Name: assessing spatial memory impairment in a mouse model of traumatic brain injury using a radial water tread maze
Uploaded: 2017-07-17T14:00:00
Description: Watch this Scientific Journal Video about Assessing Spatial Memory Impairment in a Mouse Model of Traumatic Brain Injury Using a Radial Water Tread Maze at JoVE.com

This research was supported by the Institute for Translational Health Sciences pilot project grant opportunity (UL1TR000423), the University of Washington Center on Human Development and Disability, and the University of Washington Animal Behavior Core and Brain Imaging Core. We would like to acknowledge Dr. Warren Ladiges for his role in the development and dissemination of the original Radial Water Tread maze design and protocol presented here. We also thank Toby Cole for his assistance with this project.

All procedures and animal handling were conducted in accordance with the animal care guidelines issued by the National Institutes of Health and by the University of Washington Animal Care and Use Committee.
1. Surgery
<ol>
	<li>Anesthetize the mouse at 5% isoflurane in an induction box until unconscious. Confirm anesthesia by a reduction in the breathing rate and the absence of a withdrawal reflex following toe-pinch.</li>
	<li>Maintain anesthesia via nose cone at 2-2.5% throughout surgery. ...

<ol>
	<li>Levin, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurobehavioral+outcome+of+closed+head+injury:+Implications+for+clinical+trials.">Neurobehavioral outcome of closed head injury: Implications for clinical trials.</a> J. Neurotrauma. 12 (4), 601-610 (1995).</li><li>Schretlen, D., Shapiro, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+quantitative+review+of+the+effects+of+traumatic+brain+injury+on+cognitive+functioning.">A quantitative review of the effects of traumatic brain injury on cognitive functioning.</a> Int Rev Psychiatry. 15 (4), 341-349 (2003).</li><li>Cline, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+application+of+a+radial+water+tread+maze+can+distinguish+cognitive+deficits+in+mice+with+traumatic+brain+injury.">Novel application of a radial water tread maze can distinguish cognitive deficits in mice with traumatic brain injury.</a> Brain Res. 1657, 140-147 (2017).</li><li>Ellenbroek, B., Youn, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rodent+models+in+neuroscience+research:+Is+it+a+rat+race?.">Rodent models in neuroscience research: Is it a rat race?.</a> Dis. Model. Mech. 9 (10), 1079-1087 (2016).</li><li>Morris, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developments+of+a+water-maze+procedure+for+studying+spatial+learning+in+the+rat.">Developments of a water-maze procedure for studying spatial learning in the rat.</a> J. Neurosci Methods. 11 (1), 47-60 (1984).</li><li>Barnes, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Memory+deficits+associated+with+senescence:+A+neurophysiological+and+behavioral+study+in+the+rat.">Memory deficits associated with senescence: A neurophysiological and behavioral study in the rat.</a> J. Comp. Physiol. Psych. 93 (1), 74-104 (1979).</li><li>Frick, K., Stillner, E., Berger-Sweeney, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mice+are+not+little+rats:+Species+differences+in+a+one-day+water+maze+task.">Mice are not little rats: Species differences in a one-day water maze task.</a> Neuroreport. 11 (16), 3461-3465 (2000).</li><li>Whishaw, I., Tomie, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Of+Mice+and+Mazes:+Similarities+Between+Mice+and+Rats+on+Dry+Land+But+Not+Water+Mazes.">Of Mice and Mazes: Similarities Between Mice and Rats on Dry Land But Not Water Mazes.</a> Physiol Behav. 60 (5), 1191-1197 (1995).