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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.


(a) Schematic representation of rat brain sections at three rostrocaudal planes (AP −4.3 mm, LL ± 3.0 mm, DV 1.4 mm from bregma) taken from the atlas of Paxinos and Watson (1997). In stippling, the extension of the area reached by the infusions in the dorsal hippocampus (CA1). (b) Photomicrograph shows the placement of the cannula; the “X” indicates the place corresponding to the area of drug infusion in hippocampus. Scale bar: 1 mm.
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fig3: (a) Schematic representation of rat brain sections at three rostrocaudal planes (AP −4.3 mm, LL ± 3.0 mm, DV 1.4 mm from bregma) taken from the atlas of Paxinos and Watson (1997). In stippling, the extension of the area reached by the infusions in the dorsal hippocampus (CA1). (b) Photomicrograph shows the placement of the cannula; the “X” indicates the place corresponding to the area of drug infusion in hippocampus. Scale bar: 1 mm.

Mentions: To check cannula placement, 24 h after the end of the behavioral procedures, animals were deeply anesthetized and killed by decapitation 15 min later, and histological localization of the infusion sites was established using a binocular magnifying glasses. Coordinates were based on Paxinos and Watson (1997) [18]. Schematic representation of rat brain sections showing the approximated extension of the area (gray) reached by the infusions of 1 μL of methylene blue in the CA1 region of the dorsal hippocampus is shown in Figure 3, which also include a tissue slice showing the position of a cannula. Only data from animals with cannulae located in the intended site were included in the final analysis.


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)

(a) Schematic representation of rat brain sections at three rostrocaudal planes (AP −4.3 mm, LL ± 3.0 mm, DV 1.4 mm from bregma) taken from the atlas of Paxinos and Watson (1997). In stippling, the extension of the area reached by the infusions in the dorsal hippocampus (CA1). (b) Photomicrograph shows the placement of the cannula; the “X” indicates the place corresponding to the area of drug infusion in hippocampus. Scale bar: 1 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4561985&req=5

fig3: (a) Schematic representation of rat brain sections at three rostrocaudal planes (AP −4.3 mm, LL ± 3.0 mm, DV 1.4 mm from bregma) taken from the atlas of Paxinos and Watson (1997). In stippling, the extension of the area reached by the infusions in the dorsal hippocampus (CA1). (b) Photomicrograph shows the placement of the cannula; the “X” indicates the place corresponding to the area of drug infusion in hippocampus. Scale bar: 1 mm.
Mentions: To check cannula placement, 24 h after the end of the behavioral procedures, animals were deeply anesthetized and killed by decapitation 15 min later, and histological localization of the infusion sites was established using a binocular magnifying glasses. Coordinates were based on Paxinos and Watson (1997) [18]. Schematic representation of rat brain sections showing the approximated extension of the area (gray) reached by the infusions of 1 μL of methylene blue in the CA1 region of the dorsal hippocampus is shown in Figure 3, which also include a tissue slice showing the position of a cannula. Only data from animals with cannulae located in the intended site were included in the final analysis.

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.