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At least 1,009 records · Page 56Linked to original sources
PubMed2000

Pre-training blocks the improving effect of tetrahydroaminoacridine and D-cycloserine on spatial navigation performance in aged rats.

We investigated the effect of pre-training on the improvement of spatial navigation performance provided by a cholinesterase inhibitor, tetrahydroaminoacridine (3 mg/kg, i.p.), and a positive modulator of NMDA receptor, D-cycloserine (10 mg/kg, i.p.), or their combination in aged rats. Pre-training consisted of spatial or non-spatial conditions and took place in either the same or a separate room. We found that any kind of pre-training was able to eliminate the enhancing effect of tetrahydroaminoacridine and D-cycloserine on spatial navigation. However, none of these pre-training conditions was able to block the age-related deficit in spatial navigation. These results indicate that tetrahydroaminoacridine and D-cycloserine, separately or in combination, do not themselves alleviate the age-related spatial memory deficit, but may enhance procedural aspects of water maze learning in aged rats.

Aging↗
PubMed2003

Assessment of spatial learning abilities of mice in a new circular maze.

In the present study, we tested the spatial learning behavior of four different mouse strains (129/Sv, BALB/c, C57BL and Swiss) in a newly developed circular maze. The maze was based on the circular Barnes maze, which was initially developed for rats. Since mice do not readily enter holes in floor, additional reinforcers (positive and negative) or pretraining procedures have been used to train the animals. Because these methods are not always desirable, we examined whether mice are more willing to enter escape holes (12), which were located in the rim of the apparatus. C57BL mice appeared to improve their performance on three different measures of spatial learning: latency to find escape hole, distance to escape hole and errors (visit to other holes). The other strains also improved their performance although this was only seen for one parameter (i.e. 129/Sv and BALB/c on latency, and Swiss on distance). When the animals were trained to find another location, it was found that only the performance of the C57BL mice was transiently impaired. The C57BL mice were also very efficient in improving their performance in a repeated acquisition paradigm (six trials per day on four successive days). Applying a probe trial procedure, a clear preference for the goal location was found. These findings indicate that these mice used a spatial search strategy. Although this circular maze can be used as an additional tool to assess spatial learning in (genetically modified) mice, it is noted that strain differences in spatial learning seem to be independent of task. Further, our data with different strains indicate that different measures of behavior should be evaluated to assess the spatial learning performance of mice.

Analysis of Variance↗
PubMed1997

Spatial event processing.

The present review advances experimental evidence on the cerebellar involvement in spatial data processing. In particular, data on Morris water maze (MWM) performances of hemicerebellectomized (HCbed) rats indicate a specific cerebellar role within the procedural aspects of spatial functions. In MWM testing, HCbed animals are impaired in developing efficient exploration strategies and display only old and rather ineffective ways for acquiring spatial information, such as peripheral circling around the pool. This behavior is not exhibited if spatial mapping abilities are preoperatively acquired. Thus, MWM experimental data point toward a procedural deficit that specifically impairs the acquisition phase. The characteristics of the cerebellar involvement in affecting the procedures needed for spatial data management are discussed in the light of recent theories on spatial data processing and on cerebellar timing and ordering functions.

Animals↗
PubMed2003

Hemispheric specialization for spatial frequency processing in the analysis of natural scenes.

Experimental data coming from visual cognitive sciences suggest that visual analysis starts with a parallel extraction of different visual attributes at different scales/frequencies. Neuropsychological and functional imagery data have suggested that each hemisphere (at the level of temporo-parietal junctions-TPJ) could play a key role in spatial frequency processing: The right TPJ should predominantly be involved in low spatial frequency (LFs) analysis and the left TPJ in high spatial frequency (HFs) analysis. Nevertheless, this functional hypothesis had been inferred from data obtained when using the hierarchical form paradigm, without any explicit spatial frequency manipulation per se. The aims of this research are (i) to investigate, in healthy subjects, the hemispheric asymmetry hypothesis with an explicit manipulation of spatial frequencies of natural scenes and (ii) to examine whether the 'precedence effect' (the relative rapidity of LFs and HFs processing) depends on the visual field of scene presentation or not. For this purpose, participants were to identify either non-filtered or LFs and HFs filtered target scene displayed either in the left, central, or right visual field. Results showed a hemispheric specialization for spatial frequency processing and different 'precedence effects' depending on the visual field of presentation.

Cognition↗
PubMed1999

A neural network model with dopamine-like reinforcement signal that learns a spatial delayed response task.

