It is located at the top of the head. This is the place where the Kundalini Energy finally rests, from this point you connect to the Divine Consciousness and attain the thoughtless state. The Chitta (Mind element) must be centered in the central channel - not in the left or the right. Kundalini reaches the Sahastrar using the centered mind through the central channel. On reaching the Sahastrar there is a chemical process which releases hormones which activate all the glands and make them healthy and make you feel relaxed. Whatever fatigue you feel during work is mainly due to thoughts, 90% energy is wasted due to mental thoughts and only 10% due to physical strain. Through Meditation you can save and reserve this energy and use it in whatever work you do thus you put in full energy, concentration and commitment into your work and the outcome will be much better.