City rats: From rat behaviour to human spatial cognition in urban environments

The structure and shape of an urban environment influence our ability to find our way about in the city^1-2^. Indeed, urban designers who face the challenge of planning environments that facilitate wayfinding^3^, have a consequent need to understand the relations between the urban environment and spatial cognition^4^. Previous studies have suggested that certain qualities of city elements, such as a distinct contrast with the background (e.g. The Eiffel Tower in Paris), or a clear morphology (e.g. the grid layout of Manhattan's streets) affect spatial behaviour and cognition^1,5-7^. However, only a few empirical studies have examined the relations between the urban environment and spatial cognition. Here we suggest that testing rats in experimental environments that simulate certain facets of urban environment can provide an insight into human spatial behaviour in urban environments with a similar layout. Specifically, we simulated two city layouts: (1) a grid street layout such as that of Manhattan; and (2) an irregular street layout such as that of Jerusalem. We found that the rats that were tested in the grid layout covered more ground and visited more locations, compared with the restricted movement demonstrated by the rats tested in the irregular layout. This finding in rats is in accordance with previous findings that urban grids conduce to high movement flow throughout the city, compared to low movement flow in irregular urban layouts^8-9^. Previous studies revealed that the spatial behaviour of rats and humans is controlled by the same underlying mechanisms^10-11^. In the same vein, we show that rats demonstrate spatial movement patterns that recall those of humans in similar urban environments. Rat behaviour may thus offer an in-vivo means for testing and analyzing the spatial cognitive principles of specific urban designs and for inferring how humans may perceive a particular urban environment and orient in it

Locomotor activity in common spiny mice (Acomys cahirinuse): The effect of light and environmental complexity

BACKGROUND: Rodents typically avoid illuminated and open areas, favoring dark or sheltered environments for activity. While previous studies focused on the effect of these environmental attributes on the level of activity, the present study tested whether the spatio-temporal structure of activity was also modified in illuminated compared with dark and complex compared with open arenas. For this, we tested common spiny mice (Acomys cahirinus) in empty or stone-containing arenas with lights on or lights off. RESULTS: In an illuminated or open arena, spiny mice moved in less frequent but longer trips with relatively long distances between consecutive stops. In contrast, in either a dark arena or an arena with stones, the animals took shorter and more frequent trips, with more stops per trip and shorter inter-stop distances. In illuminated arenas spiny mice remained mainly along the walls, whereas locomotion in the center was more prevalent in dark empty arenas, and was carried out along convoluted paths. Increasing environmental complexity by adding stones to either illuminated or dark arenas increased locomotion along straight trajectories and away from walls. CONCLUSIONS: Earlier findings of reduced activity in illuminated or open areas have been extended in the present study by demonstrating changes in the spatio-temporal structure of locomotor behavior. In the more complex arenas (with stones) spiny mice traveled along short straight segments whereas in the open their trips were longer and took the shape of a zigzag path which is more effective against fast or nearby predators. Alternatively, the zigzag path may reflect a difficulty in navigation

Animals do not commit suicide but do display behaviors that are precursors of suicide in humans

Although my commentary begins with a report about a monkey committing suicide, I agree with the target article\u27s concluding statement that we cannot currently prove that any animal has committed suicide. The author’s proposed continuist approach is based on animal behaviors reminiscent of symptoms preceding suicide in humans (e.g., deep depression and grief). However, in both humans and nonhuman animals, these are just potential precursors of suicide, and dying as a result of grief is not necessarily suicide. In the absence of supporting evidence, the continuist hypothesis of animal suicide is not sustained

Rodents in open space adjust their behavioral response to the different risk levels during barn-owl attack

BACKGROUND: Previous studies have revealed that the response of prey species to predatory risk comprised either freezing (when the prey remained immobile), or fleeing (when it ran frantically in order to remove itself from the vicinity of the predator). Other studies, however, have suggested that the prey will adjust its behavior to risk level. The present study was designed to follow the attacks of a barn owl (Tyto alba) on common spiny mice (Acomys cahirinus) and social voles (Microtus socialis guntherei), in order to reveal the correspondence between the behavior of the owl, the risk level at each phase of the owl's attack, and the defensive behavior of the rodents. RESULTS: Spiny mice dramatically increased the traveled distance upon the appearance of the owl, and kept moving during its attack while taking long trajectories of locomotion. Defensive response in voles dichotomized: in some voles traveled distance dropped when the owl appeared, reaching zero during its attack. In other voles, traveled distance dramatically increased once the owl appeared and further increased under its attack. These defensive responses developed by gradual tuning of normal locomotor behavior in accordance with the level of risk. CONCLUSIONS: The phenotypic difference in defensive behavior between voles and spiny mice probably stems from their different habitats and motor capacities. Agility and running capacity, together with a relatively sheltered natural habitat, make fleeing the most appropriate response for spiny mice during owl attack. Clumsiness and relatively limited motor capacities, together with an open natural habitat, account for the dichotomy to freezing or fleeing in voles. Thus, the apparent species-specific anti-predator response in spiny mice and voles is based on species-specific normal locomotor behavior, which depends on the species-specific ecology and motor capacity, and behaviors like defensive attack or escape jump that are specific to life threat. The latter behaviors are brief, and irregularly inlaid in the ongoing locomotor behavior. Finally, our results show that in both voles and spiny mice there is a gradual transition from normal to defensive behavior in accordance with the increase in risk level

