A critical period for enhanced synaptic plasticity in newly generated neurons of the adult brain.

David P Wolfer

David P Wolfer

David P Wolfer

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Using retrovirus-mediated birthdating and labeling, this paper demonstrates that newly formed neurons in the adult mouse dentate gyrus exhibit a period of enhanced long-term potentiation that lasts for 1-1.5 months. Reminiscent of critical period plasticity in the developing nervous system, this enhanced plasticity of adult-born neurons depends on the regulated expression of NR2B-containing NMDA receptors.

René Hen

René Hen

René Hen

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This paper identifies a critical period during the maturation of young hippocampal neurons when they display increased synaptic plasticity. Specifically, the authors show that long-term potentiation (LTP) is maximal in young granule cells when they are 4 to 6 weeks old, and then, as they mature further, they become undistinguishable from old granule cells.

This paper confirms earlier findings by Wojtowicz and colleagues {1} that this increased plasticity is mediated by NR2B-containing NMDA receptors and is also in good agreement with recent findings by Frankland and colleagues {2} who have shown that this 4-6 week critical period coincides with a period during which young hippocampal neurons are preferentially recruited by hippocampal-dependent learning paradigms.

Michael Ehlers

Michael Ehlers

Michael Ehlers

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This study reports that adult-born granule neurons in the hippocampus exhibit a very similar critical period plasticity as neurons in the developing nervous system. Using a combination of retroviral labeling of newborn neurons together with ex vivo slice electrophysiology, the authors find that long-term potentiation (LTP) of medial perforant path synapses onto adult-born dentate gyrus (DG) granule cells (GCs) is increased in amplitude. This enhanced LTP occurs during a short ~2 week period from 4-6 weeks after birth of the new DG GCs, and requires activation of NR2B-containing NMDA receptors, which contribute a larger proportion of synaptic NMDA current on newborn GCs relative to mature GCs. Thus, developmental programs of critical period plasticity and associated alterations in NMDA receptor-mediated transmission and plasticity are recapitulated in new neurons born in the adult mammalian brain.

Y Peng Loh

Y Peng Loh

Y Peng Loh

+ -1 Evaluators

This paper reports an interesting finding that adult brain neurons have a critical period where the neurons show enhanced long-term potentiation with increased potentiation amplitude and decreased induction threshold. By following GFP-labeled newly-born adult dentate granule cells, a critical period of 1-1.5 months was identified and the increased plasticity depended on developmentally regulated synaptic expression of NR2B-containing NMDA receptors. This critical period may be important for mediating experience-induced plasticity and stabilizing mature circuitry.