Patients with schizophrenia aren’t the only ones who hear voices.
According to international research, approximately five percent of the population hears voices, even though they are otherwise healthy.
So what is the difference — in terms of brain activity — between those who are healthy and hear voices and those who suffer from mental illness? How can understanding the differences help those suffering from schizophrenia?
These are some of the questions behind current research being conducted at the University of Bergen in Norway.
For a five-year period, researchers from the Bergen fMRI Group have been studying the brain processes that cause people to hear voices. A recent report published in Frontiers in Human Neuroscience shows some of the group’s startling results.
“We have found that the primary auditory cortex of healthy people who hear voices responds less to outside stimulus than the corresponding area of the brain in people who don’t hear voices,” said lead author Kristiina Kompus, Ph.D., from the Department of Biological and Medical Psychology.
The primary auditory cortex is the region of the brain that processes sound.
The findings show that healthy people who hear voices share some attributes with schizophrenia patients, as the cortical region in both groups reacts less to outside stimulus.
However, there is an important difference between the two groups: those with schizophrenia have a reduced ability to regulate the primary auditory cortex using cognitive control, while those who hear voices but are healthy are able to do so.
“Because of this cognitive control, healthy people who hear voices are able to direct their attention outwards. This sets them apart from schizophrenics, who have a tendency to direct their attention inwards due to their decreased ability to regulate their primary auditory cortex,” said Kompus.
“These discoveries have brought us one step closer to understanding the hallucinations of schizophrenics and why the voices become a problem for some people but not for others.”
“We will do further research on the brain structure of people with auditory hallucinations. In particular, we wish to look at the brain’s networks that process outside voices.
“This is to establish whether these voice hallucinations and the outside voices occur in the same parts of the brain. We also wish to establish if hearing voices is a genetic trait,” she said.
Source: University of Bergen