According to a new study published in Scientific Reports, people with a family history of bipolar disorder have reduced prefrontal cortex activity. One of the primary functions of the prefrontal cortex is to plan a person’s response to complex and difficult problems.
Examining a total of a 144 Japanese people–93 with psychiatric illnesses such as schizophrenia, bipolar disorder, and major depressive disorder, and 51 healthy controls–the researchers found significant prefrontal cortex dysfunction in those with family histories of mental health issues, compared to healthy controls and people with illnesses without family histories of them.
The scientists used near-infrared spectroscopy (NIRS), a functional neuroimaging technology, to measure prefrontal cortex activation during a verbal fluency test. During the test, the study subjects were instructed to come up with as many nouns as possible that start with a Japanese hiragana letter (‘a’, ‘ki’, and ‘ha’, each for 20 seconds). In the pre- and post-task intervals, patients were instructed to pronounce English vowels repeatedly.
This is the first study to focus on family histories of mental illnesses when measuring prefrontal cortex activity. The scientists hope that more studies investigating genetic factors underlying major psychiatric disorders and prefrontal activation will be conducted.
Ohi, K. et al. Impact of Familial Loading on Prefrontal Activation in Major Psychiatric Disorders: A Near-Infrared Spectroscopy (NIRS) Study. Sci. Rep. 7, 44268; doi: 10.1038/srep44268 (2017).