Scientists Discover What Causes a 'Noisy' Memory in Schizophrenia

Researchers have uncovered a bit more about schizophrenia. They've found that the inability to ignore irrelevant stimuli may underlie the impaired working memory and cognition often experienced by individuals diagnosed with the condition.

"Our assumption was that understanding the impairments in the component processes of working memory-the ability to hold and manipulate information in the mind-among patients with schizophrenia could be fundamental to understanding not only cognitive function in the disorder, which is widespread and has debilitating consequences, but also the disorder itself," said Teal Eich at Columbia University, one of the researchers, in a news release.

The researchers examined patients with schizophrenia and compared them to a control group of health volunteers. Both groups participated in an item recognition task while undergoing a functional magnetic resonance imaging scan. The scientists particularly focused on analyzing potential activation differences in the ventro-lateral prefrontal cortex (VLPFC), a part of the brain associated with working memory.

"Our findings show that these patients have specific deficit in inhibiting information in working memory, leading to impaired distinctions between relevant and irrelevant thoughts," said Eich. "This result may provide valuable insights into the potential brain mechanisms underlying the reasons why these affected individuals are unable to control or put out of mind certain thoughts or ideas."

The findings also have implications for cognitive functions in general. It suggests that these functions require both the activation of one set of regions and the inhibition of others. The failure to suppress activation may be just as disruptive to cortical functions as deficits in cortical activation.

"We need to determine whether the cortical inhibitory deficits described in this study can be attributed to particular brain chemical signaling abnormalities," said John Krystal, Editor of Biological Psychiatry. "If so, this type of study could be used to guide therapeutic strategies to enhance working memory function."

The findings are published in the journal Biological Psychiatry.