</li><li>Francis, D., Zaharia, M., Shanks, N., Anisman, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress-induced+disturbances+in+Morris+water-maze+performance:+Interstrain+variability.">Stress-induced disturbances in Morris water-maze performance: Interstrain variability.</a> Physiol Behav. 58 (1), 57-65 (1995).</li><li>Wahlsten, D., Rustay, N., Metten, P., Crabbe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+search+of+a+better+mouse+test.">In search of a better mouse test.</a> Trends Neurosci. 26 (3), 132-136 (2003).</li><li>Crawley, , et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+phenotypes+of+inbred+mouse+strains:+implications+and+recommendations+for+molecular+studies.">Behavioral phenotypes of inbred mouse strains: implications and recommendations for molecular studies.</a> Psychopharmacology. (Berl). 132 (2), 107-124 (1997).</li><li>Wahlsten, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+data+from+different+labs:+lessons+from+studies+of+gene-environment+interaction.">Different data from different labs: lessons from studies of gene-environment interaction.</a> J. Neurobiol. 54 (1), 283-311 (2002).</li><li>Rogers, D. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+SHIRPA+and+discriminant+analysis+to+characterise+marked+differences+in+the+behavioural+phenotype+of+six+inbred+mouse+strains.">Use of SHIRPA and discriminant analysis to characterise marked differences in the behavioural phenotype of six inbred mouse strains.</a> Behav Brain Res. 105 (2), 207-217 (1999).</li><li>Wolfer, D. P., Stagljar-Bozicevic, M., Errington, M. L., Lipp, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+Memory+and+Learning+in+Transgenic+Mice:+Fact+or+Artifact?.">Spatial Memory and Learning in Transgenic Mice: Fact or Artifact?.</a> Physiology. 13 (3), 118-123 (1998).</li><li>Koopmans, G., Blokland, A., Vannieuwenhuijzen, P., Prickaerts, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+spatial+learning+abilities+of+mice+in+a+new+circular+maze.">Assessment of spatial learning abilities of mice in a new circular maze.</a> Physiol Behav. 79 (4-5), 683-693 (2003).</li><li>Deacon, R., Rawlins, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+impairments+of+hippocampal-lesioned+mice+in+a+paddling+pool.">Learning impairments of hippocampal-lesioned mice in a paddling pool.</a> Behav Neurosci. 116 (3), 472-478 (2002).</li><li>Pettan-Brewer, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+radial+water+tread+maze+tracks+age-related+cognitive+decline+in+mice.">A novel radial water tread maze tracks age-related cognitive decline in mice.</a> Pathobiol Aging Age Relat Dis. 3, 1-4 (2013).</li><li>Wiley, J., Pettan-Brewer, C., Ladiges, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenylbutyric+acid+reduces+amyloid+plaques+and+rescues+cognitive+behavior+in+AD+transgenic+mice.">Phenylbutyric acid reduces amyloid plaques and rescues cognitive behavior in AD transgenic mice.</a> Aging Cell. 10 (3), 418-428 (2011).</li><li>Enns, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disruption+of+Protein+Kinase+A+in+Mice+Enhances+Healthy+Aging.">Disruption of Protein Kinase A in Mice Enhances Healthy Aging.</a> PLoS ONE. 4 (6), (2009).</li><li>Ivonen, H., Nurminen, L., Harri, M., Tanila, H., Puolivali, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothermia+in+mice+tested+in+Morris+water+maze.">Hypothermia in mice tested in Morris water maze.</a> Behav Brain Res. 141 (2), 207-213 (2003).</li><li>Shultz, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Granulocyte-macrophage+colony-stimulating+factor+is+neuroprotective+in+experimental+traumatic+brain+injury.">Granulocyte-macrophage colony-stimulating factor is neuroprotective in experimental traumatic brain injury.</a> J Neurotrauma. 31 (10), 976-983 (2014).</li></ol>

