Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “spatial memory”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2002

Spatial memory dissociations in mice lacking GluR1.

Gene-targeted mice lacking the AMPA receptor subunit GluR1 (GluR-A) have deficits in hippocampal CA3-CA1 long-term potentiation. We now report that they showed normal spatial reference learning and memory, both on the hidden platform watermaze task and on an appetitively motivated Y-maze task. In contrast, they showed a specific spatial working memory impairment during tests of non-matching to place on both the Y-maze and an elevated T-maze. In addition, successful watermaze and Y-maze reference memory performance depended on hippocampal function in both wild-type and mutant mice; bilateral hippocampal lesions profoundly impaired performance on both tasks, to a similar extent in both groups. These results suggest that different forms of hippocampus-dependent spatial memory involve different aspects of neural processing within the hippocampus.

Animals↗
PubMed1999

In mice tonic estrogen replacement therapy improves non-spatial and spatial memory in a water maze task.

We investigated the effects of estrogen replacement therapy on water maze non-spatial and spatial navigation in mice. Three groups of mice were ovariectomized and two of these groups being implanted with s.c. pellets that produce blood levels of estrogen close to those found in estrous (estrogen low, 75-100 pg/ml blood) or proestrous (estrogen high, 300-400 pg/ml). The behavioral assessment was initiated 7 days after pellet implantation. Non-spatial navigation to a clearly visible platform was stimulated by low and high levels of estrogen. However, spatial navigation to a hidden platform was improved by low estrogen levels. We found that estrogen improves two different types of memory processes that depend on striatal (non-spatial navigation) and hippocampal (spatial) memory systems.

Animals↗
PubMed2000

Chronic [D-Ala2]-growth hormone-releasing hormone administration attenuates age-related deficits in spatial memory.

The age-related decline in growth hormone is one of the most robust endocrine markers of biological aging and has been hypothesized to contribute to the physiological deficits observed in aged animals. However, there have been few studies of the impact of this hormonal decline on brain aging. In this study, the effect of long-term subcutaneous administration of [D-Ala2]-growth hormone-releasing hormone (GHRH) on one measure of brain function, memory, was investigated. Animals were injected daily with 2.3 microg of [D-Ala2]-GHRH or saline from 9 to 30 months of age, and the spatial learning and reference memory of animals were assessed by using the Morris water maze and compared with those of 6-month-old animals. Results indicated that spatial memory decreased with age and that chronic [D-Ala2]-GHRH prevented this age-related decrement (24% improvement in the annulus-40 time and 23% improvement in the number of platform crossings compared with saline treated, age-matched controls; p < .05 each). No changes were noted in sensorimotor performance. [D-Ala2]-GHRH attenuated the age-related decline in plasma concentrations of insulinlike growth factor-1 (IGF-1) (p <.05). These data suggest that growth hormone and IGF-1 have important effects on brain function, that the decline in growth hormone and IGF-1 with age contributes to impairments in reference memory, and that these changes can be reversed by the chronic administration of GHRH.

Aging↗
PubMed1999

Sex dimorphisms in the rate of age-related decline in spatial memory: relevance to alterations in the estrous cycle.

The present experiments demonstrate the existence of sex differences in the rate of development and the magnitude of age-dependent impairments in cognitive and sensorimotor abilities. Although no sex differences were found in spatial reference memory at a young age, the mnemonic ability of female rats deteriorated more rapidly than that of male rats. A major drop in reference memory of the females occurred at the age of 12 months, whereas in the males the onset of impairments occurred later, at the age of 18 months. In spatial working memory, on the other hand, the magnitude of decline was greater in females than in males, although the onset of these impairments occurred at the age of 24 months in both sexes. A sexual dimorphism-aging interaction also was observed in sensorimotor performance. Up to the age of 18 months the females outperformed the males. Subsequently, by the age of 24 months, the performance of the females declined to a level similar to that of the males. The deficits observed in reference and working memory seem to be cognitive in origin and not attributable to alterations in sensory and motor abilities. In addition, the earlier onset of reference memory impairments in females generally coincides with the onset of alterations in the estrous cycle, suggesting that a decline in the estrogenic milieu of the females could be a factor in accelerating the rate of age-related cognitive impairments in the female rat.

