Fig. 5: In silico predicted dendritic activity during sensory-evoked cortical output.

a Example simulation for the PT model example in Fig. 3e shows membrane potential (V_m) during Ca²⁺ AP, which is predicted to be evoked by passive whisker deflection. b Histogram of the durations of sensory-evoked dendritic potentials. The vast majority of the dendritic responses are characterized by fast potentials (black). Dendritic Ca²⁺ APs occur only in a small minority of the trials (orange). c Durations (left) and amplitudes (right) of the in silico predicted dendritic responses (n = 197,636 trials with Ca²⁺ APs, 1,048,576 trials without Ca²⁺ APs) versus those reported previously from whole-cell recordings near the primary BP of PTs in the barrel cortex for the same experimental condition (i.e., passive whisker deflections in anesthetized rats)⁴⁶. Box plots represent medians and 25^th to 75^th percentiles. Whiskers extend to 1.5 times the interquartile range. d We quantified the occurrences of sensory-evoked Ca²⁺ signals that Takahashi et al. measured via Ca²⁺ imaging in apical dendrites of PTs in barrel cortex upon passive whisker deflections (n = 229 PTs)¹¹, which matched the in silico predicted sensory-evoked Ca²⁺ AP occurrences (n = 360 PT models). Box plots represent medians and 25^th to 75^th percentiles. Whiskers extend to 1.5 times the interquartile range. e Membrane potentials at the Ca²⁺ domain for 1000 example simulations with sensory-evoked 1 AP responses (top), bursts of 2 APs (center) and bursts of 3 APs (bottom), respectively. The orange trace highlights exemplary sensory-evoked Ca²⁺ AP corresponding to panel (a). f Left: Probability across all PT models that somatic responses without APs occur (i.e., 0 APs), or with 1 AP, bursts of 2 APs or bursts of 3 APs occur, respectively, during trials when sensory-evoked Ca²⁺ APs occur. Right: Probability across all PT models that sensory-evoked Ca²⁺ APs occur during trails with 0 APs, or 1 AP responses or bursts of 2 APs or bursts of 3 APs, respectively. g Occurrences of Ca²⁺ APs differ substantially depending on the somatic response – i.e., virtually all trials with a burst of 3 APs, and across all PT models, showed a Ca²⁺ AP, whereas a vast majority of trials with 0, 1 or 2 AP responses showed no Ca²⁺ AP, but instead a fast dendritic depolarization (see also Supplementary Fig. S7). Source data for panels (c, d and f) are provided in the Source Data file.