In a recent review published in Physics of Life Review, Amal Alachkar, PhD, UCI professor of teaching in the Department of Pharmaceutical Sciences, explores the fundamental mind-body problem and how physical systems gave rise to consciousness: “inner” subjective experience and perception of the “outer” physical world.
The study proposes the idea that consciousness arose as a natural evolutionary consequence of biological adaptations in the brains and nervous systems of complex organisms.
Alachkar’s study observed consistent patterns shared in unrelated phenomena throughout life evolution and noticed that photosynthetic proteins, circadian rhythms’ molecules – in the earliest forms of life- and later in nearly all sunlight-capture molecules throughout evolution contain the aromatic* amino acid tryptophan, which appears to be essential for their sunlight-capture capacity.
Her study proposes that tryptophan-containing molecules evolved to assume more complex functions in animals and humans (consciousness) while maintaining their photon-capture features.
A translational implication is that consciousness states can be altered/manipulated pharmacologically by chemicals that have aromatic structures (mainly tryptophan), such as psychedelics. Tryptophan-derived psychedelics may produce an altered state of consciousness that is associated with a loss of a sense of self and a feeling of “oneness” or “unity.” Anesthesia is associated with partial loss of the state of consciousness, and many anesthetic drugs produce loss of consciousness through mechanisms related to tryptophan.
“Consciousness is a hallmark of human life, and yet, its true nature has evaded scientific explanation for centuries,” says Alachkar. “I hope the concepts proposed in this perspective invite further interdisciplinary dialogue at examining the role of aromaticity beyond tryptophan, such as other aromatic amino acids and nucleobases of RNA and DNA, as it pertains to consciousness.”
*Aromatic molecules refer to the planar ring structures created by stable covalent bonds between atoms, as seen in benzene.