Name: t-maze forced alternation and left-right discrimination tasks for assessing working and reference memory in mice
Uploaded: 2012-02-26T14:00:00
Duration: 17 min 45 s
Description: Watch this Scientific Journal Video about T-maze Forced Alternation and Left-right Discrimination Tasks for Assessing Working and Reference Memory in Mice at JoVE.com

We thank Kazuo Nakanishi for his help in developing Image TM program for behavioral analysis. This research was supported by Grant-in-Aid for Exploratory Research (19653081), Grant-in-Aid for Scientific Research (B) (21300121), Grant-in-Aid for Scientific Research on Innovative Areas (Comprehensive Brain Science Network) from the Ministry of Education, Science, Sports and Culture of Japan, grant from Neuroinformatics Japan Center (NIJC), and grants from CREST &amp; BIRD of Japan Science and Technology Agency (JST).

1. Apparatus setting
<ol>
 <li>The automatic modified T-maze apparatus (O&#x2019;HARA &amp; Co., Tokyo, Japan) is constructed of white plastic runways with 25-cm high walls1. The maze is partitioned off into 6 areas (A1, A2, S1, S2, P1, P2) by sliding doors (s1, s2, s3, a1, a2, p1, p2) (Figure 1) that can be automatically opened downward. The stem of the T is composed of area S2 (13 x 24 cm) and the arms of the T comprise areas A1 and A2 (11.5 x 20.5 cm). Areas P1 and P2 comprise the connecting passages from the arm (area A1 or A2) to the start compartment (area S1).</li>
 <li>The end of each arm is equipped with a pellet dispenser that automatically provides a sucrose pellet (20 mg, Formula 5 TUT, TestDiet, Richmond, IN, USA) as a reward. The pellet intake by the mouse is detected by the infrared sensor and is automatically recorded by a computer.</li>
 <li>The Charge Coupled Device (CCD) camera is mounted above the apparatus to monitor the mouse&#x2019;s behavior, and images of the apparatus and mouse are captured by the computer.</li>
 <li>Place the T-maze apparatus in a soundproof room (170 x 210 x 200 cm, O&#x2019;HARA &amp; Co., Tokyo, Japan) as possible. The apparatus is illuminated by fluorescent lights at 100 lux in our laboratory. The light intensity could be weaker than this lux level but should be held at a constant level during all the experiments.</li>
</ol>
2. Animal preparation
<ol>
 <li>House about two to four mice per cage in a temperature-controlled room (23&plusmn;2&deg;C) with a 12-h light/dark cycle (lights on at 7:00 AM), according to guidance and protocols established by local Animal Care and Use Committee.</li>
 <li>Transfer all the cages containing mice into the soundproof room from the housing room at least 30 min before the first trial begins. </li>
 <li>All the experiments should be always performed during the same time period (e.g., 9:00 AM to 6:00 PM). During the testing period, the subjects from each genotype or experimental condition should be tested in counterbalanced order, since there could be a potential effect of the time in a day on the performance of the task.</li>
</ol>


