What are NOT structural classifications of neurons?

Neurons are not classified structurally based on their size, shape, or the length of their axons; these factors are more related to their functional classifications. Additionally, classifications based on the specific neurotransmitters they release, or their roles in different neural circuits, do not fall under structural classifications. Instead, structural classifications typically focus on the number of processes extending from the cell body, such as unipolar, bipolar, or multipolar neurons.