Aging↗
PubMed1998

Aging of glutamate receptors: correlations between binding and spatial memory performance in mice.

C57B1/6 mice aged 3, 10, and 26 months were tested for spatial learning in the Morris water maze. Ten and 26 month old mice were ad libitum-fed or diet restricted (60% of ad libitum-fed calories). Diet restriction significantly improved memory performance among the 10 and 26 month olds. In age/diet group comparisons, aged ad libitum-fed mice had significantly higher average proximity scores, indicating poorer performance, in probe trials for place learning than the 3 month olds and diet restricted 10 month olds. Diet restricted 26 month olds did not differ significantly from 3 month olds or any other groups in probe trial measures. The group means for average proximity scores were significantly correlated with binding densities for the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors in the frontal cortex and CA1 region of the hippocampus. Alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate (AMPA) binding correlated with group proximity scores in frontal and parietal cortices and within the CA1 and CA3 regions of the hippocampus. Kainate and metabotropic binding sites showed no significant correlations with behavior. These results suggest that there is a sparing of spatial memory with diet restriction in aging C57B1/6 mice and that the effects of aging on NMDA and AMPA receptors may be associated with age-related declines in spatial learning.

Aging↗
PubMed2002

Role of the anterodorsal and anteroventral nuclei of the thalamus in spatial memory in the rat.

This study tests the hypothesis that the anterior thalamic nuclei play a significant role in spatial learning and memory. Adult, male Sprague-Dawley rats with bilateral ibotenic acid lesions of the anterior thalamus were tested for 5 days in a repeated acquisition water maze task. Compared with Controls, rats with nearly complete lesions of both anterodorsal (AD) and anteroventral (AV) thalamic nuclei (AD/AV) were only mildly impaired in their spatial learning and memory. Larger lesions that extended into the anteromedial (AM) thalamic nucleus (AD/AV+) caused a more severe impairment and complete lesions of all three anterior nuclei (AD/AV/AM) resulted in even greater impairment that extended to all aspects of the task. In probe trials, only the Control animals had a preference for the correct quadrant. Approximately one-half of the rats were tested for a second week to determine if the impaired groups would benefit from further training. AD/AV/AM rats showed little improvement, but the other groups all improved significantly in all aspects of the task except the probe trial. Together, these data indicate that the anterior thalamic nuclei contribute to spatial learning and memory, but neither AV nor AD independently plays a dominant role.

Animals↗
PubMed1996

Effect of intraventricular injections of dihydro-beta-erythroidine (DH beta E) on spatial memory in the rat.

The analysis of the behavioral effect of the nicotinic acetylcholine receptor (nAChR) antagonists has been generally based on drugs which act at the associated ion channel. In contrast dihydro-beta-erythroidine (DH beta E) is a competitive antagonist at the nAChR. Using rats, DH beta E was injected intraventricularly prior to training in two spatial tests, the Morris Water Maze and a Win-Stay radial maze. In addition DH beta E 300 nmol was used to reverse the effect of (-)-nicotine on locomotor activity. In the Morris Water Maze DH beta E (300 nmol) disrupted memory of the platform location as measured by crosses of the area in a probe trial. At 300 nmol DH beta E showed no sensorimotor effects in a visible platform test. In the Win-Stay task there was a significant, dose dependent disruption of spatial memory. A dissociation of nicotine's effects on locomotor activity was observed, in that DH beta E 300 nmol was able to significantly attenuate (-)-nicotine enhancement of horizontal motor activity, but did not affect the initial reduction of vertical activity. Nicotinic processing of memory appears to be involved in these tests of spatial memory.

Animals↗
PubMed1984

Spatial memory over long retention intervals: nonmemorial factors are not necessary for accurate performance on the radial-arm maze by rats.

