The eye turns light into the brain's language of electrical signals. Cones, are tuned to light spectrum reacting to red, to green and to blue light. Rods, which are 100 times more light sensitive, let us see in darkness. In rods and cones, light initiates chemical reactions that activate neurotransmitters to send nerve signals to the brain with the basic components of light, color, and shape the sensation of vision a complex mental process called perception in the occipital cortex, The reticular formation is a complex network of brainstem nuclei and neurons that serve as integration center to coordinate functions necessary for survival. Kynurenine (KYN) is a metabolite of tryptophan (TRP) formed in the kynurenine pathway involved in neurotransmission, neuronal cell membrane excitability, and neurodegeneration The pineal gland produces melatonin, which modulates sleep patterns in circadian and seasonal cycles it has profuse blood flow, supplied from the choroidal branches of the posterior cerebral artery. It plays important role in the spiritual evolution more than any other part of the body, gets the highest concentration of energy.