The RWT maze protocol presented here successfully distinguishes between CCI-induced TBI mice and sham controls, and represents a feasible, mouse-centric, alternative to the MWM and Barnes circular maze. While the results reported here speak only to the use of the RWT maze in a TBI mouse model, this apparatus has been used successfully in aged and transgenic models where stress-induced noncompliance resulting from swim-based testing made using the MWM impractical15,17</...

Memory impairments are among the most common symptoms reported by patients following traumatic brain injury (TBI)1,2. Accurate identification and assessment of analogous memory deficits in animal models of TBI, therefore, are essential to our understanding of this condition and its management. Here, we present a protocol to test spatial memory in a mouse model of TBI using a Radial Water Tread (RWT) maze. This apparatus was previously shown to assess cognitive deficits in mouse models of controlled cortical impact (CCI)-induced TBI3, and represents a potential alternative to rat-validated, swim-based tests of cognition.
The growing diversity and availability of transgenic mouse models has led to a recent increase in the use of mice over rats in scientific research4. Despite this shift, researchers continue to rely on behavioral and cognitive tasks that were originally designed and validated for rat use. The most common tests currently used to assess cognition in mice, the Morris Water Maze (MWM) and the Barnes circular maze, were specifically designed to capitalize on instinctual behaviors found in rats5,6. Considering the genetic, neuroethological, and cognitive differences that exist between these two species4, it is unsurprising that mice consistently underperform on these tasks7,8.
Species-dependent differences in testing ability are particularly concerning in swimming-based cognitive tests, such as the MWM. While both rats and mice are proficient swimmers, researchers have identified several mouse strains that perform remarkably poorly on swimming-based cognitive tasks9,10,11,12,13. Even in wild-type animals, rats generally outperform mice7,8. While this could be interpreted as a species-specific difference in spatial memory, analogous follow-up testing using a dry-land maze revealed no species-dependent differences in cognitive performance8. A number of factors unrelated to cognition could account for this finding, including species-dependent differences in either swimming ability or search strategy. Indeed, factor analysis of mouse-specific search strategies in the MWM show that noncognitive factors (in particular, thigomotaxis and passivity [i.e., floating]) may play a more significant role in MWM performance than spatial learning14.
Here, we demonstrate the use of a cognitive test designed to capitalize on the instinctual behavior of mice, and which does not require swimming, to measure spatial memory impairment in a mouse model of CCI-induced TBI. While the RWT maze (Figure 1A-B) was conceived as a novel hybrid of the MWM and Barnes circular maze, it was specifically designed to take advantage of thigmotactic behavior instinctual to mice15,16. The apparatus consists of a 32 inch diameter galvanized steel tub in which nine evenly spaced exit holes have been bored. The holes are centered 2-1/4 inches above the floor of the tub and are sized to fit commonly available 1-1/2 inch ABS DWV SPG x SJ trap adapters. Eight of the exits are capped from the outside and blinded to a depth of 1 inch with rubber stoppers. The ninth is connected by a 90&#176; acrylonitrile butadiene styrene (ABS) elbow to an opaque plastic box from which the mouse can be easily removed after testing. Over the course of a brief acquisition period, the mouse is trained to use the unique visual cues lining the maze to locate this escape box. During testing, the maze is filled with an inch of cold water (12-14 &#176;C), sufficiently aversive enough to promote escape, but not deep enough that the mouse is required to swim.
The RWT maze represents a low-cost, low-maintenance alternative to the MWM, and has been used successfully in aged and transgenic mice15,17,18,19, and CCI-induced mouse models of TBI3. The protocol outlined here represents a simple and effective method for measuring spatial memory impairment requiring no pre-injury training, and could be easily modified to suit the particular needs of a research laboratory.

<table border="0" cellpadding="0" cellspacing="0" width="937">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:304px;">35 Gal. Hot Dipped Steel Round Tub</td>
			<td style="width:123px;">Home Depot</td>
			<td style="width:344px;">&#160;Internet #206638142</td>
			<td style="width:167px;">Needed: 1</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">1-1/2 in. ABS DWV SPG x SJ Trap Adapter</td>
			<td>Home Depot</td>
			<td>Internet #100344703, Store SKU #188956</td>
			<td>Needed: 9</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">1-3/4 in. x 1-7/16 in. Black Rubber Stopper</td>
			<td>Home Depot</td>
			<td>Internet #100114974 Store SKU #755844</td>
			<td>Needed: 8</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">1-1/2 in. ABS DWV 90 Degree Hub x Hub Elbow</td>
			<td>Home Depot</td>
			<td>Internet #100346663 Store SKU #188603</td>
			<td>Needed: 1</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:304px;">HDX 
			10 Gal. Storage Tote</td>
			<td>Home Depot</td>
			<td>Internet #202523587 Store SKU #258804 Store SO SKU #258804</td>
			<td>Needed: 1</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Impact One Stereotaxic Impactor for CCI</td>
			<td>Leica Biosystems&#160;</td>
			<td>39463920</td>
			<td>Needed: 1</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Vernier Stereotaxic w/ Manual Fine Drive Stereotaxic Instrument for Small Animals</td>
			<td>Leica Biosystems&#160;</td>
			<td>39463001</td>
			<td>Needed: 1</td>
		</tr>
	</tbody>
</table>

assessing spatial memory impairment in a mouse model of traumatic brain injury using a radial water tread maze