This study investigated how the simulated response of dopamine neurons to reward-related stimuli could be used as reinforcement signal for learning a spatial delayed response task. Spatial delayed response tasks assess the functions of frontal cortex and basal ganglia in short-term memory, movement preparation and expectation of environmental events. In these tasks, a stimulus appears for a short period at a particular location, and after a delay the subject moves to the location indicated. Dopamine neurons are activated by unpredicted rewards and reward-predicting stimuli, are not influenced by fully predicted rewards, and are depressed by omitted rewards. Thus, they appear to report an error in the prediction of reward, which is the crucial reinforcement term in formal learning theories. Theoretical studies on reinforcement learning have shown that signals similar to dopamine responses can be used as effective teaching signals for learning. A neural network model implementing the temporal difference algorithm was trained to perform a simulated spatial delayed response task. The reinforcement signal was modeled according to the basic characteristics of dopamine responses to novel stimuli, primary rewards and reward-predicting stimuli. A Critic component analogous to dopamine neurons computed a temporal error in the prediction of reinforcement and emitted this signal to an Actor component which mediated the behavioral output. The spatial delayed response task was learned via two subtasks introducing spatial choices and temporal delays, in the same manner as monkeys in the laboratory. In all three tasks, the reinforcement signal of the Critic developed in a similar manner to the responses of natural dopamine neurons in comparable learning situations, and the learning curves of the Actor replicated the progress of learning observed in the animals. Several manipulations demonstrated further the efficacy of the particular characteristics of the dopamine-like reinforcement signal. Omission of reward induced a phasic reduction of the reinforcement signal at the time of the reward and led to extinction of learned actions. A reinforcement signal without prediction error resulted in impaired learning because of perseverative errors. Loss of learned behavior was seen with sustained reductions of the reinforcement signal, a situation in general comparable to the loss of dopamine innervation in Parkinsonian patients and experimentally lesioned animals. The striking similarities in teaching signals and learning behavior between the computational and biological results suggest that dopamine-like reward responses may serve as effective teaching signals for learning behavioral tasks that are typical for primate cognitive behavior, such as spatial delayed responding.

Animals↗
PubMed1999

Sex differences and menstrual cycle effects in human spatial memory.

A typical test of spatial memory requires subjects to relocate a number of objects in their original, previously studied positions. It has been argued that this test includes multiple separate processing components (Postma, A., De Haan, E.H.F., 1996. Quarterly Journal of Experimental Psychology 48A (1), 178-199; Postma, A., Izendoorn, R., De Haan, E.H.F., 1998. Brain and Cognition 36, 334-345). One has to encode the precise positions occupied, assign the various objects to the correct (relative) locations, and achieve an integration of both types of spatial information. The present study examined the presence of sex differences and the role of hormonal factors for these selective components of spatial memory. A computerised, immediate (working) memory version of the test was used, comparing 23 males and 34 females on three experimental conditions: positions only, object-to-position-assignment, and the combined condition, requiring integration of the other two components. In line with previous research (Postma et al., 1998) males showed a selective advantage for fine-grained, metric positional reconstruction (i.e. positions-only). Interestingly, a within-subjects comparison in the females only revealed a menstrual cycle effect for exactly the same dimension of spatial memory. In the nonmenstrual phase, females were better than during menstruation. This clearly implies a role for sex hormones in spatial memory, even though a subsequent analysis of testosterone samples in saliva did not reveal a significant correlation with measures of spatial memory in both males and females.

Adolescent↗
PubMed1999

Dissociation of human caudate nucleus activity in spatial and nonspatial working memory: an event-related fMRI study.

We employed a novel event-related fMRI design and analysis technique to explore caudate nucleus contributions to spatial and nonspatial working memory. The spatial condition of a delayed-response task revealed greater mnemonic activation in four of six subjects when the delay period preceded immediately a probe stimulus requiring an overt motor response, as contrasted with a probe requiring no response. This effect was not seen in frontal or parietal cortical areas, and was seen in the caudate nucleus in a formally identical object condition in just one of six subjects. We hypothesized that this pattern of activity represented spatially dependent motor preparation. A second experiment confirmed this hypothesis: delay-period activity of the caudate nucleus showed greater time dependence in a task that featured spatial and motoric memory demands than in a comparable nonspatial task that featured the same response contingencies. These results suggest an important subcortical locus of the dissociation between spatial and nonspatial working memory, and a role for the human caudate nucleus in the integration of spatially coded mnemonic information with motor preparation to guide behavior.