A. Markowska, O. Buresová, and J. Bures (1983, Behavioral and Neural Biology, 38, 97-112) argued that the apparent persistence of accurate spatial working memory over delays of several hours arises from the formation of response strategies and the use of olfactory stimuli that develop with extended training at long delays. To test this explanation rats with extensive prior training at long delays were forced to enter the first four arms in a random order. On test days, the maze was rotated 180 degrees during the 2-h retention interval to determine whether the rats were using intramaze or extramaze (i.e., spatial) cues to guide their choices. On both rotation and control days, postdelay choices were spatially guided, averaging over 90% correct. Accurate spatial working memory at long delays is a reproducible phenomenon and does not appear to result from nonmemorial artifacts.

Animals↗
PubMed1987

Dissociation of item and order spatial memory in rats following medial prefrontal cortex lesions.

In order to test whether there is a correspondence in function of prefrontal cortex in rats and humans, rats with medial prefrontal cortex lesions were tested for item and order memory for a list of items (spatial locations in a maze). Results indicate that for order memory rats with medial prefrontal cortex lesions cannot remember the order of presentation of four or eight specific spatial locations. This inability to remember order information can be seen even when animals with lesions have to remember only two spatial locations, can self-order the sequence of four or eight spatial locations, or have been presented with the same study phase on every trial. In contrast, for item memory animals with medial prefrontal cortex lesions retain the first item of the list in the variable study phase situation and remember all the items of the list in a constant study phase situation. However, there are also deficits for the last items within a list in the variable study phase situation for both win-stay and win-shift procedures. This deficit might be a function of an impairment in the utilization of appropriate temporal strategies, which normally would facilitate recognition memory in the win-stay and win-shift tasks. In general, the data suggest a partial, but not complete, dissociation of item-order memory. Furthermore, the data suggest that the medial prefrontal cortex is involved in temporal structuring of information.

Animals↗
PubMed1999

Reduced cerebrospinal fluid levels of alpha-secretase-cleaved amyloid precursor protein in aged rats: correlation with spatial memory deficits.

The amyloid precursor protein undergoes proteolysis at several sites to yield a number of functionally relevant peptides, including beta-amyloid and the soluble amyloid precursor protein derivatives alpha-soluble amyloid precursor protein and beta-soluble amyloid precursor protein. beta-Amyloid is the primary constituent of senile plaques associated with Alzheimer's disease, while a-soluble amyloid precursor protein promotes synaptogenesis and plays a role in neuroprotective processes. We tested for age-related alterations in these amyloid precursor protein proteolytically derived peptides by measuring the levels of alpha-soluble amyloid precursor protein, total soluble amyloid precursor proteins (alpha- and beta-soluble amyloid precursor protein combined) and beta-amyloid in cerebrospinal fluid from three-, 13- and 23-month-old Fischer-344 rats. Western blot analysis using selective antibodies revealed 50% less total soluble amyloid precursor protein and a-soluble amyloid precursor protein in cisternal cerebrospinal fluid from 23-month-old rats compared with three- and 13-month-old animals. Mass spectrometric analysis indicated, however, that beta-amyloid in cerebrospinal fluid was not different between the three age groups. In a second group of young (five to six months of age) and aged (24-25 months of age) rats, spatial working and reference memory were assessed in a water maze followed by collection of cerebrospinal fluid. As a group, the aged rats consistently performed below the young rats in both working and reference memory tests. The aged rats also had 49% less cerebrospinal fluid alpha-soluble amyloid precursor protein than did their younger counterparts. There was a positive correlation (r= 0.52-0.57, P < 0.001) between performance in spatial memory tasks and cerebrospinal fluid alpha-soluble amyloid precursor protein in these young and aged rats. These results suggest that there is a positive association between cerebrospinal fluid levels of alpha-soluble amyloid precursor protein and cognitive performance in rats, and that alpha-soluble amyloid precursor protein may be involved in the spatial learning and memory changes that accompany ageing.

Aging↗
PubMed1996

Effects of MK-801 on spatial memory in homing and nonhoming pigeon breeds.