Despite the recent increase in use of mouse models in scientific research, researchers continue to use cognitive tasks that were originally designed and validated for rat use. The Radial Water Tread (RWT) maze test of spatial memory (designed specifically for mice and requiring no swimming) has been shown previously to successfully distinguish between controlled cortical impact-induced TBI mice and sham controls. Here, a detailed protocol for this task is presented. The RWT maze capitalizes on the natural tendency of mice to avoid open areas in favor of hugging the sides of an apparatus (thigmotaxis). The walls of the maze are lined with nine escape holes placed above the floor of the apparatus, and mice are trained to use visual cues to locate the escape hole that leads out of the maze. The maze is filled with an inch of cold water, sufficient to motivate escape but not deep enough to require that the mouse swim. The acquisition period takes only four training days, with a test of memory retention on day five and a long-term memory test on day 12. The results reported here suggest that the RWT maze is a feasible alternative to rat-validated, swimming-based cognitive tests in the assessment of spatial memory deficits in mouse models of TBI.

The RWT maze (Figure 1) was used to investigate injury-dependent spatial memory deficits in mice randomly assigned to receive&#160;either controlled cortical impact-induced TBI or sham surgery. The injury was generated using a solenoid-driven cortical impact with a 3 mm convex tip and the following injury parameters: 6 m/s strike velocity, 1 mm depth of penetration, and 200 ms contact time. Mice received cognitive testing starting at 35 days post-surgery, and...

Watch this Scientific Journal Video about Assessing Spatial Memory Impairment in a Mouse Model of Traumatic Brain Injury Using a Radial Water Tread Maze at JoVE.com

Assessing Spatial Memory Impairment in a Mouse Model of Traumatic Brain Injury Using a Radial Water Tread Maze

Here we present a protocol for a mouse-specific test of cognition that does not require swimming. This test can be used to successfully distinguish controlled cortical impact-induced traumatic brain injury mice from sham controls.

Despite the recent increase in use of mouse models in scientific research, researchers continue to use cognitive tasks that were originally designed and ...

The overall goal of this Radial Water Tread Maze protocol is to test spatial memory in a mouse model of traumatic brain injury using a mouse centric cognitive task that does not require swimming. This method can be especially useful for testing cognition in mouse models, where motor deficits and or a lack of motivation makes swimming based cognitive testing protocols such as the Morris Water Maze impractical. Though this method could provide insight into group differences and cognition in a controlled cortical impact model of traumatic brain injury in mice, it can also be useful for measuring cognition in aged, and transgenic mouse models that are known to perform poorly in swimming based tests.On all testing days, perform the following preparatory steps. First, allow the mice to acclimate to the test room, while in their home cages for at least 30 minutes. The round maze features visual cues along the inner walls.The movable escape box positioned at one of nine different exit holes. While the mice acclimate, sanitize the exits and the box using a 70%ethanol spray. Next, fill the maze with roughly one inch of cold water.Keeping the water temperature consistent between trials is very important. So measure accurately, and adjust as needed. Now, position the escape box at one of the nine exit holes.Using a heating source to keep the box warm, ideally using a heating pad. Also, seal the box from light. The escape box should always be dark, warm and relatively odorless.The light source is also likely to be a cue so do not change its position between trials. Remove the test mouse from its cage gently by the tail, and place it in the center of the apparatus. Then immediately start timing how long it takes for the mouse to find the exit.If a mouse climbs into a terminating hole, and does not spontaneously reenter the maze after 20 seconds, do not stop the trial. Instead, guide the mouse back into the center of the maze by hand, and let the mouse complete the trial. If after three minutes, the mouse hasn't exited the maze, score the trial as a failure, and record the time as three minutes.Then by hand, carefully guide the animal along the straightest path to the exit. Once in the escape box, allow the mouse to remain there for one minute. Then transfer it back to its home cage while the maze gets reset.Between trials, thoroughly sanitize the escape box and exits with a 70%ethanol spray to prevent the mouse from using old factory cues to locate the correct escape route. This can be done pretty quickly. Now, repeat the trial on the same mouse twice more for a total of three consecutive trials.Every testing day consists of three trials per mouse. No more, and no less. In addition to sanitizing, drain the maze and refresh the water between testing different mice.Be sure to keep the water temperature between 12 and 14 degrees Celsius. Use containers of ice or colder hot water to adjust the tap water temperature into this range. Between testing days, it is important to make certain that the visual cues in the maze, and in the space surrounding the maze remain consistent.A complete testing regime includes five consecutive testing days all run in the same manner. The fifth day is considered the measure for memory retention. Provided no tests are performed between day six and 11, a test on day 12 can be used to measure long term memory.The radial water maze was used to investigate injury dependence spatial memory deficits in mice receiving either controlled cortical impact induced traumatic brain injury or a sham injury. The TBI surgery is described in detail in the text protocol and in a JoVE article by Romin, Gao and Chen from 2014. Briefly put, the injury was generated using a solenoid driven cortical impact with a three millimeter convex tip.The shams were operated on but impacted by the device. 35 days post surgery, the described testing regime was performed. All the mice passed the criteria test for a desire to escape the maze.So all were included in the analysis. The results show a clear difference between the TBI mice and sham controls. Escape latency was significantly longer for injured mice on the first day of training, and on both of the two memory test days.Thus, the described TBI affected the animal's capacity to learn. After watching this video, you should have a good understanding of how to properly perform cognition testing using a mouse specific test of spatial cognition. Once mastered, this technique can be done in less than 15 minutes per animal if it is performed properly.While attempting this procedure, it is important to remember that the positioning of visual cues and the water temperature must remain consistent across all trials.

