Fig. 6
From: Propagation of temporal and rate signals in cultured multilayer networks
PSP dynamics in multilayer networks. a Average postsynaptic potential of neurons in sparse networks. Data were averaged from n = 6 networks (density = 342 ± 57 neurons·mm−2, mean ± STD) where a single neuron was recorded in layers 1–4 (black to red) of each network. The shaded area represents the standard deviation averaged over trials and then averaged over neurons. The dashed line represents the average spiking threshold of 15 mV above resting membrane potential37. Right: same data shown at higher temporal magnification and superimposed with the PSTHs from Fig. 2. b Same as in a but for dense networks (n = 5 networks, density = 572 ± 117 neurons·mm−2, mean ± STD). c Recordings from a neuron in layer 2 showing variability in the subthreshold potentials leading to threshold crossings (22 trials, mean membrane potential shown in red). d Example of excitatory (bottom), inhibitory (top), and compound (middle) post-synaptic potentials in a neuron when the light stimulus was delivered in layers 1–4 (black to red). e EPSP and IPSP amplitudes recorded simultaneously in layers 1–4 vs layer (n = 6 networks, density = 510 ± 131 neurons·mm−2, mean ± STD). Amplitudes between individual EPSPs and IPSPs were correlated (Pearson correlation: R = 0.75, P = 2.1 × 10−5, n = 24). Gray lines mark individual measurements. f PSP delay (stimulus onset to time at maximal slope) vs layer. Paired t-test statistic for the difference between E and I delays: L1: P = 0.002, L2: P = 0.012, L3: P = 0.003, L4: P = 0.51. *P < 0.05, **P < 0.01 In e, f, data are presented as mean ± SEM and individual data are shown as gray lines
