Fig. 5: Differential modulation of neurons in L4 and L6 by light and dark.

a, Ca²⁺-fluorescence traces for all neurons in an example L6 population in two consecutively acquired Ca²⁺-imaging movies. Both Ca²⁺-imaging movies have transitions between environmental lighting being on (Light) and off (Dark, gray boxes). Color-coded fluorescence traces are sorted by neuronal light–dark preference index. Laser power 38 mW. b, Example fluorescence traces from three neurons in a. Black ticks below example Ca²⁺-traces indicate inferred action potential firing. Time scale in the individual Ca²⁺-traces applies to both the color-coded plot and the individual traces. Fluorescence scale bar applies to all individual Ca²⁺-traces. c, Color-coded fluorescence traces as in a but for an example population in layer 4 from the same imaging session in the same animal as the data in a and b. d, Example Ca²⁺-fluorescence traces from a L4 population with periods where the environmental lighting is on or off (gray box). Laser power 18 mW. e, Overview image of an example neuronal population in layer 6 (left) and the same population of neurons color-coded by light–dark preference (right). f, As in e, but for an example population in layer 4. g, Distributions of light–dark preference index (blue) for all recorded neurons in L6 in periods where the animal was mobile (velocity > 5 cm s⁻¹), including also distributions for shuffle-controlled firing rates (red, N = 880 neurons from 9 datasets from 4 animals). h, As for g, but for periods where the animal was stationary (velocity < 5 cm s⁻¹). Datasets as for g. i, As for g, but for all neurons in L4 (N = 298 neurons from 9 datasets from 3 animals). j, As for h, but for the neurons in L4.