**1. Processing in brain**

Human brain is the processing centre of human nervous system. Average adult human brain weighs about 1.5 kg and [1, 2] is composed of about 10 billion nerve cells or neurons. On aver‐ age, each neuron is connected to other neurons through about 10,000 synapses. The brain's network of neurons forms a massively parallel information processing system.

On the other hand, approximates arithmetic, such as the ability to calculate whether '26 + 32' is closer to 60 or 75, is not processed in the same manner or in the same part of your brain. Memorization of the results of operations such as multiplication tables reduces the need to use complex cognitive processing, such as going through the learning processes every time

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

the task is given. The idea of storing for long‐term retrieval is supported by the long‐term memories in the human brain, where the retrieval of results from the memory reduces the effort on cognitive processes.

The ability of the brain to process computational operations in real time is reflective of an active working memory. In many of the mental calculations, one makes on a day‐to‐day basis can be analysed by looking into the activities in the prefrontal cortex (see **Figure 1**). The stud‐ ies using neuroimages indicate 10 separate regions in the brain that contribute to even simple task of subtraction of two numbers. The main areas of activation for this simple task include fusiform gyrus, parietal cortices, lateral and medial parts of the temporal lobe and inferior parts of the frontal lobes.

The interconnections between the modules and the way they interact with each other for different set of arithmetic operations are different. It is also found that there is a separate net‐ work for estimation (bilateral inferior parietal cortex) as opposed to computation (left parietal and frontal cortices). These features point out the fact that there is one specific unit for per‐ forming computation; instead it is a collaborative effort between various regions in the brain.

**Figure 1.** Functional units in brain.

These features of brain are similar to the normal CPU architecture—a separate unit for arith‐ metic and logic functions, with a difference in the mode of operation. Instead of doing algo‐ rithmic approach, the brain works based on what it learned or we can say that the patterns it has learned. If we can implement this key feature of brain in hardware, then we can have a brain‐like fast processing unit.

In the brain the basic functional unit is a cell, called neuron. For each function, there will be separate set of neuron cells, which are learned to do that particular task. If we can develop a neuromorphic circuit for the neuron cell and can make it learn to do particular tasks, we can use it to develop a brain‐like processing unit, that is what is achieved through this project work.
