I has recently decided to go vegan. Do you follow any special diet?
No , vegetarianism had its origin from ancient India and ancient Greece.
There are a few versions of it. It is usually referred to abstaining from all animal products in the diet, and also big industrial farming of aniamls.
The diet was closely connected with the idea of nonviolence toward animals (called "ahimsa" in India),done as a religious practice
Donald Watson coined the tern in 1944 when he co founded the Vegan Society in England.  They defined it as the doctrine that man should live without exploiting animals.
Vegetarianism is strongly linked with a number of religions that originated in ancient India.such as buddhism, Hinduism.The killing of animals was sacred 
If you are strictly vegan, you need to take supplemental vitamins, like vitamin B12. 
Yeah,B12 is a food supplement,  Nutritional neuroscience is the scientific discipline that studies the effects various components of the balanced diet