scholarly journals Effects of Early Training and Nicotine Treatment on the Performance of Male NMRI Mice in the Water Maze

2003 ◽  
Vol 10 (4) ◽  
pp. 303-317 ◽  
Author(s):  
Paloma Vicens ◽  
M. Carmen Carrasco ◽  
Rosa Redolat
Keyword(s):  
Spatial Learning ◽  
Water Maze ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Nicotine Treatment ◽  
Age Related ◽  
Spatial Reference Memory ◽  
First Time ◽  
Early Training

This research aimed to evaluate the effect of nicotine treatment and prior training on a spatial learning task in differently aged NMRI male mice. In a longitudinal study, mice were randomly assigned to one of 14 experimental groups receiving different combinations of chronically injected nicotine (0.35 mg/kg) administered for 10 days (5 days before and during 5 days acquisition of task) or control treatments and training in the water maze at different ages. The mice displayed shorter escape latencies when evaluated at 6 and 10 months than when tested in this task at 2 months for the first time, demonstrating that early training preserves performance in the water maze up to 8 months after the initial experience. Nicotine treatment did not significantly change performance in the water maze at any age tested. Early practice in a spatial reference memory task appears to have lasting consequences and can potentially contribute to preventing some age-related spatial learning deficits.

Bilateral peripheral vestibular lesions produce long-term changes in spatial learning in the rat

2003 ◽  
Vol 13 (1) ◽  
pp. 9-16
Author(s):  
Noah A. Russell ◽  
Arata Horii ◽  
Paul F. Smith ◽  
Cynthia L. Darlington ◽  
David K. Bilkey
Keyword(s):  
Spatial Learning ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Maze Learning ◽  
Vestibular Information ◽  
Spatial Reference Memory ◽  
Long Term Changes ◽  
Control Lesion

In order to investigate whether bilateral peripheral vestibular lesions cause long-term impairment of spatial learning, rats were tested in a reference memory radial arm maze learning task at least 5 weeks following a bilateral labyrinthectomy (BL) or sham control lesion. All control rats reached criterion (i.e., 1 error or less, averaged across 7 trials for 3 consecutive days of training) but only 4 of the 8 BL rats had reached criterion by day 21 of the training sessions. The control rats reached criterion more quickly than the lesioned rats (Control, 7.0 ± 0.63 days, Lesioned, 15.8 ± 1.4 days, t 10 = 5.84, p < 0.0001). This difference resulted from the greater number of errors made by the BL animals. However, the latency to respond was comparable as a result of the increased locomotor activity of the BL group (i.e., ’hyperkinesis), and the overall rate of acquisition of the task, as indicated by analysis of the exponential decrease in errors over the entire training period, was not significantly different between the 2 groups. The results of this study demonstrate that BL in rats produces long-term changes in performance in a spatial reference memory task, which are not simply due to the inability to move but may relate to the way that the brain uses vestibular information to create spatial representations and determines behavioural strategies on the basis of these representations.

scholarly journals Dentate spikes and learning: disrupting hippocampal function during memory consolidation can improve pattern separation

2019 ◽  
Vol 121 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Sanna Lensu ◽  
Tomi Waselius ◽  
Markku Penttonen ◽  
Miriam S. Nokia
Keyword(s):  
Associative Learning ◽  
Memory Consolidation ◽  
Memory Task ◽  
Reference Memory ◽  
Learning Task ◽  
Pattern Separation ◽  
Spatial Reference ◽  
Neural Representations ◽  
Spatial Reference Memory ◽  
Reference Memory Task

Hippocampal dentate spikes (DSs) are short-duration, large-amplitude fluctuations in hilar local field potentials and take place while resting and sleeping. During DSs, dentate gyrus granule cells increase firing while CA1 pyramidal cells decrease firing. Recent findings suggest DSs play a significant role in memory consolidation after training on a hippocampus-dependent, nonspatial associative learning task. Here, we aimed to find out whether DSs are important in other types of hippocampus-dependent learning tasks as well. To this end, we trained adult male Sprague-Dawley rats in a spatial reference memory task, a fixed interval task, and a pattern separation task. During a rest period immediately after each training session, we either let neural activity to take place as usual, timed electrical stimulation of the ventral hippocampal commissure (vHC) to immediately follow DSs, or applied the vHC stimulation during a random neural state. We found no effect of vHC stimulation on performance in the spatial reference memory task or in the fixed interval task. Surprisingly, vHC stimulation, especially contingent on DSs, improved performance in the pattern separation task. In conclusion, the behavioral relevance of hippocampal processing and DSs seems to depend on the task at hand. It could be that in an intact brain, offline memory consolidation by default involves associating neural representations of temporally separate but related events. In some cases this might be beneficial for adaptive behavior in the future (associative learning), while in other cases it might not (pattern separation). NEW & NOTEWORTHY The behavioral relevance of dentate spikes seems to depend on the learning task at hand. We suggest that dentate spikes are related to associating neural representations of temporally separate but related events within the dentate gyrus. In some cases this might be beneficial for adaptive behavior in the future (associative learning), while in other cases it might not (pattern separation).

