Figure 1
Stimulation setup and localization of PPC in mice. (A) Schematic of the texture presentation set-up that allows for 2-photon imaging of the PPC using a cranial window in a head restrained mouse. P100 (rough) and P1200 (smooth) correspond to the graininess of the sandpaper employed. (B) Schematic of the trial structure, where the translation stage presenting the textures slides in and out of position. The loudspeaker symbols indicate the 1-ms auditory tones just before the start and at the end of the stage translation, respectively. The shaded beige rectangles indicate the time windows with auditory cues from the translation stage movement and the green rectangle indicates the time window when the textures are in reach for whisker touches. Cue and touch-stimulus vectors used for the analysis windows are shown as well. (C) Location of the γ-whisker barrel in S1 and of V1, as determined with IOS (blue and red overlay, respectively) seen through a 4-mm cranial window. The white rectangle indicates the FOV from Fig. 2A. (D) Schematic of known anatomical inputs (red arrows) and outputs (green arrows) to PPC. (E–I) Fluorescence images of retrogradely labelled cell bodies that project to PPC (orange-red) with CTB-Alexa594 (CTB), and anterogradely GFP labelled PPC axonal projections (green), along with DAPI-stained cell nuclei (blue) to determine the anatomical connections of the site identified by IOS. In (E) coronal section of the mouse brain displaying M2 and the dorsal striatum (CP, caudate putamen). Note the concentration of the PPC axons in layer 1 of M2 (white arrow). In (F) close-up of the region indicated by the white box (upper layer 2/3) at the top of (E) with PPC projecting orange-red M2 cell bodies and M2 projecting PPC axons in green. In (G) close-up of the region indicated by the white box at the bottom of (E) with PPC axons projecting to the dorsal striatum in green. In (H) coronal section displaying the dentate gyrus (DG) and LP, with LP-projecting green PPC axons. In (I) close-up of the region indicated by the white box in (H) with PPC projecting orange-red LP cell bodies intermingled with LP-projecting green PPC axons.