Adult↗
PubMed2001

How are visuospatial working memory, executive functioning, and spatial abilities related? A latent-variable analysis.

This study examined the relationships among visuospatial working memory (WM) executive functioning, and spatial abilities. One hundred sixty-seven participants performed visuospatial short-term memory (STM) and WM span tasks, executive functioning tasks, and a set of paper-and-pencil tests of spatial abilities that load on 3 correlated but distinguishable factors (Spatial Visualization, Spatial Relations, and Perceptual Speed). Confirmatory factor analysis results indicated that, in the visuospatial domain, processing-and-storage WM tasks and storage-oriented STM tasks equally implicate executive functioning and are not clearly distinguishable. These results provide a contrast with existing evidence from the verbal domain and support the proposal that the visuospatial sketchpad may be closely tied to the central executive. Further, structural equation modeling results supported the prediction that, whereas they all implicate some degree of visuospatial storage, the 3 spatial ability factors differ in the degree of executive involvement (highest for Spatial Visualization and lowest for Perceptual Speed). Such results highlight the usefulness of a WM perspective in characterizing the nature of cognitive abilities and, more generally, human intelligence.

Cognition↗
PubMed1988

Effects of opioid microinjections into the medial septal area on spatial memory in rats.

Recent work has demonstrated that posttraining systemic opioid antagonist administration facilitates the acquisition of a radial arm maze task in new spatial environments. In this study, we examined the effect of posttraining naloxone and beta-endorphin microinjections into the medial septal area on the acquisition of a radial maze task in new spatial environments. The results of these experiments demonstrated that posttraining intraseptal naloxone administration facilitated, whereas posttraining intraseptal beta-endorphin administration impaired, the acquisition of criterion performance on a maze task performed in new spatial environments. Further, intraventricular beta-endorphin administration did not produce effects that were comparable to those observed following intraseptal beta-endorphin administration, which indicates that the septal region is a brain site that is sensitive to the effects of opioids on spatial memory in new environments. Further, posttraining intraseptal beta-endorphin administration had no effect on working memory in a familiar spatial environment, whereas pretraining intraseptal beta-endorphin administration had no effect on the performance of a previously acquired spatial task.

Animals↗
PubMed1996

Intact spatial learning in both young and aged rats following selective removal of hippocampal cholinergic input.

Studies using the selective cholinergic immunotoxin 192 IgG-saporin have demonstrated that lesions of the cholinergic input to the hippocampus from the medial septum/vertical limb of the diagonal band (MS/VDB) do not disrupt spatial learning in the water maze in young rats. However, age-related deficits in spatial learning correlate with the integrity of cholinergic neurons in the MS/VDB, suggesting that these neurons may be more crucial for spatial learning in aged rats. To investigate this hypothesis directly, we selectively lesioned these neurons in aged rats that demonstrated relatively intact spatial learning in an initial screening as well as in a comparison set of young rats. Intact and lesioned rats of both ages rapidly acquired a new place discrimination in a different spatial environment. These results indicate that the cholinergic input to the hippocampus is not differentially involved in spatial learning in aged rats.

Aging↗
PubMed2005

Sensory preconditioning in spatial learning using a touch screen task in pigeons.

The authors used a touch screen-based visual-search task to investigate spatial integration in pigeons. First, pigeons were presented with a consistent spatial relationship between compound visual landmarks (LMs) A-X and B-Y, separately. Next, pigeons learned to find a hidden goal on the monitor in the presence of LMs A and B. The goal bore a consistent spatial relationship to LM A, but not to LM B. On nonreinforced probe tests, the peak and distribution of responses to LM X suggest that pigeons computed a novel X-goal spatial relationship on the basis of X-A and A-goal spatial vectors. Responses to LM Y, however, revealed no evidence of spatial integration. These results replicate and extend those of A. P. Blaisdell and R. G. Cook (2005) using an open-field task.

Animals↗
PubMed2026

Volumetric DNA microscopy for mapping spatial transcriptomes in three dimensions.