Homing pigeon breeds, the product of artificial selection on the basis of navigational and spatial ability, differ from nonhoming breeds in hippocampal size and distribution of N-methyl-D-aspartate (NMDA) dependent receptors. The effects of MK-801 (0.1 mg/kg administered intraperitoneally), a noncompetitive NMDA antagonist, on spatial reference memory (RM) were compared between the 2 breeds in a radial arm maze task. MK-801 disrupted the acquisition of RM in the nonhoming group but not the homing group, which was equivalent to the 2 saline-only control groups. As in previous findings with mammals, working memory was not affected by MK-801. This behavioral dissociation, coupled with differences in NMDA-dependent long-term potentiation between breeds, suggests an exceptional opportunity to investigate the role and function of the dorsomedial telencephalon region in spatial RM, through anatomical, neurochemical, and behavioral comparisons between homing and nonhoming pigeon breeds.

Animals↗
PubMed1987

Verbal and spatial memory span in patients with extrapyramidal diseases.

Spatial span (Corsi's block-tapping test) and verbal span (Wechsler's Digits Forward test) were measured in 651 normal subjects and in three groups of extrapyramidal patients (Progressive supranuclear palsy, Parkinson, and Huntington's Chorea). Analysis showed Huntington's Chorea patients scored lower on both tests than did controls and other groups.

Adult↗
PubMed1992

Effects of medetomidine, an alpha-2 adrenoceptor agonist, and atipamezole, an alpha-2 antagonist, on spatial memory performance in adult and aged rats.

The effects of a novel, highly selective alpha-2 agonist, medetomidine, and its antagonist, atipamezole, were studied on the working memory of rats performing a spatial delayed alternation task. Testing was performed in two stages, at the age of 8.3 months (mean) and again when the rats were 17.6 months (mean). A low dose (3 micrograms/kg) and a high dose (30 micrograms/kg) of medetomidine improved the performance of the old rats in the memory task but had no effect on the young rats. The dose-response curve of medetomidine resembles that of guanfacine, another alpha-2 agonist. At the low dose of medetomidine (3 micrograms/kg) the animals showed no signs of sedation. Since medetomidine even at a low dose has a beneficial effect on the memory performance of old rats, it could be a good candidate for the treatment of age-associated memory dysfunction.

Adrenergic alpha-Agonists↗
PubMed2003

The role of the executive system in visuo-spatial memory functioning.

Participants were presented with a spatial sequence in which between 4 and 10 cells were highlighted. On each trial list length was unknown to the participant who was required to serially recall the last four cells. Processing of longer lists is assumed to call upon the executive system, which is thought to be involved in updating the contents of the short-term visuo-spatial store. Study 1 revealed that loading the executive system with concurrent random letter generation impaired performance on the spatial task especially recall of the early serial positions. However, contrary to expectation the degree of impairment was no greater on the longer lists, where it had been assumed that updating would be occurring. Study 2 confirmed this finding and demonstrated that relative to sequences of known length, under conditions of uncertainty when the list length was unknown, spatial recall was impaired even on short sequences. The present results support the growing consensus, which is suggestive of closer links between visuo-spatial and executive processes. However, it remains unclear whether or not updating is actually occurring on the longer sequences, and if it is, what specific executive processes are involved.

Adolescent↗
PubMed1992

Spatial and temporal contributions to the structure of spatial memory.

Three experiments investigated the effects of spatial and temporal contiguity in item recognition, location judgment, and distance estimation tasks. Ss learned the locations of object names in spatial arrays, which were divided into 2 regions. The names of locations were presented during map learning so that critical pairs appeared close in space and close in time, close in space but far in time, far in space but close in time, and far in space and far in time. Names primed each other in recognition only when they were neighbors in both space and time. In contrast, the effects of spatial and temporal contiguity in priming in location judgments were additive. Finally, temporal contiguity affected estimates of Euclidean distance when locations were close together, but not when they were far apart.

Adult↗
PubMed1999

Excitotoxic septal lesions result in spatial memory deficits and altered flexibility of hippocampal single-unit representations.

