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Evidence of Maintenance Tagging in the Hippocampus for the Persistence of Long-Lasting Memory Storage.

Tomaiuolo M, Katche C, Viola H, Medina JH - Neural Plast. (2015)

Bottom Line: Its implication on long-term memory (LTM) formation led to postulate the behavioral tagging mechanism.Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting memory storage.The present results can be explained by a broader version of the behavioral tagging hypothesis and highlight the idea that the durability of a memory trace depends either on late tag mechanisms induced by a training session or on events experienced close in time to this tag.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Celular y Neurociencias "Dr. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, C1121ABG Buenos Aires, Argentina.

ABSTRACT
The synaptic tagging and capture (STC) hypothesis provides a compelling explanation for synaptic specificity and facilitation of long-term potentiation. Its implication on long-term memory (LTM) formation led to postulate the behavioral tagging mechanism. Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting memory storage. The proposed maintenance tagging has several characteristics: (1) the tag is transient and time-dependent; (2) it sets in a late critical time window after an aversive training which induces a short-lasting LTM; (3) exposing rats to a novel environment specifically within this tag time window enables the consolidation to a long-lasting LTM; (4) a familiar environment exploration was not effective; (5) the effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. The present results can be explained by a broader version of the behavioral tagging hypothesis and highlight the idea that the durability of a memory trace depends either on late tag mechanisms induced by a training session or on events experienced close in time to this tag.

No MeSH data available.


Related in: MedlinePlus

The effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. (A1, B1) Schematic representation of the experimental protocol is presented on the top of each panel. (A2) Animals were trained in the IA and exposed to an OF 11 h later. Shortly after exploration, rats were CA1 infused with SCH 23390 (1.5 μg/1 μL per side) or veh. Two other groups of rats were infused with veh or SCH in the absence of OF. Test was performed 7 days after training. (B2) Animals were trained in the IA and 8 h after training they were CA1 infused with antisense (ASO) or missense (MSO) oligonucleotide of arc. 3 h later they were exposed to an OF. Two other groups of rats were infused with MSO or ASO in the absence of OF. Test was performed 7 days after training. Data are presented as mean ± SEM.
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fig4: The effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. (A1, B1) Schematic representation of the experimental protocol is presented on the top of each panel. (A2) Animals were trained in the IA and exposed to an OF 11 h later. Shortly after exploration, rats were CA1 infused with SCH 23390 (1.5 μg/1 μL per side) or veh. Two other groups of rats were infused with veh or SCH in the absence of OF. Test was performed 7 days after training. (B2) Animals were trained in the IA and 8 h after training they were CA1 infused with antisense (ASO) or missense (MSO) oligonucleotide of arc. 3 h later they were exposed to an OF. Two other groups of rats were infused with MSO or ASO in the absence of OF. Test was performed 7 days after training. Data are presented as mean ± SEM.

Mentions: It is well known that the novelty signal processing involved the release of dopamine in the hippocampus from the ventral tegmental area (VTA) [23]. Moreover, novel exploration was suggested to induce D1/D5 protein synthesis-dependent process in the hippocampus [7]. Dopaminergic neurons of the VTA innervate the CA1 region in the hippocampus [24] and these dopaminergic connections also control the late posttraining protein synthesis- and BDNF-dependent persistence of LTM storage via activation of D1/D5 receptor [16, 21]. To study if the promoting effect of novel OF on long-lasting IA LTM was dependent on hippocampal D1/D5 functionality, rats were CA1-infused (Figure 3) with SCH 23390 (1.5 μg/1 μL per side), an antagonist of D1/D5 dopamine receptors, shortly after OF exploration at 11 h after IA training. As shown in Figure 4(a), SCH 23390 blocked IA LTM expression at 7 days (veh versus SCH: P > 0.05, n = 12-13; OF (11 h after IA) veh versus SCH: ∗∗∗P < 0.001, n = 12-13; Newman-Keuls test after ANOVA), indicating that hippocampal D1/D5 receptors are required for novelty-induced promotion of LTM persistence.