The architecture and function of biological systems are inherently three-dimensional, yet most existing spatial transcriptomic technologies remain restricted to thin tissue sections, limiting their capacity to resolve cellular organization and microenvironments within intact tissue volumes. To address this limitation, we developed volumetric DNA microscopy, a scalable, optics-free approach for spatial transcriptome profiling directly within intact biological specimens. The method encodes spatial information into DNA molecules that form a dense intermolecular network in situ, enabling the reconstruction of three-dimensional spatial relationships through short-read sequencing and computational analysis. Here we detail the complete workflow including in situ cDNA synthesis, spatial encoding through DNA nanoball formation, dual-scale proximity bridging between neighboring nanoballs and spatial reconstruction via geodesic spectral embedding. Sequencing libraries can be generated within 7-8 d by a competent graduate-level molecular biologist, followed by standardized downstream computational analysis. Because the workflow requires only routine molecular biology reagents and a benchtop sequencer, volumetric DNA microscopy provides a versatile platform for exploring genetic and morphological features in intact tissues.

Spatial Transcriptomics↗
PubMed2001

Spatial awareness in urologists: are they different?

OBJECTIVE: To compare innate spatial awareness skills, using the MIST-VR system (Ethicon Ltd, Edinburgh, a computer-based virtual reality system that objectively tests spatial awareness) among three groups of people (consultant urologists, urological trainees and controls who were not surgeons), because urological surgeons require spatial awareness for endoscopic and laparoscopic surgery, but trainees are selected by academic prowess rather than surgical aptitude. SUBJECTS AND METHODS: The MIST-VR system was used to test 122 volunteers in three groups, i.e. 39 consultant urologists, 46 urological trainees and 37 controls (not surgeons). The demographic data recorded for each group included age, sex, eyesight, handedness, and endoscopic and laparoscopic experience. Volunteers performed a repetitive series of three tasks using the system. Their performance was measured in terms of time, errors and economy of movement, as well as the duration and accuracy of diathermy in Task 3. RESULTS: The consultants were significantly older than the trainees and controls (both P<0.001) and had more endoscopic experience (P=0.005). In Task 1, the trainees made significantly fewer errors (P=0.045) and had a greater economy of movement (P=0.03) than the controls. In Task 2 the trainees performed the task more rapidly than the consultants (P=0.04) and controls (P=0.02). Trainees were more economical in movement than were consultants (P=0.031) and controls (P=0.046). In the more complex Task 3, trainees outperformed consultants in terms of errors (P=0.03), economy of movement (P=0.046), total diathermy time (P=0.005) and diathermy error (P=0.03). Controls performed similarly to the consultants. Although there was a trend towards better performance by trainees over controls, this was only significant for time (P=0.04) and total diathermy time (P=0.011). A few participants had results that were >2 SD above the mean and several people could not complete Task 3. CONCLUSIONS: Urologists do not differ from the general population in terms of innate spatial ability in this setting. There are several people who may have a defect in spatial awareness but the incidence was the same in each group. Urological trainees outperformed consultants in these tasks; the reasons for this are unclear. The MIST-VR system is of no help in aptitude testing for urological trainees, although it may have a role in teaching laparoscopic surgery. Testing other psychometric components may be more important for acquiring surgical skills than innate spatial-awareness skills. Further studies are required to investigate this possibility.

Adult↗
PubMed2004

Spatial memory, recognition memory, and the hippocampus.

There is wide agreement that spatial memory is dependent on the integrity of the hippocampus, but the importance of the hippocampus for nonspatial tasks, including tasks of object recognition memory is not as clear. We examined the relationship between hippocampal lesion size and both spatial memory and object recognition memory in rats. Spatial memory was impaired after bilateral dorsal hippocampal lesions that encompassed 30-50% total volume, and as lesion size increased from 50% to approximately 100% of total hippocampal volume, performance was similarly impaired. In contrast, object recognition was intact after dorsal hippocampal lesions that damaged 50-75% of total hippocampal volume and was impaired only after larger lesions that encompassed 75-100% of hippocampal volume. Last, ventral hippocampal lesions that encompassed approximately 50% of total hippocampal volume impaired spatial memory but did not affect object recognition memory. These findings show that the hippocampus is important for both spatial memory and recognition memory. However, spatial memory performance requires more hippocampal tissue than does recognition memory.

Animals↗
PubMed2026

Reconstructing the early spatial spread of pandemic respiratory viruses in the United States.

