Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Maze Learning”

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 847 records · Page 47Linked to original sources
PubMed1997

Inhibitory avoidance and appetitive learning in aged normal mice: comparison with transgenic mice having elevated plasma growth hormone levels.

Groups of 25-month-old ("old") B6C3 hybrid male mice, 6-month-old ("young") normal males, and their age-matched transgenic (TG) siblings overexpressing the bovine growth hormone gene were given an inhibitory avoidance training trial (0.20-mA electric shock, 1.0-s duration). The old B6C3 hybrids and the young TG mice displayed poorer retention (shorter latencies to enter the shock compartment) 24 h and 42 days after training than did the young normal mice. In a subsequent multiple-trial acquisition test, young TG and old normal mice required more trials to reach the criterion of complete inhibition of step-through responding for 300 s than did young normal mice. Young normal and young TG mice did not differ in trials to extinction, but TG mice met the extinction criterion sooner than did old normal mice, suggesting poorer longterm retention. In tests of T-maze appetitive learning, young normal, old normal, and young TG mice did not differ in acquisition or 24-h retention. Contrary to expectation, TG mice acquired T-maze reversal learning in fewer trials than did young normal or old normal mice. The TG and young normal mice did not differ in retention when retested 44 days after initial training, but old normal mice showed poorer retention than did the young normals. Results of locomotor activity and shock response tests suggested that learning impairments were not due to differences in locomotor activity or shock response thresholds in these animals. Tests in an elevated plus maze indicated that young TG mice were less anxious in a novel environment than their normal siblings, which may contribute to their impaired inhibitory avoidance learning. These findings suggest that 6-month-old TG mice overexpressing the bovine growth hormone gene display alterations in inhibitory avoidance (but not appetitive) learning similar to those occurring in 25-month-old normal mice. The neurobiological mechanisms mediating inhibitory avoidance and T-maze appetitive learning in these animals may be largely dissociated.

Aging↗
PubMed1995

Simulation of spatial learning in the Morris water maze by a neural network model of the hippocampal formation and nucleus accumbens.

Cells in the hippocampal formation show spatial firing correlates thought to be critical to the role played by this structure in spatial learning. Place cells in the hippocampus proper show location-specific activity, whereas cells in the postsubiculum fire as a function of momentary directional heading. One question which has received little attention is how these spatial signals are used by motor structures to actually guide spatial behavior. Here we present a model of how one kind of spatial behavior, instrumental learning in the Morris water maze, could be guided by the spatial information in the hippocampal formation. For this, we concentrate on the hippocampal projection to the nucleus accumbens, which is strongly implicated in instrumental learning. In the model, simulated firing patterns of place cells and head direction cells activate "motor" cells in the "accumbens." Each motor cell causes a particular locomotor movement in a simulated rat. In this way, the "rat" locomotes through the simulated environment. Each step places the animal in a slightly different location and directional orientation, which, in turn, activates a different set of place and head direction cells, thus causing the next locomotor response, and so on. Connection strengths between cells are initially set randomly. When the animal encounters the reward location, however, connections are altered, so that recently active synapses are strengthened. Thus, successful moves in a particular locational and directional context are "stamped in." Simulated rats show rapid learning, similar in many ways to that of actual rats. In particular, they generate efficient routes to the goal after minimal experience, and can do so from somewhat novel starting positions. Consideration of the model architecture shows that 1) combined use of directional and place information is an example of a linearly inseparable problem and that 2) some types of novel route generation, often thought to require a "cognitive mapping" strategy, can be generated from the S-R type model used here.

Animals↗
PubMedDate not supplied

Effects of prenatal cocaine on Morris and Barnes maze tests of spatial learning and memory in the offspring of C57BL/6J mice.

Cocaine was administered to gravid C57BL/6J mice on embryonic days E8-18 at doses of either 17.5 or 20 mg/kg x 2 per day; controls received equal volumes of vehicle. The two cocaine dose groups were indistinguishable in their effects on maternal weight gain, offspring survival or body weight; therefore, the two groups were combined. Offspring were assessed as adults in straight channel swimming, cued and spatial reference-memory and working memory versions of the Morris water maze (MWM), and in the Barnes spatial maze to escape from a light, tone and fan. Cocaine offspring had shorter latencies in the straight channel and increased cumulative distance from the platform and path length in the spatial version of the Morris maze, but only when the platform size was reduced, not under standard platform conditions. In the working memory test, cocaine offspring showed deficits in acquisition and, following random trials, on relearning during a final test phase. In the Barnes maze, cocaine offspring were delayed in utilizing more efficient search strategies and took longer to find the goal. Taken together, the data suggest that prenatal cocaine induces modest but significant long-term alterations in both reference and working memory-based spatial learning and memory.

