Fig 6. Differential sensitivity to irradiance and duration among neurons.
A, The threshold irradiance to evoke an action potential was related to the membrane time constant (τm) for the blue LED pulse of either 0.1 s (closed diamonds) or 1 s (open circles). B, Reduction of threshold irradiance of the type-1 neurons with prolongation of the pulse duration. C, The latency to evoke an action potential was related to τm. D, The delayed firing of type-1 neurons with prolongation of the pulse duration. Statistical significance was evaluated with Mann-Whitney U test; *, P < 0.05 and **, P < 0.005.