GPS tracking technology and re-visiting the relationship between the avian visual Wulst and homing pigeon navigation.

Within their familiar areas homing pigeons rely on familiar visual landscape features and landmarks for homing. However, the neural basis of visual landmark-based navigation has been so far investigated mainly in relation to the role of the hippocampal formation. The avian visual Wulst is the telencephalic projection field of the thalamofugal pathway that has been suggested to be involved in processing lateral visual inputs that originate from the far visual field. The Wulst is therefore a good candidate for a neural structure participating in the visual control of familiar visual landmark-based navigation. We repeatedly released and tracked Wulst-lesioned and control homing pigeons from three sites about 10-15 km from the loft. Wulst lesions did not impair the ability of the pigeons to orient homeward during the first release from each of the three sites nor to localise the loft within the home area. In addition, Wulst-lesioned pigeons displayed unimpaired route fidelity acquisition to a repeated homing path compared to the intact birds. However, compared to control birds, Wulst-lesioned pigeons displayed persistent oscillatory flight patterns across releases, diminished attention to linear (leading lines) landscape features, such as roads and wood edges, and less direct flight paths within the home area. Differences and similarities between the effects of Wulst and hippocampal lesions suggest that although the visual Wulst does not seem to play a direct role in the memory representation of a landscape-landmark map, it does seem to participate in influencing the perceptual construction of such a map.

Use of the sun compass by monocularly occluded homing pigeons in a food localisation task in an outdoor arena.

Functional asymmetries of the avian visual system can be studied in monocularly occluded birds, as their hemispheres are largely independent. Right and left monocularly occluded homing pigeons and control birds under binocular view have been trained in a food localisation task in an octagonal outdoor arena provided with one coloured beacon on each wall. The three groups were tested after the removal of the visual beacons, so to assess their sun compass learning abilities. Pigeons using the left eye/right hemisphere system exhibited slower learning compared to the other monocular group. During the test in the arena void of visual beacons, the three groups of birds, regardless of their visual condition, were generally able to identify the training sector by exclusively relying on sun compass information. However, the directional choices of the pigeons with the left eye/right hemisphere in use were significantly affected by the removal of the beacons, while both control pigeons and birds with the right eye/left hemisphere in use displayed unaltered performances during the test. A subsample of pigeons of each group were re-trained in the octagonal arena with visual beacons present and tested after the removal of visual beacons after a 6 h fast clock-shift treatment. All birds displayed the expected deflection consistent to the sun compass use. While birds using either the left or the right visual systems were equally able to learn a sun compass-mediated spatial task, the left eye/right hemisphere visual system displayed an advantage in relying on visual beacons.

Deconstructing the flight paths of hippocampal-lesioned homing pigeons as they navigate near home offers insight into spatial perception and memory without a hippocampus.

The aim of this study was to exploit detailed analyses of GPS-recorded tracks to better characterise the impact of hippocampal (HF) lesion on spatial memory and perception in the context of homing pigeon navigation when reliant on familiar landscape features near the home loft following repeated releases from the same three locations. As reported previously, following HF lesion, a low spatio-temporal resolution analysis revealed that homing pigeons fly less direct paths home once near the loft. We now further show that 1) HF-lesioned pigeons are less likely to display fidelity to a particular flight path home when released from the same locations multiple times, 2) intact pigeons are more likely to exploit leading-line landscape features, e.g., a road or the border of a woodlot, in developing flight-path fidelity and 3) even when flying a straight path HF-lesioned homing pigeons are more likely to display relatively rapid, oscillatory heading changes as if casting about for sensory, presumably visual information. The flight behaviour differences between the intact and HF-lesioned pigeons persisted across the four releases from the three locations, although the differences became smaller with increasing experience. Taken together, the GPS-track data offer a detailed characterisation of the effects of HF lesion on landscape-based, homing pigeon navigation, offering new insight into the role of the hippocampal formation in supporting memory-related, e.g., fidelity to a familiar route home, and perhaps perceptual-related, e.g., oscillating headings, navigational processes.

Vegetation height and structure drive foraging habitat selection of the lesser kestrel (Falco naumanni) in intensive agricultural landscapes.

