You can find a video of Seung‘s Davos ’10 talk here. He talks about neuroscience from ~ 2:00 to ~ 5:00. The “powerful microscope” he discusses is the transmission electron microscope. In my mind he is on track in discussing the wide potential of connectomics. But, one quibble, which Seung surely knows quite well:
Although we do have the entire 302-neuron connectome of the nematode C. elegans, from what I can tell scientists still aren’t quite able to model all of its properties on a computer. In fact, it’s difficult for neuroscientists to even model the 11-neuron gastric mill network of the lobster, dependent as it is on intrinsic oscillator neurons and other non-linear activity.
So, we do no doubt need better ML algorithms to “read” and make sense of the TEM data. But, we also need tons more physio data (i.e., here), to construct and validate working input-output models of all important neural and glial cell classes, before we will be able to understand what Seung calls the “essence that makes us uniquely human.”
How many cell types are there in the brain? Masland noted in 2004 that there are ~ 60 cell types in the retina, and reports one guess that there are ~1000 cell types in the cortex. These are currently classified by electrophysio profile, morphology (dendritic arborization / cell size / position), and type of neurotransmitter. But eventually all putative cell types should be validated by their distinct genetics, perhaps determined via the Gal4/UAS system of transgenes to drive the cell-specific expression of some fluorescent protein.
The connectivity between our brain cells matters, but that’s not all that matters. Not all brain cells are made alike.
Meinerzthagen IA. 2010 The organisation of invertebrate brains: Cells, synapses and circuits. Acta Zoologica 91: 64-71 . DOI: 10.1111/j.1463-6395.2009.00425.x
Masland RH. 2004 Neuronal cell types. Current Bio 14: 497-500. doi:10.1016/j.cub.2004.06.035