1 Neuroscience of the Yogic Theory of 2 Mind and Consciousness 3 Vaibhav Tripathi1* and Pallavi Bharadwaj2 *For correspondence: [email protected] (VT) 4 1Boston University; 2Massachusetts Institute of Technology † Present address: Department of 5 Psychological and Brain Sciences, Boston University, Boston, MA, ‡ USA 02215; Laboratory for 6 Abstract Yoga as a practice and philosophy of life has been followed for more than 4500 years Information and Decision Systems, 7 Massachusetts Institute of with known evidence of Yogic practices in the Indus Valley Civilization. A plethora of scholars have Technology, Cambridge, MA 02139 8 contributed to the development of the field, but in last century the profound knowledge 9 remained inaccessible and incomprehensible to the general public. Last few decades have seen a 10 resurgence in the utility of Yoga and Meditation as a practice with growing scientific evidence 11 behind it. Significant scientific literature has been published, illustrating the benefits of Yogic 12 practices including asana, pranayama and dhyana on mental and physical well being. 13 Electrophysiological and recent functional Magnetic Resonance Imaging (fMRI) studies have 14 found explicit neural signatures for Yogic practices. In this article, we present a review of the 15 philosophy of Yoga, based on the dualistic Sankhya school, as applied to consciousness 16 summarized by Patanjali in his Yoga Sutras followed by discussion on the five vritti (modulations 17 of mind), practice of pratyahara, dharana, dhyana, different states of samadhi, and samapatti. We 18 introduce Yogic Theory of Mind and Consciousness (YTMC), a cohesive theory that can model 19 both external modulations and internal states of the mind. We propose that attention, sleep and 20 mind wandering should be understood as unique modulatory states of the mind. YTMC allows us 21 to model the external states, internal states of meditation, samadhi and even the disorders of 22 consciousness. Further, we list some testable neuroscientific hypotheses that could be answered 23 using YTMC, analyse the benefits, outcomes and possible limitations. 24 25 Introduction 26 The quest to understand consciousness has been an old one. Questions about our existence, "Who 27 am I?", "What is the world?", "Where am I?" has baffled philosophers for centuries. A plethora of 28 philosophical systems were developed in India to answer these questions which eventually con- 29 densed into six orthodox schools and at least four unorthodox schools (Box 1). Sankhya school 30 dealt with the nature of reality broken down in it’s constituent parts (Box 2). Yoga emerged as a 31 more practical philosophy to realize the true reality and has been practiced since the Indus Valley 32 civilization. The philosophy matured for a few thousand years when the rules and principles were 33 compiled into the brief sutras by Patanjali (Box 3). 34 Consciousness as a field of study gained momentum in the Western world when Descartes de- 35 scribed the mind-body problem and stated the popular statement, "I think therefore I am". The de- 36 velopment of Electroenchephalogram (EEG) and other medical devices made it possible to record 37 people when they apparently lost consciousness either during sleep (Borbély et al., 1981) or al- 38 tered their states during anesthesia (Akeju et al., 2016) or during meditation (Travis and Wallace, 39 1999; Baijal and Srinivasan, 2010). Crick and Koch stimulated an interest in the field with their 40 works (Crick and Koch, 1990; Francis Crick and Christof Koch, 2003). 41 The recent development of neuroimaging and stimulation modalities like fMRI, TMS, tDCS in- 42 creased the quest to understand our different states of consciousness and many theories have 1 of 26 43 developed to allow for better experiments including Integrated Information Theory (IIT) (Tononi 44 et al., 2016), Higher Order Theories (Lau and Rosenthal, 2011), Global workspace theory (Dehaene 45 and Changeux, 2011), and recent ones like Attention Schema Theory (AST) (Graziano, 2020) and 46 Dendritic Integration Theory (Aru et al., 2020; Bachmann et al., 2020). Though the current theories 47 offer many explanations for the different day to day experiences, it does not integrate well with 48 the internal states as experienced during meditation, samadhi or even sleep. 49 We present a new theory called the Yogic Theory of Mind and Consciousness (YTMC) which is 50 based on Sankhya and Yoga philosophy. Instead of taking the materialistic emergent approach to 51 mind, consciousness, and intelligence, Sankhya takes a holistic approach to the description of the 52 world. Sankhya postulates that the reality is composed of consciousness (Purusha), also called seer, 53 soul, brahman etc., and nature (Prakriti). The approach is convergent to what some philosophers 54 have begun to hypothesize that consciousness could be a fundamental property (Kastrup, 2018) 55 and it is "hard" to "understand" it (Chalmers, 1995). 