Modulation of quinpirole-induced compulsive-like behavior in rats by environmental changes: Implications for OCD rituals and for exploration and navigation

BACKGROUND: Rats treated chronically with the D(2–3 )dopamine agonist quinpirole were previously proposed as an animal model of obsessive-compulsive disorder (OCD) since their behavior is based on repeated, compulsive-like persistent traveling between a few places in the open field. The aim of the present study was to determine properties of the physical environment that shape such behavior. For this, quinpirole-treated rats were first exposed to an arena with an array of objects (landmarks) and after the development of compulsive-like behavior, the arena was manipulated by multiplying the number of objects, changing their spacing, relocating object array, or removing the objects. RESULTS: When the number of objects was retained but they were spaced further apart, rat routes converged at 1–2 of the objects and at the corner at which the rats had been introduced into the arena (start corner). When object spacing was retained but their number was increased, the rats traveled between the objects with the routes converging only at the start corner. Finally, when object array was relocated to different places within the arena, the rats extended their routes from the start corner to the object array, regardless of array location. CONCLUSION: Quinpirole-treated rats organized and updated their progression primarily according to the proximal layout of landmarks, but did so with excessive repetitions compared with saline-treated rats. The behavior of quinpirole-treated rats paralleled human OCD rituals that are linked to the immediate physical environment, featuring an excessive rate of performance. Finally, when only a few objects were present, they were perceived by the rats as positional cues (beacons) that routes converged at them. In contrast, in the presence of many objects, the routes passed between the objects as if using them as directional cues

Laser optical separation of chiral molecules

The optical trapping of molecules with an off-resonant laser beam involves a forward-Rayleigh scattering mechanism. It is shown that discriminatory effects arise on irradiating chiral molecules with circularly polarized light; the complete representation requires ensemble-weighted averaging to account for the influence of the trapping beam on the distribution of molecular orientations. Results of general application enable comparisons to be drawn between the results for two limits of the input laser intensity. It emerges that, in a racemic mixture, there is a differential driving force whose effect, at high laser intensities, is to produce differing local concentrations of the two enantiomers

Akibat Hukum Penanggalan Kekebalan (Immunity Waiver) Kepada Pejabat Diplomatik Ditinjau dari Konvensi Wina 1961 (Studi Kasus Penanggalan Kekebalan terhadap Asisten Atase Militer Malaysia di Selandia Baru Tahun 2014)

Asisten atase militer sebagai pejabat diplomatik dalam menjalankan misi diplomatiknya diberikan hak istimewa dan kekebalan dengan harapan bisa melangsungkan misi tersebut tanpa hambatan. Dalam prakteknya banyak pejabat diplomatik yang menyalahi aturan dari negara penerima dan menggunakan hak kekebalan serta keistimewaan tersebut sebagai suatu perlindungan untuk terbebas dari proses hukum. Pada Kenyataanya juga diatur bahwa kekebalan tidak bersifat mutlak dan bisa ditanggalkan. Permasalahan yang diteliti adalah bagaimana pengaturan mengenai penanggalan kekebalan menurut Konvensi Wina 1961 dan akibat hukum yang timbul dengan adanya penanggalan kekebalan terhadap asisten atase militer suatu negara. Metode pendekatan yang digunakan dalam penulisan hukum ini adalah yuridis normatif. Spesifikasi penelitian yang digunakan adalah deskriptif analisis. Metode analisis data dalam penlitian ini adalah normatif kualitatif. Metode pengumpulan data dilakukan penulis melalui studi kepustakaan. Berdasarkan hasil penelitian disimpulkan bahwa suatu hak kekebalan yang dimiliki oleh pejabat diplomatik bisa ditanggalkan oleh negara pengirim menurut Konvensi Wina 1961. Malaysia selaku negara pengirim menanggalkan kekebalan asisten atase militernya untuk berlangsungnya proses hukum di Selandia Baru sebagai negara penerima. Asisten atase militer Malaysia resmi dijatuhi hukuman oleh negara penerima dan setelah selesai menuntaskannya ia dideportasi kembali ke Malaysia.Abstrak ditulis dalam bahasa Indonesia dan bahasa Inggris. Merupakan uraian singkat yang memuat tujuan, hasil penelitian, kesimpulan, serta implikasinya