To check it out, look here . Below is the cover that Anna submitted but was not used.
Dendrites play an important role in determining the computational properties of neurons. In this issue, Vlasits et al. demonstrate that, similar to the plugboard of an Enigma machine (depicted on the cover), the arrangement of inputs on dendrites in the retina determines the type of output that is produced. Thus inputs play a role in the code that a neuron generates.
Image concept and design by Anna Vlasits, photograph by Bob Lord. Photograph source for illustration of Enigma Machine, https://commons.wikimedia.org/wiki/File:Enigma-plugboard.jpg which has a CC BY-SA 3.0 license.