Habitat selection in animals is a fundamental ecological process with key conservation implications. Assessing habitat selection in endangered species and populations occupying the extreme edges of their distribution range, or living in highly anthropized landscapes, may be of particular interest as it may provide hints to mechanisms promoting potential range expansions. We assessed second- and third-order foraging habitat selection in the northernmost European breeding population of the lesser kestrel (Falco naumanni), a migratory falcon of European conservation interest, by integrating results obtained from 411 direct observations with those gathered from nine GPS-tracked individuals. The study population breeds in the intensively cultivated Po Plain (northern Italy). Direct observations and GPS data coincide in showing that foraging lesser kestrels shifted their habitat preferences through the breeding cycle. They positively selected alfalfa and other non-irrigated crops during the early breeding season, while winter cereals were selected during the nestling-rearing phase. Maize was selected during the early breeding season, after sowing, but significantly avoided later. Overall, vegetation height emerged as the main predictor of foraging habitat selection, with birds preferring short vegetation, which is likely to maximise prey accessibility. Such a flexibility in foraging habitat selection according to spatio-temporal variation in the agricultural landscape determined by local crop management practices may have allowed the species to successfully thrive in one of the most intensively cultivated areas of Europe. In the southeastern Po Plain, the broad extent of hay and non-irrigated crops is possibly functioning as a surrogate habitat for the pseudo-steppe environment where most of the European breeding population is settled, fostering the northward expansion of the species in Europe. In intensive agricultural landscapes, the maintenance of alfalfa and winter cereals crops and an overall high crop heterogeneity (deriving from crop rotation) is fundamental to accommodate the ecological requirements of the species in different phases of its breeding cycle.

[CircuLite Synergy ventricular assist device: a new approach to end-stage congestive heart failure]. / Sistema di assistenza ventricolare CircuLite Synergy: un nuovo approccio all'insufficienza cardiaca terminale.

BACKGROUND: The Synergy system, a miniature partial circulatory support device, is implanted by an off-pump, minimally invasive surgical approach. The system has been optimized to improve performance in an EU clinical trial for chronic ambulatory heart failure. This therefore offers the possibility of treating elderly chronic heart failure patients who might not usually be considered for long-term circulatory support. METHODS: From June 2007 to December 2012, 63 patients were implanted with the Synergy system (12 patients ≥70 years) using four different releases of the device. Briefly, the system draws blood through the inflow cannula from the left atrium into the micro-pump (placed in a right subclavicular pocket) and pumps it through an outflow graft to the right subclavian artery. In this paper, we present an intermediate analysis of the clinical trial as performed on April 30, 2013, leading to the placing of the CE mark. RESULTS: Mean duration of support is ongoing at 230 days (range 23-1387). Follow-up showed improved hemodynamic response, with additional improvements in 6-min walk distance (299 ± 144 to 420 ± 119 m) and Minnesota Living with Heart Failure Questionnaire (69.5 ± 20.4 to 49.2 ± 24.3). Older patients had longer mean durations of support (337 vs 188 days). On average, elderly and younger patients showed similar improvements in hemodynamics and 6-min walk distance (107 ± 120 vs 130 ± 121 m). Major adverse cardiac events included bleeding (n=4) with one bleeding related to renal failure resulting in death. CONCLUSIONS: Clinical use of the Synergy device was associated with a significant functional improvement. Very low adverse event rates were reported with the latest device release. Older patients had smaller body sizes and worse renal function than younger patients. Both groups experienced similar hemodynamic benefits and functional improvements. The risk of bleeding and renal dysfunction appears to be increased in the elderly, though still within acceptable ranges compared to other full support devices. Minimally invasive long-term circulatory support devices, like Synergy, offer a new treatment option that might be available even for the elderly chronic heart failure population.

An Unusual Left Ventricular Apical Mass.

Left ventricular apical masses constitute a rare finding. Imaging properties together with the clinical history of the patient usually allow an etiologic definition. We report a challenging case of an ambiguous left ventricular apical mass of uncertain nature till histological examination. Points of interest were singular clinical history and echocardiographic findings, although not conclusive in hypothesis generating. Furthermore to the best of our knowledge, this is one of the rare attempt to excise a deep left ventricular mass with a mini-invasive surgical approach.

[Quantification of aortic valve area using three-dimensional echocardiography]. / Utilidad de la ecocardiografía tridimensional en la cuantificación del área valvular aórtica.

