Enhanced excitability but mature action potential waveforms at mossy fiber terminals of young, adult-born hippocampal neurons in mice

Adult-born granule neurons pass through immature critical periods where they display enhanced somatic excitability and afferent plasticity, which is believed to endow them with unique roles in hippocampal learning and memory. Using patch clamp recordings in mouse hippocampal slices, here we show that young neuron hyper-excitability is also observed at presynaptic mossy fiber terminals onto CA3 pyramidal neurons. However, action potential waveforms mature faster in the bouton than in the soma, suggesting rapid efferent functionality during immature stages. Electrophysiological recordings in murine hippocampal slices show that action potential waveforms mature faster in the bouton than in the soma of adult-born granule neurons

Automated summary

Adult-born granule neurons in the hippocampus exhibit enhanced excitability and plasticity during immature stages, which is believed to contribute to their unique roles in learning and memory. Our findings reveal hyper-excitability in the presynaptic terminals of mossy fibers onto CA3 pyramidal neurons, and suggest rapid functionality in immature neurons. Electrophysiological recordings in mouse hippocampal slices demonstrate faster maturation of action potential waveforms in the presynaptic bouton of adult-born granule neurons compared to the soma.