Tag Archives: hallucination

Credit: Pixabay.

Hallucinations may be the side effect of over-processing in brain’s visual center

Credit: Pixabay.

Credit: Pixabay.

Hallucinations are the apparent perception of something not present, be them a tiny dragon in your cupboard, the smell of burned tires in your coffee, or menacing voices in your head. Hallucinations are reported by millions of people around the world affected by mental conditions such as schizophrenia and depression, but they can also be caused by psychedelics like LSD or ‘magic mushrooms’. In a new study, researchers at the University of Oregon found that mice

given a psychedelic drug had dampened activity in the brain’s visual center. Their results suggest that hallucinations may occur when the brain over-interprets the information in front of it.

What’s going on inside the hallucinating brain

The research team at the University of Oregon in Eugene injected mice with a hallucinogenic drug called 4-iodo-2,5-dimethoxyphenylisopropylamine (DOI). Like other hallucinogenic substances, DOI produces its effects by binding with serotonin 2A receptors. Serotonin is often called ‘the happy chemical’ because it contributes to wellbeing and happiness. However, it is involved in a wide range of functions in the body, including vision. Previous research showed that drugs which block these receptors in the brain prevent hallucinations in people with schizophrenia.

The hallucinating mice were placed in front of a digital screen which flashed various pictures. All the while, researchers examined the brain activity of the mice and compared it to normal conditions. They found that while the mice were hallucinating on the images, brain activity in the visual cortex — the region of the brain responsible for interpreting visual information — was dampened.

This was a very counter-intuitive finding. One would expect that neurons in the visual cortex would fire in over-drive when a person is hallucinating, not the other way around. However, this makes sense if you look at it from the context of visual processing. The most important clue was that the visual signals sent to the visual cortex were almost the same as those sent in the absence of the drug, which shows that the brain still received the same information. What differed was the way that information was processed.

Writing in the journal Cell Reportsthe researchers conclude that hallucinations may be the product of over-interpretation. Essentially, the brain is filling the blanks in what it perceives as missing information.

“Understanding what’s happening in the world is a balance of taking in information and your interpretation of that information,” Cristopher Niell, a neuroscientist at the University of Oregon in Eugene, said in a statement. “If you’re putting less weight on what’s going on around you but then over-interpreting it, that could lead to hallucinations.”

The study’s main limitation is that it worked only with mice, but the findings could reasonably translate to humans as well. Hallucinating mice shared many characteristics seen in humans, such as visible movement and behavioral changes.

The authors are also careful to mention that over-interpretation isn’t the only cause for hallucinatory experiences. Instead, there are likely many causes and uncovering each of them may be important in a medical setting for the treatment of schizophrenia and other mental disorders that cause hallucinations.

Looking into someone’s eyes for 10 minutes alters your state of mind and can cause hallucinations

Staring straight into someone’s eyes can be pretty intense, and is usually avoided by most people. But a team of researchers has shown that it’s even more intense than you’d think: it actually alters your consciousness, and often causes hallucinations.

Image via Imgneed.

This particular study was conducted on only 20 volunteers, but the results were consistent across all participants. They weren’t told what the purpose of the study was, only knowing that it had to do with a “meditative experience with eyes open”. They were placed in pairs of 2 in a dimly lit room and asked to look at their partner’s eyes for 10 minutes straight. After that, they were asked to complete questionnaires related to what they experienced during and after the experiment.

Not only did the experiment bring on strange ‘out of body’ experiences for the volunteers, it also caused them to see hallucinations of monsters, their relatives, and themselves in their partner’s face. Quite a strange trip, for only looking into someone’s eyes.

“The participants in the eye-staring group said they’d had a compelling experience unlike anything they’d felt before,” Christian Jarrett writes for the British Psychological Society’s Research Digest. 

Scientists aren’t sure what it is, but something about starting into human eyes seems to bring out these strange reactions.

Jarrett explains:

“On the dissociative states test, they gave the strongest ratings to items related to reduced colour intensity, sounds seeming quieter or louder than expected, becoming spaced out, and time seeming to drag on. On the strange-face questionnaire, 90 percent of the eye-staring group agreed that they’d seen some deformed facial traits, 75 percent said they’d seen a monster, 50 percent said they saw aspects of their own face in their partner’s face, and 15 percent said they’d seen a relative’s face.”

The results are consistent with another, 2010 study, in which participants were asked to look at their reflection in a mirror for 10 minutes, focusing on the eyes. The paper, entitled Strange-Face-in-the-Mirror Illusion, reports that after less than a minute, the volunteers started seeing illusions and experiencing strange emotions.

“The participants’ descriptions included huge deformations of their own faces; seeing the faces of alive or deceased parents; archetypal faces such as an old woman, child or the portrait of an ancestor; animal faces such as a cat, pig or lion; and even fantastical and monstrous beings,” Susana Martinez-Conde and Stephen L. Macknik write for Scientific American. “All 50 participants reported feelings of ‘otherness’ when confronted with a face that seemed suddenly unfamiliar. Some felt powerful emotions.”

Although in all fairness, it may have nothing to do with eyes at all. This phenomenon might be caused by neural adaptation – in other words, if you’re continuously looking at the same thing, your neurons become less and less stimulated, the perception starts to fade, and you start to see other things where other things simply aren’t.

Caffeine consumption linked to hallucinations

You can’t believe everything people say, but you sometimes can’t even believe what you hear, especially if you’ve had 3 or more cups of coffee. Australian researchers from La Trobe University have just published a study suggesting that people on a major coffee buzz are prone to hear and seethings that aren’t there.

The thins is that this might raise new concerns about caffeine use, but if you ask me, for the average coffee consumer who hears about studies like this all the time, this is hardly going to amount to anything more than background noise.

They employed a simple method to test this; they asked a number of subjects, some caffeineted (over 3 cups) and some not; they put on headphones, and told them to focus on the noise, and that White Christmas would be playing on the background – which was a plain lie. The researchers concluded that more than five cups of coffee can be clearly linked with hallucinations – most of the subjects stating that they heard the music.

Of course this study refers only to mild hallucinations, and there a huge gap between hearing White Christmas and full scale hallucinations; but then again, that’s how it starts, doesn’t it ?