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Feb 24, 2021

Dissociation and the self: What part of the brain makes you, you?

This article provides information about ongoing scientific research and does not provide any medical advice.

What is the self? Is it a constant sense of being the same? Is it your self-conception, or the collective perceptions of others that determine who you really are? Or, is it a core authenticity that’s obscured by the need to fit into society? And, if you recognize having a variety of selves—a "work self", an extroverted version of yourself, a "true self"—that compete with one another, can you integrate them into a whole that gels nicely?

The arts and humanities have contemplated these questions for centuries and sought to capture how notions of the self change over time. Yet, while we might recognize the complexity of accurately defining selfhood, most of us go through the world feeling a sense of integration that we casually recognize as the self. And if that basic awareness of being at home in one's body and mind were to disappear, it would be frightening.

Dissociation is the state of failing to recognize your current or former self. A certain level of dissociation is an everyday event: We often step out of our immediate environment or consciousness when we daydream or have “highway hypnosis”—the sense of not having been aware of driving, especially on a familiar route. Dissociation has even been considered a cognitive skill associated with absorption in a task. But we count on emerging from these states.

Dissociation becomes pathological when the brain fails to recognize the self as the self. It has been described as an “out of body” experience, where a person may see what’s happening to them but not feel affected by or in control of their body and mind—this is especially true of drug-induced dissociation. The most well-known form of dissociation is multiple personality disorder (aka dissociative identity disorder), but dissociation is also behind dissociative amnesia, a fairly common symptom arising from trauma.

Dissociation has long been considered primarily an internal psychological problem, where thoughts and feelings are suppressed as a means of defending a person’s conscious mind against a trauma that they can’t cope with. Suppressing a trauma can result in an inability to remember details of traumatic events, or in converting the traumatic feelings into physical ailments, as Freud found in his “hysterical” patients. Interestingly, people susceptible to hypnosis had more of a tendency to develop dissociative or “hysterical” symptoms, and a review by Timo Giesbrecht et al (2008) suggests that trauma isn’t the only culprit when it comes to pathological dissociation; instead, they argue, a variety of other cognitive failures, such as disinhibition, are predictive of dissociative episodes.

Regardless of how it’s triggered, dissociation is a subjective experience—it involves personal perception. But it’s not simply a matter of perspective, as a recent paper published in Nature shows. In it, Karl Deisseroth and colleagues at Stanford University examine the biological basis of cognitive dissociation: their work describes the brain circuitry that produces the experience of dissociation and identifies a protein that’s present during the cellular choreography seen during dissociative episodes. The scientists used ketamine to manufacture dissociative states in mice, observing that dissociative behavior was accompanied by rhythmic and coordinated neuron firing in the area of the brain associated with dissociation. They also pinpointed and observed the same rhythm—coordinated neuron firing at intervals of 3 hertz (that is, 3 times per second)—in the posteromedial cortex of a man with epilepsy who experienced dissociation prior to seizures.

After establishing that the rhythm corresponded with dissociative episodes, the researchers induced dissociation—in mice by using light, and in the human subject via electrical stimulation—to trigger the rhythm in the associated brain area. Then, they experimented further on the mice to learn that a certain protein—an ion channel that regulates electrical activity in the brain—was responsible for the 3 hertz rhythm that they were seeing.

The upshot? Identifying this protein as the physiological root of dissociation may give researchers a path towards medically targeting one of the most debilitating aspects of a variety of diseases, including PTSD. This is especially important, because dissociative disorders are associated with a high risk of self-destructive behaviors and suicide, and given the prevalence of PTSD in the United States, they pose a serious public health concern.

Still, it’s worth remembering the benefits of temporary and controlled dissociative moments, such as we might find in daydreaming or through meditation. Stepping outside of ourselves is a key ingredient in empathy, too. And Buddhist meditation—as with many religions—encourages the practice of releasing thoughts and feelings in an effort to achieve a heightened awareness of the world around us. A unified sense of selfhood is crucial to healthy functioning, but there’s a long philosophical tradition suggesting that an over-emphasis on selfhood is problematic, too.

By Aimee Fountain













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