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121.
Previous studies in our laboratory have shown that when presented with a sudden stimulus simulating an oncoming predator,
Mongolian gerbils can compute the optimal trajectory to a safe refuge, taking into account the position of the threat, the
location of a clearly visible refuge, and several other contextual variables as well. In the present studies, the main goal
was to explore the abilities of gerbils to use mental representations of spaces that were visually occluded by opaque barriers
to compute efficient escape trajectories. In all studies, gerbils were placed into a round open field containing a single
refuge. On each trial, an overhead visual stimulus was caused to ‘fly’ overhead, eliciting robust escape movements from the
gerbils. By manipulating the shape and position of a series of opaque barriers that were interposed between the gerbils and
the refuge, we were able to show that gerbils can compute the shortest route to an invisible target, even when the available
routes to the target are made complex by using elaborate barrier shapes. These findings suggest that gerbils can maintain
representations of their locations with respect to salient environmental landmarks and refuges, even when such locations are
not continuously visible. 相似文献
122.
Insects, birds, and mammals have been shown capable of encoding spatial information in memory using multiple strategies or
frames of reference simultaneously. These strategies include orientation to a goal-specific cue or beacon, to the position
of the goal in an array of local landmarks, or to its position in the array of distant landmarks, also known as the global
frame of reference. From previous experiments, it appears that birds and mammals that scatter hoard rely primarily on a global
frame of reference, but this generalization depends on evidence from only a few species. Here we examined spatial memory in
a previously unstudied scatter hoarder, the southern flying squirrel. We dissociated the relative weighting of three potential
spatial strategies (beacon, global, or relative array strategy) with three probe tests: transposition of beacon and the rotation
or the expansion of the array. The squirrels’ choices were consistent with a spatial averaging strategy, where they chose
the location dictated by at least two of the three strategies, rather than using a single preferred frame of reference. This
adaptive and flexible heuristic has not been previously described in animal orientation studies, yet it may be a common solution
to the universal problem of encoding and recalling spatial locations in an ephemeral physical landscape. 相似文献
123.
Although it is well known that frugivorous spider monkeys (Ateles geoffroyi yucatanensis) occupy large home ranges, travelling long distances to reach highly productive resources, little is known of how they move
between feeding sites. A 11 month study of spider monkey ranging patterns was carried out at the Otochma’ax Yetel Kooh reserve,
Yucatán, Mexico. We followed single individuals for as long as possible each day and recorded the routes travelled with the
help of a GPS (Global Positioning System) device; the 11 independently moving individuals of a group were targeted as focal
subjects. Travel paths were composed of highly linear segments, each typically ending at a place where some resource was exploited.
Linearity of segments did not differ between individuals, and most of the highly linear paths that led to food resources were
much longer than the estimate visibility in the woodland canopy. Monkeys do not generally continue in the same ranging direction
after exploiting a resource: travel paths are likely to deviate at the site of resource exploitation rather than between such
sites. However, during the harshest months of the year consecutive route segments were more likely to retain the same direction
of overall movement. Together, these findings suggest that while moving between feeding sites, spider monkeys use spatial
memory to guide travel, and even plan more than one resource site in advance.
This contribution is part of the special issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson
2007). 相似文献
124.
This study was aimed at uncovering physical and geometric properties that make a particular landmark a target of exploration
and navigation. Rats were tested in a square open-field arena with additional portable corners featuring the same properties
as the arena corners. It was found that the routes of progression converged upon the added corners, whether located at the
arena wall or the arena center. Route convergence upon the added corners involved numerous visits to these corners. However,
time spent at the added corners was relatively short compared with the arena corners, including that from which rats were
introduced into the arena. There was no differential effect of testing rats in light or dark, or with a low versus a high
portable corner. It is suggested that the added corners were distinct against the background of the arena enclosure, whereas
the four arena corners and walls were encoded by the rats as one geometric module. This distinctness, together with the greater
accessibility of the added corners, made them salient landmarks and a target of exploration. Thus, the impact of a landmark
extended beyond its specific self-geometry to include accessibility and distinctness, which are contextual properties. In addition to the contextual impact on locomotor behavior there was also a temporal effect,
with security initially dominating the rats’ behavior but then declining along with an increased attraction to salient landmarks.
