This is how the brain distinguishes reality from imagination

The areas of the brain that allow us to distinguish reality from imagination have been identified: the discovery, published in the journal Neuron by University College London, could improve the diagnosis and treatment of conditions such as schizophrenia and could even inspire new virtual reality technologies for increasingly realistic experiences . "Think of an apple as vividly as possible: during imagination , many of the brain regions that are activated when you see a real apple light up ," notes neuroscientist Nadine Dijkstra. "Until recently, it was unclear how the brain distinguishes between these real and imagined experiences." To find out, the researchers asked 26 volunteers to look for a specific visual pattern in a slightly fuzzy image shown on a screen, indicating whether the pattern was actually present. At the same time, the participants were asked to imagine a pattern that was the same or different from the one they were looking for and to indicate how vivid their mental images were. When the patterns were the same and participants reported that their imagination was very vivid, they were more likely to say they saw a real pattern, even when nothing was presented on the screen. This means they mistook their mental images for reality. During the experiment, brain activity was monitored using functional magnetic resonance imaging . The images showed that a region of the brain known as the fusiform gyrus (located behind the temples, in the lower part of the temporal lobe) is involved in helping us determine whether what we see comes from the outside world or is generated by our imagination . Typically, activation in the fusiform gyrus is weaker during imagination than during perception, which helps the brain keep the two separate. However, the study showed that sometimes, when participants imagined very vividly , the activation in the fusiform gyrus was particularly strong , and they ended up mistaking their imagination for reality . The study also showed that the fusiform gyrus works with other brain areas to help us distinguish between real and non-real. In particular, activity in the anterior insula (a region of the prefrontal cortex) increased in line with activity in the fusiform gyrus when participants said that something was real, even if it was actually imaginary.