Cover legend: This pseudocolored confocal image shows a vGluT1-expressing muscle-spindle sensory ending in the gluteus maximus muscle of a 10-day-old wild-type mouse. Superimposed on the image are extracellular electrophysiological recordings of a soleus muscle nerve in a wild-type mouse (upper trace) and a mouse homozygous mutant for the PDZ-domain protein Whirlin. The recordings, made during four episodes of soleus muscle stretch, demonstrate that stretch-induced activity in Whirlin mutant proprioceptive afferents is much reduced compared to those in wild-type. Cover image produced by Ira Schieren and Joriene de Nooij. For more information, see the article by de Nooij et al. (pages 3073–3084).