Although possible sources and functions of the resting state networks (RSN) of the brain have been proposed, most evidence relies on circular logic and reverse inference. We propose that autonomic arousal provides an objective index of psychophysiological states during rest that may also function as a driving source of the activity and connectivity of RSN. Recording blood oxygenation level-dependent (BOLD) signal using functional magnetic resonance imaging and skin conductance simultaneously during rest in human subjects, we found that the spontaneous fluctuations of BOLD signals in key nodes of RSN are associated with changes in non-specific skin conductance response, a sensitive psychophysiological index of autonomic arousal. Our findings provide evidence of an important role for the autonomic nervous system to the spontaneous activity of the brain during ‘rest’.

Although amnestic mild cognitive impairment (aMCI; often considered a prodromal phase of Alzheimer’s disease, AD) is most recognized by its implications for decline in memory function, research suggests that deficits in attention are present early in aMCI and may be predictive of progression to AD. The present study used functional magnetic resonance imaging to examine differences in the brain during the attention network test between 8 individuals with aMCI and 8 neurologically healthy, demographically matched controls. While there were no significant behavioral differences between groups for the alerting and orienting functions, patients with aMCI showed more activity in neural regions typically associated with the networks subserving these functions (e.g., temporoparietal junction and posterior parietal regions, respectively). More importantly, there were both behavioral (i.e., greater conflict effect) and corresponding neural deficits in executive control (e.g., less activation in the prefrontal and anterior cingulate cortices). Although based on a small number of patients, our findings suggest that deficits of attention, especially the executive control of attention, may significantly contribute to the behavioral and cognitive deficits of aMCI.

Attentional dysfunction is among the most consistent observations of autism spectrum disorders (ASD). However, the neural nature of this deficit in ASD is still unclear. In this study, we aimed to identify the neurobehavioral correlates of attentional dysfunction in ASD. We used the Attention Network Test-Revised and functional magnetic resonance imaging to examine alerting, orienting, and executive control functions, as well as the neural substrates underlying these attentional functions in unmedicated, high-functioning adults with ASD (n = 12) and matched healthy controls (HC, n = 12). Compared with HC, individuals with ASD showed increased error rates in alerting and executive control, accompanied by lower activity in the mid-frontal gyrus and the caudate nucleus for alerting, and by the absence of significant functional activation in the anterior cingulate cortex (ACC) for executive control. In addition, greater behavioral deficiency in executive control in ASD was correlated with less functional activation of the ACC. These findings of behavioral and neural abnormalities in alerting and executive control of attention in ASD may suggest core attentional deficits, which require further investigation.

The anterior cingulate cortex (ACC) and frontoinsular cortex (FI) have been implicated in processing information across a variety of domains, including those related to attention and emotion. However, their role in rapid information processing, for example, as required for timely processing of salient stimuli, is not well understood. Here, we designed an emotional face priming paradigm and employed functional magnetic resonance imaging to elucidate their role in these mechanisms. Target faces with either neutral or fearful emotion were briefly primed by either neutral or fearful faces, or by blank ovals. Activation in the pregenual ACC and the FI, together with other regions, such as the amygdala, were preferentially activated in response to fearful face priming, suggesting that these regions are involved in the rapid processing of salient facial emotional information.

Our recent work showed that self-trait judgment is associated with increased activity in the ventral medial prefrontal cortex (VMPFC) in non-religious Chinese, but in the dorsal medial prefrontal cortex (DMPFC) in Chinese Christians. The current work further investigated neural substrates of self-referential processing in Chinese Buddhists. Using functional magnetic resonance imaging, we scanned 14 Chinese Buddhists, while they conducted trait judgments of the self, Zhu Rongji (the former Chinese premier), Sakyamuni (the Buddhist leader) and Jesus (the Christian leader). We found that, relative to Zhu Rongji judgment, self-judgment in Buddhist participants failed to generate increased activation in the VMPFC but induced increased activations in the DMPFC/rostral anterior cingulate cortex, midcingulate and the left frontal/insular cortex. Self-judgment was also associated with decreased functional connectivity between the DMPFC and posterior parietal cortex compared with Zhu Rongji judgment. The results suggest that Buddhist doctrine of No-self results in weakened neural coding of stimulus self-relatedness in the VMPFC, but enhanced evaluative processes of self-referential stimuli in the DMPFC. Moreover, self-referential processing in Buddhists is characterized by monitoring the conflict between the doctrine of No-self and self-focus thinking during self-trait judgment.

The frontoinsular cortex (FI) and the anterior cingulate cortex (ACC) are known to be involved in empathy for others’ pain. However, the functional roles of FI and ACC in empathetic responses have not yet been clearly dissociated in previous studies. In this study, participants viewed color photographs depicting human body parts (hands or feet) in painful or non-painful situations and performed either pain judgment (painful/non-painful) or laterality judgment (left/right) of the body parts. We found that activation of FI, rather than ACC, showed significant increase for painful compared to non-painful images, regardless of the task requirement. These findings suggest a clear functional dissociation between FI and ACC in which FI is more domain-specific than ACC in processing of empathy for pain.

One current conceptualization of attention subdivides it into functions of alerting, orienting, and executive control. Alerting describes the function of tonically maintaining the alert state and phasically responding to a warning signal. Automatic and voluntary orienting are involved in the selection of information among multiple sensory inputs. Executive control describes a set of more complex operations that includes monitoring and resolving conflicts in order to control thoughts or behaviors. Converging evidence supports this theory of attention by showing that each function appears to be subserved by anatomically distinct networks in the brain and differentially innervated by various neuromodulatory systems. Although much research has been dedicated to understanding the functional separation of these networks in both healthy and disease states, the interaction and integration among these networks still remain unclear. In this study, we aimed to characterize possible behavioral interaction and integration in healthy adult volunteers using a revised attentional network test (ANT-R) with cue-target interval and cue validity manipulations. We found that whereas alerting improves overall response speed, it exerts negative influence on executive control under certain conditions. A valid orienting cue enhances but an invalid cue diminishes the ability of executive control to overcome conflict. The results support the hypothesis of functional integration and interaction of these brain networks.

Background

Alexithymia is a personality trait characterized by deficiency in understanding, processing, or describing emotions. Recent studies have revealed that alexithymia is associated with less activation of the anterior cingulate cortex, a brain region shown to play a role in cognitive and emotional processing. However, few studies have directly investigated the cognitive domain in relation to alexithymia to examine whether alexithymic trait is related to less efficient voluntary control.

Methodology/ Principal Findings

We examined the relationship between alexithymic trait and voluntary control in a group of healthy volunteers. We used the 20-item Toronto Alexithymia Scale (TAS-20) to measure alexithymic trait. Additionally, we examined state and trait voluntary control using the revised Attention Network Test (ANT-R) and the Adult Temperament Questionnaire (ATQ), respectively. Alexithymic trait was positively correlated with the overall reaction time of the ANT-R, and negatively correlated with the Effortful Control factor of the ATQ.

Conclusions/Significance

Our results suggest that alexithymic trait is associated with less efficient voluntary control.