Hyperactive brain-waves Linked with Schizophrenia, MIT Researchers Say

Abnormally high brain-wave oscillations are linked with delusions and hallucinations in people suffering from schizophrenia, researchers at the Massachusetts Institute of Technology have found.

Schizophrenia is a chronic and severe brain disorder that has affected people for years. People with this disorder hear voices that others can't. They may also believe that others are plotting against them. These people may become agitated and withdraw themselves from the society, according to National Institute of Mental Health.

According to the researchers, communication network in the brain gets disrupted, making some areas of brain highly active.

Another recent study had found that high levels of glutamate in the brain may accelerate the progression of the condition. Previous studies, also conducted by MIT researcher Susumu Tonegawa and colleagues, had shown that mice lacking the gene for calcineurin- a brain protein- display symptoms of schizophrenia.

In this study, Tonegawa and team tracked activity of individual neurons in the hippocampus of mice lacking the gene coding for calcineurin. The hippocampus is associated with consolidation of information from short-term memory.

For the study, mice were made to run along a track while researchers measured their brain activity. It is already known that in normal mice, "place cells" in the hippocampus fire in a sequence. Each signal corresponds to a specific location on the track. These "mental images" are played every time the mice sleep or take a break from running. Usually, these replays occur along very high frequency brain-wave oscillations known as ripple events.

The team found that the test mice had abnormally high ripple events and that the place cells fired randomly, possibly altering the mental replay of events.

According to the researchers, this difference in brain activity may explain some of the symptoms associated with schizophrenia.

"We think that in this mouse model, we may have some kind of indication that there's a disorganized thinking process going on," said Junghyup Suh, a research scientist at the Picower Institute and one of the study authors. "During ripple events in normal mice we know there is a sequential replay event. This mutant mouse doesn't seem to have that kind of replay of a previous experience."

The study also highlights the role of calcineurin in neural activity regulation. The scientists hypohsize that without the protein, the long-term potentiation (LTP) becomes more prevalent and the synapses in the brain get stronger.

"It looks like this abnormally high LTP has an impact on activity of these cells specifically during resting periods, or post exploration periods. That's a very interesting specificity," Tonegawa said in a news release. "We don't know why it's so specific."

The study is published in the journal Neuron.