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> The short answer is that the cerebral cortex is usually identified as having 6 layers. These can't be correlated with layers in a neural network, however. I d
by daveguy 10y ago
> The short answer is that the cerebral cortex is usually identified as having 6 layers. These can't be correlated with layers in a neural network, however. I do seem to recall a spitball number of 30-ish in relation to the visual cortex, but I've been unable to find any references as to what that number would actually represent, let alone if it's been superseded.
That short answer is very misleading. Those 6 layers are histological layers of density and structure in the cerebral cortex (eg how the cross sections look a little different). You might have many (30+) layers of cells with high interconnectivity in each of those 6 layers. Current estimate is 100 billion for the number of neurons, but the estimate of inter-connectivity is on the order of 100 trillion synapses. The human brain complexity many orders of magnitude higher than anything we have ever "simulated" in silicon.
- Cybiote 10y agoIt's not misleading because they were careful to point out that these 6 'layers' have nothing in common with how layers are defined in Neural networks. In Neural nets, layers are effectively subgraphs that are bipartite. They can also be computational stages in some networks like convolutional. The brain's layers are both much more loose in their allowed interconnections but also more modular in their functionality. There are different visual areas (usually 5) at different locations of the neocortex that connect to each other (feedforward and back) in complex ways. As residents of the neocortex, each visual area will thus have 6 layers which are in turn dividable into sublayers (often 1 - 4). These layers are structural but are also partially organizational tools for the scientists.
- ak217 10y agoThanks, this is good detail. Would you recommend any reading on the up-to-date understanding of brain architecture?