INTRODUCTION AND OBJECTIVES: To determine whether the reproducibility of left ventricular outflow tract (LVOT) area measurement is greater with three-dimensional echocardiographic (3D-echo) planimetry than with conventional 2D-echo. To determine the LVOT circularity index by means of 3D-echo. To determine the usefulness of measuring the LVOT area by 3D-echo for quantifying the severity of valvular aortic stenosis. METHODS: The study included 40 patients, of whom 22 had an aortic stenosis. The LVOT area was measured using both 2D-echo and 3D-echo, and the circularity index, using 3D-echo alone. In addition, the severity of valvular aortic stenosis was categorized using both 2D-echo and 3D-echo. RESULTS: The levels of inter- and intra-observer agreement on LVOT area measurements were better with 3D-echo. The circularity index was 1.50 (0.25), and there was a very poor linear correlation with LVOT area (r=-0.34; P=.47). Patients with valvular aortic stenosis were categorized according to the severity of their stenoses using both 2D-echo and 3D-echo. The level of agreement between the two techniques was poor (kappa=0.36). CONCLUSIONS: Measurements of the LVOT area made using 3D-echo were more reproducible than those made using 2D-echo. Consequently, 3D-echo may be a better technique for assessing the LVOT area. In addition, 3D-echo showed that the LVOT is elliptical in form and that its size is not related to its circularity. Moreover, 3D-echo could also be helpful in classifying the severity of valvular aortic stenosis.

Utilidad de la ecocardiografía tridimensional en la cuantificación del área valvular aórtica / Quantification of Aortic Valve Area Using Three-Dimensional Echocardiography

Introducción y objetivos. Determinar si la estimación del área del tracto de salida del ventrículo izquierdo (TSVI) mediante planimetría con ecografía tridimensional (Eco-3D) es más reproducible que con ecografía bidimensional (Eco-2D). Determinar el grado de circularidad del TSVI mediante Eco-3D. Determinar el impacto de la valoración del área del TSVI mediante Eco-3D en la cuantificación de la severidad de la estenosis aórtica valvular. Métodos. Se reclutó a 40 pacientes con valvulopatía aórtica, 22 con estenosis aórtica. Se calculó el área del TSVI mediante Eco-2D y Eco-3D. Se calculó el índice de circularidad del TSVI mediante Eco-3D. Por último, se clasificó la severidad de las estenosis aórticas mediante Eco-2D y Eco-3D. Resultados. El grado de acuerdo tanto entre observadores como intraobservador a la hora de determinar el área del TSVI fue superior cuando se usó Eco-3D. El índice de circularidad fue 1,5 ± 0,25 y presentó un grado de asociación lineal con el área del TSVI muy bajo (r = ­0,34; p = 0,47). Los pacientes con estenosis aórtica valvular fueron clasificados de acuerdo con su severidad determinada con Eco-2D y Eco-3D. El grado de acuerdo entre los métodos fue débil (κ = 0,36). Conclusiones. La medición del área del TSVI mediante Eco-3D es más reproducible que con Eco-2D. Por lo tanto, probablemente se trate de un método más preciso para evaluarla. La Eco-3D demuestra que el TSVI tiene una forma elíptica y que su tamaño no se relaciona con su morfología más o menos circular. La Eco-3D podría ayudar a clasificar la severidad de la estenosis aórtica (AU)

Introduction and objectives. To determine whether the reproducibility of left ventricular outflow tract (LVOT) area measurement is greater with three-dimensional echocardiographic (3D-echo) planimetry than with conventional 2D-echo. To determine the LVOT circularity index by means of 3D-echo. To determine the usefulness of measuring the LVOT area by 3D-echo for quantifying the severity of valvular aortic stenosis. Methods. The study included 40 patients, of whom 22 had an aortic stenosis. The LVOT area was measured using both 2D-echo and 3D-echo, and the circularity index, using 3D-echo alone. In addition, the severity of valvular aortic stenosis was categorized using both 2D-echo and 3D-echo. Results. The levels of inter- and intra-observer agreement on LVOT area measurements were better with 3D-echo. The circularity index was 1.50 (0.25), and there was a very poor linear correlation with LVOT area (r=­0.34; P=.47). Patients with valvular aortic stenosis were categorized according to the severity of their stenoses using both 2D-echo and 3D-echo. The level of agreement between the two techniques was poor (κ=0.36). Conclusions. Measurements of the LVOT area made using 3D-echo were more reproducible than those made using 2D-echo. Consequently, 3D-echo may be a better technique for assessing the LVOT area. In addition, 3D-echo showed that the LVOT is elliptical in form and that its size is not related to its circularity. Moreover, 3D-echo could also be helpful in classifying the severity of valvular aortic stenosis (AU)