Introduction to neurons

In this section, we will discuss neurons, which are the basic building blocks of ANNs. In the following photograph, we can see actual real-life neurons as observed through a microscope:

Fig 2.3: A photograph of a neuron

You can find this photograph at https://commons.wikimedia.org/wiki/Neuron#/media/File:Pyramidal_hippocampal_neuron_40x.jpg.

The question now is how can we recreate neurons in ML? We need to create them since the whole purpose of deep learning is to mimic the human brain, one of the most powerful tools on the planet. So, the first step toward creating an ANN is to recreate a neuron.

Before creating a neuron in ML, we will examine the depiction of neurons created by Spanish neuroscientist Santiago Ramon y Cajal in 1899. 

Santiago Ramon y Cajal observed two neurons that had branches at the top and many threads below (https://commons.wikimedia.org/wiki/File:PurkinjeCell.jpg).

Nowadays, we have advanced technology that...