Single granule cells reliably discharge targets in the hippocampal CA3 network in vivo


Processing of neuronal information depends on interactions between the anatomical connectivity and cellular properties of single cells. We examined how these computational building blocks work together in the intact rat hippocampus. Single spikes in dentate granule cells, controlled intracellularly, generally failed to discharge either interneurons or CA3 pyramidal cells. In contrast, trains of spikes effectively discharged both CA3 cell types. Increasing the discharge rate of the granule cell increased the discharge probability of its target neuron and decreased the delay between the onset of a granule cell train and evoked firing in postsynaptic targets. Thus, we conclude that the granule cell to CA3 synapses are 'conditional detonators,' dependent on granule cell firing pattern. In addition, we suggest that information in single granule cells is converted into a temporal delay code in target CA3 pyramidal cells and interneurons. These data demonstrate how a neural circuit of the CNS may process information.

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Figure 1: Classification of extracellular units.
Figure 2: Spike transmission between a granule cell and its interneuron and pyramidal cell targets in CA3c.
Figure 3: Spike transmission dynamics.
Figure 4: Frequency dependence of granule cell–CA3 spike transmission.
Figure 5: Spike transmission from a granule cell to CA3c during physiological granule cell firing patterns.


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This work was supported by grants from the National Institutes of Health (NS34994, MH54671, MH12403, NS43157, 5P41RR009754).

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Correspondence to György Buzsáki.

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Henze, D., Wittner, L. & Buzsáki, G. Single granule cells reliably discharge targets in the hippocampal CA3 network in vivo. Nat Neurosci 5, 790–795 (2002).

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