Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Spatial 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 865 records · Page 48Linked to original sources
PubMed1996

Spatial attention and implicit sequence learning: evidence for independent learning of spatial and nonspatial sequences.

This research investigated whether regular spatial orienting sequences can be learned implicitly and independently of response requirements. In a new version of a serial response task introduced by M. J. Nissen and P. Bullemer (1987) participants had to discriminate between objects that could occur at different locations. Independent sequences determined the succession of locations and objects. Even participants who were not aware of any regularities exhibited evidence for learning of both sequences (Experiment 1). Experiment 2 showed that the joint learning of spatial and object sequences was as efficient as learning of single sequences and that it even occurred when learning required memory for past sequence elements and attention was blocked through a secondary tone-counting task. Results are consistent with the idea that independent systems may exist for the implicit acquisition of spatial and nonspatial regularities.

Adult↗
PubMedDate not supplied

Molecular, cellular, and neuroanatomical substrates of place learning.

Learning and remembering the location of food resources, predators, escape routes, and immediate kin is perhaps the most essential form of higher cognitive processing in mammals. Two of the most frequently studied forms of place learning are spatial learning and contextual conditioning. Spatial learning refers to an animal's capacity to learn the location of a reward, such as the escape platform in a water maze, while contextual conditioning taps into an animal's ability to associate specific places with aversive stimuli, such as an electric shock. Recently, transgenic and gene targeting techniques have been introduced to the study of place learning. In contrast with the abundant literature on the neuroanatomical substrates of place learning in rats, very little has been done in mice. Thus, in the first part of this article, we will review our studies on the involvement of the hippocampus in both spatial learning and contextual conditioning. Having demonstrated the importance of the hippocampus to place learning, we will then focus attention on the molecular and cellular substrates of place learning. We will show that just as in rats, mouse hippocampal pyramidal cells can show place specific firing. Then, we will review our evidence that hippocampal-dependent place learning involves a number of interacting physiological mechanisms with distinct functions. We will show that in addition to long-term potentiation, the hippocampus uses a number of other mechanisms, such as short-term-plasticity and changes in spiking, to process, store, and recall information. Much of the focus of this article is on genetic studies of learning and memory (L&M). However, there is no single experiment that can unambiguously connect any cellular or molecular mechanism with L&M. Instead, several different types of studies are required to determine whether any one mechanism is involved in L&M, including (i) the development of biologically based learning models that explain the involvement of a given mechanism in L&M, (ii) lesion experiments (genetics and pharmacology), (iii) direct observations during learning, and (iv) experiments where learning is triggered by turning on the candidate mechanism. We will show how genetic techniques will be key to unraveling the molecular and cellular basis of place learning.

Animals↗
PubMed2005

Dyslexics are impaired on implicit higher-order sequence learning, but not on implicit spatial context learning.

Developmental dyslexia is characterized by poor reading ability and impairments on a range of tasks including phonological processing and processing of sensory information. Some recent studies have found deficits in implicit sequence learning using the serial reaction time task, but others have not. Other skills, such as global visuo-spatial processing may even be enhanced in dyslexics, although deficits have also been noted. The present study compared dyslexic and non-dyslexic college students on two implicit learning tasks, an alternating serial response time task in which sequential dependencies exist across non-adjacent elements and a spatial context learning task in which the global configuration of a display cues the location of a search target. Previous evidence indicates that these implicit learning tasks are based on different underlying brain systems, fronto-striatal-cerebellar circuits for sequence learning and medial temporal lobe for spatial context learning. Results revealed a double dissociation: dyslexics showed impaired sequence learning, but superior spatial context learning. Consistent with this group difference, there was a significant positive correlation between reading ability (single real and non-word reading) and sequence learning, but a significant negative correlation between these measures and spatial context learning. Tests of explicit knowledge confirmed that learning was implicit for both groups on both tasks. These findings indicate that dyslexic college students are impaired on some kinds of implicit learning, but not on others. The specific nature of their learning deficit is consistent with reports of physiological and anatomical differences for individuals with dyslexia in frontal and cerebellar structures.

