Starting at 1 is always amusing when talking to computer people.  Computer people seem happy to dismiss most of the brain because &quot;neural network—all we need is data!&quot;  But, the brain isn&#x27;t just a bowl of neurons freely connecting to each other.  There&#x27;s a quite rigid structure to brains that give rise to things like the perception of free will and language acquisition (i.e. why no other animals have language).<p>The brain <i>is</i> organized in layers, but the layers don&#x27;t care about respecting order.  layer 5 can be directly connected to layer 0, forwards and backwards, as well as anywhere else in-between.  Brains rely a lot more on inhibiting signals than generating signals.  Plus, depending on how you count, we are made up of three brains put together: left, right, cerebellum, and those are seldom considered in our current fascination with single-task &quot;AI&quot; systems.  You can put a shark fin on your head then swim for a while, but you&#x27;re still not a shark.<p>To go deeper down the rabbit hole, start off with <a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Cerebellum-Brain-Implicit-Press-Science-ebook&#x2F;dp&#x2F;B005DKQQG4" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Cerebellum-Brain-Implicit-Press-Scienc...</a> (warning: dense) or skim <a href="http:&#x2F;&#x2F;neuroscience.uth.tmc.edu&#x2F;s3&#x2F;chapter05.html" rel="nofollow">http:&#x2F;&#x2F;neuroscience.uth.tmc.edu&#x2F;s3&#x2F;chapter05.html</a> or use <a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Mapping-Mind-Rita-Carter&#x2F;dp&#x2F;0520266285" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Mapping-Mind-Rita-Carter&#x2F;dp&#x2F;0520266285</a> as an easy getting started reference.<p>As for &quot;neuroscience narrative argues that function and learning cannot be decoupled&quot; — saying <i>learning</i> is a bit of a stretch.  The brain only cares about correlating coincident events (&quot;neurons that fire together wire together&quot;) and wiring together neurons that fire at the same time ends up causing what we see as emergent behaviors (semantic memories bound to episodic memory, operant conditioning, etc).