3. Food restriction
<ol>
 <li>Until the beginning of the experiment, give free access to standard pellet chow and water to mice. </li>
 <li>From 1 week before the pre-training sessions, weigh mice daily and feed them with standard pellet chow to maintain 80% to 85% of their free-feeding body weight throughout the experiment.</li>
 <li>Provide daily with eight sucrose pellets per mouse in addition to standard pellet chow in their home cage to habituate to the sucrose pellets until beginning the pre-training sessions.</li>
</ol>
4. Habituation to the apparatus and pre-training
<ol>
 <li>Place six sucrose pellets per mouse into the center of each one of the six compartments of the apparatus, and deposit one pellet into each tray of the food dispensers.</li>
 <li>Place all mice in a cage into the apparatus and allow them to freely explore the apparatus with all doors open for 30 min. </li>
 <li>From 1 day after the habituation, mice are daily subjected to pre-training. With all the doors closed and the pellet deposited in the food tray, place mouse into area A1. If the mouse consumes the pellet or 5 min elapse, transfer the mouse to area A2 and begin pre-training again. Such training is repeated five times a day, and continued until the mice consume more than 80% of the pellets. </li>
 <li>After the pre-training sessions are complete, the mice are subjected to either a forced alternation task or left-right discrimination task.</li>
</ol>
5. Forced alternation task
<ol>
 <li>In the forced alternation task, each trial consists of a forced choice run followed by a free choice run. </li>
 <li>Run the application program (Image TM) for the onset of the task, and place a mouse in the start box (area S1).</li>
 <li>Click the start button, and a forced-choice run starts. In this run, the doors of start box (door s2) and of either area A1 (door a1) or area A2 (door a2) are opened, and a sucrose pellet is automatically delivered to the food tray of the area with the door open. The mouse is allowed to enter the area and to consume the pellet. When the mouse has eaten the pellet, the door near the food tray of the arm that the mouse currently stays (either door p1 or p2) is opened. Then, the mouse approaches the door (either s1 or s3) neighboring the start box, and either the door p1 or p2 is closed and the door s1 (or s3) is opened so that the mouse can return to the start box. If the mouse fails to eat the pellet within 30 sec, the response is recorded as an "Omission Error". Then, the pellet is automatically removed from the food tray and the door of the arm that the mice stayed (either p1 or p2) is opened, and then the mouse can return to the start box.</li>
 <li>Following the forced-choice run, the free-choice run automatically begins. The door s2 and both doors a1 and a2 are opened. The mouse is allowed to choose between the two arms. If the mouse enters the opposite arm that it was forced to choose in the forced-choice run, its response is considered to be "Correct" and the mouse receives a sucrose pellet. If the mouse fails to eat the pellet within 30 sec, the response is recorded as an &#x201C;Omission Error&#x201D;, and the pellet is automatically removed from the food tray. If the mouse goes to the same arm as that visited in the forced-choice task, the mouse is confined within the area for 10 sec as a penalty (&#x201C;Error&#x201D; response). Then, the doors of p1 (or s1) and p2 (or s3) are opened, and the mouse can return to the start box.</li>
 <li>A mouse is subjected to 10 consecutive trials in a session per day (cutoff time, 50 min). Control mice are trained daily to reach a group average of 80% correct response in a session. The group average of correct response is calculated by averaging the % correct responses of each mouse in a session in each group.</li>
 <li>After control and/or experimental mice are trained to the criterion, you can further test the mice in the delayed alternation task by inserting 3-, 10-, 30-, or 60-s delays between the forced-choice and the free-choice runs.</li>
 <li>After each session, return the mice to their home cage, and clean the apparatus with super hypochlorous water (pH 6-7) to prevent a bias based on olfactory cues.</li>
</ol>
6. Left-right discrimination task
<ol>
 <li>In the left-right discrimination task, each mouse is given a free choice run of 10 or 20 trials. A sucrose pellet is always delivered to the food tray of one of the arms, namely, the goal arm. Mice have to learn to enter the goal arm. The location of the goal arm is invariable across trials and sessions, and is counterbalanced across control and experimental mice.</li>
 <li>Run the application program (Image TM) for the onset of the task, and place a mouse into the start box (area S1). </li>
 <li>Click the start button, and a free-choice run starts. In this run, the door s2 and both doors a1 and a2 are opened, and a pellet dispenser automatically delivers a pellet to the food tray of the goal arm. The mouse is allowed to freely choose between the left and right arms. When the mouse enters the goal arm, it is considered a correct response. If the mouse eats the pellet or 30 sec elapse, door p1 (or p2) is opened. When the mouse approaches the start box by passing through the area P1 (or P2), door s1 (or s3) is opened so that the mouse can return to the start box.</li>
 <li>A mouse is usually subjected to 10 to 20 consecutive trials in a session per day (cutoff time, 50 min). Control mice are trained daily to reach a group average of 80% correct response in a session. The group average of correct response is calculated by averaging the % correct responses of each mouse in a session in each group. </li>
 <li>After mice reach the criterion, you can give additional sessions to the mice either to assess retention memory and relearning by inserting a delay of several weeks between the sessions or to assess behavioral flexibility by placing the reward in the opposite, previously unbaited arm (i.e. reversal learning), as necessary. </li>
 <li>After each session, return the mice to their home cage, and clean the apparatus with super hypochlorous water (pH 6-7) to prevent a bias based on olfactory cues.</li>
</ol>
7. Image analysis
<ol>