Adolescent↗
PubMed2003

Combined beta-adrenergic and cholinergic antagonism produces behavioral and cognitive impairments in the water maze: implications for Alzheimer disease and pharmacotherapy with beta-adrenergic antagonists.

This study examined the effects of beta-adrenergic and muscarinic blockade on spatial learning and strategy use in the water maze. Male Long-Evans rats received systemic injections of propranolol (PRO; 10 or 20 mg/kg) or scopolamine (SCO; 0.3 or 1.0 mg/kg) either singly or in combination. To separate strategies learning from spatial learning approximately half of the rats underwent water maze strategies pretraining prior to drug administration and spatial training. PRO did not impair performance in any group. SCO impaired naive but not pretrained rats. PRO and SCO given together in high doses impaired all aspects of behavior in both naive and pretrained rats, and caused sensorimotor disturbances in some groups. PRO (10 mg/kg) and SCO (0.3 mg/kg) together caused a specific spatial reversal learning impairment in pretrained rats without causing strategies impairments or sensorimotor disturbances. Nadolol administered with SCO failed to produce the same impairments as PRO, suggesting that PRO produced its effects by acting on central nervous system sites. These results point to a greater than additive impairing effect of PRO and SCO on adaptive behavior, and a specific role for beta-adrenergic and cholinergic systems working in conjunction in spatial learning. They also suggest that some of the behavioral and cognitive impairments seen in Alzheimer patients or patients receiving pharmacotherapy with beta-adrenergic antagonists in which cholinergic activity is also compromised may result from the combined impairment of beta-adrenergic and cholinergic systems.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Effects of metrifonate on the hippocampal theta rhythm of freely moving intact and MS-lesioned mice.

Changes in hippocampal electroencephalogram (EEG) have been suggested to be closely associated with spatial learning ability. Spatial learning can be improved in medial septal (MS)-lesioned mice by metrifonate, a cholinesterase inhibitor. We designed this study to investigate the effects of metrifonate on the hippocampal theta oscillation of intact and MS-lesioned mice. Intact and MS-lesioned C57BL mice were treated with acute injections of metrifonate (doses: 15, 50 and 100 mg/kg ip). These included a dose that considerably improved spatial memory of MS-lesioned mice in our earlier study. In addition, subtype selective muscarinic agents, BIBN-99, AF267B and AF150(S) were used. Recordings of hippocampal theta during movement and awake immobility revealed a dramatic reduction of theta in the lesioned animals. Metrifonate induced prominent changes in the EEG of intact mice, but not of MS-lesioned mice. The effect of metrifonate was not mimicked by two selective M(1)-agonists and was augmented by a combined injection of a selective M(2)-antagonist. These data suggest that improved spatial learning by the cholinesterase inhibitor metrifonate is unrelated to its effects on the hippocampal EEG. These two effects may be mediated through different muscarinic receptor subtypes.

Animals↗
PubMed2002

Learning and recall of story content and spatial location after unilateral temporal-lobe excision in children and adolescents.

The present study examined verbal and spatial learning and memory in children and adolescents who had undergone unilateral temporal lobectomy versus controls. All participants were trained to criterion before a delay to assess learning efficiency. There were no significant differences between the groups in rate of learning the verbal task. The right temporal-lobe group, but not the left, had difficulty learning spatial information. These findings indicate a specific effect of early right temporal-lobe lesions on spatial learning. As material-specificity is more often found in adults for verbal information, the present results highlight the unique role of the temporal-lobe in development.

Adolescent↗
PubMed2005

Spatial context learning in visual search and change detection.

Humans conduct visual search more efficiently when the same display is presented for a second time, showing learning of repeated spatial contexts. In this study, we investigate spatial context learning in two tasks: visual search and change detection. In both tasks, we ask whether subjects learn to associate the target with the entire spatial layout of a repeated display (configural learning) or with individual distractor locations (nonconfigural learning). We show that nonconfigural learning results from visual search tasks, but not from change detection tasks. Furthermore, a spatial layout acquired in visual search tasks does not enhance change detection on the same display, whereas a spatial layout acquired in change detection tasks moderately enhances visual search. We suggest that although spatial context learning occurs in multiple tasks, the content of learning is, in part, task specific.

