Dendritic lh normalizes temporal summation in hippocampal CA1 neurons.

Most mammalian central neurons receive synaptic input over complicated dendritic arbors. Therefore, timing of synaptic information should vary with synapse location. However, I report that temporal summation at CA1 pyramidal somata does not depend on the location of synaptic input. This spatial normalization of temporal integration requires a dendritic hyperpolarization-activated current (lh). Shaping of synaptic activity by deactivating a nonuniform lh could counterbalance filtering by dendrites and effectively remove location-dependent variability in temporal integration, thus enhancing synchronization of neuronal populations and functional capabilities of the hippocampal CA1 region.