Answer:
Scratchboard
Explanation:
Scratch boards are made of several layers that you chisel into with a Scratch awl to make art. Usually the top layer is black with the layers underneath being white.
Neurons communicate with each other via electrical events called 'action potentials' and chemical neurotransmitters. At the junction between two neurons (synapse), an action potential causes neuron A to release a chemical neurotransmitter.