Resting state low-frequency fluctuations in prefrontal cortex reflect degrees of harm avoidance and novelty seeking: an exploratory NIRS study

Takashi Nakao,Shinpei Yoshimura,Daisuke Shimizu,Georg Northoff,Tomoya Matsumoto,Yasumasa Okamoto,Machiko Morita,Shigeru Morinobu,Shigeto Yamawaki

doi:10.3389/fnsys.2013.00115

Abstract

Harm avoidance (HA) and novelty seeking (NS) are temperament dimensions defined by Temperament and Character Inventory (TCI), respectively, reflecting a heritable bias for intense response to aversive stimuli or for excitement in response to novel stimuli. High HA is regarded as a risk factor for major depressive disorder and anxiety disorder. In contrast, higher NS is linked to increased risk for substance abuse and pathological gambling disorder. A growing body of evidence suggests that patients with these disorders show abnormality in the power of slow oscillations of resting-state brain activity. It is particularly interesting that previous studies have demonstrated that resting state activities in medial prefrontal cortex (MPFC) are associated with HA or NS scores, although the relation between the power of resting state slow oscillations and these temperament dimensions remains poorly elucidated. This preliminary study investigated the biological bases of these temperament traits by particularly addressing the resting state low-frequency fluctuations in MPFC. Regional hemodynamic changes in channels covering MPFC during 5-min resting states were measured from 22 healthy participants using near-infrared spectroscopy (NIRS). These data were used for correlation analyses. Results show that the power of slow oscillations during resting state around the dorsal part of MPFC is negatively correlated with the HA score. In contrast, NS was positively correlated with the power of resting state slow oscillations around the ventral part of MPFC. These results suggest that the powers of slow oscillation at rest in dorsal or ventral MPFC, respectively, reflect the degrees of HA and NS. This exploratory study therefore uncovers novel neural bases of HA and NS. We discuss a neural mechanism underlying aversion-related and reward-related processing based on results obtained from this study.

Highlights

Temperament and character are the basic elements of personality that vary among individuals
This study was undertaken to investigate the relations between temperament dimensions (i.e., Harm avoidance (HA) and novelty seeking (NS)) and the power of slow oscillation in a resting state
We demonstrated a unique relation between them in that HA and NS are oppositely associated, respectively, with the power of slow oscillations in different subregions in the medial prefrontal cortex (MPFC)

Summary

Introduction

Temperament and character are the basic elements of personality that vary among individuals. In contrast to character, which is strongly influenced by experiential factors, temperament is probably more biologically based and stable across a person’s life span. Increased levels of HA are thought to play a role as a risk factor for development of depression (Joffe et al, 1993; Richter et al, 2000; Farmer et al, 2003; Abrams et al, 2004; Smith et al, 2005; Celikel et al, 2009; Quilty et al, 2010) and anxiety disorders (Jylha and Isometsa, 2006; Mertol and Alkin, 2012). A high level of NS is associated with increased risk of exhibiting substance abuse (Cloninger et al, 1988; Gerra et al, 2003) and pathological gambling disorder (Won Kim and Grant, 2001). It is important to characterize the biological bases of these temperament traits widely, in terms of psychology but of psychiatry

Methods

Findings

Discussion

Conclusion