Fig. 4: Three-dimensional optogenetic stimulation and laminar recordings in freely moving mice.

A Depth-resolved activation of sorted units (spike shapes: left column). For each unit, the firing rate was calculated 3–8 ms after light onset (the gray shaded area in the middle column), and the background firing rate preceding light onset was subtracted to quantify the light-evoked rate modulation for different units, depths, and fibers (right column, responses for a certain fiber is coded with a pseudocolor). Fiber 7 was nonfunctional and was removed for clarity. The emitted intensities from the 11.8 and 30 μm fibers were estimated before implantation to be in the ranges of 0.5–1 and 1.5–3 mW, respectively. B Units with significant activations for 11.8 (upper, blue lines) and 30 μm (bottom, red lines) fibers from two animals. The number of units that responded to the light is denoted by n. The total numbers of units were 12 for animal 960 and 25 for animal 959. C Optogenetic effect for left and right optical fiber on behavior measured in body rotations. In both hemispheres, all two, three, four, and five fibers were stimulated in nine trials each, resulting in 36 trials in total for each hemisphere. The amount of body turning was estimated through visual inspection across four cameras. Error bars denote the standard deviation of the mean. Two-sided t-test, not corrected for multiple comparisons. D Behavioral effect for depth-resolved stimulation in cortex (Crtx) versus striatum (Str) for the 30 μm fibers in the right hemisphere. The behavior was estimated according to panel C. The number of trials is denoted by n. Error bars denote the standard deviation of the mean. Two-sided t-test, not corrected for multiple comparisons. E Cortical recordings during the stimulation of six different superficial 30 µm fibers (stimulated fibers are indicated by a blue circle) organized bilaterally at three different positions along the anterior (A)–posterior axis (P). To rule out that longer latencies for the stimulation on the contralateral hemisphere (right column) were due to light leakage to the recorded hemisphere, we calculated the peak latency (vertical dashed blue line) for the minimum light intensity in the recorded hemisphere that generated a response (blue response curve in the middle inset). Source data are provided as a Source Data file.