Computations on metric maps in mammals: getting oriented and choosing a multi-destination route.

1996 ◽  
Vol 199 (1) ◽  
pp. 211-217 ◽  
Author(s):  
C R Gallistel ◽  
A E Cramer

The capacity to construct a cognitive map is hypothesized to rest on two foundations: (1) dead reckoning (path integration); (2) the perception of the direction and distance of terrain features relative to the animal. A map may be constructed by combining these two sources of positional information, with the result that the positions of all terrain features are represented in the coordinate framework used for dead reckoning. When animals need to become reoriented in a mapped space, results from rats and human toddlers indicate that they focus exclusively on the shape of the perceived environment, ignoring non-geometric features such as surface colors. As a result, in a rectangular space, they are misoriented half the time even when the two ends of the space differ strikingly in their appearance. In searching for a hidden object after becoming reoriented, both kinds of subjects search on the basis of the object's mapped position in the space rather than on the basis of its relationship to a goal sign (e.g. a distinctive container or nearby marker), even though they have demonstrably noted the relationship between the goal and the goal sign. When choosing a multidestination foraging route, vervet monkeys look at least three destinations ahead, even though they are only capable of keeping a maximum of six destinations in mind at once.

1996 ◽  
Vol 199 (1) ◽  
pp. 129-140 ◽  
Author(s):  
R Wehner ◽  
B Michel ◽  
P Antonsen

Social hymenopterans such as bees and ants are central-place foragers; they regularly depart from and return to fixed positions in their environment. In returning to the starting point of their foraging excursion or to any other point, they could resort to two fundamentally different ways of navigation by using either egocentric or geocentric systems of reference. In the first case, they would rely on information continuously collected en route (path integration, dead reckoning), i.e. integrate all angles steered and all distances covered into a mean home vector. In the second case, they are expected, at least by some authors, to use a map-based system of navigation, i.e. to obtain positional information by virtue of the spatial position they occupy within a larger environmental framework. In bees and ants, path integration employing a skylight compass is the predominant mechanism of navigation, but geocentred landmark-based information is used as well. This information is obtained while the animal is dead-reckoning and, hence, added to the vector course. For example, the image of the horizon skyline surrounding the nest entrance is retinotopically stored while the animal approaches the goal along its vector course. As shown in desert ants (genus Cataglyphis), there is neither interocular nor intraocular transfer of landmark information. Furthermore, this retinotopically fixed, and hence egocentred, neural snapshot is linked to an external (geocentred) system of reference. In this way, geocentred information might more and more complement and potentially even supersede the egocentred information provided by the path-integration system. In competition experiments, however, Cataglyphis never frees itself of its homeward-bound vector - its safety-line, so to speak - by which it is always linked to home. Vector information can also be transferred to a longer-lasting (higher-order) memory. There is no need to invoke the concept of the mental analogue of a topographic map - a metric map - assembled by the insect navigator. The flexible use of vectors, snapshots and landmark-based routes suffices to interpret the insect's behaviour. The cognitive-map approach in particular, and the representational paradigm in general, are discussed.


Development ◽  
1987 ◽  
Vol 99 (3) ◽  
pp. 327-332 ◽  
Author(s):  
S.B. Carroll ◽  
G.M. Winslow ◽  
V.J. Twombly ◽  
M.P. Scott

At least 13 genes control the establishment of dorsoventral polarity in the Drosophila embryo and more than 30 genes control the anteroposterior pattern of body segments. Each group of genes is thought to control pattern formation along one body axis, independently of the other group. We have used the expression of the fushi tarazu (ftz) segmentation gene as a positional marker to investigate the relationship between the dorsoventral and anteroposterior axes. The ftz gene is normally expressed in seven transverse stripes. Changes in the striped pattern in embryos mutant for other genes (or progeny of females homozygous for maternal-effect mutations) can reveal alterations of cell fate resulting from such mutations. We show that in the absence of any of ten maternal-effect dorsoventral polarity gene functions, the characteristic stripes of ftz protein are altered. Normally there is a difference between ftz stripe spacing on the dorsal and ventral sides of the embryo; in dorsalized mutant embryos the ftz stripes appear to be altered so that dorsal-type spacing occurs on all sides of the embryo. These results indicate that cells respond to dorsoventral positional information in establishing early patterns of gene expression along the anteroposterior axis and that there may be more significant interactions between the different axes of positional information than previously determined.


2019 ◽  
Vol 14 (4) ◽  
pp. 851-862
Author(s):  
Herong Gui ◽  
Rongjie Hu ◽  
Honghai Zhao ◽  
Jun Li ◽  
Xiaomei Song ◽  
...  

Abstract Among all recorded water disasters in China coalmines, 10% can be attributed to surface water, making it one of the top water hazards. Based on the analysis of cases of surface water hazards in China coalmines, this article determined surface water sources and inrush conduits as the major factors that have caused water inrush disasters in mines, and classified surface water hazards in China coalmines into 15 types according to those major factors and gave definitions of each type of surface water hazard. Then, it is proposed that there are different types of surface water hazards in different coal-bearing regions by analyzing the relationship to terrain features, climatic impact and mining conditions. Finally, we discuss how typical water sources and inrush conduits work together in hazard formation, in addition to the characteristics and corresponding preventative technologies. The propositions can be of reference for exchanges with other mining countries and regions on surface water hazard treatment.


