“
Recently, brain scans of schizophrenics taken while they were having auditory hallucinations have helped explain this ancient disorder. For example, when we silently talk to ourselves, certain parts of the brain light up on an MRI scan, especially in the temporal lobe (such as in Wernicke’s area). When a schizophrenic hears voices, the very same areas of the brain light up. The brain works hard to construct a consistent narrative, so schizophrenics try to make sense of these unauthorized voices, believing they originate from strange sources, such as Martians secretly beaming thoughts into their brains. Dr. Michael Sweeney of Ohio State writes, “Neurons wired for the sensation of sound fire on their own, like gas-soaked rags igniting spontaneously in a hot, dark garage. In the absence of sights and sounds in the surrounding environment, the schizophrenic’s brain creates a powerful illusion of reality.” Notably, these voices seem to be coming from a third party, who often gives the subject commands, which are mostly mundane but sometimes violent. Meanwhile, the simulation centers in the prefrontal cortex seem to be on automatic pilot, so in a way it’s as though the consciousness of a schizophrenic is running the same sort of simulations we all do, except they’re done without his permission. The person is literally talking to himself without his knowledge. HALLUCINATIONS The mind constantly generates hallucinations of its own, but for the most part they are easily controlled. We see images that don’t exist or hear spurious sounds, for example, so the anterior cingulate cortex is vital to distinguish the real from the manufactured. This part of the brain helps us distinguish between stimuli that are external and those that are internally generated by the mind itself. However, in schizophrenics, it is believed that this system is damaged, so that the person cannot distinguish real from imaginary voices. (The anterior cingulate cortex is vital because it lies in a strategic place, between the prefrontal cortex and the limbic system. The link between these two areas is one of the most important in the brain, since one area governs rational thinking, and the other emotions.) Hallucinations, to some extent, can be created on demand. Hallucinations occur naturally if you place someone in a pitch-black room, an isolation chamber, or a creepy environment with strange noises. These are examples of “our eyes playing tricks on us.” Actually, the brain is tricking itself, internally creating false images, trying to make sense of the world and identify threats. This effect is called “pareidolia.” Every time we look at clouds in the sky, we see images of animals, people, or our favorite cartoon characters. We have no choice. It is hardwired into our brains. In a sense, all images we see, both real and virtual, are hallucinations, because the brain is constantly creating false images to “fill in the gaps.” As we’ve seen, even real images are partly manufactured. But in the mentally ill, regions of the brain such as the anterior cingulate cortex are perhaps damaged, so the brain confuses reality and fantasy.
”
”
Michio Kaku (The Future of the Mind: The Scientific Quest to Understand, Enhance, and Empower the Mind)