Electrophysiological differentiation of new neurons in the olfactory bulb - PubMed (original) (raw)

Electrophysiological properties of a restricted group of GFP+ cells in the glomerular layer (see Results for explanation). a, Voltage-clamp recordings; depolarizing steps to potentials from -70 to 60 mV after 300 msec preconditioning to -120 mV. b, Current-clamp responses to the injection of depolarizing current pulses showing repetitive action potentials. c, Spontaneous activity at rest, leading to repetitive action potentials. d, Giant depolarizing synaptic potentials, occasionally seen in GFP+ cells. e, Spontaneous synaptic currents blocked by 1 m

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kynurenate (recorded at P20, 10 d survival). f, Responses to focal application of GABA and glutamate (both 100 μ

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; P39, 17 d survival). Decay time constants were 1.64 sec for GABA and 2.33 sec for glutamate. g-i, Current-voltage relationships for _I_Na, _I_K(V), and _I_A. _I_Na was measured as peak inward current, _I_K(V) is the asymptotic current evoked by depolarizing steps from a holding potential of -50 mV in the presence of 0.1 μ

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TTX, and _I_A is the peak outward current obtained by subtracting the _I_K(V) currents from total outward currents evoked by depolarizing steps at identical potentials from a holding potential of -120 mV. j-l, Conductance-voltage relationships obtained by dividing the I-V data shown in _g_--i by the corresponding driving forces. The g-V relationships could be fitted by Boltzmann equations having the following parameters (amplitude, midpoint, and slope): _g_Na, 18.3 nS, -39.0 mV, 4.91 mV; _g_K(V), 8.26 nS, -10.4 mV, 13.7 mV; _g_A, 16.7 nS, -10.2 mV, 18.6 mV.