 <li>Behaviors in the T-maze apparatus are recorded by a video camera attached to a computer and the image is stored in a TIFF format. The application used for acquiring and analyzing the behavioral data (Image TM) is based on the public domain Image J program (developed by Wayne Rasband at the National Institute of Mental Health and available at <a hef="http://rsb.info.nih.gov/ij/">http://rsb.info.nih.gov/ij/</a>), which was modified by Tsuyoshi Miyakawa (available through O'HARA &amp; Co., Tokyo, Japan). </li>
 <li>The Image TM program automatically generates the text files for percentage of correct response, latency (sec) to complete a session, distance traveled during the session, and the number of omission errors in the session. Also, the trace images of a mouse, raw position data, and raw response data (correct, omission, or error) in each run are produced and saved.</li>
</ol>
8. Statistical analysis
Analyze each behavioral data by two-way (EXPERIMENTAL CONDITION (e.g., GENOTYPE) x SESSION or EXPERIMENTAL CONDITION x DELAY) repeated measures analysis of variance. 
9. Representative Results
An example of T-maze performance by &alpha;-CaMKII+/- male mice and their wild-type control littermates (C57BL/6J background) (11-18 weeks old, n=10 per group for forced alternation or left-right discrimination task) is shown in Figures 2-4. Because &alpha;-CaMKII+/- mice exhibit high levels of aggression toward cage mates2,3, both the mutants and control mice were singly housed in a plastic cage (22.7 x 32.3 x 12.7 cm) after weaning. The experiments were approved by the Institutional Animal Care and Use Committee of Fujita Health University.
In forced alternation task, control mice will increasingly learn to make correct choices, and can usually reach the criterion of a mean 80% correct response in about 1 to 2 weeks (Figure 2A). Compared to the control mice, &alpha;-CaMKII+/- mice showed a significantly lower percentage of correct responses (GENOTYPE: F(1,18)=29.04, p&lt;0.0001) and shorter latency (GENOTYPE: F(1,18)=8.88, p=0.008; GENOTYPE x SESSION: F(9,162)=2.24, p=0.0218) and traveled a shorter distance (GENOTYPE: F(1,18)=8.67, p=0.0086; GENOTYPE x SESSION: F(9,162)=3.19, p=0.0014) than control mice (Figure 2A, B, and C). No significant effect of genotype was found in omission errors (Figure 2D). Also, in the delayed alternation task, the correct choice percentages of &alpha;-CaMKII+/- mice were significantly lower than those of wild-type mice at any delay time (GENOTYPE: F(1,18)=38.781, p&lt;0.0001; DELAY: F(3,54)=8.074, p=0.0002; GENOTYPE x DELAY: F(3,54)=0.223, p=0.88; Figure 3). These results indicate that the mutants displayed impaired performance compared to control mice although the mutant mice could perform the task faster than controls, suggesting that &alpha;-CaMKII deficiency induces a working memory deficit.
In the left-right discrimination task, the correct choice percentages of the &alpha;-CaMKII+/- mutants gradually increased across sessions, similar to control mice (Figure 4A). Also, when a 1-month delay was inserted between sessions, there were no significant differences in the percent correct between the mutant and control mice. As in the forced alternation task, &alpha;-CaMKII+/- mutants showed a significantly shorter latency to complete a session (GENOTYPE: F(1,18)=12.12, p=0.0027) and shorter distance traveled in the apparatus during a session (GENOTYPE: F(1,18)=25.08, p&lt;0.0001; GENOTYPE x SESSION: F(15,270)=2.83, p=0.0004) than control mice across the training sessions (Figure 4B and C). These data indicate that &alpha;-CaMKII deficiency dose not affect reference memory as assessed by this task. In the reversal-learning sessions, however, &alpha;-CaMKII+/- mutants showed a significantly lower percentage of correct responses (GENOTYPE: F(1,18)=10.92, p=0.0039; GENOTYPE x SESSION: F(5,90)=5.54, p=0.0002; Figure 4A) and had more omission errors (GENOTYPE: F(1,18)=17.12, p=0.0006; Figure 4D) than control mice. These findings suggest that &alpha;-CaMKII+/- mutant mice have reduced behavioral flexibility.
<img src="/files/ftp_upload/3300/3300fig1.jpg" alt="Figure 1" /> 
Figure 1. (A) T-maze apparatus for forced alternation and left-right discrimination tasks. The figure is cited from Takao et al. (2008). (B) The image was captured by a CCD camera mounted above the apparatus. The T-maze is partitioned off into 6 areas (A1, A2, S1, S2, P1, P2) by sliding doors (s1, s2, s3, a1, a2, p1, p2). (C) Configuration and orientation of the apparatus and extra-maze cues in a soundproof room. Two apparatuses are placed facing in the same direction toward a wall in a soundproof room, and objects, such as a door of the room, fluorescent lights on the ceiling, walls of the room, CCD cameras of the apparatuses, and racks to accommodate mouse cages are set.
<img src="/files/ftp_upload/3300/3300fig2.jpg" alt="Figure 2" /> 
Figure 2. T-maze forced alternation task. Mice received 10 daily trials per session. Data of (A) percentage of correct responses, (B) latency (sec), (C) distance traveled (cm), and (D) number of omission errors represented as means with standard errors for each block of two sessions, and were analyzed by a two-way repeated measures ANOVA. &alpha;-CaMKII+/- mice showed a lower percentage of correct responses (p&lt;0.0001) and a shorter latency (p=0.008), and traveled a shorter distance (p=0.0086) than control mice across sessions.
<img src="/files/ftp_upload/3300/3300fig3.jpg" alt="Figure 3" /> 
Figure 3. T-maze forced alternation task with delays of 3, 10, 30, and 60 sec. Approximately 24 h after the final training session, mice were subjected to five delay sessions. The percentage of correct responses for each delay is represented as means with standard errors, and were analyzed by a two-way repeated measures ANOVA. &alpha;-CaMKII+/- mice showed a lower percentage of correct responses than control mice at any delay time (p&lt;0.0001).
<img src="/files/ftp_upload/3300/3300fig4.jpg" alt="Figure 4" /> 
Figure 4. T-maze left-right discrimination task. Mice received daily 10 or 20 trials in a session. Data of (A) percentage of correct responses, (B) latency (sec), (C) distance traveled (cm), and (D) number of omission errors are represented as means with standard errors for each block of 20 trials, which were analyzed by a two-way repeated measures ANOVA. During the initial training sessions and the relearning sessions 1 month after the last training session, the percentage of correct responses did not significantly differ between &alpha;-CaMKII+/- mutant and control mice. Mutant mice, however, showed a significantly lower percentage of correct responses than control mice during the reversal learning sessions (p=0.0039).