The septal nuclei are reciprocally connected with the hippocampal formation and contribute importantly to spatial and memory processing. Using excitotoxic lesions of the septal area, we investigated whether neurodegeneration in subcortical projections to hippocampus can compromise flexible information processing by hippocampal single units. In agreement with the mild effects of excitotoxic septal lesions on hippocampal physiology compared with fimbria-fornix lesions and septal inactivation, we observed limited lesion effects on single-unit activity. The location specificity of hippocampal complex spike cells remained unchanged, but a less reliable location-dependent discharge was observed in experimental animals with a pronounced postoperative working memory deficit. Testing in the absence of ambient illumination and in a new environment revealed that the spatial correlates of complex spike cells in lesioned animals may rely on a more limited set of sensory cues. Altered sensory cues resulted in a significantly different response pattern between the control and lesion group in the new environment, a situation that normally results in place field reorganization. Such a group difference was not observed during dark testing, a condition in which place field reorganization is less prominent. A contribution of hippocampal interneurons to the observed alterations in the spatial properties of the principal cells was suggested by decreased theta modulation in the lesioned group. Because excitotoxic lesions result in memory deficits that resemble age-related memory problems in the absence of age-related degenerative processes, we suggest that septal neurodegeneration could directly contribute to those behavioral changes with advanced age that correlate with functional alterations in the hippocampal formation.

Action Potentials↗
PubMed1998

Lesions of perirhinal cortex produce spatial memory deficits in the radial maze.

Rats with bilateral electrolytic lesions of perirhinal cortex (PRC) or sham control (SHAM) lesions were tested in spatial reference and working memory tasks in the radial arm maze. In experiment 1, one arm of the maze was baited and always located in a fixed position relative to the extra-maze environment. PRC lesioned animals made a significantly greater number of errors than did SHAM animals during initial training in this reference memory task and exhibited a delay-dependent impairment on trial 5 in a series when a delay period of 5, 60, 120, or 240 s was inserted between trials 4 and 5. In experiment 2, when a second group of the animals was tested on the standard radial arm maze working memory task, the performance of the PRC group was markedly impaired relative to controls. These data demonstrate that electrolytic PRC lesions result in a deficit in both spatial reference and spatial working memory tasks. These effects are interpreted as being consistent with the idea that PRC plays an important role in episodic memory processes. These processes may include the storage of information, which is required for the performance of spatial tasks.

Animals↗
PubMed1992

Septo-hippocampal and nBM-cortical cholinergic neurones exhibit differential time-courses of activation as a function of both type and duration of spatial memory testing in mice.

We previously showed that the initial acquisition session of a spatial discrimination (mixed reference/working memory) test in an 8-arm radial maze induced differential activations in the ascending cholinergic septo-hippocampal and nBM-cortical pathways in mice. This data showed that the duration of post-test cholinergic activation was longer in the nBM-cortical pathway than in the septo-hippocampal projection. Moreover, the post-test durations but not the immediate post-test amplitudes of activation in each pathway decreased progressively as a function of repeated daily acquisition sessions. In the present study we have thus tested the hypotheses that the time-courses of post-test cholinergic activation in the septo-hippocampal and nBM-cortical pathways may vary both as a function of the type of memory used (working vs. reference) and according to the duration of repeated daily testing. Cholinergic activity in vivo in the hippocampus or frontal cortex of mice was quantified using measures of sodium-dependent high-affinity choline uptake at two different times (30 s and 15 min) following specific spatial working or reference memory testing in an 8-arm radial maze. The memory tests were administered daily over a 13-day period to attain high levels of performance in each type of task. In comparison to control groups both types of memory testing induced significant post-test cholinergic activations in each brain region on Day 15. However, cholinergic activity remained elevated in frontal cortex at 15 min post-test following reference memory testing, whereas significantly shorter durations of cortical and hippocampal cholinergic activation were observed following working memory testing using short (1 min) retention intervals. The possible significance of these differential modifications to the time-course of the post-test activations in these cholinergic pathways in working and reference memory processes and the putative transsynaptic mechanisms involved are discussed.

Animals↗