Membrane potential and its electrode-recorded counterpart in an electricalmodel of an olfactory sensillum

Insect receptor neurons are surrounded with auxiliary cells and encased in a hair. Their electrical activity is usually recorded with an electrode loc ated at the tip of the hair. Analytical expressions giving the membrane pot ential along the sensory dendrite and the tip-recorded potential are derive d for a neuron in steady-state conditions. They formally close the gap betw een theoretical models and experimental measurements, when transduction mec hanisms and active membrane properties are not taken into account. It is sh own that the tip-recorded potential reflects correctly the relative variati ons of the dendritic membrane potential as a function of stimulus intensity over a large range of parameters. The geometric and electrical characteris tics of the sensillum that need be known to compute the dendritic membrane potential from the tip-recorded potential are given.