Study discovers brain regions that help distinguish imagination from reality

Areas of the brain that help a person distinguish between what is true, and what imagined was discovered in a new study conducted by UCL researchers.

Studies, published, have shown that the region in the brain known as a spindle corner – located behind the temples, on the bottom of the temporal lobe of the brain – is involved in the aid of brain in determining whether we see from the outside world or generated by our imagination.

Scientists hope that their findings will increase the understanding of cognitive processes, which are not intended when someone has difficulty assessing what is true and what is not, for example in schizophrenia, and ultimately can lead to development in diagnosing and treating these conditions.

Imagine an apple in the eye of the mind as vividly as possible. During imagination, many of the same areas of the brain activate in the same way as when you see a real apple. Until recently, it was not clear how the brain distinguished these real and imaginary experiences. “

Dr. Nadine Dijkstra, main author, Department of Imaging Neuroscience in UCL

In the study, scientists asked 26 participants to look at simple visual patterns, while imagining them at the same time.

In particular, the participants were asked to look for a specific weak pattern on a loud background on the screen and indicate whether the pattern was actually present or not. The real pattern was presented only for half the time.

At the same time, the participants were also instructed to imagine a pattern that was the same or different than the one they were looking for, and indicated how vivid their mental images were.

When the patterns were the same and the participants reported that their imagination was very alive, they more often stated that they saw a real pattern, even in rehearsals in which nothing was presented. This means that they confused their mental images with reality.

While participants performed tasks, their brain activity was monitored using functional magnetic resonance imaging (FMRI). This technology enabled scientists to determine which parts of the brain showed activity patterns that helped distinguish reality from the imagination.

The team said that the power of activity in the spindle bend can predict whether people assessed experience for real or imagined, regardless of whether it was really true.

When the activity in the spindle bend was strong, people more often indicate that the pattern really was there.

Usually, activation of the spindle bend is weaker during imagination than during perception, which helps the brain keep both separately. However, this study showed that sometimes, when the participants imagined very vividly, the activation of the spindle corner was very strong, and the participants confused their imagination for reality.

The elderly author, Professor Steve Fleming (UCL Psychology & Language Sciences) said: “Brain activity in this area of ​​visual cortex corresponded to forecasts from computer simulation about how the difference between internal and external experience is determined.”

Dr. Dijkstra added: “Our discoveries suggest that the brain uses the strength of sensory signals to distinguish between imagination from reality.”

The study also showed that the spindle bend works with other areas of the brain to help us decide what is true and what is imagined.

In particular, activity in the front sow – the brain region in the prefrontal cortex (the front part of the brain, which acts as a control center of tasks, such as decision making, problem solving and planning) – increased with activity in the spindle bend when the participants said something real, even if it was imagined.

Professor Fleming said: “These areas of the prefrontal cortex were previously involved in Metapów – the ability to think about our own minds. Our results indicate that the same areas of the brain are also involved in deciding what is true.”

These results offer a new insight into what can go wrong in the brain in psychiatric conditions, such as schizophrenia, in which patients struggle with separating imagination and reality. Discoveries can also affect future virtual reality technologies, identifying how and when imaginary experiences seem true.

The research was conducted in cooperation with Professor Peter Kok (Department of Imaging Neuroscience in UCL) and a former UCL Masters Student Thomas von Rein. The study was financed from a subsidy of the European Research Council and Wellcome.