes/monodomes ne présentent pas de stratégie locale comparée à l'espèce obligatoirement polygyne F paralugubris (perte des ailes précoce même si il n'y a pas eu accouplement, insémination possible sans avoir volé activement et faibles réserves de graisse). Elles conservent toujours leurs ailes, ne s'accouplent pas lorsqu'elles sont empêchées de voler et possèdent de grandes quantités de graisse révélant de fortes capacités de survie. D'autre part, les jeunes femelles ailées de F. lugubris provenant de populations polygynes/polydomes ont peu de réserves lipidiques et ont un comportement de reproduction proche de celles de F. paralugubris. Après leur dispersion, les jeunes sexués femelles de fourmis des bois peuvent soit fonder une nouvelle société par parasitisme social temporaire d'un nid d'une autre espèce (sous-genre Serviformica) soit être adoptées dans un nid déjà existant de leur propre espèce. Chez F. lugubris, nous avons pu démontrer que les jeunes sexués femelles de colonies monogynes/monodomes présentent un succès élevé au parasitisme sociale temporaire en comparaison au plus faible succès obtenu avec des sexués provenant de colonies polygynes/polydomes. Cependant, les données physiologiques suggèrent que seules les jeunes sexués femelles de populations mono-gynes/monodomes peuvent disperser efficacement et fonder un nouveau nid par parasitisme social temporaire. Au niveau intraspécifique, les jeunes femelles sont acceptées à un taux élevé dans les nids polygynes mais aussi dans les nids monogynes tant que ces nids possèdent encore de jeunes sexués. En conclusion, F. lugubris est caractérisée par un polymorphisme dans ses structures sociales et ses stratégies de dispersion (système mixte d'accouplement et de fondation) ce qui représente une forte plasticité comportementale en relation avec les conditions environnementales et écologiques. Par conséquent, les mesures de conservation de cette espèce devraient s'attacher à maintenir un maximum de diversité au niveau des habitats.

Intelligence-led crime scene processing. Part I : Forensic intelligence.

Forensic science is generally defined as the application of science to address questions related to the law. Too often, this view restricts the contribution of science to one single process which eventually aims at bringing individuals to court while minimising risk of miscarriage of justice. In order to go beyond this paradigm, we propose to refocus the attention towards traces themselves, as remnants of a criminal activity, and their information content. We postulate that traces contribute effectively to a wide variety of other informational processes that support decision making inmany situations. In particular, they inform actors of new policing strategies who place the treatment of information and intelligence at the centre of their systems. This contribution of forensic science to these security oriented models is still not well identified and captured. In order to create the best condition for the development of forensic intelligence, we suggest a framework that connects forensic science to intelligence-led policing (part I). Crime scene attendance and processing can be envisaged within this view. This approach gives indications abouthowto structure knowledge used by crime scene examiners in their effective practice (part II).