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901.
Daniel Tomsic Martín Bern de Astrada Julieta Sztarker Hector Maldonado 《Neurobiology of learning and memory》2009,92(2):176
Investigations using invertebrate species have led to a considerable progress in our understanding of the mechanisms underlying learning and memory. In this review we describe the main behavioral and neuronal findings obtained by studying the habituation of the escape response to a visual danger stimulus in the crab Chasmagnathus granulatus. Massed training with brief intertrial intervals lead to a rapid reduction of the escape response that recovers after a short term. Conversely, few trials of spaced training renders a slower escape reduction that endures for many days. As predicted by Wagner’s associative theory of habituation, long-term habituation in the crab proved to be determined by an association between the contextual environment of the training and the unconditioned stimulus. By performing intracellular recordings in the brain of the intact animal at the same time it was learning, we identified a group of neurons that remarkably reflects the short- and long-term behavioral changes. Thus, the visual memory abilities of crabs, their relatively simple and accessible nervous system, and the recording stability that can be achieved with their neurons provide an opportunity for uncovering neurophysiological and molecular events that occur in identifiable neurons during learning. 相似文献
902.
William E. DeCoteau Daniel McElvaine Linnea Smolentzov Raymond P. Kesner 《Neurobiology of learning and memory》2009,92(4):552-558
It has been suggested that certain prefrontal areas contribute to a neural circuit that mediates visual object memory. Using a successive go/no-go visual scene discrimination task, object-based long-term memory was assessed in two rodent prefrontal regions. Rewarded trials consisted of a standard scene of four toy objects placed over baited food wells. The objects and their locations composing the standard scene remained constant for the duration of the study. Trials in which one of the standard scene objects was replaced with a novel object were not rewarded. Following the establishment of a significant difference between latency to approach the rewarded standard scene compared to latency to approach non-rewarded scenes, quinolinic acid or control vehicle was infused into either the prelimbic and infralimbic cortices or the anterior cingulate cortex. Following a 1 week recovery period, subjects were retested. Animals with prelimbic/infralimbic cortex lesions displayed a profound and sustained deficit, whereas, animals with anterior cingulate cortex lesions showed a slight initial impairment but eventually recovered. Both lesion groups acquired a simple single object discrimination task as quickly as controls indicating that the deficits on the original scene discrimination task were not due to motivational, response inhibition, or perceptual problems. 相似文献
903.
The definition of episodic memory includes the concept of mental time travel: the ability to re-experience a previously experienced trajectory through continuous dimensions of space and time, and to recall specific events or stimuli along this trajectory. Lesions of the hippocampus and entorhinal cortex impair human episodic memory function and impair rat performance in tasks that could be solved by retrieval of trajectories. Recent physiological data suggests a novel model for encoding and retrieval of trajectories, and for associating specific stimuli with specific positions along the trajectory. During encoding in the model, external input drives the activity of head direction cells. Entorhinal grid cells integrate the head direction input to update an internal representation of location, and drive hippocampal place cells. Trajectories are encoded by Hebbian modification of excitatory synaptic connections between hippocampal place cells and head direction cells driven by external action. Associations are also formed between hippocampal cells and sensory stimuli. During retrieval, a sensory input cue activates hippocampal cells that drive head direction activity via previously modified synapses. Persistent spiking of head direction cells maintains the direction and speed of the action, updating the activity of entorhinal grid cells that thereby further update place cell activity. Additional cells, termed arc length cells, provide coding of trajectory segments based on the one-dimensional arc length from the context of prior actions or states, overcoming ambiguity where the overlap of trajectory segments causes multiple head directions to be associated with one place. These mechanisms allow retrieval of complex, self-crossing trajectories as continuous curves through space and time. 相似文献
904.
Some animals have been shown to be able to remember which type of food they hoarded or encountered in which location and how
long ago (what–where–when memory). In this study, we test whether magpies (Pica pica) also show evidence of remembering these different aspects of a past episode. Magpies hid red- and blue-dyed pellets of scrambled
eggs in a large tray containing wood shavings. They were allowed to make as many caches as they wanted. The birds were then
returned either the same day or the next day to retrieve the pellets. If they returned the same day, one colour of pellets
was replaced with wooden beads of similar size and colour, while if they returned the next day this would happen to the other
colour. Over just a few trials, the birds learned to only search for the food pellets, and ignore the beads, of the appropriate
colour for the given retention interval. A probe trial in which all items were removed showed that the birds persisted in
searching for the pellets and not the beads. This shows that magpies can remember which food item they hoarded where, and
when, even if the food items only differ from each other in their colour and are dispersed throughout a continuous caching
substrate. 相似文献
905.
Lara D. LaDage Timothy C. Roth II Rebecca A. Fox Vladimir V. Pravosudov 《Animal cognition》2009,12(3):419-426
An animal’s memory may be limited in capacity, which may result in competition among available memory cues. If such competition
exists, natural selection may favor prioritization of different memory cues based on cue reliability and on associated differences
in the environment and life history. Food-caching birds store numerous food items and appear to rely on memory to retrieve
caches. Previous studies suggested that caching species should always prioritize spatial cues over non-spatial cues when both
are available, because non-spatial cues may be unreliable in a changing environment; however, it remains unclear whether non-spatial
cues should always be ignored when spatial cues are available. We tested whether mountain chickadees (Poecile gambeli), a food-caching species, prioritize memory for spatial cues over color cues when relocating previously found food in an
associative learning task. In training trials, birds were exposed to food in a feeder where both spatial location and color
were associated. During subsequent unrewarded test trials, color was dissociated from spatial location. Chickadees showed
a significant pattern of inspecting feeders associated with correct color first, prior to visiting correct spatial locations.
Our findings argue against the hypothesis that the memory of spatial cues should always take priority over any non-spatial
cues, including color cues, in food-caching species, because in our experiment mountain chickadees chose color over spatial
cues. Our results thus suggest that caching species may be more flexible in cue use than previously thought, possibly dependent
upon the environment and complexity of available cues. 相似文献
906.
文章综述了惊恐障碍患者对威胁性信息的注意偏向、解释偏向、记忆偏向等认知偏向。对威胁性信息的优先注意激发焦虑体验,对模糊信息的灾难化解释增加焦虑水平,对引起焦虑感信息的记忆保持促使惊恐体验更易于提取,这3种认知偏向促使具有焦虑倾向的个体对惊恐障碍更易感,也是惊恐障碍形成和保持的关键因素 相似文献
907.
908.
909.
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
910.
Two experiments with 3½‐ to 6½‐year‐old children showed that theory‐of‐mind development is associated with the growth of episodic memory. Episodic memory was assessed by manipulating informational conditions such that they permit or prevent the formation of episodic memories in terms of re‐experiencing the recalled event. Only experienced events, e.g. seeing how one puts a picture of a frog into a box, can be remembered by re‐experience. Events known through indirect information cannot be re‐experienced, e.g. putting pictures into the box when blindfolded and being later shown on video what was on these cards. Children were also tested on a battery of theory‐of‐mind tasks assessing their understanding of the origins of knowledge. There was a significant interaction in both experiments showing that recall of directly experienced items improved in relation to indirectly presented items the higher children's theory‐of‐mind scores. The discussion suggests that episodic memory development is specifically linked to the growing ability to introspect an ongoing experience and interpret it as representing an actual past event. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献