Each combines several elements of the basic neuron shape. In terms of function, scientists classify neurons into three broad types: sensory, motor, and interneurons. Sensory neurons are triggered ...

and the size of primary sensory neuron somas. Larger-bodied species with larger primary sensory neurons exhibited a higher abundance of microglia, while smaller animals tended to have fewer or none.

To answer these questions, Dr. Iosilevskii and Dr. Katz studied the development of the sensory neuron PVD. This neuron has a highly branched structure, with repetitive subunits resembling a ...