Understanding the geographic spread of emerging respiratory viruses is critical for pandemic preparedness, yet the early spatiotemporal dynamics of the 2009 H1N1 pandemic influenza and severe acute respiratory syndrome coronavirus 2 in the United States remain unclear. While mobility and genomic data have revealed important aspects of pandemic spatial spread, several key questions remain: Did the two pandemics follow similar spatial transmission routes? How rapidly did they spread across the United States? What role did stochastic processes play in early spatial transmission? To address these questions, we integrated high-resolution disease data with a robust, data-efficient inference framework combining air travel, commuting flows, and pathogen superspreading potentials to reconstruct their spatial spread across US metropolitan areas. The two pandemics exhibited distinct transmission pathways across locations; however, both pandemics established local circulation in most metropolitan areas within weeks, driven by several shared transmission hubs. Early spatial spread was more strongly associated with air travel than with commuting, though stochastic dynamics introduced substantial uncertainty in transmission routes, creating challenges for timely detection and control. Simulations indicate that broad wastewater surveillance coverage beyond top transmission hubs coupled with effective infection control may slow initial spatial expansion. Our findings highlight the rapid, stochastic spread of pandemic respiratory pathogens and the difficulties of early outbreak containment.

Humans↗
PubMed2026

Hex-MASP for mapping the whole-tissue spatial proteome and the intrabrain distribution of monoclonal antibodies.

Whole-tissue level spatial proteomics provides critical insights into region-specific biological regulations but remains challenging. Previously, we introduced the micro-scaffold assisted spatial proteomics (MASP) concept for whole-tissue mapping. However, this prototype required substantial development in spatial resolution, practicality, and throughput for practical application. Here we present a next-generation MASP technique (hex-MASP) featuring i) a new design of hexagonal-micro-wells fabricated with optimized projection micro-stereolithography 3D-printing, achieving high spatial resolution, sampling robustness, and mechanical strength for reproducibly compartmentalizing even tough tissues; ii) enhanced throughput/effectiveness in sample preparation and LC-MS analysis with high quantitative quality. Applied to mouse brain, hex-MASP achieved in-depth, whole-tissue mapping for >6,000 proteins in mouse brains, with high spatial accuracy and excellent data quality. The substantially improved resolution revealed critical regional details across the entire brain, that were not previously captured, enabling precise depiction of protein distribution heterogeneity. This technique enabled the identification of many unreported regionally enriched proteins across brain structures. We further applied hex-MASP to investigate the intrabrain distribution of intracerebroventricularly dosed antibody therapeutics and related proteins, which enabled whole-tissue mapping of protein drugs revealed insights into antibody brain penetration and distribution. Hex-MASP represents a robust, scalable platform for whole-tissue spatial proteomics.

Animals↗
PubMed2005

Scale-dependent feedback and regular spatial patterns in young mussel beds.

In the past decade, theoretical ecologists have emphasized that local interactions between predators and prey may invoke emergent spatial patterning at larger spatial scales. However, empirical evidence for the occurrence of emergent spatial patterning is scarce, which questions the relevance of the proposed mechanisms to ecological theory. We report on regular spatial patterns in young mussel beds on soft sediments in the Wadden Sea. We propose that scale-dependent feedback, resulting from short-range facilitation by mutual protection from waves and currents and long-range competition for algae, induces spatial self-organization, thereby providing a possible explanation for the observed patterning. The emergent self-organization affects the functioning of mussel bed ecosystems by enhancing productivity and resilience against disturbance. Moreover, self-organization allows mussels to persist at algal concentrations that would not permit survival of mussels in a homogeneous bed. Our results emphasize the importance of self-organization in affecting the emergent properties of natural systems at larger spatial scales.

Animals↗
PubMed2006

The acquisition of spatial constructions in American sign language and English.

Spatial relations in American Sign Language (ASL) are often signed from the perspective of the signer and so involve a shift in perspective and mental rotation. This study examined developing knowledge of language used to refer to the spatial relations front, behind, left, right, towards, away, above, and below by children learning ASL and English. Because ASL is a classifier language in which noun referents are placed into groups, each spatial relation also appeared with person, animal, and vehicle classifiers. Twenty-three children and adults who learned ASL before the age of 5 years and 23 native English-speaking adults and children participated. Both language groups participated in a comprehension task in which they chose which of 2 pictures depicted a signed or spoken relation. Results showed that children learning ASL acquired the constructions for spatial relations that typically involve perspective shifts and mental rotation later than constructions that do not involve these abilities and later than English-speaking children. Children learning ASL did not differ from English-speaking children in learning constructions that did not involve these abilities. Results also suggest that users of ASL initially comprehend spatial relations more accurately with person and animal classifiers than with the classifier for vehicles. The results are relevant to understanding the acquisition of spatial relations in ASL.

Adolescent↗