According to Dr. Christof Koch, consciousness is every stuff a person experiences each day. But is it such easy to understand it like that? The answer is NO. Understanding of the concept of consciousness in terms of both psychological and neuroscientific ways is really challenging. A variety of parameters are needed to be considered. Several questions come to the minds of scientists working on cognitive neuroscience, which creates either some scientific or philosophical theories. The enlightenment of both psychological and neurobiological factors contributes to the consciousness is provocation in the scope of cognitive neuroscience1,2.
The brain is composed of distinct specifically designed networks [1]. So, consciousness is considered as an affiliation of extensive workspace which may unify the cooperated and contended inputs from different parts of the brain [2]. Consciousness primarily implies subjective experience which means everything we interact with forms our emotions and memories3. Awareness involving self-awareness and external awareness and arousal are the main constituents of the consciousness, and there is a conformity between awareness and arousal despite involving distinct brain structures10. The vegetative state can be a case in the point of unconsciousness. Such people are fully aroused, and their self-consciousness and being aware of their environment are absent5.
It must be considered the interaction between brain function and consciousness. According to some research, the energy consumed by the brain is more during intrinsic brain activity than that evoked brain activity4. A noticeable amount of energy is exploited by the brain in the case of the abstraction of a certain duty. The cost-based analysis of brain activity demonstrated the significance of intrinsic activity4. Further analysis revealed that disorders of consciousness are embodied by modulations of intrinsic brain activity in which striking alterations of the perception and feedback mechanism to environmental triggers deteriorate5.

With the goal of better understanding the concept of consciousness, the issue attracts scientists to elucidate the association between the mind and body6. Classification of the theories for better understanding of consciousness can be may as first-order theories and high-order theories3. The contents of high-order theories overweigh that of first-order ones in such ways:
- In order to create consciousness, first-order representation is limited, some high-order mechanisms are required. Regarding high-order theories, when presenting an external subject, first-order perceptual states arise spontaneously without forming consciousness [1].
- Transitivity principle refers to the necessity of minimal inner awareness of personal continuous mental activities over the formation of first-order representation3.
As you can see, high-order theory is an effort to explain which kinds of cognitive factors are needed to create consciousness3. Research showed that the prefrontal cortex has a role to play in the higher cognitive mechanisms7,8,9. As for high-order theory, the re-representation of nonconscious representations of neural states of first-order networks by a high-order network containing the prefrontal cortex exhibits consciousness.

According to the perspective of Integrated Information Theory, consciousness is the integration of information and is a boundary in which cause-effect formation over itself at any one time11. On the other hand, the inference-based theory of consciousness comprises the biological systems functioning as interference mechanisms11,12,13,14. The Inference-based theory considers properties of consciousness, which involves inference of the divergent sources of the sensory stimulation by living biological systems15. On the other hand, consciousness is supposed to be a process in which the interconnection between organisms and the environment occurs11.
References:
- FRITH C. The Quest for Consciousness: A Neurobiological Approach. Am J Psychiatry. Published online 2005. doi:10.1176/appi.ajp.162.2.407
- Kouider S. Neurobiological Theories of Consciousness. In: Encyclopedia of Consciousness. ; 2009. doi:10.1016/B978-012373873-8.00055-4
- Brown R, Lau H, LeDoux JE. Understanding the Higher-Order Approach to Consciousness. Trends Cogn Sci. Published online 2019. doi:10.1016/j.tics.2019.06.009
- Raichle ME, Mintun MA. Brain work and brain imaging. Annu Rev Neurosci. Published online 2006. doi:10.1146/annurev.neuro.29.051605.112819
- Boly M, Phillips C, Tshibanda L, et al. Intrinsic Brain Activity in Altered States of Consciousness . Ann N Y Acad Sci. Published online 2008. doi:10.1196/annals.1417.015
- Zeman A. What in the world is consciousness? Prog Brain Res. Published online 2005. doi:10.1016/S0079-6123(05)50001-3
- Miller EK, Cohen JD. An integrative theory of prefrontal cortex function. Annu Rev Neurosci. Published online 2001. doi:10.1146/annurev.neuro.24.1.167
- Nee DE, D’Esposito M. The representational basis of working memory. In: Current Topics in Behavioral Neurosciences. ; 2018. doi:10.1007/7854_2016_456
- D’Esposito M, Postle BR. The cognitive neuroscience of working memory. Annu Rev Psychol. Published online 2015. doi:10.1146/annurev-psych-010814-015031
- Laureys S. The neural correlate of (un)awareness: Lessons from the vegetative state. Trends Cogn Sci. Published online 2005. doi:10.1016/j.tics.2005.10.010
- Cooke JE. What is consciousness? Integrated information vs. inference. Entropy. Published online 2021. doi:10.3390/e23081032
- Friston K. Am I self-conscious? Front Psychol. Published online 2018.
- Friston KJ, Wiese W, Hobson JA. Sentience and the origins of consciousness: From cartesian duality to Markovian monism. Entropy. Published online 2020. doi:10.3390/E22050516
- Cooke JE. The living mirror theory of consciousness. J Conscious Stud. Published online 2020.
- Varela F. Autopoiesis and a biology of intentionality. Autopoiesis Percept A Work with ESPRIT …. Published online 1992.
Figure References:
- Boly M, Phillips C, Tshibanda L, et al. Intrinsic Brain Activity in Altered States of Consciousness . Ann N Y Acad Sci. Published online 2008. doi:10.1196/annals.1417.015
- Brown R, Lau H, LeDoux JE. Understanding the Higher-Order Approach to Consciousness. Trends Cogn Sci. Published online 2019. doi:10.1016/j.tics.2019.06.009
Inspector: Beril GÜREL