assessing-spatial-memory-impairment-mouse-model-traumatic-brain

Research

JoVE Journal

Behavior

Shallow Water (Paddling) Variants of Water Maze Tests in Mice

When Richard Morris devised his water maze in 19817, most behavioral work was done in rats. However, the greater understanding of mouse genetics led to the mouse becoming increasingly important. But researchers found that some strains of mutant mice were prone to problems like passively floating or diving when they were tested in the Morris water maze11. This was unsurprising considering their natural habitat; rats swim naturally (classically, the "sewer rat"), whereas mice evolved in the dry areas of central Asia.
To overcome these problems, it was considered whether shallow water would be a sufficient stimulus to provide escape motivation for mice. This would also avoid the problems of drying the small creatures with a towel and then putting them in a heated recovery chamber to avoid hypothermia, which is a much more serious problem than with rats; the large ratio of surface area to volume of a mouse makes it particularly vulnerable to rapid heat loss.
Another consideration was whether a more natural escape strategy could be used, to facilitate learning. Since animals that fall into water and swim away from the safety of the shore are unlikely to pass on their genes, animals have evolved a natural tendency to swim to the edge of a body of water. The Morris water maze, however, requires them to swim to a hidden platform towards the center of the maze - exactly opposite to their evolved behavior. Therefore the paddling maze should incorporate escape to the edge of the apparatus. This feature, coupled with the use of relatively non-aversive shallow water, embodies the "Refinement" aspect of the "3 Rs" of Russell and Burch8.
Various types of maze design were tried; the common feature was that the water was always shallow (2 cm deep) and escape was via a tube piercing the transparent wall of the apparatus. Other tubes ("false exits") were also placed around the walls but these were blocked off. From the inside of the maze all false exits and the single true exit looked the same. Currently a dodecagonal (12-sided) maze is in use in Oxford, with 12 true/false exits set in the corners. In a recent development a transparent paddling Y-maze has been tested successfully.

Shallow Water Paddling Variants of Water Maze Tests in Mice

Mice can swim, but many strains appear to find this activity stressful. To overcome this problem mazes have been devised where escape from shallow water is used to motivate behaviour. These have been demonstrated to support learning at least as good as the traditional and widely used Morris water maze.

When Richard Morris devised his water maze in 19817, most behavioral work was done in rats. However, the greater understanding of mouse genetics led to ...

Use of an Eight-arm Radial Water Maze to Assess Working and Reference Memory Following Neonatal Brain Injury

Working and reference memory are commonly assessed using the land based radial arm maze.&#160;However, this paradigm requires pretraining, food deprivation, and may introduce scent cue confounds. The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs. Specifically, subjects are required to avoid the arms previously used for escape during each testing day (working memory) as well as avoid the fixed arms, which never contain escape platforms (reference memory). Re-entries into arms that have already been used for escape during a testing session (and thus the escape platform has been removed) and re-entries into reference memory arms are indicative of working memory deficits. Alternatively, first entries into reference memory arms are indicative of reference memory deficits. We used this maze to compare performance of rats with neonatal brain injury and sham controls following induction of hypoxia-ischemia and show significant deficits in both working and reference memory after eleven days of testing. This protocol could be easily modified to examine many other models of learning impairment.

