Extended Data Figure 7: Membrane properties of retrobead-positive NAc/CeM-projecting BLA neurons and rabies-virus-expressing BLA neurons.
From: A circuit mechanism for differentiating positive and negative associations
a, Access resistance, membrane resistance, and membrane capacitance were estimated from the current response of the cell to a 4 mV square voltage pulse using the Q-method35. Access and membrane resistance as well as the membrane capacitance and membrane potential were not significantly different between the two populations (unpaired t-tests: t20 = 0.788, P = 0.4400; t20 = 1.599, P = 0.1256; t20 = 1.847, P = 0.0796; and t18 = 0.2521, P = 0.8038, respectively). The holding current corresponds to the current injected to clamp the cell at −70 mV. This value was not significantly different between NAc and CeM projectors (unpaired t-test, t20 = 1.046, P = 0.3079). b, Confocal image of a BLA–NAc projectors expressing ChR2–eYFP transduced by rabies virus (RV) and recorded ex vivo in whole-cell patch-clamp. The cell was filled with biocytin during recording and stained with streptavidin-CF405 (in grey). c, Current response to a 1-s blue light pulse in a cell expressing rabies virus, 5 days after injection. d, Five days after viral injection, rabies-virus-expressing cells were able to respond with an action potential to every pulse of a 20 Hz light stimulation (5 ms pulses, top trace, blue line shows onset of light pulse). They also responded with an action potential to 250 pA, 5 ms current pulses injected at 20 Hz (middle trace). Rabies-virus-expressing cells also showed spontaneous post-synaptic excitatory and inhibitory currents (EPSCs and IPSCs, respectively) when clamped at −70 mV (bottom trace, 0 pA holding for this cell). e, Current/voltage curves are similar in retrobead (RB, grey circles, n = 5 cells) and rabies-virus-expressing cells (black circles, n = 3 cells). f, Average action potential for 11 retrobead-positive BLA–NAc projectors (grey) and six BLA–NAc projectors expressing rabies virus. g, Membrane properties of retrobead-positive versus rabies-virus-expressing neurons. None of the properties investigated were significantly altered in rabies-virus-expressing neurons (unpaired t-tests: access resistance, t15 = 1.299, P = 0.2135; membrane resistance, t15 = 2.057, P = 0.0575; membrane capacitance, t15 = 1.215, P = 0.2430; action potential threshold, t15 = 0.0756, P = 0.9407; holding current, t16 = 1.002, P = 0.3314). Results show mean and s.e.m.
