Figure 1.

The Brownian-optogenetic-noise-photostimulation (BONP). (A) Scheme of the experimental arrangement. Somatosensory neurons from the cerebral cortex were physiologically activated with mechanical protraction of the mouse whiskers (test stimulation pulse) and with BONP (continuous noise). The trace labeled with EFP indicates the Evoked Field potential (EFP) recorded on the surface of the barrel cortex (same scales as in B). The upper left panel shows an input-output graph of the intensity of the whisker protraction (test stimulation) vs. the maximal whisker-EFP amplitude. The magenta dashed lines indicate the selected test-stimulus. The upper right panel illustrates the power spectrum of the input noise (Brownian noise) employed in the BONP. The lower right panel shows a picture of the barrel cortex illuminated with the BONP. The light with more intensity covered an area of about 1 mm². (B) The whisker-EFP of neurons from the somatosensory cortex responding to whisker protraction (test stim.). (C) The same as (B) but for the response to continuous BONP (input noise). (D) Histological micrograph of neurons expressing ChR2-YFP from the layers IV-V of the somatosensory cortex of a Thy1-ChR2-YFP transgenic mouse. (E) The same as (D) but for a wild-type mouse. We obtained these micrographs employing the technique of CLARITY and a multiphoton microscope with YFP filter with a 20X water immersion objective.