Effects of Intraventricular Encapsulated Hngf-Secreting Fibroblasts in Aged Rats

1996 ◽  
Vol 5 (2) ◽  
pp. 205-223 ◽  
Author(s):  
Mark D. Lindner ◽  
Cristin E. Kearns ◽  
Shelley R. Winn ◽  
Beata Frydel ◽  
Dwaine F. Emerich
Keyword(s):  
Morris Water Maze ◽  
Basal Forebrain ◽  
Water Maze ◽  
Genetically Modified ◽  
Learning Task ◽  
Activity Levels ◽  
Aged Rats ◽  
Semipermeable Membranes ◽  
Age Related ◽  
Forebrain Neurons

Exogenous NGF administered into the central nervous system (CNS) has been reported to improve cognitive function in aged rats. However, concerns have been expressed about the risks involved with supplying NGF to the CNS. In this study, baby hamster kidney cells (BHK) genetically modified to secrete human NGF (hNGF) were encapsulated in semipermeable membranes and implanted intraventricularly. ChAT/LNGFR-positive basal forebrain neurons were shown to atrophy and degenerate with age, especially in cognitively impaired rats. The encapsulated BHK-NGF cells produced less than 10% of doses previously reported to be effective, but this was sufficient to increase the size of ChAT/LNGFR-positive basal forebrain neurons in the aged and learning-impaired rats to the size of the neurons in young healthy rats. The hNGF from these encapsulated cells also improved performance in a repeated-acquisition version of the Morris water maze spatial learning task in learning-impaired 20.6- and 26.7- mo-old rats. Furthermore, there was no evidence that these doses of hNGF impaired Morris water maze performance in the youngest 3.3-5.4 mo rats, and analyses of mortality rates, body weights, somatosensory thresholds, potential hyperalgesia, and activity levels, suggested that these levels of exogenous hNGF are not toxic or harmful to aged rats. These results suggest that CNS-implanted semipermeable membranes, containing genetically modified xenogeneic cells continuously producing these levels of hNGF, attenuate age-related cognitive deficits in nonimmunosuppressed aged rats, and that both the surgical implantation procedure and long-term exposure to low doses of hNGF appear safe in aged rats.

Intracranial self-stimulation facilitates a spatial learning and memory task in the Morris water maze

Neuroscience ◽  
2008 ◽  
Vol 154 (2) ◽  
pp. 424-430 ◽  
Author(s):  
J. Ruiz-Medina ◽  
I. Morgado-Bernal ◽  
D. Redolar-Ripoll ◽  
L. Aldavert-Vera ◽  
P. Segura-Torres
Keyword(s):  
Learning And Memory ◽  
Morris Water Maze ◽  
Spatial Learning ◽  
Water Maze ◽  
Memory Task ◽  
Spatial Learning And Memory ◽  
Self Stimulation

scholarly journals Age-related declines in a two-day reference memory task are associated with changes in NMDA receptor subunits in mice

2007 ◽  
Vol 8 (1) ◽  
Author(s):  
Kathy R Magnusson ◽  
Brandi Scruggs ◽  
Xue Zhao ◽  
Rebecca Hammersmark
Keyword(s):  
Nmda Receptor ◽  
Memory Task ◽  
Reference Memory ◽  
Nmda Receptor Subunits ◽  
Age Related ◽  
Reference Memory Task

scholarly journals Hippocampal synaptic plasticity: role in spatial learning or the automatic recording of attended experience?

1997 ◽  
Vol 352 (1360) ◽  
pp. 1489-1503 ◽  
Author(s):  
R. G. M. Morris ◽  
U. Frey
Keyword(s):  
Synaptic Plasticity ◽  
Nmda Receptor ◽  
Spatial Learning ◽  
Memory Task ◽  
Learning Rule ◽  
Nmda Antagonist ◽  
Long Term Potentiation ◽  
Reference Memory ◽  
Automatic Recording ◽  
Dependent Manner

Allocentric spatial learning can sometimes occur in one trial. The incorporation of information into a spatial representation may, therefore, obey a one–trial correlational learning rule rather than a multi–trial error–correcting rule. It has been suggested that physiological implementation of such a rule could be mediated by N –methyl–D–aspartate (NMDA) receptor–dependent long–term potentiation (LTP) in the hippocampus, as its induction obeys a correlational type of synaptic learning rule. Support for this idea came originally from the finding that intracerebral infusion of the NMDA antagonist AP5 impairs spatial learning, but studies summarized in the first part of this paper have called it into question. First, rats previously given experience of spatial learning in a watermaze can learn a new spatial reference memory task at a normal rate despite an appreciable NMDA receptor blockade. Second, the classical phenomenon of ‘blocking’ occurs in spatial learning. The latter finding implies that spatial learning can also be sensitive to an animal's expectations about reward and so depend on more than the detection of simple spatial correlations. In this paper a new hypothesis is proposed about the function of hippocampal LTP. This hypothesis retains the idea that LTP subserves rapid one–trial memory, but abandons the notion that it serves any specific role in the geometric aspects of spatial learning. It is suggested that LTP participates in the ‘automatic recording of attended experience’: a subsystem of episodic memory in which events are temporarily remembered in association with the contexts in which they occur. An automatic correlational form of synaptic plasticity is ideally suited to the online registration of context–event associations. In support, it is reported that the ability of rats to remember the most recent place they have visited in a familiar environment is exquisitely sensitive to AP5 in a delay–dependent manner. Moreover, new studies of the lasting persistence of NMDA–dependent LTP, known to require protein synthesis, point to intracellular mechanisms that enable transient synaptic changes to be stabilized if they occur in close temporal proximity to important events. This new property of hippocampal LTP is a desirable characteristic of an event memory system.

scholarly journals The application of a rodent-based Morris water maze (MWM) protocol to an investigation of age-related differences in human spatial learning.

2017 ◽  
Vol 131 (6) ◽  
pp. 470-482 ◽  
Author(s):  
Jimmy Y. Zhong ◽  
Kathy R. Magnusson ◽  
Matthew E. Swarts ◽  
Cherita A. Clendinen ◽  
Nadjalisse C. Reynolds ◽  
...  
Keyword(s):  
Morris Water Maze ◽  
Spatial Learning ◽  
Water Maze ◽  
Age Related
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