Abstract
The Behavioral Inhibition System (BIS) as defined within the Reinforcement Sensitivity Theory (RST) modulates reactions to stimuli indicating aversive events. Gray’s trait Anxiety determines the extent to which stimuli activate the BIS. While studies have identified the amygdala-septo-hippocampal circuit as the key-neural substrate of this system in recent years and measures of resting-state dynamics such as randomness and local synchronization of spontaneous BOLD fluctuations have recently been linked to personality traits, the relation between resting-state dynamics and the BIS remains unexplored. In the present study, we thus examined the local synchronization of spontaneous fMRI BOLD fluctuations as measured by Regional Homogeneity (ReHo) in the hippocampus and the amygdala in twenty-seven healthy subjects. Correlation analyses showed that Gray’s trait Anxiety was significantly associated with mean ReHo in both the amygdala and the hippocampus. Specifically, Gray’s trait Anxiety explained 23% and 17% of resting-state ReHo variance in the left amygdala and the left hippocampus, respectively. In summary, we found individual differences in Gray’s trait Anxiety to be associated with ReHo in areas previously associated with BIS functioning. Specifically, higher ReHo in resting-state neural dynamics corresponded to lower sensitivity to punishment scores both in the amygdala and the hippocampus. These findings corroborate and extend recent findings relating resting-state dynamics and personality while providing first evidence linking properties of resting-state fluctuations to Gray’s BIS.
Highlights
As a theory of personality firmly rooted in neurobiology, Gray’s Reinforcement Sensitivity Theory (RST; [1]) has grown into one of the most influential theories of personality, strongly influencing research in a number of disciplines including psychology, pharmacology, animal research, and neuroscience [2]
Correlation analyses showed that sensitivity to punishment (SP)-scores were significantly associated with Regional Homogeneity (ReHo) in both the amygdala (r = 2.48; p,.012) and the hippocampus (r = 2.41; p,.035, Figure 1)
We explored the association between local synchronization of resting-state dynamics as measured by ReHo and Gray’s trait Anxiety as defined by the RST
Summary
As a theory of personality firmly rooted in neurobiology, Gray’s Reinforcement Sensitivity Theory (RST; [1]) has grown into one of the most influential theories of personality, strongly influencing research in a number of disciplines including psychology, pharmacology, animal research, and neuroscience [2]. The RST postulates behavior to be mediated by the activity of three motivational systems: the Fight-Flight System, the Behavioral Approach System (BAS), and the Behavioral Inhibition System (BIS). The latter is triggered by signals of punishment or nonreward, which leads to an inhibition of motor-activity and increased levels of arousal and attention (for a partially revised version of the theory, see [3]). Defined to reflect trait sensitivity to punishment, Gray’s trait Anxiety determines the extent to which aversive stimuli activate the BIS [4]. A number of mental disorders including depression, anxiety disorders, and psychosomatic illnesses have been associated with extreme BIS responsiveness [2]
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