Experimental design and LFP response to electrical stimulation of mouse whiskers and changes of cerebellar LTD in alert mutant mice. (A) Facial dermatomes of the whisker region were electrically stimulated with a pair of needles under the skin. Sensory information comes into the Crus II area from the trigeminal nucleus (Tn) in the brainstem, which receives afferent signals from the trigeminal ganglion (Tg), (B) Early response associated with sensory input in the cerebellum via the trigeminal nucleus is characterized by P1-N1-N2-P2-N3 components. Averaged superimposed traces of the evoked field potential components before 8-Hz stimulation protocol, (black trace) and 30 min after 8-Hz stimulation protocol (gray trace) in control (top) and in mutant mice (bottom). Arrowheads indicate shifted latencies of postsynaptic components after 8-Hz stimulation. (C-H) Time course of N1, N2 and N3 amplitude (C-E) and latency (F-H) changes before (negative time periods) and after (positive time periods) the 8-Hz stimulation protocol (not shown) in 6 Ptprr
−/− mice and in 6 control mice. Mean normalized data represent the peak amplitude of the different components (C-E) and the time difference at peak latency (F-H) between each 5-min interval and the mean value measured in control conditions. Significant differences between mutant and control mice are indicated with asterisks (Student’s t-test, *p < 0.05; **p < 0.01; ***p < 0.001).