  The algorithm of brain learning and memory is still undetermined. The
backpropagation algorithm of artificial neural networks was thought not
suitable for brain cortex, and there is a lack of algorithm for memory engram.
We designed a brain version of backpropagation algorithm, which are
biologically plausible and could be implemented with virtual neurons to
complete image classification task. An encoding algorithm that can
automatically allocate engram cells is proposed, which is an algorithm
implementation for memory engram theory, and could simulate how hippocampus
achieve fast associative memory. The role of the LTP and LTD in the cerebellum
is also explained in algorithm level. Our results proposed a method for the
brain to deploy backpropagation algorithm, and sparse coding method for memory
engram theory.
