There is a fundamental difference between computers and brains. While both processes use signals to communicate with each other, brains are electrochemical systems. In a computer, an electrical signal travels from one point to another, while a neuron is continually changing its excitability. The same information can affect the probability of an action potential being produced across several synapse connections. This is why computer programs cannot replicate human mental processes.
Use parallel processing
Computers and brains share a fundamental feature: they use distributed, massively parallel processing. In contrast, a brain is serially processed through a central processing unit, or CPU. Both systems use an architecture that separates the memory from the CPU and provide addressable memory. The key difference between a computer and brain is in the way they operate. This is an essential distinction, and should be remembered whenever comparing computers and human minds.
Reconnecting the brain
Although both systems are complex, the human brain is more flexible. Unlike computers, a human brain can be rewired. This property allows neurons to separate and reconnect, and change their basic properties. This ability is unmatched in a computer, and the difference is most pronounced in our cerebellum. A computer has a limited number of neurons, which does not allow for the rewiring of the brain.
Depending on multiple factors
The speed at which the brain processes information is a fundamental difference between a computer and a human. While computers poll memory addresses in an effort to find a specific piece of information, the brain uses content-addressed memory. As a result, the speed of processing a single brain cell depends on multiple factors. Similarly, the rate at which electrical signals pass through different parts of the neuron.
Although both are highly advanced systems, the brain has some significant advantages. Its massive-scale computations are similar to those of a computer. Its flexibility is another major advantage. It can adapt to changing conditions, such as environmental changes and even the physical environment. This means that the brain is more malleable than a computer. However, it is more difficult to reprogram a human brain, and it may be difficult to understand its capabilities.