By recording neuronal activity from a Japanese monkey model of Parkinson’s disease, the researchers have elucidated the neural mechanisms underlying parkinsonian symptoms. Disturbance of information flow through the “direct pathway” in the basal ganglia is responsible for parkinsonian symptoms, and its restoration has beneficial effects on the symptoms.

The researchers demonstrated that auditory gamma oscillation is globally distributed among the temporal, parietal, and frontal cortices by using intracranial recordings implanted for the diagnostic purpose of the intractable epilepsy. Elucidation of the mechanism of gamma oscillation, which is decreased in psychiatric disorders such as schizophrenia, is expected to be useful for the development of future diagnosis and treatment.

Comprehensive expression analysis of genes associated with developmental disorders and psychiatric disorders in the common marmoset brain revealed that these genes are expressed in a specific brain region. Also, by comparing the expression patterns of the mouse and human brain, it was clarified that there are many common expression patterns between marmosets and humans.

The researchers performed comprehensive DNA methylation analyses of neurons from patients with bipolar disorder, and found that many genes were hypomethylated in patients, while genes important for neuronal function were hypermethylated. Differentially methylated regions in neurons were significantly enriched in genomic regions suggested by a genome-wide association study of bipolar disorder, indicating an association with genetic factors.

The researchers developed a fast and wide field-of-view two-photon microscopy with practically no optical aberrations. Combining high-performance large lenses and devices and a fast laser scanning mirror enables the recording of over 16,000 neurons in awake mice. Functional network analysis with single-cell resolution reveals the small-world behavior of the cortex.