My two centses on our five senses. Source saying we don't regenerate neurons in the olfactory bulb: http://www.cell.com/neuron/abstract/S0896-6273(12)00341-8 A few video sources: https://www.youtube.com/playlist?list=PLWGnWkUjYqae9oPgkXp_EmxUL4y_qq3C6 A few books: Universal Sense by Seth Horowitz Evolution by Carl Zimmer The Brain by David Eagleman And everything ever spoken or written by Jason Pargin