Location-dependent differences between somatic and dendritic IPSPs

Recent experimental evidence suggests that inhibitory synapses are associat ed with different actions depending upon their location (Miles et al., Neur on 16(1996) 815-823). We investigated that question of whether this effect is due to different subspecies of GABA(A) receptors giving rise to distinct responses (Pearce, Neuron 10 (1993) 189-20) or cable filtering by the dend ritic tree. The effects of electrotonic filtering on GABA(A) receptor media ted IPSPs were studied in hippocampal pyramidal cells. We implemented two m odels with different morphologies where these differences could be explaine d by electrotonic filtering alone. Our parameter search resulted in realist ic passive cell models where the dependence of electrotonic attenuation on morphological distance agreed with that seen in reconstructed cells. (C) 19 99 Elsevier Science B.V. All rights reserved.