<ol>
	<li>Takao, K., Toyama, K., Nakanishi, K., Hattori, S., Takamura, H., Takeda, M., Miyakawa, T., Hashimoto, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+long-term+memory+retention+and+working+memory+in+sdy+mutant+mice+with+a+deletion+in+Dtnbp1,+a+susceptibility+gene+for+schizophrenia.">Impaired long-term memory retention and working memory in sdy mutant mice with a deletion in Dtnbp1, a susceptibility gene for schizophrenia.</a> Mol. Brain. 1, 11-11 (2008).</li><li>Chen, C., Rainnie, D. G., Greene, R. W., Tonegawa, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+fear+response+and+aggressive+behavior+in+mutant+mice+deficient+for+alpha-calcium-calmodulin+kinase+II.">Abnormal fear response and aggressive behavior in mutant mice deficient for alpha-calcium-calmodulin kinase II.</a> Science. 266, 291-294 (1994).</li><li>Yamasaki, N., Maekawa, M., Kobayashi, K., Kajii, Y., Maeda, J., Soma, M., Takao, K., Tanda, K., Ohira, K., Toyama, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alpha-CaMKII+deficiency+causes+immature+dentate+gyrus,+a+novel+candidate+endophenotype+of+psychiatric+disorders.">Alpha-CaMKII deficiency causes immature dentate gyrus, a novel candidate endophenotype of psychiatric disorders.</a> Mol. Brain. 1, 6-6 (2008).</li><li>Aultman, J. M., Moghaddam, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+contributions+of+glutamate+and+dopamine+receptors+to+temporal+aspects+of+rodent+working+memory+using+a+clinically+relevant+task.">Distinct contributions of glutamate and dopamine receptors to temporal aspects of rodent working memory using a clinically relevant task.</a> Psychopharmacology. 153, 353-364 (2001).</li><li>Papaleo, F., Yang, F., Garcia, S., Chen, J., Lu, B., Crawley, J. N., Weinberger, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dysbindin-1+modulates+prefrontal+cortical+activity+and+schizophrenia-like+behaviors+via+dopamine&#47;D2+pathways.">Dysbindin-1 modulates prefrontal cortical activity and schizophrenia-like behaviors via dopamine&#47;D2 pathways.</a> Molecular Psychiatry. , 1-14 (2010).</li><li>Douglas, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cues+for+spontaneous+alternation.">Cues for spontaneous alternation.</a> J. Comp. Physiol. Psychol. 62, 171-183 (1966).</li><li>Dudchenko, P. A., Davidson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rats+use+a+sense+of+direction+to+alternate+on+T-mazes+located+in+adjacent+rooms.">Rats use a sense of direction to alternate on T-mazes located in adjacent rooms.</a> Anim. Cogn. 5, 115-118 (2002).</li><li>Dudchenko, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+the+tasks+used+to+test+working+memory+in+rodents.">An overview of the tasks used to test working memory in rodents.</a> Neurosci Biobehav. Rev. 28, 699-709 (2004).</li><li>Gerlai, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+continuous+alternation+task+in+T-maze+detects+hippocampal+dysfunction+in+mice:+A+strain+comparison+and+lesion+study.">A new continuous alternation task in T-maze detects hippocampal dysfunction in mice: A strain comparison and lesion study.</a> Behav. Brain. Res. 95, 91-101 (1998).</li><li>Wood, E. R., Dudchenko, P. A., Robitsek, R. J., Eichenbaum, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hippocampal+neurons+encode+information+about+different+types+of+memory+episodes+occurring+in+the+same+location.">Hippocampal neurons encode information about different types of memory episodes occurring in the same location.</a> Neuron. 27, 623-633 (2000).</li><li>Lee, I., Griffin, A. L., Zilli, E. A., Eichenbaum, H., Hasselmo, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gradual+translocation+of+spatial+correlates+of+neuronal+firing+in+the+hippocampus+toward+prospective+reward+locations.">Gradual translocation of spatial correlates of neuronal firing in the hippocampus toward prospective reward locations.</a> Neuron. 51, 639-650 (2006).</li><li>Crabbe, J. C., Wahlsten, D., Dudek, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+of+mouse+behavior:+interactions+with+laboratory+environment.">Genetics of mouse behavior: interactions with laboratory environment.</a> Science. 284, 1670-1672 (1999).</li><li>Wahlsten, D., Metten, P., Phillips, T. J., Boehm, S. L., Burkhart-Kasch, S., Dorow, J., Doerksen, S., Downing, C., Fogarty, J., Rodd-Henricks, K. <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, 283-311 (2003).</li><li>Matsuo, N., Yamasaki, N., Ohira, K., Takao, K., Toyama, K., Eguchi, M., Yamaguchi, S., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+activity+changes+underlying+the+working+memory+deficit+in+alpha-CaMKII+heterozygous+knockout+mice.">Neural activity changes underlying the working memory deficit in alpha-CaMKII heterozygous knockout mice.</a> Front Behav. Neurosci. 3, 20-20 (2009).</li><li>Takao, K., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigating+gene-to-behavior+pathways+in+psychiatric+disorders:+the+use+of+a+comprehensive+behavioral+test+battery+on+genetically+engineered+mice.">Investigating gene-to-behavior pathways in psychiatric disorders: the use of a comprehensive behavioral test battery on genetically engineered mice.</a> Ann. N. Y. Acad. Sci. 1086, 144-159 (2006).</li><li>Takao, K., Yamasaki, N., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+brain-behavior+phenotypying+of+genetically-engineered+mice+on+research+of+neuropsychiatric+disorders.">Impact of brain-behavior phenotypying of genetically-engineered mice on research of neuropsychiatric disorders.</a> Neurosci. Res. 58, 124-132 (2007).</li><li>Ikeda, M., Hikita, T., Taya, S., Uraguchi-Asaki, J., Toyo-oka, K., Wynshaw-Boris, A., Ujike, H., Inada, T., Takao, K., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+YWHAE,+a+gene+encoding+14-3-3epsilon,+as+a+possible+susceptibility+gene+for+schizophrenia.">Identification of YWHAE, a gene encoding 14-3-3epsilon, as a possible susceptibility gene for schizophrenia.</a> Hum. Mol. Genet. 17, 3212-3222 (2008).</li><li>Nakatani, J., Tamada, K., Hatanaka, F., Ise, S., Ohta, H., Inoue, K., Tomonaga, S., Watanabe, Y., Chung, Y. J., Banerjee, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+behavior+in+a+chromosome-engineered+mouse+model+for+human+15q11-13+duplication+seen+in+autism.">Abnormal behavior in a chromosome-engineered mouse model for human 15q11-13 duplication seen in autism.</a> Cell. 137, 1235-1246 (2009).</li><li>Hashimoto-Gotoh, T., Iwabe, N., Tsujimura, A., Takao, K., Miyakawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KF-1+Ubiquitin+Ligase:+An+Anxiety+Suppressor.">KF-1 Ubiquitin Ligase: An Anxiety Suppressor.</a> Front. Neurosci. 3, 15-24 (2009).</li><li>Ohno, M., Hiraoka, Y., Matsuoka, T., Tomimoto, H., Takao, K., Miyakawa, T., Oshima, N., Kiyonari, H., Kimura, T., Kita, T., Nishi, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nardilysin+regulates+axonal+maturation+and+myelination+in+the+central+and+peripheral+nervous+system.">Nardilysin regulates axonal maturation and myelination in the central and peripheral nervous system.</a> Nat. Neurosci. 12, 1506-1513 (2009).</li><li>Tanaka, H., Ma, J., Tanaka, K. F., Takao, K., Komada, M., Tanda, K., Suzuki, A., Ishibashi, T., Baba, H., Isa, T., Shigemoto, R., Ono, K., Miyakawa, T., Ikenaka, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mice+with+altered+myelin+proteolipid+protein+gene+expression+display+cognitive+deficits+accompanied+by+abnormal+neuron-glia+interactions+and+decreased+conduction+velocities.">Mice with altered myelin proteolipid protein gene expression display cognitive deficits accompanied by abnormal neuron-glia interactions and decreased conduction velocities.</a> J. Neurosci. 29, 8363-8371 (2009).</li><li>Sagata, N., Iwaki, A., Aramaki, T., Takao, K., Kura, S., Tsuzuki, T., Kawakami, R., Ito, I., Kitamura, T., Sugiyama, H., Miyakawa, T., Fukumaki, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+behavioural+study+of+GluR4+knockout+mice:+implication+in+cognitive+function.">Comprehensive behavioural study of GluR4 knockout mice: implication in cognitive function.</a> Genes. Brain Behav. 9, 899-909 (2010).</li></ol>

