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Updating stored memory requires adult hippocampal neurogenesis.

Suárez-Pereira I, Carrión ÁM - Sci Rep (2015)

Bottom Line: Indeed, we show that immature neurons were selectively recruited to hippocampal circuits during the updating of stored information.Thus, our data demonstrate a new role for neurogenesis in cognitive processes, adult hippocampal neurogenesis being required for the updating of stored OR memories.These findings suggest that manipulating adult neurogenesis may have a therapeutic application in conditions associated with traumatic stored memory, for example.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, Carretera de Utrera Km 1, 41013 Sevilla, Spain.

ABSTRACT
Adult hippocampal neurogenesis appears to influence hippocampal functions, such as memory formation for example. While adult hippocampal neurogenesis is known to be involved in hippocampal-dependent learning and consolidation processes, the role of such immature neurons in memory reconsolidation, a process involved in the modification of stored memories, remains unclear. Here, using a novel fast X-ray ablation protocol to deplete neurogenic cells, we have found that adult hippocampal neurogenesis is required to update object recognition stored memory more than to reinforce it. Indeed, we show that immature neurons were selectively recruited to hippocampal circuits during the updating of stored information. Thus, our data demonstrate a new role for neurogenesis in cognitive processes, adult hippocampal neurogenesis being required for the updating of stored OR memories. These findings suggest that manipulating adult neurogenesis may have a therapeutic application in conditions associated with traumatic stored memory, for example.

No MeSH data available.


Related in: MedlinePlus

Adult hippocampal neurogenesis is required to update stored ORM.(a) Temporal effect of X-ray irradiation on the immature, doublecortin (DCX) labelled hippocampal cells. (b–d) The effect of depleting adult neurogenesis on reconsolidation. Reconsolidation in sham and irradiated mice was compared in three different circumstances: (b) reactivation without novelty; (c) reactivation with novelty; and (d) no reactivation with or without context exposure. In all cases irradiation was performed 3 days after the OR training. (e) Differential temporal requirements for the maturation of adult immature neurons in ORM reconsolidation. The temporal course of X-irradiation in the ORM studies is shown in the upper panel. (f) The functional role of the hippocampus in PR-LTM retrieval is confirmed by infusion of the TTX/CNQX cocktail (orange shadows). In each graph, the letters A, B and C represent the different objects used; *represent significant differences between the sessions and the training session in the same experimental group; +represent significant differences between the LTM sessions and the reactivation session in the same experimental group; and • represent significant differences between the LTM session of each irradiated group with respect to the sham mice. A symbol, p < 0.05, two symbols, p < 0.01, and three symbols, p < 0.001.
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f1: Adult hippocampal neurogenesis is required to update stored ORM.(a) Temporal effect of X-ray irradiation on the immature, doublecortin (DCX) labelled hippocampal cells. (b–d) The effect of depleting adult neurogenesis on reconsolidation. Reconsolidation in sham and irradiated mice was compared in three different circumstances: (b) reactivation without novelty; (c) reactivation with novelty; and (d) no reactivation with or without context exposure. In all cases irradiation was performed 3 days after the OR training. (e) Differential temporal requirements for the maturation of adult immature neurons in ORM reconsolidation. The temporal course of X-irradiation in the ORM studies is shown in the upper panel. (f) The functional role of the hippocampus in PR-LTM retrieval is confirmed by infusion of the TTX/CNQX cocktail (orange shadows). In each graph, the letters A, B and C represent the different objects used; *represent significant differences between the sessions and the training session in the same experimental group; +represent significant differences between the LTM sessions and the reactivation session in the same experimental group; and • represent significant differences between the LTM session of each irradiated group with respect to the sham mice. A symbol, p < 0.05, two symbols, p < 0.01, and three symbols, p < 0.001.

Mentions: To determine whether adult neurogenesis is required to carry out hippocampal-dependent reconsolidation, we have used a local irradiation method developed previously to rapidly eradicate neurogenesis in vigilant, movement restricted mice8, (Fig. 1a and Fig. S1a). The brain irradiation protocol does not produce collateral effects on mature neurons (Fig. S1b) nor a neuroinflammatory response (Fig. S2), yet it allows us to perform behavioural tests 4–6 hours after irradiation, a time window not accessible with standard methods.