Adult↗
PubMed2000

Spatial learning-induced increase in the argyrophilic nucleolar organizer region of dorsolateral telencephalic neurons in goldfish.

Spatial learning and memory related morphological changes in the argyrophilic nucleolar organizer region (AgNOR) of telencephalic neurons in goldfish were quantitatively evaluated by means of AgNOR neurohistochemical stain. The AgNORs and nuclei of nerve cells of two different telencephalic regions of goldfish trained in a spatial task or submitted to a similar non-contingent behavioral procedure (control group) were morphometrically evaluated. Results show that the area of AgNORs in goldfish dorsolateral telencephalic neurons increased significantly in the spatial learning group but not in control group. This effect seems to be highly specific as it did not appear in the dorsolateral area of the control group neither in the dorsomedial area of both groups. As the size of AgNORs in the nerve cell nuclei reflect the level of transcriptive activity, these morphological changes could be revealing increased protein synthesis in goldfish dorsolateral telencephalic neurons related with learning and memory. These findings could contribute to determining the subregions of the teleost telencephalon implicated in spatial learning and could indicate that the AgNOR staining technique would be a useful tool in assesing learning and memory related neuronal activity.

Animals↗
PubMed1988

Place navigation in rats is impaired by lesions of medial septum and diagonal band but not nucleus basalis magnocellularis.

The role of forebrain cholinergic projections in place navigation learning was assessed in two experiments. Following surgery, rats were required to learn the spatial location of an underwater platform on the basis of distal room cues. Bilateral injections of ibotenic acid into the nucleus basalis magnocellularis depleted choline acetyltransferase (ChAT) from the anterior and temporoparietal cortex but not the hippocampus. Separate histological studies confirmed the accuracy of the lesions and demonstrated a marked loss of cortical acetylcholinesterase. These rats subsequently showed no deficits in spatial learning or memory. In a second experiment, bilateral lesions of the vertical limb of the diagonal band of Broca and medial septum depleted ChAT from the hippocampus and posterior cortex but not the anterior cortex. Histological studies confirmed the accuracy of the lesion and showed a pronounced loss of acetylcholinesterase from the hippocampus. These rats were deficient in spatial learning and showed reduced spatial bias during transfer tests. The data are discussed in the light of the hypothesis that the cholinergic innervation of the hippocampus plays a key role in spatial reference memory processes involved in place navigation.

Animals↗
PubMed2000

Different hippocampal activity profiles for PKA and PKC in spatial discrimination learning.

Protein kinases are considered essential for the processing and storage of information in the brain. However, the dynamics of protein kinase activation in the hippocampus during spatial learning are poorly understood. In this study, rats were trained to learn a holeboard spatial discrinmination task and the activity profiles for cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and Ca2+/ phospholipid-dependent protein kinase C (PKC) in the hippocampus were examined. Hippocampal PKA activity increased rapidly on Day 1 of spatial learning and remained moderately high at later stages of acquisition. In contrast, PKC activity increased in particulate fractions compared with cytosolic fractions after habituation training and was maximal at Day 3 of spatial acquisition. The results establish a temporal dissociation between PKA and PKC during acquisition of spatial discrimination learning.

Animals↗
PubMed2002

Hippocampal lesioned rats are able to learn a spatial position using non-spatial strategies.

In the last two decades, many experiments have demonstrated that the hippocampus plays a role in the learning and processing of spatial and contextual information. Despite these demonstrations, some recent publications have indicated that the hippocampus is not the only structure involved in spatial learning and that even after hippocampal lesions, rats can perform spatial tasks. However, it is not well established whether animals with hippocampal dysfunction still have some spatial learning capacities or develop non-spatial solutions; these may require lengthier acquisition training. We now report the effects of conventional, dorsal hippocampal ablation on rats' performance on the water maze. We tested rats using a short (4 days) versus a long (16 days) acquisition period. We demonstrated that animals with dorsal hippocampal lesions have some residual capacity for learning the localization of a hidden escape platform in a pool during both a reference memory task and a working memory task. The animals with dorsal hippocampal lesions learned to escape at a fixed location, but only with extended training. It is suggested that these animals used non-spatial strategies to compensate for a spatial memory impairment. The results are discussed with respect to the experimental procedure and the strategy applied by the lesioned rats.

