Human brain can store 4.7 billion books

The human brain has a capacity that is ten times greater than first thought and can retain 4.7 billion books, scientists have discovered.

This is according to US scientists who have measured the storage capacity of synapses - the brain connections that are responsible for storing memories.

They discovered that, on average, one synapse can hold roughly 4.7 bits of information. This means that the human brain has a capacity of one petabyte, or 1,000,000,000,000,000 bytes.

One petabyte is the same as 20 million four-drawer filing cabinets filled with text,13.3 years of HD-TV recordings, 4.7 billion books or 670 million web pages.

"The discovery is a real bombshell in the field of neuroscience," Professor Terry Sejnowski