1993 ◽  
Vol 46 (3) ◽  
pp. 364-370 ◽  
Author(s):  
A. S. Etienne ◽  
V. Séguinot

According to comprehensive theories of navigation, animals navigate by using two complementary strategies: (1) dead reckoning informs the subject in a continuous manner on its actual location with respect to an Earthbound or absolute coordinate system; while (2) long-term associations between particular landmarks and specific locations allow the animal to find its way within a familiar environment. If the subject structures familiar space as a system of interconnected places – the so-called ‘cognitive map’ – it may know through dead reckoning where it is located on its map and relate its route-based expectations to the actually perceived scenario of local cues.


2018 ◽  
Vol 115 (11) ◽  
pp. 2824-2829 ◽  
Author(s):  
Thierry Hoinville ◽  
Rüdiger Wehner

In the last decades, desert ants have become model organisms for the study of insect navigation. In finding their way, they use two major navigational routines: path integration using a celestial compass and landmark guidance based on sets of panoramic views of the terrestrial environment. It has been claimed that this information would enable the insect to acquire and use a centralized cognitive map of its foraging terrain. Here, we present a decentralized architecture, in which the concurrently operating path integration and landmark guidance routines contribute optimally to the directions to be steered, with “optimal” meaning maximizing the certainty (reliability) of the combined information. At any one time during its journey, the animal computes a path integration (global) vector and landmark guidance (local) vector, in which the length of each vector is proportional to the certainty of the individual estimates. Hence, these vectors represent the limited knowledge that the navigator has at any one place about the direction of the goal. The sum of the global and local vectors indicates the navigator’s optimal directional estimate. Wherever applied, this decentralized model architecture is sufficient to simulate the results of quite a number of diverse cue-conflict experiments, which have recently been performed in various behavioral contexts by different authors in both desert ants and honeybees. They include even those experiments that have deliberately been designed by former authors to strengthen the evidence for a metric cognitive map in bees.


Forests ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 778 ◽  
Author(s):  
Aihua Shen ◽  
Chaofan Wu ◽  
Bo Jiang ◽  
Jinsong Deng ◽  
Weigao Yuan ◽  
...  

Biomass is a key biophysical parameter used to estimate carbon storage and forest productivity. Spatially-explicit estimation of biomass provides invaluable information for carbon stock calculation and scientific forest management. Nevertheless, there still exists large uncertainty concerning the relationship between biomass and influential factors. In this study, aboveground biomass (AGB) was estimated using the random forest algorithm based on remote sensing imagery (Landsat) and field data for three regions with different topographic conditions in Zhejiang Province, China. AGB distribution and change combined with stratified terrain classifications were analyzed to investigate the relations between AGB and topography conditions. The results indicated that AGB in three regions increased from 2010 to 2015 and the magnitude of growth varied with elevation, slope, and aspect. In the basin region, slope had a greater influence on AGB, and we attributed this negative AGB-elevation relationship to ecological forest construction. In the mountain area, terrain features, especially elevation, showed significant relations with AGB. Moreover, AGB and its growth showed positive relations with elevation and slope. In the island region, slope also played a relatively more important role in explaining the relationship. These results demonstrate that AGB varies with terrain conditions and its change is a consequence of interactions between the natural environment and anthropogenic behavior, implying that biomass retrieval based on Landsat imagery could provide considerable important information related to regional heterogeneity investigations.


2020 ◽  
Vol 121 ◽  
pp. 101307 ◽  
Author(s):  
Mathilde Bostelmann ◽  
Pierre Lavenex ◽  
Pamela Banta Lavenex

2011 ◽  
Vol 105 (6) ◽  
pp. 2989-3001 ◽  
Author(s):  
Ryan M. Yoder ◽  
Benjamin J. Clark ◽  
Joel E. Brown ◽  
Mignon V. Lamia ◽  
Stephane Valerio ◽  
...  

Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interpretation because the same visual cues may have been perceptible across arenas. To address this issue, we tested the relationship between HD cell activity and path integration by recording HD cells while rats navigated within a 14-unit T-maze and in a multiroom maze that consisted of unique arenas that were located in different rooms but connected by a passageway. In the 14-unit T-maze, the HD signal remained relatively stable between the start and goal boxes, with the preferred firing directions usually shifting <45° during maze traversal. In the multiroom maze in light, the preferred firing directions also remained relatively constant between rooms, but with greater variability than in the 14-unit maze. In darkness, HD cell preferred firing directions showed marginally more variability between rooms than in the lighted condition. Overall, the results indicate that self-motion cues are capable of maintaining the HD cell signal in the absence of familiar visual cues, although there are limits to its accuracy. In addition, visual information, even when unfamiliar, can increase the precision of directional perception.


2015 ◽  
Vol 727-728 ◽  
pp. 637-640
Author(s):  
Ying Liu ◽  
Zheng Hu ◽  
Shi Gang Zhang

Failure mode analysis formechatronics systems has many problems in real applications in terms of excessivedependency on experience, lack of uniform description and tedious analysis work. In order to increaseits effectiveness, an automatic failure modes analysis framework is constructedand an extended fuzzy cognitive map is used as a reasoning technique toanalysis the effect of the failures. A function-failure correlation model witha standard description is adopted to describe the relationship between failuremodes and functions, so that designers and engineers from different fields cancomprehend and communicate within the same framework. Functional flows andfailure modes are defined as basic concepts in the fuzzy cognitive map, whichprovides an easy way to carry out an automatic cause and effect reasoning.


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