Animals↗
PubMed2003

Cognitive deficits induced by 56Fe radiation exposure.

Exposing rats to particles of high energy and charge (e.g., 56Fe) disrupts neuronal systems and the behaviors mediated by them; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, and our previous study showed that radiation disrupted Morris water maze spatial learning and memory performance, the present study used an 8-arm radial maze (RAM) to further test the cognitive behavioral consequences of radiation exposure. Control rats or rats exposed to whole-body irradiation with 1.0 Gy of 1 GeV/n high-energy 56Fe particles (delivered at the alternating gradient synchrotron at Brookhaven National Laboratory) were tested nine months following exposure. Radiation adversely affected RAM performance, and the changes seen parallel those of aging. Irradiated animals entered baited arms during the first 4 choices significantly less than did controls, produced their first error sooner, and also tended to make more errors as measured by re-entries into non-baited arms. These results show that irradiation with high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere.

Aging↗
PubMed2004

Evidence for time-place learning in the Morris water maze without food restriction but with increased response cost.

Time-place learning is the ability to distinguish between resources that vary in location at different times of day. Only one previous report has demonstrated successful time-place learning without using food as reward. In this experiment, satiated rats failed to form time-place discriminations in a Morris water maze while food deprived rats did, leading to the conclusion that food system activation is necessary for time-place learning. However, in addition to food system activation, response cost was also increased, which previously has been demonstrated to be effective in allowing the formation of time-place discriminations. The purpose of these two experiments is to test whether food system activation or heightened response cost allowed for time-place learning in the Morris water maze. In the first experiment, we replicate the failure to find time-place discriminations in the Morris water maze without food restriction and without increased response cost. In the second experiment, we found that increased response cost without food restriction was effective in allowing the formation of a time-place discrimination. The implications of this result are discussed in light of the timing mechanism used for time-place discriminations, the nature of the response cost, and the event-time-place tripartite association.

Animals↗
PubMed2005

Neonatal exposure to monosodium glutamate disrupts place learning ability in adult rats.

The activation of glutamatergic NMDA receptors of the hippocampus is closely associated with expression of place learning. Neonatal exposure to monosodium glutamate leads to abnormal expression of NMDA receptor subunits in the hippocampus, but its effect on place learning is unknown. Place learning acquisition and retrieval were assessed in mature adult rats after subcutaneous injection of monosodium glutamate (4 mg/g body weight) in eight neonatal rat pups at postnatal days one, three, five, and seven. Eight untreated rats were used as controls. At four months of age, the rats were challenged over a period of nine days with a place learning task. The task used an acquisition-retrieval paradigm in a Morris maze. Place learning acquisition was impaired in the experimental rats, which were unable to reduce their escape latencies during the nine training days. Controls improved between the fifth and ninth days of training. Test trials showed that retrieval of spatial information was also impaired in the experimental animals. These results show that both place learning acquisition and retrieval abilities in mature rats are impaired by neonatal treatment with monosodium glutamate. These findings may be related to the abnormal expression of NMDA receptor subunits in the hippocampus.

Animals↗
PubMed1994

Developmental changes in spatial learning in the Morris water-maze in young meadow voles, Microtus pennsylvanicus.

