Researchers at Stanford University have identified a specific region in the brain responsible for anchoring us in our physical selves. This area launches us into the bizarre realm of out-of-body experiences when disrupted.
The discovery centers on a sausage-shaped piece of brain tissue called the anterior precuneus.
Located in the hidden valley between your brain’s hemispheres, this region acts as the control center for your physical self-awareness – your understanding that your thoughts, perceptions, and body belong to you and not someone else.
Dr. Josef Parvizi, a neurology professor at Stanford, made this breakthrough after a patient with epilepsy described experiencing something profoundly strange: “My sense of self is changing, almost like I am a third observer to conversations that are happening in my mind that I’m not part of. Plus, they just feel like I’m floating in space.”
The Science Behind Your Sense of Self
When Parvizi’s team electrically stimulated this specific brain region in eight patients, every single one reported changes in their sense of physical self. Some described floating sensations, others felt disconnected from their bodies entirely.
This wasn’t just coincidence. The researchers had found a direct line to our physical self-awareness.
The study, published in the journal Neuron, reveals that the anterior precuneus serves as our brain’s anchor to reality.
“We think this could be a way for the brain to tag every experience in the environment as mine,” explains Christophe Lopez, a researcher at the National Center for Scientific Research in France who wasn’t directly involved in the study.
The Surprising Truth About Out-of-Body Experiences
Here’s where things get interesting: out-of-body experiences aren’t just random neural misfirings or purely psychological phenomena. They happen when your brain receives conflicting sensory information about your body’s position in space.
The anterior precuneus acts as a processing hub for signals from your inner ear, which tracks your body’s motion and position. When these signals don’t match what your eyes are telling you – for instance, your inner ear senses movement while your eyes see stillness – your brain gets confused.
And sometimes, the brain’s best solution to this confusion is to place your consciousness outside your body entirely.
This explains why these experiences can occur during seizures, when taking certain drugs like ketamine, or during electrical stimulation of this brain region. Each of these disrupts the normal functioning of the anterior precuneus.
Beyond the Floating Sensation
The implications of this discovery extend far beyond explaining weird brain experiences. Patrick Purdon, a Harvard researcher studying ketamine’s effects on the brain, notes that the anesthetic drug appears to produce an “artificial rhythm” that disrupts the anterior precuneus – much like electrical stimulation does.
This raises an intriguing possibility: could targeted electrical stimulation replace anesthetic drugs like ketamine?
“You could get the specific brain areas that you want without having to cause a brain-wide and system-wide effect that might carry with it a lot of side effects,” Purdon suggests.
Even more fascinating is the potential connection to depression treatment. Ketamine has shown remarkable effectiveness as an antidepressant. If stimulating the precuneus could reproduce ketamine’s effects without the drug itself, we might have a new approach to treating depression.
The Dual Nature of Self
The research also highlights something profound about human consciousness: our sense of self has multiple components. The PMC (posteromedial cortex) region, which includes the anterior precuneus, contributes to both our narrative self and our physical self.
Your narrative self is your internal autobiography – the story you tell about who you are, your memories, and your personal history. Your physical self is your awareness of occupying a specific point in space and time.
Most of us take this physical self-awareness for granted. As Parvizi puts it: “As you are sitting in your chair, you have an understanding that it is you looking at me, your point of view in space and in your environment.”
But for some – like patients with certain neurological conditions or those experiencing drug effects – this fundamental sense can temporarily dissolve.
When Your Self Becomes Untethered
Out-of-body experiences have been reported across cultures and throughout history. They’re often associated with near-death experiences, deep meditation, and certain psychological states. Some people describe floating above their physical body, watching events unfold below. Others report traveling to different locations entirely.
While these experiences have often been interpreted as spiritual or supernatural, this research offers a neurological explanation. When the anterior precuneus malfunctions – whether due to seizure activity, drugs, or electrical stimulation – our physical self becomes untethered.
The brain, struggling to make sense of conflicting sensory information, creates the perception that consciousness has separated from the body.
This doesn’t necessarily diminish the profound impact these experiences can have on those who undergo them. Many people report life-changing insights and shifts in perspective after out-of-body experiences, regardless of their cause.
The Wider Implications
Understanding the neural basis for out-of-body experiences opens doors to fascinating research possibilities. If scientists can reliably trigger and study these states, they might gain new insights into consciousness itself.
The research also highlights the incredible complexity of our brains. A small, sausage-shaped region hidden between our brain hemispheres plays a crucial role in one of our most fundamental experiences – the sense that we exist within our bodies.
This finding adds to our growing understanding of the neural correlates of consciousness – the specific brain activities that correspond to conscious experiences. By mapping these correlates, scientists inch closer to answering the hard problem of consciousness: how physical brain processes give rise to subjective experience.
Beyond Medical Applications
The discovery has implications beyond medicine and neuroscience. Philosophers have long debated the nature of self and consciousness. This research provides empirical evidence that our sense of embodiment – of being anchored in a physical form – depends on specific brain mechanisms that can be disrupted.
For virtual reality developers, understanding how the brain creates our sense of embodiment could lead to more immersive experiences. If we know what neural signals create the feeling of being present in our bodies, perhaps we can better trick the brain into feeling present in virtual ones.
For those studying altered states of consciousness – whether induced by meditation, psychedelic substances, or other means – this research provides a physiological framework for understanding certain aspects of these experiences.
The Future of Brain Research
Parvizi’s discovery marks a significant step forward in our understanding of consciousness and self-awareness. But as with all groundbreaking research, it raises as many questions as it answers.
How does the anterior precuneus interact with other brain regions to create our sense of self? What role does it play in conditions like depersonalization disorder, where people chronically feel detached from their bodies and thoughts? Could targeted stimulation of this region help treat such conditions?
As neuroscientists continue mapping the brain’s role in creating our subjective experience, we may find answers to these questions and many more. The brain, with its billions of neurons and trillions of connections, still holds countless secrets about how it generates our conscious experience.
A Personal Connection
Out-of-body experiences, while scientifically fascinating, are also deeply personal for those who experience them. Whether occurring during a seizure, under anesthesia, or in a near-death situation, these episodes often leave a lasting impression.
Understanding their neural basis doesn’t diminish their significance. Instead, it adds another dimension to our appreciation of the brain’s remarkable capacities.
For patients with certain forms of epilepsy, knowing that their strange sensations of disembodiment have a physical cause might provide some comfort. For researchers developing new treatments for conditions ranging from depression to chronic pain, this knowledge offers new potential targets.
The Continuing Mystery of Consciousness
While this research illuminates one aspect of self-awareness, the broader mystery of consciousness remains. How does neural activity – essentially electrical and chemical signals – translate into subjective experience? Why does stimulating the anterior precuneus create the feeling of floating rather than some other sensation?
These questions touch on the frontier of neuroscience, where biology meets philosophy. As researchers continue probing the brain’s secrets, we may develop better frameworks for understanding the relationship between physical brain states and subjective experience.
In the meantime, discoveries like Parvizi’s remind us of the brain’s extraordinary complexity and the fascinating journey of self-discovery that modern neuroscience represents.
For now, when you feel firmly anchored in your body as you read these words, you can thank your anterior precuneus – silently doing its job, keeping your sense of self right where it belongs.
References
- Hamilton, J. (2023, July 3). Scientists have found part of the brain that triggers out-of-body experiences. NPR. Retrieved from npr.org.
- Parvizi, J. et al. (2023). Neural correlates of physical self-awareness in the anterior precuneus. Neuron.
