The electrotonic structure of a neuron largely shapes the propagation of synaptic potentials along its dendrites. To obtain detailed passive cable models of adult hippocampal granule cells, we performed simultaneous dual somatic and somatoaxonal recordings in acute slices from adult mice. Current pulses were injected via one pipette while voltage responses were recorded with the other pipette. The morphology of the fluorescently labeled cells was reconstructed using two-photon microscopy. An automated filament-tracing software was used to obtain objective morphological data. Specific membrane resistance (Rm = 39.2 ±?2.3 kW cm 2), specific membrane capacitance (Cm = 1.01 ± 0.03 mF cm -2 ), and intracellular resistivity (Ri = 198.8 ± 21.8 W cm, n=8) were obtained by direct least-squares fitting of the model's response to the experimental data assuming homogeneous membrane properties. Both the rise as well as the fast and slow components of the decay in the voltage response could be precisely reproduced by the model cells. Simulations showed that steady-state voltage attenuation was small. However, propagation of sinusoidal potentials from the soma into the dendrites was confined to frequencies below the [gamma] range (< 40 Hz). Simulations of transient synaptic conductance changes revealed that fast initial charge redistribution led to a strong attenuation of single, distal synaptic potentials and to a narrow synaptic coincidence detection window. Work was supported by DFG (Bi642/2)