Non-invasive stimulation of the cerebellum at a delta frequency normalizes brain activity in the frontal cortex of lab rats with schizophrenia-like thinking disorders, according to a first-of-its-kind new study from the University of Iowa Carver College of Medicine. These findings were published online ahead of print March 28 in the journal Molecular Psychiatry.
In this experiment, the researchers also used optogenetics to stimulate the rats’ cerebellum at the precise delta-wave frequency of 2 Hertz, which restored normal delta wave activity in the rats’ frontal cortex and normalized the rats’ performance on a timing test. This cerebellar stimulation also improved a lab animal's ability to estimate the passage of time, which is a cognitive deficit often observed in human beings with schizophrenia. (Cerebellar is the sister word to cerebral and means "relating to or located in the cerebellum.")

In patients with schizophrenia, dopamine signaling in the frontal cortex tends to be abnormal. By blocking dopamine signaling in the frontal cortex of lab rats, the researchers at UI were able to reproduce schizophrenia-like cognitive and timing problems in animal models.
This cutting-edge research was led by Krystal Parker, who says, "My long-term goal is to understand the cerebellar contribution to cognition." In a statement, Parker, who is a University of Iowa assistant professor of psychiatry and the first faculty hire to the brand new Iowa Neuroscience Institute, said:

"Cerebellar interactions with the frontal cortex in cognitive processes has never been shown before in animal models. In addition to showing that the signal travels from the cerebellum to the frontal cortex, the study also showed that normal timing behavior was rescued when the signal was restored . . . We think timing is a window into cognitive function. It allows us to probe executive processes like working memory, attention, planning—all those things are abnormal in schizophrenia."

Parker's lab is working with the lab of Nandakumar Narayanan at the University of Iowa. Together, they are unearthing previously unknown and enigmatic influences that the cerebellum has on cognition. Contrary to the long-held belief that the cerebellum wasn't involved in cognitive processes, it now appears that the cerebellum plays a complex role in executive function, creativity, attention, planning, emotional regulation, reward-seeking behavior, etc.


Dysfunctions or abnormalities within the structure of the cerebellum—or atypical cerebellar functional connectivity with other brain regions—appears to be linked to disorders such as schizophrenia, autism, and Tourette's syndrome.


The latest findings by Parker and colleagues provide fresh insights into how the cerebellum influences neural networks in the frontal lobes and the role of the cerebellum in cognitive processing. This study also suggests that delta-frequency cerebellar stimulation might help improve cognitive problems in human patients with schizophrenia.
Although this study focused on schizophrenia, the researchers point out that similar cognitive problems linked to cerebellar abnormalities are observed in autism spectrum disorders (ASD), Parkinson's disease, addiction, OCD, bipolar disorder, and depression. The researchers are optimistic that if cerebellar stimulation proves helpful for schizophrenia, it might also be beneficial for patients with any of these other conditions.