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Using the Morris water maze to assess spatial learning and memory in weanling mice.

Barnhart CD, Yang D, Lein PJ - PLoS ONE (2015)

Bottom Line: However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed.While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains.These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.

ABSTRACT
Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

No MeSH data available.


Related in: MedlinePlus

Results of the visual cue test.(A) Escape latency on d 7 of training and during the visual cue test expressed as a percentage of baseline escape latency (escape latency on the first training day). Additional parameters that influence performance in the MWM were assessed during the visual cue test including: (B) mean swim velocity and (C) rest time, both of which are presented as a function of training day. No statistically significant differences were identified using paired t-test (A) or repeated measures ANOVA (B,C).
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pone.0124521.g003: Results of the visual cue test.(A) Escape latency on d 7 of training and during the visual cue test expressed as a percentage of baseline escape latency (escape latency on the first training day). Additional parameters that influence performance in the MWM were assessed during the visual cue test including: (B) mean swim velocity and (C) rest time, both of which are presented as a function of training day. No statistically significant differences were identified using paired t-test (A) or repeated measures ANOVA (B,C).

Mentions: Performance in the MWM is influenced by sensorimotor function and motivation, and these parameters can be assessed using a visual cue test [16]. The visual cue test was administered to weanling mice immediately following the probe test on day 8 of training. Data were normally distributed. T tests and repeated measures two-way ANOVA revealed no significant sex-dependent effects on visual cue parameters, so data from both sexes were combined. Escape latency during the visual cue test was decreased to 46% of the escape latency on the first day of training, which is referred to as the baseline escape latency (Fig 3A). This was a shorter escape latency than observed on d 7 of training, although the difference between escape latency during the visual cue test and training d 7 was not statistically significant by t test (t(28) = 1.31). Mean swim velocity did not change significantly over the course of training and was not significantly different in the visual cue test versus during training (F(6, 90) = 1.79) (Fig 3B). Weanlings spent an average of almost 5 s floating (rest time) during the first day of training. Rest time was reduced after the first day (Fig 3C). However, after correcting for violation of sphericity using the Greenhouse-Geisser correction, this difference was not significant as determined by repeated measures ANOVA (F(2.8, 42.8) = 2.59, ns). Several interesting behavioral phenomena were also observed during the visual cue test, including deflection off of the target (3 out of 16 animals), excessive floating or rest time (3 out of 16 animals), and failure to leave the initial quadrant (2 out of 16 animals).


Using the Morris water maze to assess spatial learning and memory in weanling mice.

Barnhart CD, Yang D, Lein PJ - PLoS ONE (2015)

Results of the visual cue test.(A) Escape latency on d 7 of training and during the visual cue test expressed as a percentage of baseline escape latency (escape latency on the first training day). Additional parameters that influence performance in the MWM were assessed during the visual cue test including: (B) mean swim velocity and (C) rest time, both of which are presented as a function of training day. No statistically significant differences were identified using paired t-test (A) or repeated measures ANOVA (B,C).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401674&req=5

pone.0124521.g003: Results of the visual cue test.(A) Escape latency on d 7 of training and during the visual cue test expressed as a percentage of baseline escape latency (escape latency on the first training day). Additional parameters that influence performance in the MWM were assessed during the visual cue test including: (B) mean swim velocity and (C) rest time, both of which are presented as a function of training day. No statistically significant differences were identified using paired t-test (A) or repeated measures ANOVA (B,C).
Mentions: Performance in the MWM is influenced by sensorimotor function and motivation, and these parameters can be assessed using a visual cue test [16]. The visual cue test was administered to weanling mice immediately following the probe test on day 8 of training. Data were normally distributed. T tests and repeated measures two-way ANOVA revealed no significant sex-dependent effects on visual cue parameters, so data from both sexes were combined. Escape latency during the visual cue test was decreased to 46% of the escape latency on the first day of training, which is referred to as the baseline escape latency (Fig 3A). This was a shorter escape latency than observed on d 7 of training, although the difference between escape latency during the visual cue test and training d 7 was not statistically significant by t test (t(28) = 1.31). Mean swim velocity did not change significantly over the course of training and was not significantly different in the visual cue test versus during training (F(6, 90) = 1.79) (Fig 3B). Weanlings spent an average of almost 5 s floating (rest time) during the first day of training. Rest time was reduced after the first day (Fig 3C). However, after correcting for violation of sphericity using the Greenhouse-Geisser correction, this difference was not significant as determined by repeated measures ANOVA (F(2.8, 42.8) = 2.59, ns). Several interesting behavioral phenomena were also observed during the visual cue test, including deflection off of the target (3 out of 16 animals), excessive floating or rest time (3 out of 16 animals), and failure to leave the initial quadrant (2 out of 16 animals).

Bottom Line: However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed.While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains.These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.

ABSTRACT
Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

No MeSH data available.


Related in: MedlinePlus