Updating stored memory requires adult hippocampal neurogenesis.

Suárez-Pereira I, Carrión ÁM - Sci Rep (2015)

Adult hippocampal neurogenesis is required to update stored ORM.(a) Temporal effect of X-ray irradiation on the immature, doublecortin (DCX) labelled hippocampal cells. (b–d) The effect of depleting adult neurogenesis on reconsolidation. Reconsolidation in sham and irradiated mice was compared in three different circumstances: (b) reactivation without novelty; (c) reactivation with novelty; and (d) no reactivation with or without context exposure. In all cases irradiation was performed 3 days after the OR training. (e) Differential temporal requirements for the maturation of adult immature neurons in ORM reconsolidation. The temporal course of X-irradiation in the ORM studies is shown in the upper panel. (f) The functional role of the hippocampus in PR-LTM retrieval is confirmed by infusion of the TTX/CNQX cocktail (orange shadows). In each graph, the letters A, B and C represent the different objects used; *represent significant differences between the sessions and the training session in the same experimental group; +represent significant differences between the LTM sessions and the reactivation session in the same experimental group; and • represent significant differences between the LTM session of each irradiated group with respect to the sham mice. A symbol, p < 0.05, two symbols, p < 0.01, and three symbols, p < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566137&req=5

f1: Adult hippocampal neurogenesis is required to update stored ORM.(a) Temporal effect of X-ray irradiation on the immature, doublecortin (DCX) labelled hippocampal cells. (b–d) The effect of depleting adult neurogenesis on reconsolidation. Reconsolidation in sham and irradiated mice was compared in three different circumstances: (b) reactivation without novelty; (c) reactivation with novelty; and (d) no reactivation with or without context exposure. In all cases irradiation was performed 3 days after the OR training. (e) Differential temporal requirements for the maturation of adult immature neurons in ORM reconsolidation. The temporal course of X-irradiation in the ORM studies is shown in the upper panel. (f) The functional role of the hippocampus in PR-LTM retrieval is confirmed by infusion of the TTX/CNQX cocktail (orange shadows). In each graph, the letters A, B and C represent the different objects used; *represent significant differences between the sessions and the training session in the same experimental group; +represent significant differences between the LTM sessions and the reactivation session in the same experimental group; and • represent significant differences between the LTM session of each irradiated group with respect to the sham mice. A symbol, p < 0.05, two symbols, p < 0.01, and three symbols, p < 0.001.
Mentions: To determine whether adult neurogenesis is required to carry out hippocampal-dependent reconsolidation, we have used a local irradiation method developed previously to rapidly eradicate neurogenesis in vigilant, movement restricted mice8, (Fig. 1a and Fig. S1a). The brain irradiation protocol does not produce collateral effects on mature neurons (Fig. S1b) nor a neuroinflammatory response (Fig. S2), yet it allows us to perform behavioural tests 4–6 hours after irradiation, a time window not accessible with standard methods.

Bottom Line: Indeed, we show that immature neurons were selectively recruited to hippocampal circuits during the updating of stored information.Thus, our data demonstrate a new role for neurogenesis in cognitive processes, adult hippocampal neurogenesis being required for the updating of stored OR memories.These findings suggest that manipulating adult neurogenesis may have a therapeutic application in conditions associated with traumatic stored memory, for example.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, Carretera de Utrera Km 1, 41013 Sevilla, Spain.

ABSTRACT
Adult hippocampal neurogenesis appears to influence hippocampal functions, such as memory formation for example. While adult hippocampal neurogenesis is known to be involved in hippocampal-dependent learning and consolidation processes, the role of such immature neurons in memory reconsolidation, a process involved in the modification of stored memories, remains unclear. Here, using a novel fast X-ray ablation protocol to deplete neurogenic cells, we have found that adult hippocampal neurogenesis is required to update object recognition stored memory more than to reinforce it. Indeed, we show that immature neurons were selectively recruited to hippocampal circuits during the updating of stored information. Thus, our data demonstrate a new role for neurogenesis in cognitive processes, adult hippocampal neurogenesis being required for the updating of stored OR memories. These findings suggest that manipulating adult neurogenesis may have a therapeutic application in conditions associated with traumatic stored memory, for example.

No MeSH data available.


Related in: MedlinePlus