These spatiotemporal patterns characterized behavior in both lit and dark arenas, indicating that distal cues were secondary
to local proximal cues in shaping routes. 相似文献
125.
Rick Grush 《Synthese》2007,159(3):389-416
An attempt is made to defend a general approach to the spatial content of perception, an approach according to which perception
is imbued with spatial content in virtue of certain kinds of connections between perceiving organism’s sensory input and its
behavioral output. The most important aspect of the defense involves clearly distinguishing two kinds of perceptuo-behavioral
skills—the formation of dispositions, and a capacity for emulation. The former, the formation of dispositions, is argued to
by the central pivot of spatial content. I provide a neural information processing interpretation of what these dispositions
amount to, and describe how dispositions, so understood, are an obvious implementation of Gareth Evans’ proposal on the topic.
Furthermore, I describe what sorts of contribution are made by emulation mechanisms, and I also describe exactly how the emulation
framework differs from similar but distinct notions with which it is often unhelpfully confused, such as sensorimotor contingencies
and forward models. 相似文献
126.
Body shadows orient attention to the body-part casting the shadow. We have investigated the automaticity of this phenomenon, by addressing its time-course and its resistance to contextual manipulations. When targets were tactile stimuli at the hands (Exp.1) or visual stimuli near the body-shadow (Exp.2), cueing effects emerged regardless of the delay between shadow and target onset (100, 600, 1200, 2400 ms). This suggests a fast and sustained attention orienting to body-shadows, that involves both the space occupied by shadows (extra-personal space) and the space the shadow refers to (own body). When target type became unpredictable (tactile or visual), shadow-cueing effects remained robust only for tactile targets, as visual stimuli showed no overall reliable effects, regardless of whether they occurred near the shadow (Exp.3) or near the body (Exp.4). We conclude that mandatory attention shifts triggered by body-shadows are limited to tactile targets and, instead, are less automatic for visual stimuli. 相似文献
127.
128.
129.
We used several cue–target SOAs (100, 500, 1000 ms) and three different degrees of cue predictability (Non-predictive-50%, Predictive-75%, Counter-predictive-25%), to investigate the role of awareness of cue–target predictability on cueing effects. A group of participants received instructions about the informative value of the cue, while another group did not receive such instructions. Participants were able to extract the predictive value of a spatially peripheral cue and use it to orient attention, whether or not specific instructions about the predictive value of the cue were given, and no matter their ability to correctly report it in a post-test questionnaire. In the non-predictive block, bad estimators who received no instructions showed regular cueing effects, while good estimators exhibited smaller and non-significant facilitatory effects at the short SOA and an absence of significant IOR at longer SOAs. However, for the instructions group, the pattern of results reversed. 相似文献
130.
The present study investigated whether memory for extinction in an appetitive task (the sand maze) could be attenuated by administration of cycloheximide (protein synthesis inhibitor) or propranolol (β-adrenergic receptor antagonist). Ninety-day-old male Long-Evans rats were trained to retrieve a sweet cereal reinforcer from an open container in the sand maze. One day following this non-spatial training, rats received three extinction trials in which they were placed in the maze with the reinforcer present, but unattainable. Thirty minutes prior to the first extinction trial, rats received an intraperitoneal injection of cycloheximide (1mg/kg), propranolol (25mg/kg), or vehicle (1mg/kg distilled water). Twenty-four hours later, rats were tested in the sand maze with the reinforcer again available. Results from the test trial showed that both cycloheximide and propranolol groups found the reinforcer more quickly than controls. Two weeks later, rats were trained on a spatial version of the sand maze in which they had to search for a buried reinforcer using extramaze cues. Cycloheximide and propranolol groups learned this task significantly faster than the control group, demonstrating the long-lasting effect of cycloheximide and propranolol on the blocking of memory for extinction. 相似文献