The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs.

Working and reference memory are commonly assessed using the land based radial arm maze.&#160;However, this paradigm requires pretraining, food ...

The Double-H Maze: A Robust Behavioral Test for Learning and Memory in Rodents

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their behavioral flexibility and required memory duration, the number of goals and pathways, and also the overall task complexity. A confounding feature in many of these tasks is the lack of control over the strategy employed by the rodents to reach the goal, e.g., allocentric (declarative-like) or egocentric (procedural) based strategies. The double-H maze is a novel water-escape memory task that addresses this issue, by allowing the experimenter to direct the type of strategy learned during the training period. The double-H maze is a transparent device, which consists of a central alleyway with three arms protruding on both sides, along with an escape platform submerged at the extremity of one of these arms.
Rats can be trained using an allocentric strategy by alternating the start position in the maze in an unpredictable manner (see protocol 1; &#167;4.7), thus requiring them to learn the location of the platform based on the available allothetic cues. Alternatively, an egocentric learning strategy (protocol 2; &#167;4.8) can be employed by releasing the rats from the same position during each trial, until they learn the procedural pattern required to reach the goal. This task has been proven to allow for the formation of stable memory traces.
Memory can be probed following the training period in a misleading probe trial, in which the starting position for the rats alternates. Following an egocentric learning paradigm, rats typically resort to an allocentric-based strategy, but only when their initial view on the extra-maze cues differs markedly from their original position. This task is ideally suited to explore the effects of drugs/perturbations on allocentric/egocentric memory performance, as well as the interactions between these two memory systems.

The goal of this protocol is to investigate spatial cognition in rodents. The double-H water maze is a novel test, which is particularly useful to elucidate the different components of learning, consolidation and memory, as well as the interplay of memory systems.

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their ...

Morris Water Maze Test: Optimization for Mouse Strain and Testing Environment

The Morris water maze (MWM) is a commonly used task to assess hippocampal-dependent spatial learning and memory in transgenic mouse models of disease, including neurocognitive disorders such as Alzheimer&#8217;s disease. However, the background strain of the mouse model used can have a substantial effect on the observed behavioral phenotype, with some strains exhibiting superior learning ability relative to others. To ensure differences between transgene negative and transgene positive mice can be detected, identification of a training procedure sensitive to the background strain is essential. Failure to tailor the MWM protocol to the background strain of the mouse model may lead to under- or over- training, thereby masking group differences in probe trials. Here, a MWM protocol tailored for use with the F1 FVB/N x 129S6 background is described. This is a frequently used background strain to study the age-dependent effects of mutant P301L tau (rTg(TauP301L)4510 mice) on the memory deficits associated with Alzheimer&#8217;s disease. Also described is a strategy to re-optimize, as dictated by the particular testing environment utilized.

This manuscript describes a Morris water maze (MWM) protocol tailored for use with a commonly used mouse model of Alzheimer's disease. The MWM is widely used in transgenic mouse models. Implementation of a procedure sensitive to the background strain of the mouse model is essential for detecting group differences.

 The Morris water maze (MWM) is a commonly used task to assess hippocampal-dependent spatial learning and memory in transgenic mouse models of disease, ...

Detecting Behavioral Deficits in Rats After Traumatic Brain Injury

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, few studies have investigated the long-term effects of injury in rodent models of TBI. Shown here are behavioral measures that are well-established in TBI research for times early after injury, such as two weeks, until two months. Some of these methods have previously been used at later times after injury, up to one year, but by very few laboratories. The methods demonstrated here are a short neurological assessment to test reflexes, a Beam-Balance to test balance, a Beam-Walk to test balance and motor coordination, and a working memory version of the Morris water maze that can be sensitive to deficits in reference memory. Male rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid percussion injury (FPI) or sham injury. Rats can be tested on the short neurological assessment (neuroscore), the beam-balance, and the Beam-Walk multiple times, while testing on the water maze can only be done once. This difference is because rats can remember the task, thus confounding the results if repeated testing is attempted in the same animal. When testing from one to three days after injury, significant differences are detected in all three non-cognitive tasks. However, differences in the Beam-Walk task were not detectable at later time points (after 3 months). Deficits were detected at 3 months in the Beam-Balance and at 6 months in the neuroscore. Deficits in working memory were detected out to 12 months after injury, and a deficit in a reference memory first appeared at 12 months. Thus, standard behavioral tests can be useful measures of persistent behavioral deficits after FPI.

