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Biological neural networks do not use backpropagation, or at least, there's no evidence of that yet. Backpropagation is a placeholder for stuff we don't unders
by 29athrowaway 6y ago
Biological neural networks do not use backpropagation, or at least, there's no evidence of that yet.
Backpropagation is a placeholder for stuff we don't understand.
- deleted 6y ago[deleted]
- cl3misch 6y agoIsn't "backpropagation" just a synonym for the partial derivative of the scalar cost function with respect to the weights? And in the mathematical formulation of biological neural networks these derivatives can't be computed analytically. Your comment sounds like "backpropagation" is some kind of natural phenomenon.
- 29athrowaway 6y ago> Your comment sounds like "backpropagation" is some kind of natural phenomenon. No it's not, read again.
- ta988 6y agoNot exactly the same kind of backpropagation but signals fly the other way in neurons as well https://en.wikipedia.org/wiki/Neural_backpropagation https://en.wikipedia.org/wiki/Neural_backpropagation
- etienne618 6y agoIt seems that backpropagation might be a good abstraction for biological learing rules after all: "local predictive coding converges asymptotically (and in practice rapidly) to exact backprop gradients on arbitrary computation graphs using only local learning rules" from https://arxiv.org/abs/2006.04182 https://arxiv.org/abs/2006.04182
- 29athrowaway 6y agoIn biology there are excitatory networks and inhibitory networks.