Figure 1.

LFP RF mapping reveals coarse functional somatotopy in PPC. A, Example recording represents the average LFP after 20 consecutive single whisker deflections. The integral (gray shading) of the 0–100 poststimulus window is used to quantify the single-whisker LFP integral. Arrows indicate onset and offset for whisker deflection. B, Control condition with piezo in place but without whisker contact to illustrate the tactile nature of LFP in PPC after whisker deflection. C, Example LFP RF heat map for an individual PPC neuron showing LFP integral across individual whiskers, normalized to the maximal integral value. The preferred single whisker was used to color code the recording site; here γ (Fig. 1D, asterisk). Inset, Digital reconstruction of serial tangential sections together with S1 landmarks (barrels in L4) and position of recorded neuron from the example in A–C. D, All recording locations projected onto a standardized reference frame. Color code of recording location matches the color code of the whisker that generated the maximum response. E, From top to bottom: medial to lateral PPC subregions. Bar plots represent the normalized mean LFP integral per whisker row for the five PPC subregions, delineated by extrapolation of barrel row organization (n = 33 recordings from N = 29 rats). Coarse somatotopy can be inferred from a gradual shift from dorsal (A-row) to ventral (E-row) whiskers along the mediolateral axis. P: posterior, M: medial, L: lateral.