Animals↗
PubMed2005

The effect of intrahippocampal injections of ritanserin (5HT2A/2C antagonist) and granisetron (5HT3 antagonist) on learning as assessed in the spatial version of the water maze.

5HT(2A/2C) and 5HT(3) receptors have an important role in cognitive behavior specially in spatial learning and memory but the literature concerning the role of these receptors in hippocampus in cognition remains controversial. In the present study a 5HT(2A/2C) antagonist ritanserin (0, 2, 4, 8 microg/0.5 microl) and a 5HT(3) antagonist granisetron (0.0, 0.05, 0.25, 0.5 microg/0.5 microl) were injected bilaterally into the CA1 region of rat hippocampus, 20 min before each training session in Morris Water Maze (MWM) task. Compare with control group, ritanserin (4 microg/0.5 microl) significantly reduced the escape latency and traveled distance of swimming to platform, but granisetron (0.25 microg/0.5 microl) significantly increased those parameters. Both drugs had no effect on escape latency and traveled distance of a non-spatial visual discrimination task. These results suggest a differential role of 5HT(2A/2C) and 5HT(3) receptors during spatial learning that ritanserin improves rat performance in spatial discrimination task whereas granisetron impairs it.

Analysis of Variance↗
PubMed1997

Cognitive deficits induced by global cerebral ischaemia: prospects for transplant therapy.

Global ischaemia induced by interruption of cerebral blood flow results in damage to vulnerable cells, notably in the CA1 and hilar hippocampal fields, and is frequently associated with memory deficits. This review examines cognitive deficits that occur in animal models of global ischaemia in rats and monkeys, the extent to which these deficits are associated with CA1 cell loss, and the evidence for functional recovery following transplants of foetal CA1 cells and grafts of conditionally immortalised precursor cells. In rats, impairments are seen most consistently in tasks of spatial learning and spatial working memory dependent on use of allocentric environmental cues. In monkeys, ischaemic deficits have been shown to a moderate extent in delayed object recognition tasks, but animals with a selective excitotoxic CA1 lesion show a profound impairment in conditional discrimination tasks, suggesting that these may be a more sensitive measure of ischaemic impairments. Several studies have reported correlational links between the extent of CA1 cell loss following two or four vessel occlusion (2 VO, 4 VO) in rats and behavioural impairments, but recent findings indicate that at intermediate levels of damage these relationships are weak and variable, and emerge clearly only when animals with maximal CA1 cell loss are included, suggesting that the deficits involve more than damage to the CA1 field. Nevertheless, ischaemic rats and CA1-lesioned marmosets with grafts of foetal CA1 cells show substantial improvements; in rats these are not found with grafts from other hippocampal fields. Conditionally immortalised cell lines and trophic grafts are currently being assessed for their functional potential in animal models, because clinical use of foetal cells will not be practicable. Recent findings suggest that an expanded population of neuroepithelial cells derived from the conditionally immortalised H-2Kb-tsA58 transgenic mouse improve spatial learning as effectively as CA1 foetal grafts in rats subjected to 4 VO, and clonal lines from the same source show similar promise. Lines derived from precursor cells have the potential to develop into different types of cell (neuronal or glial) depending on signals from the host brain. These cell lines may therefore have the capacity to repair damaged host circuits more precisely than is possible with foetal grafts, and offer a promising, approach both to functional recovery and to elucidating graft-host interactions.

Animals↗
PubMed2003

Role of the neocortex in the water maze task in the rat: a detailed behavioral and Golgi-Cox analysis.

