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. Author manuscript; available in PMC: 2011 Mar 25.
Published in final edited form as: Neuron. 2010 Mar 25;65(6):873–885. doi: 10.1016/j.neuron.2010.02.028

Figure 2. A17 Morphology Limits the Spread of Synaptically Evoked Depolarizations into Neighboring Neurites and Varicosities.

Figure 2

(A) Application of DC current to an infinite neurite of 0.1, 0.13, 0.3, or 0.5 mm diameter was modeled and compared to the cable theory solution. Incorporation of varicosities at uniform intervals (20 mm) reduced the steady-state length constant.

(B) Simulation design: a synaptic conductance, derived to match the time course of AMPAR EPSCs recorded experimentally, was imposed at individual varicosities along a single neurite while monitoring the consequent depolarization at all varicosities on the stimulated neurite and in a neighboring neurite on the same cell (for simplicity, nonstimulated neurites are not shown).

(C) Postsynaptic depolarizations were large and had a nonlinear dependence on distance from the soma, suggesting that electrical compartmentalization occurs within neurites.

(D and E) Normalization of responses (to that of the stimulated varicosity) reveals the relative electrical coupling between varicosities on the stimulated neurite (D) and those on neighboring, unstimulated neurites (E). See also Figure S1.