Fig 10. Trial to trial reliability of responses to a natural image with simulated eye movements (NI) and to drifting sinusoidal gratings (DG).

(A) The response of a randomly sampled excitatory neuron in model Layer 4 to the NI stimulus. The top panel shows the spike raster histogram, the middle panel shows the incoming synaptic excitatory (red) and inhibitory (blue) conductances. The bottom panel shows the membrane potential. The thick lines show the mean of the analog signals over the 10 trials. (B) As (A), but for the DG stimulus (contrast 30%). (C-D) As (A-B) for an excitatory neuron in Layer 2/3. (E-H) Cross-correlation across trials for spikes (top) and subthreshold membrane potential activity (bottom), in response to DG and NI stimuli. The reliability is given by the peak amplitude at time zero, and the temporal precision by the standard deviation of the Gaussian fit to the cross-correlation. (E) Results averaged across all recorded excitatory neurons in model Layer 4. (F) Results averaged across all recorded excitatory neurons in model Layer 2/3. (G) Results averaged across all recorded excitatory neurons pooled across the two model layers. (H) The experimental data from [21]. Note that in that study two additional stimuli were also presented (dense noise: blue line; grating with simulated eye-movements: green line) that we have not used in this study. (I-L) The inverse of the stimulus-locked time-averaged standard deviation of membrane potential (1/SD) across trials, averaged across cells, relative to the value for ongoing activity. (I) Results averaged across all recorded excitatory neurons in model Layer 4. (J) Results averaged across all recorded excitatory neurons in model Layer 2/3. (K) Results averaged across all recorded excitatory neurons pooled across the two model layers. (L) Experimental results in V1 of the anesthetized cat [21].