The human brain is in the form of a pyramid

" … It is like you have to accept a hypothesis that there exists an all pervading power above the human brain. This is the only Hypothesis. The human brain is in the form of a Pyramid. The Param Chaitanya or the all-pervading power is coming from all sides and striking the brain of a fetus (soon after its formation). What actually happens is that, at the apex of this pyramidal brain, the Param Chaitanya passes unhindered and settles down the spine in the inverted Triangular bone area, at the base, in three and a half coils as the Kundalini Shakti. In the process it leaves its mark called the "Vacuum Channel" in the spine. Now the Param Chaitanya hitting the side s of the triangular brain has to permeate the Grey and the white matter. These have their own densities, and so governed by the physics Laws of Refraction, the Chaitanya refracts from left to right and from right to left. This is also called the Prismatic refraction effect. This phenomenon exists mostly for human brains and not so much in animals. During the refraction process, the Human attention is pulled out to both the sides and is driven in the outward direction. Both the attention and the refracted Chaitanya cross at the Agnya Chakra from both the sides on their way out. As a result of this pull, an additional force called the resultant force is created. Now the theory of the Parallelogram of forces (of Physics) comes into play. The resultant force is divided into two parts, each being at 90-degree angle to the other on both the left as well as the right side. The resultant force acts in the center of its two counterparts. One part creates the left and the right sympathetic Channel of the fetus by pushing its way down the body. The other part pushes its way out through the senses, dragging with it the Human attention both to the left and to the right. The second part is also known at the action in the outer world. From the outer world, this action brings back a reaction. (Another famous law of Physics) the path followed by the action and reaction is the same. On the left side this reaction builds one's Conditionings while on the right side it builds the Ego. In short, our Chitta accompanied by the resultant Brahma -Chaitanya's living force went to the outer world, collected a reaction and brought back with it a conditioning from the left, thereby forming the Manasa or the mind. Both the action and reaction pass through both the Agnya and the Vishuddhi Chakras. The Chitta , being dispersed in nature, has the ability to flow from the whole body. The reaction of the left is the desire element, the potential of which gives birth to the Ida Nadi on the left Sympathetic Channel. Similarly, the reaction of the right side is the action element, the potential of which forms the Pingla Nadi. The overflow of the Ida Nadi forms a balloon -like cloud at the back of the Agnya Chakra called the Super ego, while the overflow of the Pingla Nadi forms a similar cloud in front of the Agnya Chakra called the Ego. The Agnya remains directly in between these two balloons. The front of the Agnya is controlled by the Pituitary of the brain, while the back is controlled by the Pineal".

extract from H.H. Shri Mataji's Talk with Dr. Talwar, Delhi, 26th and 27th February 1987