No conflicts of interest declared.

Forced alternation and left-right discrimination tasks using the T-maze are used extensively to assess working and reference memory, respectively, in rodents4,5. In T-maze tasks, it is known that rodents can use different strategies to perform the tasks, based on spatial and non-spatial cues, such as extra-maze cues, configuration of the room cues, orientation of the maze, and so on6,7,8. Orientation of the maze in a room and its stability, absence or presence of polarizing cues in the room, and ability of rodents to see cues in the room may affect strategies. Thus, researchers need to consider configuration and orientation of apparatus and cues in a room in conducting an experiment and an interpretation of behavioral data. In our laboratory, we place two apparatus facing in the same direction toward a wall in a soundproof room and set objects, such as a door of the room, fluorescent lights on the ceiling, walls of the room, CCD cameras of the apparatuses, and racks to accommodate mouse cages, that may serve as extra-maze spatial cues for mice (see Figure 1C).
In many cases, the T-maze tests have been manually conducted by a human experimenter as follows: In each trial, the experimenter places a sucrose pellet on food tray, and opens the guillotine doors of the apparatus to start the test. Then, when a mouse enters either of the arms, the experimenter closes the doors, records the mouse behavior, and transfers the mouse from the arm to the start box by hand. The possible confounding variables of handling interacting with mouse genotype or experimental condition may affect T-maze performance. During the past decade, the modified T-maze test for a continuous alternation task that does not involve manual transfer of the subject from the goal arm back to the start box has been used.9-11 Even when the apparatus, test protocols, and many environmental variables are vigorously equated, standardized behavioral tests do not always produce similar results in the different laboratories12,13. Specific experimenters performing the testing may be unique to each laboratory and can also influence the behavior of mice. In addition, a human experimenter is generally apt to make errors, such as misplacing a sucrose pellet, opening or closing other doors, as well as mistakes in tracking the trial number and timekeeping. To reduce the influence of confounding variables and the occurrence of human errors, we have developed and used the automated T-maze apparatus controlled by a video-tracking system with the Image TM program. The improved T-maze apparatus also has advantages that allow us to use microdialysis, electrophysiology, and optogenetics techniques during T-maze performance because the doors are designed to go down into the floor. Thus, the automated apparatus is a useful tool to facilitate studies of the neurobiology of working and reference memory in rodents.
To enable automatic and successive execution of a series of trials in a session, our protocols have some potential drawbacks. For example, in forced alternation task, the time for the mice to go back to S1 from A1 or A2 could potentially affect their performance. It may not be a serious problem, though, since staying P1 or P2 area itself can be a spatial cue and a long or short stay in either area in a forced-choice run may not change a memory load. Another potential problem is that odor trail made by the mice, instead of spatial working memory, could be used. However, after as a few trials, odor trails could be overwritten multiple times and would become difficult to be utilized as cues. Also, in left-light discrimination task, odor trails may serve as olfactory cues for the mice to find the location of a reward across successive trials. The cues could influence learning and memory process across trials in a session, which may potentially be a problem. However, mice cannot use the odor trail strategy in the very first trial in a session and so the performances of the first trials would serve as an index that is devoid of a potential use of the odor trail strategy.
As shown in the representative results, the percent correct responses of the control C57BL/6J mice gradually increased across sessions in both tasks. The findings confirm that C57BL/6J mice can learn to make correct choices in the modified automatic T-maze. In this study, the mice stayed at around 80% correct choices and not more even after extensive training (see Figure 2A). Considering that they keep showing some omission errors throughout the trainings, their motivation may not be so high for the mice as to reach higher level of performance. In the forced alternation task, &alpha;-CaMKII+/- mice showed a lower percentage of correct responses than control mice. Thus, the mutant mice displayed impaired performance compared to the control mice in this task. This result is consistent with the previous findings obtained in the eight-arm radial maze test2,14, providing further evidence that &alpha;-CaMKII deficiency induces the deficits in working memory and that the forced alternation task in the automated T-maze apparatus accurately detects working memory deficits of the mutant mice. In the left-right discrimination task, the results indicate that &alpha;-CaMKII deficiency dose not affect reference memory. As shown in the results of the reversal-learning sessions, however, &alpha;-CaMKII deficiency may reduce behavioral flexibility. The mutant mice also displayed more omission errors than control mice during the reversal learning sessions. The increase in the number of omission errors could reduce the opportunity to learn which arm is associated with the reward. Therefore, the delayed learning acquisition could be due to the increase in the number of omission errors during the initial sessions, but not to impaired reversal learning. Another possibility is that the mutants could be confused by the change in rules, which might induce errors of omission and interfere with executive function. Thus, to draw a reasonable conclusion, omission errors should be examined as well as correct choice percentage.
The Image TM program generates the additional results for the latency and distance traveled to complete a session as well as the percentage of correct response and the number of omission error. The differences in the latency and distance traveled to complete a session may be interpreted as a difference in locomotor activity level, impulsive tendency to choice the arms, motivation to perform the task, habituation level to the task, different learning strategy and etc. Regarding the representative results, &alpha;-CaMKII+/- mice showed shorter latency and shorter distance traveled than those of the controls. In fact, &alpha; CaMKII+/- mice showed a hyperlocomotor activity compared to the control mice3 and this phenotype could underlie the differences in the indices.
In our laboratory, we have assessed more than 36 strains of genetically engineered mice and wild-type control mice in a T-maze test using the automated apparatus to elucidate the relation between genes, brain, and behavior15,16. We have obtained a large set of raw data of more than 1200 mice, and have reported the data for the T-maze performance in several strains of mutant mice3,16-22. The data of strains already published in the research article are included in the "Mouse Behavioral Phenotype Database" as a public database (URL: <a href="http://www.mouse-phenotype.org/" target="_blank">http://www.mouse-phenotype.org/</a>). Some of the studies demonstrated that mice with mutant Dtnbp11, Nrd120, or Plp121 genes show working memory deficits. Thus, our standardized protocol for the T-maze tasks with the automated apparatus is suitable for detecting genetic effects on memory function between mutant and wild-type control mice. The behavioral test protocols need to be standardized, replicated, and the results compared across laboratories. The improved T-maze apparatus leads to the automation of test procedures, which can contribute to the standardization of protocols used across laboratories. 
As shown in this video article, the current version of the apparatus and program can allow us to test black or agouti mice, but not albino mice. Now, we are producing a modified version of the system to enable albino mice to be tested. The system has an advantage that in vivo microdialysis, in vivo electrophysiology, and optogenetics experiments can be performed during T-maze testing, since the doors are designed to go down under the floor. For instance, some researchers may try to investigate the electrophysiological properties of neurons in hippocampus during the choice of arms although some improvements of the apparatus might be needed to minimize electrical noise from the doors and pellet removal mechanism actuators.
Taken together, T-maze forced alternation and left-right discrimination tasks using the modified automatic apparatus are useful for assessing working and reference memory and behavioral flexibility in mice.

