Biography:

Michihiko Koeda is a senior assistant professor of the psychiatry department at Nippon Medical School, Tokyo, Japan. He completed his PhD at the Medical
Research Institute of Tokyo Medical and Dental University. He was a visiting researcher at the University of Glasgow. He is continuing to investigate auditory brain
function by the use of functional MRI to clarify the pathophysiology of psychiatric symptoms, and pharmacological and/or genetic effects.

Abstract:

Evaluation of brain function by resting state fMRI is expected to be one of the convenient applications to help diagnosis of
mental disorders, such as depression and Alzheimer disease (AD). Especially, it is considered that functional connectivity
of the default mode network (DMN) would refl ect brain function of self-recognition as a biomarker at a preclinical stage of AD.
Further, the cerebral function of language is an important aspect for the evaluation of brain dysfunction in mental disorders, eg.,
epilepsy. To develop useful clinical applications, examining the infl uence of handedness shows promise, but to our knowledge,
there have been few studies on whether these networks infl uence the diff erence in handedness. We aimed to investigate the
functional connectivity of DMN and language-related area (LRA) by resting state fMRI. Further, we evaluated whether these
DMN-language networks infl uenced handedness. In the functional connectivity analysis of the 101 subjects, the main eff ect of
handedness was signifi cantly observed at the posterior cingulate from bilateral supplemental motor cortices, and the anterior
cingulate from the posterior cingulate. Further, the main eff ect of non-right-handed family history was signifi cantly observed
at the right inferior parietal cortices projected from bilateral supplemental motor areas (p<0.05, uncorrected; FDR p<0.05). As
for LRA, in right-handed subjects, a region of strong positive correlation with the right amygdala was observed at the thalamus,
middle frontal gyrus/anterior cingulate, cerebellum, and globus pallidus. On the other hand, in non-right-handed subjects,
the region of strong negative correlation with the right amygdala was observed at the bilateral inferiolateral occipital cortex,
posterior cingulate, medial frontal gyrus/anterior cingulate, superior frontal gyrus, and supplemental motor cortex (p<0.05,
uncorrected; FDR p<0.25). We could fi nd diff erent functional connectivities by diff erences of handedness or diff erences of
non-right-handed family history. Th ese results may suggest the infl uence of handedness or non-right-handed family history
when evaluating functional connectivity on mental disorders.