I did my best to ignore the cutting pain from the rope binding my arms and legs as I tried to listen in on what my captors had planned for me. From beneath the bottom of my blindfold, I could barely make out a few pairs of legs pacing around the room, but the gag in my mouth kept me from crying out for help.
“Maybe we should throw him in the river,” said one disembodied voice, with a thick Italian-Brooklyn accent Scorsese would be proud of. “Nah,” called another. “How about the wood chipper?”
The pacing stopped and the legs approached. Now hands gripped me tightly, hauling me off to my final resting place. I tried to squirm free, but the ropes only tightened around my chest, and as the breath left my lungs I felt the world around me slowly dim and go dark.
Sleep paralysis and conscious states
When I regained consciousness, I was happy to find myself safely in my bedroom, and annoyed to find that my kidnappers had made me late to work. Of course, I hadn’t really been abducted by bad stereotypes of Brooklyn mobsters – the whole thing was a dream.
More specifically, the incident I’ve just described was a case of sleep paralysis. Each night, we have multiple bouts of rapid-eye movement (REM) sleep, during which our memories from the previous day are consolidated, and when most of our dreams occur. Normally, neurons in the brainstem send inhibitory signals to our muscles, effectively causing paralysis and preventing us from acting on our dreams. Sleep paralysis occurs when these physiological processes get mistimed, and the brain “wakes up” while simultaneously sending inhibitory signals to the motor system.
The result is conscious awareness of being completely paralyzed, accompanied by vivid dream-like hallucinations of the kind I’ve just described, and often, even worse. In fact, many reported cases of hauntings, demonic possession and alien abduction throughout history are now presumed to have been particularly bad cases of sleep paralysis.
This incident and many others like it I’ve experienced over the years were critical to driving my interest in studying the function of the brain. How is it that the brain is capable of producing such a wide range of conscious states? How do things like sleep, disease and hallucinogens alter consciousness to cause such strange subjective experiences? Why are we conscious? Are animals conscious? What even IS consciousness?
The science of consciousness
Although an exact definition of consciousness is hard to pin down, for the purposes of this post we’ll call it subjective experience – that is, your ability to think, feel emotion, be self-aware, perceive, sense and interact with the world around you.
The problem of consciousness, which has been relegated to the realms of religion and philosophy for centuries, came into the world of neuroscience thanks to Francis Crick (of DNA and Rosalind-Franklin-credit-stealing fame) and Christof Koch. In 1990, they proposed that consciousness was a physically tractable problem, and could be explained entirely in terms of the brain. They suggested that brain regions controlling visual attention and short-term memory would be good places to start looking for the neural correlates of consciousness, or NCC.
Since their original publication, a wave of studies has come out implicating multiple different brain regions and physiological signatures in underlying consciousness. Researchers have approached the problem by examining sleep, anesthesia, vision, attention, psychiatric disease and hallucinations. They’ve tried to parse the problem into more manageable chunks by examining brain regions necessary for consciously perceiving specific events, rather than for being conscious in general. Studies have even looked at patients in comas or vegetative states to try and understand how their altered brain function diminishes conscious awareness. Still, consciousness is a hard problem, and the mind-boggling interconnectedness between brain regions guarantees that identification of the definitive NCC is far in the future.
Integrated information theory, panpsychism and the conscious universe
The experimental difficulties involved in pinning down the NCC have made theoretical approaches to the problem of consciousness especially attractive. In 2004, Italian neuroscientist and psychiatrist Giulio Tononi put forth a theoretical framework for consciousness called integrated information theory (IIT). Rather than starting with the brain and explaining consciousness in terms of cells and synapses, IIT proposes core components of subjective experience and makes inferences about what is required for its physical manifestation.
I won’t get too deep into detail (you can read the latest on IIT here), but put very simply, the big idea is that a conscious experience exists intrinsically, and is composed of multiple distinct phenomena that are specific and irreducible to their constituent parts. For example, you may have an experience of going to a music festival that includes a band onstage, a cold drink in your hand, bright lights and Day-Glo paint, and your friends wearing bad stereotypes of Native American headdresses. However, breaking your festival experience up into these individual pieces doesn’t capture the experience you had.
The features of a conscious experience require that its physical substrate must have cause-effect power within itself. In other words, one piece of the system should be able to cause effects, and be affected by, its neighboring pieces. Like a conscious experience itself, this cause-effect power must be irreducible, which endows the system with the ability to integrate information. The degree to which the system integrates information is denoted by the Greek letter φ, where higher φ indicates a system is “more conscious” and φ of zero implies a system has no consciousness at all. As you might expect, the qualities of the brain endow it with high φ. This mathematical formalization of consciousness has allowed for the development of clinical tools to assess levels of consciousness in comatose and vegetative patients, an extremely important problem in medicine.
There have been plenty of criticisms leveled at IIT, and most likely it doesn’t fully explain conscious experience. Still, Giulio Tononi and Christof Koch have recently added a nice thick layer of weirdness to the conversation by suggesting that the natural conclusion of IIT is panpsychism. Panpsychism is an ancient theory dating back to philosophers like Plato that claims consciousness is a fundamental property of all things in the universe. As I mentioned earlier, IIT is a theory of consciousness, not the brain. So, any number of physical objects could meet the requirements of IIT, and thus be conscious. Indeed, everything from lowly protons to advanced computing systems has been suggested to have some degree of consciousness (some readers may note the similarities to East Asian schools of thought like Dzogchen Buddhism and certain aspects of Shinto). Take a second to digest the idea that everything around you is conscious, and that you are just one mind in a world of minds. Bizarre, right?
Christof Koch is coming to my class to lead a discussion on consciousness and I’m really stoked
So why am I writing about consciousness now? As it turns out, Christof Koch will be in my Cognitive Neuroscience class tomorrow (5/19) to lead a discussion on consciousness and its biological underpinnings. These kinds of discussions about “the big questions” in neuroscience (and this big question, in particular) are what got me excited about being a scientist in the first place. After experiencing some frustration with spending a lot of time in class (instead of the lab) and getting bogged down in the minutiae of highly specific topics, this kind of high-level discussion should be a breath of fresh air. Not to mention, I’m a huge nerd and have read Consciousness: Confessions of a Romantic Reductionist and Phi: A Voyage from the Brain to the Soul about 5 times each.
Christoff is a pretty big deal in the science world, and I imagine not too many people outside his circle get the chance to have these kinds of discussions with him, least of all first-year grad students. Because I expect this to be an interesting and likely controversial topic, I’m inviting anyone reading to share with me any specific questions they might have for Christof. I’ll do my best to work them into discussion tomorrow, and follow up on this with a post about how it went.