56 YTMC proposes that mind and seer are separate entities. The mind is emergent in nature and 57 it depends upon the number and type of sensory data streams an organism can receive (sense 58 organs) and the number of ways it can act (action organs). Tanmatras or the sensitivity and sensory 59 specificity of sense organs separates the individuals within species and across species to have 60 a different percept of the world. Consciousness of an organism includes the role of the sense 61 organs, action organs, mind along with intellect, ego and memory systems which represent the 62 internal faculties and the seer which is the seat of awareness. YTMC can be generically applied 63 to different animals as recent studies have demonstrated that a wide variety of animals including 64 corvids display consciousness (Nieder et al., 2020; Birch et al., 2020). 65 YTMC includes the concept of modulations of mind like sleep, memory, mind wandering, per- 66 ception and inference from the Yoga Sutras which suggests that the mind is aligned with the seer 67 unless the mind is in one of these modulations. Meditation and finer states like samadhi can occur 68 when the mind reins in the modulations and becomes aware of the seer. Being established in the 69 seer consciousness has been the goal for self-realization according to the Yogic texts. 70 In this paper, we first introduce the organization of consciousness utilizing the Sankhya-Yoga 71 philosophies in our YTMC model followed by a discussion on the modulations of mind and how 72 activity and connectivity of systems of the YTMC model could result in these modulations. We 73 then describe various internal states as experienced during Yoga and the finer states of samadhi 74 with explanation of how they can be modelled using YTMC and propose some experiments to test 75 such states. We discuss how YTMC can explain various disorders of consciousness. We end by 76 listing some predictions we can make using the YTMC model and the description of modulations, 77 internal states and finer states. YTMC is one of the first theories of consciousness that integrate 78 both internal and external states and can provide testable predictions and experiments to establish 79 these results. 167 Organization of Consciousness and YTMC 168 According to Sankhya philosophy (Virupakshananda, 1995), the world is composed of conscious- 169 ness (Seer/Purusha) and creation (Prakriti) which itself is the total of twenty four tattvas including 170 the sense organs, tanmatras, action organs, elements, mind, intellect, and ego along with memory. 171 In our Yogic Theory of Mind and Consciousness (YTMC), we extend this philosophy into a model as 172 illustrated in Fig.1 which represent the various faculties of each individual. The sense organs brings 173 in data and knowledge about the world, filtered through the Tanmatras or sensitivity/sensory speci- 174 ficity of each sense organ (not shown separately but built into the abstraction of the sense organs). 175 The way we have thought of sense organs are not just the physical organs of sense but also in- 176 cludes the regions in the brain which are specific to the processing of each sense. For example, 177 the eyes, retinal ganglion cells, lateral geniculate nucleus then onto the early and late visual cortex 178 are all abstracted as the visual sense organ. The mind composes and interacts with these senses 179 and make decisions based on the intellect subsystem along with memory and ego subsystems and 2 of 26 8081 Box 1. Indian Philosophical Systems 82 Indian philosophical system starting with the Vedas illumined in various Upanishads, became 83 concentrated in six major schools not necessarily independent of each other. Indian thought 84 was divided into six schools of philosophy - Nyaya, Vaisheshika, Sankhya, Yoga, Mimansa and 85 Vedanta which highlighted various aspects of reality and the association of living beings with 86 that reality. Other schools of philosophy also emerged in India which did not consider the 87 Vedas as a means of knowledge and were considered unorthodox schools including Bud- 88 hhism, Jainism, Charvaka and Ajivika. 89 The Nyaya school, one of the oldest schools of philosophy emphasized the use of logic and 90 reasoning to arrive at any conclusion about the world. The purpose of the senses was to 91 gain knowledge of the world. Nyaya school emphasized epistemology or the ways to ac- 92 quire knowledge about the world. It relied on four out of the six means to gain knowledge 93 (epistemes) - Pramaana/observation, Anumaana/inference, Agama/written testimony and Upa- 94 maana/comparison, and excluded derivation and negative proof. 95 Vaisheshika was expounded by Kanada, one of the earliest atomists. He explained the reality 96 as having different types of padarathas/categories by which any matter could be understood 97 namely substance, quality, activity, commonness, particularity, and connectednes. Kanada 98 also integrates the concept of space, time, and mind.