Limits...
Left-right asymmetry defect in the hippocampal circuitry impairs spatial learning and working memory in iv mice.

Goto K, Kurashima R, Gokan H, Inoue N, Ito I, Watanabe S - PLoS ONE (2010)

Bottom Line: Although left-right (L-R) asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior.To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP) task, respectively.These results suggest that the L-R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory.

View Article: PubMed Central - PubMed

Affiliation: Japan Society for the Promotion of Science, Tokyo, Japan. kgoto@psy.flet.keio.ac.jp

ABSTRACT
Although left-right (L-R) asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior. Previously, we identified structural and functional asymmetries in the circuitry of the mouse hippocampus resulting from the asymmetrical distribution of NMDA receptor GluR ε2 (NR2B) subunits. We further examined the ε2 asymmetry in the inversus viscerum (iv) mouse, which has randomized laterality of internal organs, and found that the iv mouse hippocampus exhibits right isomerism (bilateral right-sidedness) in the synaptic distribution of the ε2 subunit, irrespective of the laterality of visceral organs. To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP) task, respectively. The iv mice improved dry maze performance more slowly than control mice during acquisition, whereas the asymptotic level of performance was similar between the two groups. In the DNMTP task, the iv mice showed poorer accuracy than control mice as the retention interval became longer. These results suggest that the L-R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory.

Show MeSH
Acquisition of the dry maze.(A) Latency to reach the food-baited hole. Here and elsewhere in the legends, error bar shows the standard error of the mean. (B) Distance traveled to reach the food-baited hole.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2984506&req=5

pone-0015468-g003: Acquisition of the dry maze.(A) Latency to reach the food-baited hole. Here and elsewhere in the legends, error bar shows the standard error of the mean. (B) Distance traveled to reach the food-baited hole.

Mentions: During the training trials, both iv/iv and iv/+ mice showed shorter search latency (time to find the baited hole) as the trials proceeded, but iv/iv mice improved performance slower than iv/+ mice (Figure 3A). To examine differences in latency between the groups, we carried out a three-way ANOVA with Group as a between-subject factor and Day and Trial as within-subject factors. During the study trials, the latency became shorter as trials proceeded, within a day as well as across days, in both iv/iv and iv/+ mice, resulting in a significant main effect of Day (F2,40 = 41.62, p<0.001) and Trial (F4,80 = 9.99, p<0.001). The performance approached the asymptotic level toward Day 3, resulting in a significant Day×Trial interaction, F8,160 = 2.37, p<0.05. Although the latency appeared to be shorter in iv/iv than iv/+ mice on Day 1, this tendency was reversed on Day 2, resulted in a significant Group×Day interaction, F2,40 = 3.73, p<0.05. A simple effect for Group×Day interaction was significant only on Day 2, F1,20 = 4.88, p<0.05. Post hoc analysis, using a sequentially rejective test procedure based on Bonferroni inequality, confirmed that iv/iv mice continued to improved their performance up to Day 3 (Day 1 vs. Day 2: t11 = 2.63, p<0.05; Day 1 vs. Day 3: t11 = 4.49, p<0.001; Day 2 vs. Day 3, t11 = 2.75, p<0.05), whereas iv/+ mice reached to the asymptotic level on Day 2 (Day 1 vs. Day 2: t9 = 5.38, p<0.001; Day 1 vs Day 3: t9 = 8.39, p<0.001; Day 2 vs. Day 3: t9 = 0.15, N.S.).


Left-right asymmetry defect in the hippocampal circuitry impairs spatial learning and working memory in iv mice.

Goto K, Kurashima R, Gokan H, Inoue N, Ito I, Watanabe S - PLoS ONE (2010)

Acquisition of the dry maze.(A) Latency to reach the food-baited hole. Here and elsewhere in the legends, error bar shows the standard error of the mean. (B) Distance traveled to reach the food-baited hole.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2984506&req=5

pone-0015468-g003: Acquisition of the dry maze.(A) Latency to reach the food-baited hole. Here and elsewhere in the legends, error bar shows the standard error of the mean. (B) Distance traveled to reach the food-baited hole.
Mentions: During the training trials, both iv/iv and iv/+ mice showed shorter search latency (time to find the baited hole) as the trials proceeded, but iv/iv mice improved performance slower than iv/+ mice (Figure 3A). To examine differences in latency between the groups, we carried out a three-way ANOVA with Group as a between-subject factor and Day and Trial as within-subject factors. During the study trials, the latency became shorter as trials proceeded, within a day as well as across days, in both iv/iv and iv/+ mice, resulting in a significant main effect of Day (F2,40 = 41.62, p<0.001) and Trial (F4,80 = 9.99, p<0.001). The performance approached the asymptotic level toward Day 3, resulting in a significant Day×Trial interaction, F8,160 = 2.37, p<0.05. Although the latency appeared to be shorter in iv/iv than iv/+ mice on Day 1, this tendency was reversed on Day 2, resulted in a significant Group×Day interaction, F2,40 = 3.73, p<0.05. A simple effect for Group×Day interaction was significant only on Day 2, F1,20 = 4.88, p<0.05. Post hoc analysis, using a sequentially rejective test procedure based on Bonferroni inequality, confirmed that iv/iv mice continued to improved their performance up to Day 3 (Day 1 vs. Day 2: t11 = 2.63, p<0.05; Day 1 vs. Day 3: t11 = 4.49, p<0.001; Day 2 vs. Day 3, t11 = 2.75, p<0.05), whereas iv/+ mice reached to the asymptotic level on Day 2 (Day 1 vs. Day 2: t9 = 5.38, p<0.001; Day 1 vs Day 3: t9 = 8.39, p<0.001; Day 2 vs. Day 3: t9 = 0.15, N.S.).

Bottom Line: Although left-right (L-R) asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior.To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP) task, respectively.These results suggest that the L-R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory.

View Article: PubMed Central - PubMed

Affiliation: Japan Society for the Promotion of Science, Tokyo, Japan. kgoto@psy.flet.keio.ac.jp

ABSTRACT
Although left-right (L-R) asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior. Previously, we identified structural and functional asymmetries in the circuitry of the mouse hippocampus resulting from the asymmetrical distribution of NMDA receptor GluR ε2 (NR2B) subunits. We further examined the ε2 asymmetry in the inversus viscerum (iv) mouse, which has randomized laterality of internal organs, and found that the iv mouse hippocampus exhibits right isomerism (bilateral right-sidedness) in the synaptic distribution of the ε2 subunit, irrespective of the laterality of visceral organs. To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP) task, respectively. The iv mice improved dry maze performance more slowly than control mice during acquisition, whereas the asymptotic level of performance was similar between the two groups. In the DNMTP task, the iv mice showed poorer accuracy than control mice as the retention interval became longer. These results suggest that the L-R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory.

Show MeSH