Sentence:  The yawning gap in neuroscientists' understanding of their topic is in the intermediate scale of the brain's anatomy. Science has a passable knowledge of how individual nerve cells, known as <WSD>neurons</WSD>, work. It also knows which visible lobes and ganglia of the brain do what. But how the neurons are organised in these lobes and ganglia remains obscure. 
Meaning of the word marked with <WSD> tags:  A cell of the nervous system, which conducts nerve impulses; consisting of an axon and several dendrites. Neurons are connected by synapses.