Summary: A new study identifies the brain mechanisms that help us distinguish real experiences from the imagined. The researchers found that the Fusiform Circunvolution, a region involved in visual processing, plays a key role in telling the reality of imagination, especially when we mentally imagine something vividly.
Using FMRI, the team showed that strong activation in this area could lead people to misunderstand the imagined images, particularly when imagining vivid visual patterns. These findings shed light on how the brain separates internal and external experiences, and how this process can decompose in disorders such as schizophrenia.
Key facts:
Fusiform gyrus paper: strong activation in this visual area increases the possibility of confusing imagined images with the real ones. Imagination can cancel reality: when mental images are vivid, the brain can treat them as real perceptions.
Source: UCL
The areas of the brain that help a person to differentiate between the real and what is imaginary have been discovered in a new study led by UCL researchers.
The investigation, published in Neuron, found that a region in the brain known as a fusiform turn, located behind the temples of one, at the bottom of the temporal lobe of the brain, is involved in helping the brain determine if what we see is from the external world or generated by our imagination.
Researchers expect their findings to increase the understanding of cognitive processes that go wrong when someone has difficulty judging what is real and what does not, as in schizophrenia, and eventually could lead to progress in the diagnosis and treatment of these conditions.
The main author, Dr. Nadine Dijkstra (Department of Image Neuroscience in UCL) said: “Imagine an apple in the eye of her mind as vividly as possible. During the imagination, many of the same brain regions are activated in the same way as when you see a real apple. Until recently, it is not clear how the brain distinguishes between these real and imagined experiences.”
For the study, the researchers asked 26 participants to analyze the simple visual patterns while imagining them at the same time.
Specifically, participants were asked to seek a specific weak pattern within a noisy background on a screen and indicate whether the pattern was really present or not. A real pattern only appeared half the time.
At the same time, the participants also received instructions to imagine a pattern that was the same or different from the one they were looking for, and indicated how vivid they were their mental images.
When the patterns were the same, and the participants reported that their imagination was very vivid, they were more likely to say that they saw a real pattern, even in the evidence in which nothing occurred. This means that they confused their mental images with reality.
While the participants performed the tasks, their brain activity was monitored using functional magnetic resonance images (FMRI). This technology allowed researchers to identify which parts of the brain showed activity patterns that helped distinguish the reality from imagination.
The team discovered that the strength of the activity in the fusiform turn could predict whether people judged an experience as real or imagined, regardless of whether it really was real.
When the activity in the fusiform turn was strong, people were more likely to indicate that the pattern was really there.
In general, activation in the fusiform turn is weaker during the imagination than during perception, which helps the brain to keep the two separated. However, this study showed that sometimes when the participants imagined very vividly, the activation of the fusiform circumvolution was very strong and the participants confused their imagination for reality.
The main author, Professor Steve Fleming (UCL Psychology & Language Sciences) said: “Brain activity in this area of the visual cortex coincided with the predictions of a computer simulation on how the difference between the experience generated internally and externally is determined.”
Dr. Dijkstra added: “Our findings suggest that the brain uses the force of sensory signals to distinguish between imagination and reality.”
The study also showed that the fusiform turn collaborates with other areas of the brain to help us decide what is real and what you imagine.
Specifically, the activity in the previous insula, a region of the brain in the prefrontal cortex (the front of the brain that acts as a control center for tasks such as decision making, problem solving and planning), increased in line with the activity in the fusiform turn when the participants said something was real, even if it imagined in fact.
Professor Fleming said: “These areas of the prefrontal cortex have been previously involved in metacognition: the ability to think about our own minds. Our results indicate that the same brain areas are also involved in deciding what is real.”
These results offer new ideas about what could go wrong in the brain during psychiatric conditions such as schizophrenia where patients fight to keep imagination and reality separate. The findings can also report future virtual reality technologies identifying how and when imagined experiences feel real.
FINANCING: The research was carried out in collaboration with Professor Peter Kok (Department of Image Neuroscience at UCL) and the former UCL Master Student Thomas von Rein. The study was funded by subsidies from the European Research and Wellcomo Council.
About this imagination and neuroscience research news
Author: poppy tombs
Source: UCL
Contact: poppy tombs – Ucl
Image: The image is accredited to Neuroscience News
Original research: open access.
“A neural base to distinguish the imagination of reality” by Nadine Dijkstra et al. Neuron
Abstract
A neural base to distinguish the imagination of reality
Humans can imagine scenarios that are decoupling of the current environment internally activating the perceptual representations.
Although it is an efficient reuse of existing resources, it is unknown how human observers classify perceptual signals such as reflecting external reality, unlike internal simulation or imagination.
Here, we show that the trials of reality are backed by the combined force of the sensory activity generated by images or perception in the fusiform turn.
Activity fluctuations in this region predict confusion between images and perception on a test base by trial and interact with a frontal brain red that encodes binary judgments of reality.
Our results show that a key mechanism through which the brain distinguishes the imagination of reality is to monitor the activity of the medium -level visual cortex.
These findings increase our understanding of reality tests and feel the foundations to characterize a generalized perceptual reality monitoring system in the human brain.