The goal of the behavioral tests presented here is to detect functional deficits in rats after traumatic brain injury. Four specific tests are presented that detect deficits in behaviors to reflect the damage to specific brain areas at times extending to one year after injury.

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, ...

Stress-Enhanced Fear Learning, a Robust Rodent Model of Post-Traumatic Stress Disorder

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders such as post-traumatic stress disorder (PTSD). To understand the biological mechanisms of fear dysregulation in PTSD, it is important to start with a valid animal model of the disorder. This protocol describes the methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of PTSD, in both rats and mice. SEFL was developed to recapitulate critical aspects of PTSD, including long-term sensitization of fear learning caused by an acute stressor. SEFL uses aspects of Pavlovian fear conditioning but produces a distinct and robust sensitized fear response far greater than normal conditional fear responses. The trauma procedure involves placing a rodent in a conditioning chamber and administering 15 unsignaled shocks randomly distributed over 90 minutes (for rat experiments; for mouse experiments, 10 unsignaled shocks randomly distributed over 60 minutes are used). On day 2, rodents are placed in a novel conditioning context where they receive a single shock; then, on day 3 they are placed back in the same context as on day 2 and tested for changes in freezing levels. Rodents that previously received the trauma display enhanced levels of freezing on the test day compared to those that received no shocks on the first day. Thus, with this model, a single highly stressful experience (the trauma) produces extreme fear of the stimuli associated with the traumatic event.

Here we describe the detailed methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of post-traumatic stress disorder, in both rats and mice. The model utilizes aspects of Pavlovian fear conditioning and freezing as an index of enhanced fear in rodents.

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders ...

Novel Object Recognition and Object Location Behavioral Testing in Mice on a Budget

Ethologically relevant behavioral testing is a critical component of any study that uses mouse models to study the cognitive effects of various physiological or pathological changes. The object location task (OLT) and the novel object recognition task (NORT) are two effective behavioral tasks commonly used to reveal the function and relative health of specific brain regions involved in memory. While both of these tests exploit the inherent preference of mice for the novelty to reveal memory for previously encountered objects, the OLT primarily evaluates spatial learning, which relies heavily on hippocampal activity. The NORT, in contrast, evaluates non-spatial learning of object identity, which relies on multiple brain regions. Both tasks require an open-field-testing arena, objects with equivalent intrinsic value to mice, appropriate environmental cues, and video recording equipment and the software. Commercially available systems, while convenient, can be costly. This manuscript details a simple, cost-effective method for building the arenas and setting up the equipment necessary to perform the OLT and NORT. Furthermore, the manuscript describes an efficient testing protocol that incorporates both OLT and NORT and provides typical methods for data acquisition and analysis, as well as representative results. Successful completion of these tests can provide valuable insight into the memory function of various mouse model systems and appraise the underlying neural regions that support these functions.

Here we provide a protocol which includes comprehensive instructions for the economical establishment of murine object location and novel object recognition behavioral testing, including the design, cost, and construction of required equipment as well as execution of behavioral testing, data collection, and analysis.

Ethologically relevant behavioral testing is a critical component of any study that uses mouse models to study the cognitive effects of various ...

Analysis of Learning and Memory Ability in an Alzheimer's Disease Mouse Model using the Morris Water Maze

A Morris water maze (MWM) experiment forces experimental animals to swim and learn to find a platform hidden in the water. It is widely used in scientific research to assess the learning and memory of animals. Due to the extensive use of the MWM test, visual experimental protocols are essential for researchers. This manuscript uses the latest studies to introduce the protocol of the MWM test. Alzheimer&#8217; Disease (AD) is characterized by a progressive loss of memory and cognitive function. An alternative and complementary treatment used for AD is Manual Acupuncture (MA). To assess the learning and memory ability of AD model mice, the MWM test was conducted. The visible platform trial, hidden platform trial, probe trial, and reversal trial of MWM were used to evaluate spatial learning and memory ability. In the visible platform trial, the swimming speed and escape latency of mice in different groups was not significantly different. In the hidden platform and reversal trials, the AD group showed a long escape latency. The escape latency decreased significantly after the MA treatment. Low platform crossover number and the proportion of time in the SW quadrant in the probe trial increased after the MA treatment (p &#60; 0.05 or p &#60; 0.01). The results of the MWM tests suggest that MA can effectively improve the spatial learning and memory abilities of AD model mice. Rigorous experimental operations provided assurance of the reliability of the results.

