Genetic influences on prefrontal activation during a verbal fluency task in adults: a twin study based on multichannel near-infrared spectroscopy

Abstract

Near-infrared spectroscopy (NIRS) studies have reported that prefrontal hemodynamic dysfunction during executive function tasks may be a promising biomarker of psychiatric disorders, because its portability and noninvasiveness allow easy measurements in clinical settings. Here, we investigated the degree to which prefrontal NIRS signals are genetically determined. Using a 52-channel NIRS system, we monitored the oxy-hemoglobin (oxy-Hb) signal changes in 38 adult pairs of right-handed monozygotic (MZ) twins and 13 pairs of same-sex right-handed dizygotic (DZ) twins during a letter version of the verbal fluency task. Heritability was estimated based on a classical twin paradigm using structured equation modeling. Significant genetic influences were estimated in the right dorsolateral prefrontal cortex and left frontal pole. The degrees of heritability were 66% and 75% in the variances, respectively. This implies that the prefrontal hemodynamic dysfunction observed during an executive function task measured by NIRS may be an efficient endophenotype for large-scale imaging genetic studies in psychiatric disorders.

Keywords: DZ; Endophenotype; FIQ; Heritability; LFT; Letter Fluency Task; MZ; NIRS; Near-infrared spectroscopy; Prefrontal hemodynamic response; SES; SNP; Twin study; Verbal fluency task; WAIS-R; Wechsler Adult Intelligence Scale-Revised; [deoxy-Hb]; [oxy-Hb]; concentration of deoxyhemoglobin; concentration of oxyhemoglobin; dizygotic; full-scale intelligence quotient; monozygotic; near-infrared spectroscopy; rCBV; regional cerebral blood volume; single nucleotide polymorphism; socioeconomic status.