Pratyahara, which means withdrawal of the senses, is the fifth limb of Patanjali's Ashtanga Yoga. The etymology of Pratyahara states that it is derived from two Sanskrit words: prati and ahara, where prati means away or against and ahara meaning food, or anything taken into ourselves. So, Pratyahara literally means "to withdraw oneself from that which nourishes the senses." In yoga, the term pratyahara implies withdrawal of the senses from getting attached to external objects. Pratyahara is the stage at which an expert learns how to control the "tentacles" of consciousness, which are known as indriyas in Sanskrit. Once through this stage, the person is able to see in subtle and the subtlest layers of multidimensional space, and to exit of his material body into them and to settle in them, accustoming himself to their subtlety, gentleness and purity.

Types of Pratyahara
There are two types of Pratyahara - Indriya Pratyahara and Prana Pratyahara; these two further lead to two subsequent types of Pratyahara - Karma Pratyahara and Mano Pratyahara.

Indriya Pratyahara implies Withdrawal Of Senses, or sensory inputs into out physical being. Since five senses create sensory overload, Indriya Pratyahara thwarts the collection in the mind.

Prana Pratyahara suggests Withdrawal Of Prana (vital energy of the body), as prana is what that drives the senses. To stop the dispersion of prana, we are required to control its flow and harmonize it.

Karma Pratyahara implies Control Of Action, which actually entails not just control of motor organs, but also right action or work.

This finally leads to Mano Pratyahara which suggests the Withdrawal of Mind. It is consciously practiced by withdrawing attention from anything that is unpleasant, and distracting for the mind, such as, by withdrawing attention from the senses, and directing it inwards.

Practices In Pratyahara
Pranayama is one of the most common practices for Pratyahara. While doing Paranayama, the person withdraws from the external on its own, and brings his focus inwards towards his breath. His connection with the external senses and stimuli get detached steadily. Besides Pranayama, another practice is to concentrate on Ajna Chakra or the third eye - the point between the eyebrows.

Another common technique to facilitate the development of Pratyahara is to first reduce physical stimuli, and then concentrate on one sense, say hearing. It's natural tendency of the mind to roam between the sensory inputs. In this situation, when there are no longer major sensory inputs, and the mind gets tired of hearing, it is compelled to turn inward. In the advanced stages, the electrical currents, which pulsate through the nerves and even the reflex muscles, are turned off by the practitioners. This may be achieved through Pranayama.