Yoga as a practice and philosophy of life has been followed for more than 4500 years with known evidence of Yogic practices in the Indus Valley Civilization. A plethora of scholars have contributed to the development of the field, but in last century the profound knowledge remained inaccessible and incomprehensible to the general public. Last few decades have seen a resurgence in the utility of Yoga and Meditation as a practice with growing scientific evidence behind it. Significant scientific literature has been published, illustrating the benefits of Yogic practices including asana, pranayama and dhyana on mental and physical well being. Electrophysiological and recent functional Magnetic Resonance Imaging (fMRI) studies have found explicit neural signatures for Yogic practices. In this article, we present a review of the philosophy of Yoga, based on the dualistic Sankhya school, as applied to consciousness summarized by Patanjali in his Yoga Sutras followed by discussion on the five vritti (modulations of mind), practice of pratyahara, dharana, dhyana, different states of samadhi, and samapatti. We introduce Yogic Theory of Mind and Consciousness (YTMC), a cohesive theory that can model both external modulations and internal states of the mind. We propose that attention, sleep and mind wandering should be understood as unique modulatory states of the mind. YTMC allows us to model the external states, internal states of meditation, samadhi and even the disorders of consciousness. Further, we list some testable neuroscientific hypotheses that could be answered using YTMC, analyse the benefits, outcomes and possible limitations.
Neuroscience of the Yogic Theory of Mind and Consciousness
