Biophysics of Consciousness, or Can My Brain Explain My Pain?

Abstract

Why brain: I was attracted to study the brain because, as a child, I saw around me a lot of emotional suffering.I then thought to myself that, if I could understand the source of such suffering in the brain, I could provide a direct solution to suffering by developing some antisuffering pill or a focal electrical stimulation to relieve the source of pain.Already, during my army service, I consulted top scientists on how I should go about it.They all strongly recommended that I should study biology in order to become acquainted with the brain and mathe matics to uncover the general princi ples of brain function.So I did.It was excellent advice.Navet: Early in my university studies, I quickly recognized my naivety in expecting a swift, miraculous solution to " human suffering" through brain interventions.The brain's complexity became apparent, from its one hundred billion neurons and their numerous types-each often linked to a specific disease-to the intricate, dynamic cir cuits they form and their constantly changing connections ("plasticity" underpinning learning).This complexity left me wondering how such a delicate system of chemical and electrical elements usually functions as a coherent whole.To grasp this, I realized I needed to focus on studying the brain's fundamental units, the neurons, both experimentally and theoretically.Inspirations: My work was profoundly influenced by two major theoretical advances: the mathematical model of Hodgkin and Huxley (1952) that detailed the initiation and propagation of the spike-that is, the brain's basic electrical "bit" of information-and by the "cable theory for dendrites" by Wilfrid Rall (1959), who was my insightful and compassionate postdoc advisor.Rall's theory clarified how thousands of synaptic inputs to a neuron's dendritic tree produce output spikes transmitted to other neurons.After many years of almost "becoming a neuron" myself, I feel that I have made good pro gress in understanding how these power ful (and very beautiful) elementary pro cessing units of the nervous system receive, process, and transmit information like sensory information. Something is missing: It is exciting to study mathematically the cardinal ele ments that (from a materialistic viewpoint) generate my feelings, my sense of identity, my creativity OverviewScientists do not typically use words like miraculous, astonishing, or amazing in their scientific work.But they do so when they speak about consciousness.This reflects the per sis tent puzzle of consciousness-it is a phenomenon we experience very intensely, but find hard to explain scientifically.Despite impressive pro gress in understanding the biophysical mechanisms operating in the brain during conscious states, the "big leap" between these mechanisms and conscious experiences remains vast, and might remain unexplained by the scientific method as we know it (but who says that science should explain all things?).This, in no way, means that we should not continue very determinedly, and with a sense of urgency, to uncover the neuronal mechanisms and computational princi ples linked to consciousness.On the contrary, understanding consciousness has far-reaching clinical, ethical, and technological implications.In this chapter, I discuss recent advancements in identifying correlations and causative links between the biophysical properties of individual neurons and neuronal cir cuits, and consciousness, facilitated by ge ne tic tools like optoge ne tics.I argue that pro gress in understanding consciousness can be significantly boosted by forming a "society of brains" where philosophers and spiritual prac ti tion ers who study consciousness "within" collaborate closely with neuroscientists who study consciousness "without."I conclude by reflecting on how interdisciplinary interactions, the inspiration for this book, have enriched my research and broadly benefited science.And still they gaz'd and still the won der grew, that one small head could carry all he knew.-Oliver Goldsmith, "The Deserted Village"