Face or building superiority in peripheral vision reversed by task requirements

Peripheral vision has been the topic of few studies compared with central vision. Nevertheless, given that visual information covers all the visual field and that relevant information can originate from highly eccentric positions, the understanding of peripheral vision abilities for object perception seems essential. The poorer resolution of peripheral vision would first suggest that objects requiring large-scale feature integration such as buildings would be better processed than objects requiring finer analysis such as faces. Nevertheless, task requirements also determine the information (coarse or fine) necessary for a given object to be processed. We therefore investigated how task and eccentricity modulate object processing in peripheral vision. Three experiments were carried out requiring finer or coarser information processing of faces and buildings presented in central and peripheral vision. Our results showed that buildings were better judged as identical or familiar in periphery whilst faces were better categorised. We conclude that this superiority for a given stimulus in peripheral vision results (a) from the available information, which depends on the decrease of resolution with eccentricity, and (b) from the useful information, which depends on both the task and the semantic category

3D rotational angiography: use of propeller rotation for the evaluation of intracranial aneurysms.

We compared two methods of 3D digital subtraction angiography (DSA)--propeller and standard rotation--for the assessment of aneurysmal morphology and its relation to neighboring vessels. Aneurysms were correctly visualized and localized with both techniques. 3D DSA with propeller rotation technique seems to be effective and allows us to reduce the amount of contrast material related to a shortened acquisition time. Technical progress including propeller rotation allows a larger range of rotation and faster rotational speeds.Comparative StudyJournal Articleinfo:eu-repo/semantics/publishe

Trench Bending Initiation: Upper Plate Strain Pattern and Volcanism. Insights From the Lesser Antilles Arc, St. Barthelemy Island, French West Indies

International audienceThe upper plate deformation pattern reflects the mechanical behavior of subduction zones. Here we focus on the consequences of the entrance of a buoyant bank into the Caribbean subduction zone during the Eocene by studying the oldest exposed rocks belonging to the Lesser Antilles volcanic arc. Using a novel geochronological data set, we show that the volcanic arc activity on the island of St. Barthelemy spanned over the mid‐Eocene to early Miocene with a westward migration of the tectono‐volcanic activity, which is comparable to what has already been observed on other volcanic islands in the Lesser Antilles. The kinematics analysis allows us to identify a switch in the stress field from pure to radial extension at the Oligo‐Miocene hinge with a subhorizontal σ3 that has a mean trend of N20°. A three‐step restoration of the regional deformation indicates that this switch from pure parallel‐to‐the‐trench extension to radial extension may reflect a strain partitioning initiation affecting the upper Caribbean Plate in response to trench bending that followed the entrance of the Bahamas Bank into the subduction zone. We show that the northern end of the Lesser Antilles arc shows a tectono‐volcanic evolution which is similar to the southern one. The north‐south dichotomy in the perpendicular‐to‐the‐trench extension, 15% in the north versus 30% in the south, may reflect different slab ends that are highly curved to the north (restraining the extension in the upper plate) versus a tear to the south (allowing a larger amount of extension within the upper plate)

Implicit and explicit object recognition at very large visual eccentricities : no improvement after loss of central vision.

International audienceLittle is known about the ability of human observers to process objects in the far periphery of their visual field and nothing about its evolution in case of central vision loss. We investigated implicit and explicit recognition at two large visual eccentricities. Pictures of objects were centred at 30° or 50° eccentricity. Implicit recognition was tested through a priming paradigm. Participants (normally sighted observers and people with 10-20 years of central vision loss) categorized pictures as animal/transport both in a study phase (Block 1) and in a test phase (Block 2). In explicit recognition participants decided for each picture presented in Block 2 whether it had been displayed in Block 1 (“yes”/“no”). Both visual (identical) and conceptual/lexical (same-name) priming occurred at 30° and at 50°. Explicit recognition was observed only at 30°. In people with central vision loss testing was only performed at 50° eccentricity. The pattern of results was similar to that of normally sighted observers but global performance was lower. The results suggest that vision, at large eccentricity, is mainly based on nonconscious coarse representations. Moreover, after 10-20 years of central vision loss, no evidence was found for an increased ability to use peripheral information in object recognition

Toward a new and noninvasive diagnostic method of papillary thyroid cancer by using peptide vectorized contrast agents targeted to galectin-1

The incidence of papillary thyroid cancer has increased these last decades due to a better detection. High prevalence of nodules combined with the low incidence of thyroid cancers constitutes an important diagnostic challenge. We propose to develop an alternative diagnostic method to reduce the number of useless and painful thyroidectomies using a vectorized contrast agent for magnetic resonance imaging. Galectin-1 (gal-1), a protein overexpressed in well-differentiated thyroid cancer, has been targeted with a randomized linear 12-mer peptide library using the phage display technique. Selected peptides have been conjugated to ultrasmall superparamagnetic particles of iron oxide (USPIO). Peptides and their corresponding contrast agents have been tested in vitro for their specific binding and toxicity. Two peptides (P1 and P7) were selected according to their affinity toward gal-1. Their binding has been revealed by immunohistochemistry on human thyroid cancer biopsies, and they were co-localized with gal-1 by immunofluorescence on TPC-1 cell line. Both peptides induce a decrease in TPC-1 cells’ adhesion to gal-1 immobilized on culture plates. After coupling to USPIO, the peptides preserved their affinity toward gal-1. Their specific binding has been corroborated by co-localization with gal-1 expressed by TPC-1 cells and by their ability to compete with anti-gal-1 antibody. The peptides and their USPIO derivatives produce no toxicity in HepaRG cells as determined by MTT assay. The vectorized contrast agents are potential imaging probes for thyroid cancer diagnosis. Moreover, the two gal-1-targeted peptides prevent cancer cell adhesion by interacting with the carbohydrate-recognition domain of gal-1.SCOPUS: ar.jinfo:eu-repo/semantics/publishe