There's a lot of differences between the mainstream CNNs and biological NNs though. For one, inference in most CNNs is just feed-forward, whereas in the brain t

There's a lot of differences between the mainstream CNNs and biological NNs though. For one, inference in most CNNs is just feed-forward, whereas in the brain the information flow is a lot more complex, modulated by all sorts of feedback loops as well as a dynamic state given by memory, expectation, attention, etc. Biological neurons are also a lot more complicated (and diverse) than the artificial ones. So those six layers aren't really very comparable to six layers in a typical modern CNN. Of course, I'm talking about just the typical current day CNN. There's a lot of ongoing work in recurrent neural nets, memory for neural nets, attention (though the idea of "attention" that is hot right now is quite simplified compared to what we usually call attention), etc.