The role of the neocortex in acquisition of the water maze task was investigated with both detailed behavioral and anatomical analyses. The neocortical areas examined were: (1). primary visual and posterior parietal areas Oc1 and Oc2M, (2). parietal area Par1, and (3). prefrontal areas Cg1, Cg3, IL, and part of Fr2 of Zilles, 1985. In Experiment 1, the effects of lesions in these areas were examined separately in different groups of naive male hooded rats. Additional rats were given water maze strategy pretraining before receiving a lesion. Strategy pretraining was used to separate water maze strategy learning from spatial learning to evaluate the contribution of the neocortical areas to these two components of task acquisition. All groups of naive lesioned rats were impaired in the task. In contrast, corresponding groups of pretrained lesioned rats performed as well as controls on all behavioral measures. In Experiment 2, the same neocortical areas lesioned in Experiment 1 were examined with the Golgi-Cox method to determine whether water maze training was associated with changes in the dendritic arborization of neocortical pyramidal cells. Contrary to expectations, no anatomical changes that could be ascribed to the behavioral training were seen in the areas and cortical layers examined. The data suggest that (1). these areas contribute to water maze strategy learning in naive rats, (2). none of the areas are crucially required for spatial learning provided rats are familiar with the general behavioral strategies required in the task before the lesion is made, and (3). any changes in neuronal morphology that occur as a consequence of the training may be subtle and widely distributed.

Animals↗
PubMed2006

Spatial relational learning in rufous hummingbirds (Selasphorus rufus).

There is increasing evidence that animals can learn abstract spatial relationships, and successfully transfer this knowledge to novel situations. In this study, rufous hummingbirds (Selasphorus rufus) were trained to feed from either the lower or the higher of two flowers. When presented with a test pair of flowers, one of which was at a novel height, they chose the flower in the appropriate spatial position rather than the flower at the correct height. This response may also have been influenced by a preference for taller flowers as acquisition of the task during experimental training occurred more readily when the reward flower was the taller of the pair. Thus, it appears that although learning abstract relationships may be a general phenomenon across contexts, and perhaps across species, the ease with which they are learned and the context in which they are subsequently used may not be the same.

Animals↗
PubMed2002

Effect of visual-spatial ability on learning of spatially-complex surgical skills.

Visual-spatial ability is thought to be important in competency in specific surgical procedures. To test this hypothesis, 37 surgical residents completed six tests of visual-spatial ability, ranging from low-level to high-level visual processing. Using previously validated and objective instruments, we then assessed their ability to complete and learn a spatially-complex surgical procedure. Residents with higher visual-spatial scores in the form-board test and the mental-rotations test did significantly better in the procedure than did those with lower scores. After practice and feedback, residents with lower scores achieved a comparable level of competency. Our results suggest that visual-spatial ability is related to competency and quality of results in complex surgery, and could potentially be used in resident selection, career counselling, and training.

Animals↗
PubMed1993

Selective lesions of neural pathways following viral inoculation of the olfactory bulb.

In the present study, herpes simplex virus type 1 (HSV1) was injected into the olfactory bulb of the rat in order to determine the impact of viral infection on neural pathways, neurotransmitters, and behavior. In many animals, these injections caused considerable neuronal loss in regions that project to the bulb including the primary olfactory cortex and locus coeruleus (LC). Short-term (2-5 days postinjection) studies using immunocytochemical colocalization of virus and transmitter markers showed that cholinergic (ACh) neurons in the horizontal nucleus of the diagonal band, serotonergic (5-HT) neurons in the dorsal and median raphe nuclei, and noradrenergic (NE) neurons in the LC became infected with virus. Almost all NE neurons in the ipsilateral LC were infected while a smaller proportion of 5-HT and ACh neurons in their respective nuclei contained virus. In order to determine long-term effects of viral infection, virus injection into the olfactory bulb was followed by antiviral treatment and sacrifice 17 days to 7 months postinjection. Quantitative analysis of selected cortical regions (olfactory bulb, cingulate cortex, parietal cortex) revealed decreased NE-immunoreactive fibers while 5-HT axons from the dorsal and median raphe nuclei were not significantly affected. No changes in acetylcholinesterase staining in these cortical regions were observed, indicating that cholinergic axons were not significantly changed. Ten of the 36 animals that survived long-term after HSV1 inoculation were also tested in a water maze task before sacrifice to determine if the viral infection was associated with spatial learning deficits. Spatial learning deficits correlated with the degree of primary olfactory cortex damage but not with 5-HT, NE, or ACh axon losses.

Animals↗