[stenl]

None, that was done 100 years ago, e.g. by Ramon y Cajal (Nobel prize 1906). But microscopic detail does not give molecular detail. What these current studies add is data on gene expression (mRNA molecules), chromatin accessibility (related to gene regulation), electrophysiology (in some cases), etc. We need such detail to connect disease genes inferred from genetics to specific brain cell types, for example.

[scotty79]

So basically just mapping each individual neuron and all of their connections is almost useless?

[stenl]

No that would be amazing. But we don’t have the technology to map all the connections in large mammalian brains. It was done in the fruitfly just this year: https://www.science.org/doi/10.1126/science.add9330

[adr1an]

Useless? No, but by today standards it doesn't amount to much. It's like having a low res pic in black and white. It worked alright in the past. That's the point.