Spatial learning in pre- and postweaning meadow voles, (Microtus pennsylvanicus) was examined in a Morris water-maze task. The learning performance of 10-day-old (preweaning) and 15-, 20- and 25-day-old (postweaning) male and female voles was assessed by measuring the latency to reach a hidden platform by each animal twice a day for 5 days. Voles of all age groups were able to learn the spatial task with Day 10 and Day 15 voles acquiring the task more slowly than did Day 20 and Day 25 voles. There were no significant sex differences in task acquisition in any of the four age groups. In addition, although swimming speed was related to age, with older animals swimming faster than younger ones, differences in swim speed did not account for the faster acquisition by the older animals. These results show that both preweaning and postweaning voles can successfully learn a spatial task. This is in contrast to preweaning laboratory rats which cannot successfully acquire a similar spatial task. These findings indicate that there are species differences in the ontogeny of spatial learning, which are likely related to the ecological and behavioural developmental characteristics of the species. Furthermore, in contrast to the sex difference in water-maze performance obtained in adult, breeding meadow voles who demonstrate a sex difference, there were no significant sex differences in the spatial performance of the juvenile voles. This suggests that sex differences in spatial learning in the meadow vole do not appear until voles reach reproductive adulthood.

Aging↗
PubMed2002

Behavioral analysis of CREB alphadelta mutation on a B6/129 F1 hybrid background.

The cyclic AMP (cAMP)-response element binding protein (CREB) is an activity-dependent transcription factor that plays a role in synaptic plasticity and memory storage in Aplysia, Drosophila, and rodents. Mice with targeted deletions of two CREB isoforms (alpha and delta; CREB alphadelta mice) have been characterized on a mixed genetic background of C57BL/6 (B6) and 129/SvEv (129), as well as on a defined F1 hybrid of B6 and FVB/N, and these results suggest that the phenotype of CREB alphadelta mice depends critically on genetic background. In an examination of the hypothesis that the role of CREB in learning and memory can be influenced by strain differences, we analyzed mice with the CREB alphadelta mutation on an F1 hybrid background of B6 and 129 strains. CREB alphadelta mice on this background had impaired short-term and long-term cued and contextual fear conditioning and normal spatial learning in the Morris water maze. Our results suggest that at least some aspects of hippocampal function are normal in CREB alphadelta mice, and that CREB alphadelta mice on the B6/129 F1 background have alterations in amygdala function. These studies underscore the importance of controlling for genetic background in the behavioral analysis of knockout and transgenic mice.

Animals↗
PubMed2005

Mice with the deleted neurofilament of low molecular weight (Nefl) gene: 2. Effects on motor functions and spatial orientation.

Mice with a null mutation of the Nefl gene were compared with normal controls in tests of motor activity, equilibrium, and spatial orientation. Despite a normal capacity to ambulate, NFL -/- mice had fewer rears in an open field, crossed fewer segments on stationary beams, and fell more frequently when suspended on a horizontal bar. In addition, the distance swum before reaching the escape platform was greater in NFL -/- mice than in controls during acquisition of place learning in the Morris water maze at the start of training. The motor impairments were linearly correlated with increased cytochrome oxidase activity seen in cerebellum and brainstem. These results indicate that, as early as 6 months, depletion of the NFL protein is sufficient to cause mild sensorimotor dysfunctions and spatial deficits, but without overt signs of paresis.

Amyotrophic Lateral Sclerosis↗
PubMed1998

Prenatal gonadal steroids affect adult spatial behavior, CA1 and CA3 pyramidal cell morphology in rats.

The present study assessed whether prenatal androgen and estrogen exposure affected adult spatial learning and hippocampal morphology. Water maze performance, the CA1 and CA3 pyramidal cell field, and the dentate gyrus-granule cell layer (DG-GCL) morphology were assessed at adulthood (70+ days of age) in males, females, androgen-treated (testosterone propionate, TP, or dihydrotestosterone propionate, DHTP) females (2-4 mg/day), estradiol benzoate (EB)-treated females (100 microgram/day), and males treated with the antiandrogen flutamide (8 mg/day). Pregnant rats were injected daily (sc) between Embryonic Day 16 and birth; all pups were delivered by cesarean section. Flutamide-treated males were castrated upon delivery, and adult castrates were used to control for activational effects. Steroid-sensitive sex differences were observed in water maze performance in favor of males. Males had larger CA1 and CA3 pyramidal cell field volumes and soma sizes than females, which were feminized with flutamide treatment. TP and EB, but not DHTP, masculinized CA1 pyramidal cell field volume and neuronal soma size; CA3 was masculinized in both TP- and DHTP-treated females, while EB was ineffective. No effects were observed in cell density, number, or DG-GCL volume or due to adult hormone levels. Thus, prenatal androgens and estrogen influence sex differences in adult spatial navigation and exert differential effects on CA1 and CA3 pyramidal cell morphology. Hence, in addition to the previously reported postnatal component, there is also a prenatal component to the critical period in which gonadal steroids organize the neural mechanisms underlying sex differences in adult spatial ability.

