This book is a research work on brain specifically on the hippocampus. Depression is a very serious and heavy burden over mankind. Its etiopathogenesis is very complicated, but mostly it involves brain specially hippocampus. Any kind of Stress leads to depression. I used immobilisation as a mode of stress and leads to depression then i gave antidepressants to see any reversal. All the changes were observed in the hippocampus in the form of neuronal density.