This compartment-specific regulation of branch excitability would therefore allow input onto more excitable dendrites to preferentially drive AP output. Dendritic processing of patterned synaptic input may support the generation and consolidation of information coding neuronal ensembles within the CA3 network. Here we show that dendritic integration Selleck CHIR99021 of synchronous synaptic inputs is highly supralinear in thin dendrites of CA3 pyramidal neurons and this supralinearity is mainly dependent on NMDARs with some contribution by fast Na+ spikes. The decay of voltage responses generated by

synchronous inputs is regulated by K+ (mainly GIRK) channel function, thereby allowing selective amplification of theta-modulated repetitive input patterns. Recent studies investigating dendritic integration in CA1 pyramidal neurons and dentate gyrus granule cells revealed that these two types of hippocampal principal neurons express very different integrative properties. While the

initiation of composite Na+ and NMDA spikes in CA1 pyramidal neuron dendrites enables them to produce strong supralinear integration (Ariav et al., 2003 and Losonczy and Magee, 2006), granule cells integrate inputs in an essentially linear fashion (Krueppel et al., 2011). This suggests find more that specific forms of dendritic integration may support different computational capabilities. Linear integration may allow sparsification and orthogonalization in the dentate gyrus through a true winner-take-all selection mechanism, whereas fast Na+ spikes evoking precisely timed APs may promote synchronized output

of CA1 cells coding the same complex input features during SWRs. Here we describe dendritic integration of synaptic inputs in principal neurons of CA3. Our results demonstrate that integrative properties of thin apical and basal dendrites of CA3PCs differ from the other two principal neuron types. They are obviously different from DG granule cells in that they express active integrative mechanisms that enable strongly supralinear integration of spatiotemporally correlated input patterns. Yet, unlike perisomatic dendrites of CA1PCs where dendritic Na+ spikes are remarkably strong even measured because at the soma, the dominant form of dendritic supralinearity in CA3 pyramids is mediated by NMDARs, and the contribution of fast Na+ spikes to the somatic response is relatively minor in the vast majority of even basal dendrites. These properties resemble integration in thin dendrites of L2/3 and L5 cortical pyramidal neurons (Schiller and Schiller, 2001, Antic et al., 2010 and Branco et al., 2010). NMDA spikes in CA3PCs provide robust amplification of the voltage response to synchronous input involving more than ∼15 synapses.