Androgens↗
PubMed2002

The Effects of L-glucose on memory in mice are modulated by peripherally acting cholinergic drugs.

D-Glucose improves memory in animals and humans and in subjects with memory pathologies. To date, the accepted conclusion drawn from animal research is that D-glucose improves memory via alterations in central cholinergic systems. However, recent evidence suggests that a sugar which does not cross the blood-brain barrier also facilitates memory (Talley, Arankowsky-Sandoval, McCarty, & Gold, 1999). The present study examined the effects of peripherally administered L-glucose, a stereoisomer of D-glucose, in male mice. Intraperitoneal administration of L-glucose (300 mg/kg) before testing enhanced place learning in the Morris water maze. Mice injected with L-glucose had significantly shorter escape latencies than mice injected with saline (1 ml/kg). Effects were observed on both reference memory and working memory tasks. L-Glucose did not facilitate performance on either task when it was simultaneously administered with cholinergic antagonists that are excluded from the central nervous system. Thus, simultaneous administration of either methyl-scopolamine (0.3 mg/kg), a peripherally acting muscarinic receptor blocker, or hexamethonium (1 mg/kg), a peripherally acting nicotinic receptor blocker, reversed the effect of L-glucose on memory. These findings suggest that the memory effects of l-glucose may be mediated by facilitated acetylcholine synthesis and/or release in the peripheral nervous system.

Animals↗
PubMed2000

Sphingolipid biosynthesis by L-PDMP after rat MCA occlusion.

L-PDMP (L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol) exhibits stimulatory effects on glycosphingolipid biosynthesis and its neurotrophic actions in cultured neuron. The effects of intraperitoneal administration of L-PDMP on sphingolipid metabolism and behavioral changes in the rat following permanent occlusion of the left middle cerebral artery (MCA) were investigated. The L-PDMP treatment induced increases in glucosylceramide (ganglioside precursor) and sphingomyelin (SM) levels in the ischemic cerebral cortex, and improved acquisition of memory and learning in the Morris water maze task. The pharmacological effects of L-PDMP have been proposed to have a significant activity on promoting cell survival and improving neural functions.

Animals↗
PubMed1988

The effect of pirenzepine on spatial learning in the Morris Water Maze.

The effects of the selective M1-muscarinic antagonist, pirenzepine, were studied on the Morris Water Maze, a test of spatial learning in the rat. Pirenzepine (0, 10 or 30 micrograms) was administered into lateral ventricle during acquisition of this task. Although 30 micrograms of pirenzepine impaired acquisition of the spatial aspects of the task, treated animals still appeared to be able to acquire a taxon strategy. A low dose of pirenzepine (10 micrograms) produced a slight deficit but this was only visible in a "spatial probe" trial. Although these results are consistent with the belief that muscarinic M1-receptors are involved in spatial learning, it cannot be excluded that the effects recorded were mediated by muscarinic M2-receptors, due to the low selectivity of pirenzepine.

Animals↗
PubMedDate not supplied

Effects of prenatal exposure to xylene on postnatal development and behavior in rats.

The effects of prenatal exposure to the organic solvent xylene (dimethylbenzene, CAS-no 1330-20-7) on postnatal development and behavior in rats were studied. Pregnant rats (Mol:WIST) were exposed to 500 ppm technical xylene 6 h per day on gestation days 7-20. The dose level was selected so as not to induce maternal toxicity or decrease the viability of offspring. In the exposed offspring, a delay in the ontogeny of the air righting reflex, a lower absolute brain weight, and impaired performance in behavioral tests for neuromotor abilities (Rotarod) and for learning and memory (Morris water maze) were found. Generally, the effects were most marked in the female offspring.

Animals↗
PubMed2005

PS1 knockin mice with the Japanese I213T mutation: effects on exploratory activity, motor coordination, and spatial learning.