Analysis of Learning and Memory Ability in an Alzheimer&#039;s Disease Mouse Model using the Morris Water Maze

Herein, a protocol to conduct the Morris water maze tests to evaluate the ability of learning and memory of Alzheimer&#8217;s Disease model mice and to assess the effect of manual acupuncture for treating them is described.

A Morris water maze (MWM) experiment forces experimental animals to swim and learn to find a platform hidden in the water. It is widely used in scientific ...

Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of acquired epilepsy. TBI can result in a focal or diffuse brain injury. Focal injury is a result of direct mechanical forces, sometimes penetrating through the cranium, creating a direct lesion in the brain tissue. These are visible during brain imaging as areas with contusion, laceration, and hemorrhage. Focal lesions induce neuronal death and glial scar formation and are present in 20%&minus;25% of all people who incur a TBI. However, in the majority of TBI cases, injury is caused by acceleration-deceleration forces and subsequent tissue shearing, resulting in nonfocal, diffuse damage. A subpopulation of TBI patients continues to develop post-traumatic epilepsy (PTE) after a latency period of months or years. Currently, it is impossible to predict which patients will develop PTE, and seizures in PTE patients are challenging to control, necessitating further research. Until recently, the field was limited to only two animal/rodent models with validated spontaneous post-traumatic seizures, both presenting with large focal lesions with massive tissue loss in the cortex and sometimes subcortical structures. In contrast to these approaches, it was determined that diffuse TBI induced using a modified weight drop model is sufficient to initiate development of spontaneous convulsive and non-convulsive seizures, even in the absence of focal lesions or tissue loss. Similar to human patients with acquired post-traumatic epilepsy, this model presents with a latency period after injury before seizure onset. In this protocol, the community will be provided with a new model of post-traumatic epilepsy, detailing how to induce diffuse non-lesional TBI followed by continuous long-term video-electroencephalographic animal monitoring over the course of several months. This protocol will detail animal handling, the weight drop procedure, the electrode placement for two acquisition systems, and the frequent challenges encountered during each of the steps of surgery, postoperative monitoring, and data acquisition.

This systematic protocol describes a new animal model of post-traumatic epilepsy after repetitive mild traumatic brain injury. The first part details steps for traumatic brain injury induction using a modified weight drop model. The second part provides instructions on the surgical approach for single- and multi-channel electroencephalographic data acquisition systems.

Traumatic brain injury (TBI) is a leading cause of acquired epilepsy. TBI can result in a focal or diffuse brain injury. Focal injury is a result of ...

Utilizing a Reconfigurable Maze System to Enhance the Reproducibility of Spatial Navigation Tests in Rodents

Several maze shapes are used to test spatial navigation performance and behavioral phenotypes. Traditionally, each experiment requires a unique maze shape, thus requiring several separate mazes in different configurations. The maze geometry cannot be reconfigured in a single environment to accommodate scalability and reproducibility. The reconfigurable maze is a unique approach to address the limitations, allowing quick and flexible configurations of maze pathways in a repeatable manner. It consists of interlocking pathways and includes feeders, treadmills, movable walls, and shut-off sensors. The current protocol describes how the reconfigurable maze can replicate existing mazes, including the T-shaped, plus-shaped, W-shaped, and figure-eight mazes. Initially, the T-shaped maze was constructed inside a single experimental room, followed by modifications. The rapid and scalable protocol outlined herein demonstrates the flexibility of the reconfigurable maze, achieved through the addition of components and behavioral training phases in a stepwise manner. The reconfigurable maze systematically and precisely assesses the performance of multiple aspects of spatial navigation behavior.

The present protocol describes a reconfigurable maze, a unique system for testing spatial navigation and behavioral phenotypes in rodents. The adaptability of this maze system enables the execution of various experiments in a single physical environment. The ease of structural rearrangement generates reliable and reproducible experimental results.

Several maze shapes are used to test spatial navigation performance and behavioral phenotypes. Traditionally, each experiment requires a unique maze ...