t-maze forced alternation and left-right discrimination tasks for assessing working and reference memory in mice

Forced alternation and left-right discrimination tasks using the T-maze have been widely used to assess working and reference memory, respectively, in rodents. In our laboratory, we evaluated the two types of memory in more than 30 strains of genetically engineered mice using the automated version of this apparatus. Here, we present the modified T-maze apparatus operated by a computer with a video-tracking system and our protocols in a movie format. The T-maze apparatus consists of runways partitioned off by sliding doors that can automatically open downward, each with a start box, a T-shaped alley, two boxes with automatic pellet dispensers at one side of the box, and two L-shaped alleys. Each L-shaped alley is connected to the start box so that mice can return to the start box, which excludes the effects of experimenter handling on mouse behavior. This apparatus also has an advantage that in vivo microdialysis, in vivo electrophysiology, and optogenetics techniques can be performed during T-maze performance because the doors are designed to go down into the floor. In this movie article, we describe T-maze tasks using the automated apparatus and the T-maze performance of &alpha;-CaMKII+/- mice, which are reported to show working memory deficits in the eight-arm radial maze task. Our data indicated that &alpha;-CaMKII+/- mice showed a working memory deficit, but no impairment of reference memory, and are consistent with previous findings using the eight-arm radial maze task, which supports the validity of our protocol. In addition, our data indicate that mutants tended to exhibit reversal learning deficits, suggesting that &alpha;-CaMKII deficiency causes reduced behavioral flexibility. Thus, the T-maze test using the modified automatic apparatus is useful for assessing working and reference memory and behavioral flexibility in mice.

Watch this Scientific Journal Video about T-maze Forced Alternation and Left-right Discrimination Tasks for Assessing Working and Reference Memory in Mice at JoVE.com

T-maze Forced Alternation and Left-right Discrimination Tasks for Assessing Working and Reference Memory in Mice

This article presents the protocol of T-maze tests using a modified automated apparatus for assessing the learning and memory functions in mice.

Forced alternation and left-right discrimination tasks using the T-maze have been widely used to assess working and reference memory, respectively, in ...

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Research

JoVE Journal

Neuroscience

Assessing Burrowing, Nest Construction, and Hoarding in Mice

Deterioration in the ability to perform "Activities of daily living" (ADL) is an early sign of Alzheimer's disease (AD). Preclinical behavioural screening of possible treatments for AD currently largely focuses on cognitive testing, which frequently demands expensive equipment and lots of experimenter time. However, human episodic memory (the most severely affected aspect of memory in AD) is different to rodent memory, which seems to be largely non-episodic. Therefore the present ways of screening for new AD treatments for AD in rodents are intrinsically unlikely to succeed. A new approach to preclinical screening would be to characterise the ADL of mice. Fortuitously, several such assays have recently been developed at Oxford, and here the three most sensitive and well-characterised are presented.
Burrowing was first developed in Oxford13. It evolved from a need to develop a mouse hoarding paradigm. Most published rodent hoarding paradigms required a distant food source to be linked to the home cage by a connecting passage. This would involve modifying the home cage as well as making a mouse-proof connecting passage and food source. So it was considered whether it would be possible to put the food source inside the cage. It was found that if a container was placed on the floor it was emptied by the next morning., The food pellets were, however, simply deposited in a heap at the container entrance, rather than placed in a discrete place away from the container, as might be expected if the mice were truly hoarding them. Close inspection showed that the mice were performing digging ("burrowing") movements, not carrying the pellets in their mouths to a selected place as they would if truly hoarding them.6



Food pellets are not an essential substrate for burrowing; mice will empty tubes filled with sand, gravel, even soiled bedding from their own cage. Moreover, they will empty a full tube even if an empty one is placed next to it8.



Several nesting protocols exist in the literature. The present Oxford one simplifies the procedure and has a well-defined scoring system for nest quality5. 



A hoarding paradigm was later developed in which the mice, rather than hoarding back to the real home cage, were adapted to living in the "home base" of a hoarding apparatus. This home base was connected to a tube made of wire mesh, the distal end of which contained the food source. This arrangement proved to yield good hoarding behaviour, as long as the mice were adapted to living in the "home base" during the day and only allowed to enter the hoarding tube at night.