Knockin (KI) mice with a PS1/I213T mutation were compared to wild-type controls on the SHIRPA primary screening battery and for exploratory activity, motor coordination, and spatial learning. By comparison to non-transgenic controls, PS1/I213T KI mice had retarded acquisition of place learning in the Morris water maze without being impaired in the probe trial and in the visible platform subtest. PS1/I213T KI mice were more likely to display whole-body startle to an auditory stimulus and a tighter grip on a horizontal grid. PS1/I213T KI mice also had fewer enclosed arm entries in the elevated plus-maze, but did not differ from controls in open-field, photocell actimeter, and T-maze spontaneous alternation tests. No intergroup difference was seen in three motor coordination tests. The dissociation between hidden and visible platform versions in the water maze is consistent with the hypothesis that elevated Abeta42 concentrations cause cognitive disturbances.

Acoustic Stimulation↗
PubMed2006

Evaluation of developmental neurotoxicity of organotins via drinking water in rats: monomethyltin.

Organotins such as monomethyltin (MMT) are widely used as heat stabilizers in PVC and CPVC piping, which results in their presence in drinking water supplies. Concern for neurotoxicity produced by organotin exposure during development has been raised by published findings of a deficit on a runway learning task in rat pups perinatally exposed to MMT (Noland EA, Taylor DH, Bull RJ. Monomethyl and trimethyltin compounds induce learning deficiencies in young rats. Neurobehav Toxicol Teratol 1982;4:539-44). The objective of these studies was to replicate the earlier publication and further define the dose-response characteristics of MMT following perinatal exposure. In Experiment 1, female Sprague-Dawley rats were exposed via drinking water to MMT (0, 10, 50, 245 ppm) before mating and throughout gestation and lactation (until weaning at postnatal day [PND] 21). Behavioral assessments of the offspring included: a runway test (PND 11) in which the rat pups learned to negotiate a runway for dry suckling reward; motor activity habituation (PNDs 13, 17, and 21); learning in the Morris water maze (as adults). Other endpoints in the offspring included measures of apoptosis (DNA fragmentation) at PND 22 and as adults, as well as brain weights and neuropathological evaluation at PND 2, 12, 22, and as adults. There were no effects on any measure of growth, development, cognitive function, or apoptosis following MMT exposure. There was a trend towards decreased brain weight in the high dose group. In addition, there was vacuolation of the neuropil in a focal area of the cerebral cortex of the adult offspring in all MMT dose groups (1-3 rats per treatment group). In Experiment 2, pregnant rats were exposed from gestational day 6 until weaning to 500 ppm MMT in drinking water. The offspring behavioral assessments again included the runway task (PND 11), motor activity habituation (PND 17), and Morris water maze (as adults). In this second study, MMT-exposed females consumed significantly less water than the controls throughout both gestation and lactation, although neither dam nor pup weights were affected. As in Experiment 1, MMT-exposure did not alter pup runway performance, motor activity, or cognitive function. These results indicate that perinatal exposure to MMT, even at concentrations which decrease fluid intake, does not result in significant neurobehavioral or cognitive deficits. While mild neuropathological lesions were observed in the adult offspring, the biological significance of this restricted finding is unclear.

Animals↗
PubMed2006

Insulin-like growth factor 1 reduces age-related disorders induced by prenatal stress in female rats.

Stress during the prenatal period can induce permanent abnormalities in adult life such as increased anxiety-like behavior and hyperactivity of hypothalamo-pituitary-adrenal (HPA) axis system. The present study was designed to investigate whether prenatal stress could induce spatial learning impairment in aged female rats. Furthermore, since it has been recently reported that insulin-like growth factor 1 (IGF-1) attenuates spatial learning deficits in aged rats and promotes neurogenesis in the hippocampus, we assessed the impact of a chronic infusion of IGF-1 on age-related disorders. Our results show that females stressed during prenatal life exhibit learning impairments in the water maze task. Chronic IGF-1 treatment restores their spatial abilities, reduces their HPA axis dysfunction and increases plasma estradiol levels. Parallel to these effects, chronic IGF-1 up-regulates neural proliferation in the dentate gyrus of the hippocampus. These findings support the hypothesis of an early programming of the vulnerability to some neurological diseases during senescence and reinforce the potential therapeutic interest of IGF-1 during brain aging.

Animals↗