The second step of Preksa Dhyana is Antaryatra (Internal Trip). It follows the Kayotsarga. Exertion in systematic meditation discipline needs good deal of nervous energy, and it is, therefore, essential to generate it. Susumna, i.e. the spinal cord is an important part of the central nervous system. Its bottom end is in the vicinity of sakti kendra i.e. centre of energy. In the practice of Antaryatra the conscious mind travels from Sakti-kendra to Jnana-kendra (centre of knowledge, top of the head) via the spinal cord. This internal trip of the conscious mind is repeated several times, and results in an increased flow of the vital energy (prana sakti) upwards. Repeated practice of this process assists in better generation of the nervous energy necessary for further meditation practice.
Nervous system is an essential and very important component for the functioning of conscious activities. It permeates the entire body through a network of nerves. The spinal cord and the brain are the commanding stations of the entire system. The former extends from the centre of energy situated in the lumbar region of the spine and enters the latter at the base of the skull, and is connected to it by the brain-stem and pons. These, therefore, are the chief centres of consciousness and the seat of the conscious mind. The nerves from the sense-organs also converge here. Sensation, motor action and perception converge to or are radiated from here. Sensory nerves and motor nerves are energized and activated by it.
Man represents the culmination of the process of evolution in the entire cosmos. Human mind alone possesses the capacity for conscious reasoning. Lower organisms do not possess a rational reasoning mind. Manï¿½s ability for rational and conceptual thinking is derived from his reasoning mind. Thus man alone is capable to direct the flow of his spiritual energy in an upward direction. If the flow is downwards, the behaviour will be guided by psychological distortions such as cruelty, greed, fear and hate; on the other hand, if the flow is reversed, these distortions will disappear. This will immensely strengthen the power of the unique human attribute-rational thinking and conscious reasoning. It is the direction of the flow of the spiritual energy which is a decider of the human behaviour.