Burrowing, nesting, and hoarding are species-typical activities that mice readily perform in the laboratory. This article describes how they can be easily and cheaply assessed. These protocols are extremely sensitive to mouse strain, brain lesions and diseases. Moreover they constitute &#x201C;environmental enrichment&#x201D; for the mice, and embody the &#x201C;Refinement&#x201D; aspect of the &#x201C;3 Rs&#x201D;18.

Deterioration in the ability to perform "Activities of daily living" (ADL) is an early sign of Alzheimer's disease (AD). Preclinical behavioural screening ...

Morris Water Maze Test for Learning and Memory Deficits in Alzheimer&#39;s Disease Model Mice

The Morris Water Maze (MWM) was first established by neuroscientist Richard G. Morris in 1981 in order to test hippocampal-dependent learning, including acquisition of spatial memoryand long-term spatial memory 1. The MWM is a relatively simple procedure typically consisting of six day trials, the main advantage being the differentiation between the spatial (hidden-platform) and non-spatial (visible platform) conditions 2-4. In addition, the MWM testing environment reduces odor trail interference 5. This has led the task to be used extensively in the study of the neurobiology and neuropharmacology of spatial learning and memory. The MWM plays an important role in the validation of rodent models for neurocognitive disorders such as Alzheimer&#x2019;s Disease 6, 7. In this protocol we discussed the typical procedure of MWM for testing learning and memory and data analysis commonly used in Alzheimer&#x2019;s disease transgenic model mice.

Morris Water Maze Test for Learning and Memory Deficits in Alzheimer&#039;s Disease Model Mice

The Morris Water Maze is a behavioral task to test hippocampal-dependent learning and memory. It has been widely used in the study of neurobiology, neuropharmacology and neurocognitive disorders in rodent models.

The Morris Water Maze (MWM) was first established by neuroscientist Richard G. Morris in 1981 in order to test hippocampal-dependent learning, including ...

Using Affordable LED Arrays for Photo-Stimulation of Neurons

Standard slice electrophysiology has allowed researchers to probe individual components of neural circuitry by recording electrical responses of single cells in response to electrical or pharmacological manipulations1,2. With the invention of methods to optically control genetically targeted neurons (optogenetics), researchers now have an unprecedented level of control over specific groups of neurons in the standard slice preparation. In particular, photosensitive channelrhodopsin-2 (ChR2) allows researchers to activate neurons with light3,4. By combining careful calibration of LED-based photostimulation of ChR2 with standard slice electrophysiology, we are able to probe with greater detail the role of adult-born interneurons in the olfactory bulb, the first central relay of the olfactory system. Using viral expression of ChR2-YFP specifically in adult-born neurons, we can selectively control young adult-born neurons in a milieu of older and mature neurons. Our optical control uses a simple and inexpensive LED system, and we show how this system can be calibrated to understand how much light is needed to evoke spiking activity in single neurons. Hence, brief flashes of blue light can remotely control the firing pattern of ChR2-transduced newborn cells.

Adult-born neurons expressing ChR2 can be manipulated in slice electrophysiological preparations in order to examine their contribution towards the function of olfactory neural circuits.

Standard slice electrophysiology has allowed researchers to probe individual components of neural circuitry by recording electrical responses of single ...

Selective Viral Transduction of Adult-born Olfactory Neurons for Chronic in vivo Optogenetic Stimulation

Local interneurons are continuously regenerated in the olfactory bulb of adult rodents1-3. In this process, called adult neurogenesis, neural stem cells in the walls of the lateral ventricle give rise to neuroblasts that migrate for several millimeters along the rostral migratory stream (RMS) to reach and incorporate into the olfactory bulb. To study the different steps and the impact of adult-born neuron integration into preexisting olfactory circuits, it is necessary to selectively label and manipulate the activity of this specific population of neurons. The recent development of optogenetic technologies offers the opportunity to use light to precisely activate this specific cohort of neurons without affecting surrounding neurons4,5. Here, we present a series of procedures to virally express Channelrhodopsin2(ChR2)-YFP in a temporally restricted cohort of neuroblasts in the RMS before they reach the olfactory bulb and become adult-born neurons. In addition, we show how to implant and calibrate a miniature LED for chronic in vivo stimulation of ChR2-expressing neurons.

Selective Viral Transduction of Adult-born Olfactory Neurons for Chronic in vivo Optogenetic Stimulation

Adult-born neurons of the olfactory bulb can be optogenetically controlled using Channelrhodopsin2-expressing lentiviral injection in the rostral migratory stream and chronic photostimulation with an implanted miniature LED.

Local interneurons are continuously regenerated in the olfactory bulb of adult rodents1-3. In this process, called adult neurogenesis, neural stem cells ...

The Mouse Forced Swim Test

The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental manipulations that are aimed at rendering or preventing depressive-like states. Mice are placed in an inescapable transparent tank that is filled with water and their escape related mobility behavior is measured. The forced swim test is straightforward to conduct reliably and it requires minimal specialized equipment. Successful implementation of the forced swim test requires adherence to certain procedural details and minimization of unwarranted stress to the mice. In the protocol description and the accompanying video, we explain how to conduct the mouse version of this test with emphasis on potential pitfalls that may be detrimental to interpretation of results and how to avoid them. Additionally, we explain how the behaviors manifested in the test are assessed.

The forced swim test is validated as an experimental approach to assess potential antidepressant efficacy in rodents. Experimental animals are placed in a tank of water and escape-related mobility behavior is quantified. The common procedures for the mouse version of this test are described.

The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental ...

Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution. Here we describe an optical method and a deconvolution algorithm to record neural activity from up to 100 neurons with single-cell and single-spike resolution. This method relies on detection of the transient increases in intracellular somatic calcium concentration associated with suprathreshold electrical spikes (action potentials) in cortical neurons. High temporal resolution of the optical recordings is achieved by a fast random-access scanning technique using acousto-optical deflectors (AODs)1. Two-photon excitation of the calcium-sensitive dye results in high spatial resolution in opaque brain tissue2. Reconstruction of spikes from the fluorescence calcium recordings is achieved by a maximum-likelihood method. Simultaneous electrophysiological and optical recordings indicate that our method reliably detects spikes (&gt;97% spike detection efficiency), has a low rate of false positive spike detection (&lt; 0.003 spikes/sec), and a high temporal precision (about 3 msec) 3. This optical method of spike detection can be used to record neural activity in vitro and in anesthetized animals in vivo3,4.

Understanding the function of the vertebrate central nervous system requires recordings from many neurons because cortical function arises on the level of populations of neurons. Here we describe an optical method to record suprathreshold neural activity with single-cell and single-spike resolution, dithered random-access scanning. This method records somatic fluorescence calcium signals from up to 100 neurons with high temporal resolution. A maximum-likelihood algorithm deconvolves the underlying suprathreshold neural activity from the somatic fluorescence calcium signals. This method reliably detects spikes with high detection efficiency and a low rate of false positives and can be used to study neural populations in vitro and in vivo.

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also ...

Vertical T-maze Choice Assay for Arthropod Response to Odorants

Given the economic importance of insects and arachnids as pests of agricultural crops, urban environments or as vectors of plant and human diseases, various technologies are being developed as control tools. A subset of these tools focuses on modifying the behavior of arthropods by attraction or repulsion. Therefore, arthropods are often the focus of behavioral investigations. Various tools have been developed to measure arthropod behavior, including wind tunnels, flight mills, servospheres, and various types of olfactometers. The purpose of these tools is to measure insect or arachnid response to visual or more often olfactory cues. The vertical T-maze oflactometer described here measures choices performed by insects in response to attractants or repellents. It is a high throughput assay device that takes advantage of the positive phototaxis (attraction to light) and negative geotaxis (tendency to walk or fly upward) exhibited by many arthropods. The olfactometer consists of a 30 cm glass tube that is divided in half with a Teflon strip forming a T-maze. Each half serves as an arm of the olfactometer enabling the test subjects to make a choice between two potential odor fields in assays involving attractants. In assays involving repellents, lack of normal response to known attractants can also be measured as a third variable.

A vertical, T-maze olfactometer is described for assaying the behavioral response of arthropods. The olfactometer allows the experimenter to measure choices performed by test subjects when subjected to two potential odor fields. Both attraction to and repulsion from odorants can be measured with this device.

Given the economic importance of insects and arachnids as pests of agricultural crops, urban environments or as vectors of plant and human diseases, ...

A Human-machine-interface Integrating Low-cost Sensors with a Neuromuscular Electrical Stimulation System for Post-stroke Balance Rehabilitation

A stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow to brain thereby preventing delivery of oxygen and nutrients. About half of the stroke survivors are left with some degree of disability. Innovative methodologies for restorative neurorehabilitation are urgently required to reduce long-term disability. The ability of the nervous system to reorganize its structure, function and connections as a response to intrinsic or extrinsic stimuli is called neuroplasticity. Neuroplasticity is involved in post-stroke functional disturbances, but also in rehabilitation. Beneficial neuroplastic changes may be facilitated with non-invasive electrotherapy, such as neuromuscular electrical stimulation (NMES) and sensory electrical stimulation (SES). NMES involves coordinated electrical stimulation of motor nerves and muscles to activate them with continuous short pulses of electrical current while SES involves stimulation of sensory nerves with electrical current resulting in sensations that vary from barely perceivable to highly unpleasant. Here, active cortical participation in rehabilitation procedures may be facilitated by driving the non-invasive electrotherapy with biosignals (electromyogram (EMG), electroencephalogram (EEG), electrooculogram (EOG)) that represent simultaneous active perception and volitional effort. To achieve this in a resource-poor setting, e.g., in low- and middle-income countries, we present a low-cost human-machine-interface (HMI) by leveraging recent advances in off-the-shelf video game sensor technology. In this paper, we discuss the open-source software interface that integrates low-cost off-the-shelf sensors for visual-auditory biofeedback with non-invasive electrotherapy to assist postural control during balance rehabilitation. We demonstrate the proof-of-concept on healthy volunteers.

A novel low-cost human-machine interface for interactive post-stroke balance rehabilitation system is presented in this article. The system integrates off-the-shelf low-cost sensors towards volitionally driven electrotherapy paradigm. The proof-of-concept software interface is demonstrated on healthy volunteers.

A stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow to brain thereby preventing ...

A Simple and Inexpensive Method for Determining Cold Sensitivity and Adaptation in Mice

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity.
Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 &#176;C to 5 &#176;C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above.
This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

The Cold Plantar Assay (CPA) measures cold responsiveness between 30 &#176;C and 5 &#176;C, and can also measure cold adaptation. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life.  The cold ...

Assessing Spatial Learning and Memory in Small Squamate Reptiles

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, interest in the cognitive processes of nonmodel species, typically within an ecological context, has also become an emerging field of study. In particular, interest in the cognitive processes in reptiles is growing although experimental studies on reptilian cognition are sparse. The few reptilian studies that have experimentally tested for spatial learning and memory have used rodent paradigms modified for use in reptiles. However, ecologically important aspects of the physiology and behavior of this taxonomic group must be taken into account when testing for spatially based cognition. Here, we describe modifications of the dry land Barnes maze and associated testing protocol that can improve performance when probing for spatial learning and memory ability in small squamate reptiles. The described paradigm and procedures were successfully used with male side-blotched lizards (Uta stansburiana), demonstrating that spatial learning and memory can be assessed in this taxonomic group with an ecologically relevant apparatus and protocol.

This paper describes a modification of the Barnes maze, a standard rodent paradigm used to assess spatial memory and learning, for use in small squamate reptiles.

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, ...