Evidence of Maintenance Tagging in the Hippocampus for the Persistence of Long-Lasting Memory Storage.

Tomaiuolo M, Katche C, Viola H, Medina JH - Neural Plast. (2015)

The effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. (A1, B1) Schematic representation of the experimental protocol is presented on the top of each panel. (A2) Animals were trained in the IA and exposed to an OF 11 h later. Shortly after exploration, rats were CA1 infused with SCH 23390 (1.5 μg/1 μL per side) or veh. Two other groups of rats were infused with veh or SCH in the absence of OF. Test was performed 7 days after training. (B2) Animals were trained in the IA and 8 h after training they were CA1 infused with antisense (ASO) or missense (MSO) oligonucleotide of arc. 3 h later they were exposed to an OF. Two other groups of rats were infused with MSO or ASO in the absence of OF. Test was performed 7 days after training. Data are presented as mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4561985&req=5

fig4: The effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. (A1, B1) Schematic representation of the experimental protocol is presented on the top of each panel. (A2) Animals were trained in the IA and exposed to an OF 11 h later. Shortly after exploration, rats were CA1 infused with SCH 23390 (1.5 μg/1 μL per side) or veh. Two other groups of rats were infused with veh or SCH in the absence of OF. Test was performed 7 days after training. (B2) Animals were trained in the IA and 8 h after training they were CA1 infused with antisense (ASO) or missense (MSO) oligonucleotide of arc. 3 h later they were exposed to an OF. Two other groups of rats were infused with MSO or ASO in the absence of OF. Test was performed 7 days after training. Data are presented as mean ± SEM.
Mentions: It is well known that the novelty signal processing involved the release of dopamine in the hippocampus from the ventral tegmental area (VTA) [23]. Moreover, novel exploration was suggested to induce D1/D5 protein synthesis-dependent process in the hippocampus [7]. Dopaminergic neurons of the VTA innervate the CA1 region in the hippocampus [24] and these dopaminergic connections also control the late posttraining protein synthesis- and BDNF-dependent persistence of LTM storage via activation of D1/D5 receptor [16, 21]. To study if the promoting effect of novel OF on long-lasting IA LTM was dependent on hippocampal D1/D5 functionality, rats were CA1-infused (Figure 3) with SCH 23390 (1.5 μg/1 μL per side), an antagonist of D1/D5 dopamine receptors, shortly after OF exploration at 11 h after IA training. As shown in Figure 4(a), SCH 23390 blocked IA LTM expression at 7 days (veh versus SCH: P > 0.05, n = 12-13; OF (11 h after IA) veh versus SCH: ∗∗∗P < 0.001, n = 12-13; Newman-Keuls test after ANOVA), indicating that hippocampal D1/D5 receptors are required for novelty-induced promotion of LTM persistence.

Bottom Line: Its implication on long-term memory (LTM) formation led to postulate the behavioral tagging mechanism.Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting memory storage.The present results can be explained by a broader version of the behavioral tagging hypothesis and highlight the idea that the durability of a memory trace depends either on late tag mechanisms induced by a training session or on events experienced close in time to this tag.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Celular y Neurociencias "Dr. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, C1121ABG Buenos Aires, Argentina.

ABSTRACT
The synaptic tagging and capture (STC) hypothesis provides a compelling explanation for synaptic specificity and facilitation of long-term potentiation. Its implication on long-term memory (LTM) formation led to postulate the behavioral tagging mechanism. Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting memory storage. The proposed maintenance tagging has several characteristics: (1) the tag is transient and time-dependent; (2) it sets in a late critical time window after an aversive training which induces a short-lasting LTM; (3) exposing rats to a novel environment specifically within this tag time window enables the consolidation to a long-lasting LTM; (4) a familiar environment exploration was not effective; (5) the effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. The present results can be explained by a broader version of the behavioral tagging hypothesis and highlight the idea that the durability of a memory trace depends either on late tag mechanisms induced by a training session or on events experienced close in time to this tag.

No MeSH data available.


Related in: MedlinePlus