We hypothesize that the major consciousness deficit observed in coma is due to the breakdown of long-range neuronal communication supported by precuneus and posterior cingulate cortex (PCC), and that prognosis depends on a specific connectivity pattern in these networks.
Attributions are constantly assigned in everyday life. A well-known phenomenon is the self-serving bias: that is, people’s tendency to attribute positive events to internal causes (themselves) and negative events to external causes (other persons/circumstances). Here, we investigated the neural correlates of the cognitive processes implicated in self-serving attributions using social situations that differed in their emotional saliences. We administered an attributional bias task during fMRI scanning in a large sample of healthy subjects (n = 71). Eighty sentences describing positive or negative social situations were presented, and subjects decided via buttonpress whether the situation had been caused by themselves or by the other person involved. Comparing positive with negative sentences revealed activations of the bilateral posterior cingulate cortex (PCC). Self-attribution correlated with activation of the posterior portion of the precuneus. However, self-attributed positive versus negative sentences showed activation of the anterior portion of the precuneus, and self-attributed negative versus positive sentences demonstrated activation of the bilateral insular cortex. All significant activations were reported with a statistical threshold of p ≤ .001, uncorrected. In addition, a comparison of our fMRI task with data from the Internal, Personal and Situational Attributions Questionnaire, Revised German Version, demonstrated convergent validity. Our findings suggest that the precuneus and the PCC are involved in the evaluation of social events with particular regional specificities: The PCC is activated during emotional evaluation, the posterior precuneus during attributional evaluation, and the anterior precuneus during self-serving processes. Furthermore, we assume that insula activation is a correlate of awareness of personal agency in negative situations.
We aimed to compare the longitudinal outcome of amnestic mild cognitive impairment (aMCI) patients with significant Pittsburgh Compound B uptake [PiB(+) aMCI] and those without [PiB(-) aMCI]. Cerebral β-amyloid was measured in 47 patients with aMCI using PiB-positron emission tomography (PET) (31 PiB(+) aMCI and 16 PiB(-) aMCI). Clinical (N = 47) and neuropsychological follow-up (N = 37), and follow-up with brain magnetic resonance imaging (N = 38) and PiB-PET (N = 30) were performed for three years. PiB(+) aMCI had a higher risk of progression to dementia (hazard ratio = 3.74, 95% CI = 1.21-11.58) and faster rate of cortical thinning in the bilateral precuneus and right medial and lateral temporal cortices compared to PiB(-) aMCI. Among six PiB(-) aMCI patients who had regional PiB uptake ratio >1.5 in the posterior cingulate cortex (PCC), three (50.0%) progressed to dementia, and two of them had global PiB uptake ratio >1.5 at the follow-up PiB-PET. Our findings suggest that amyloid imaging is important for predicting the prognosis of aMCI patients, and that it is necessary to pay more attention to PiB(-) aMCI with increased regional PiB uptake in the PCC.
The sense of agency is the attribution of oneself as the cause of one’s own actions and their effects. Accurate agency judgments are essential for adaptive behaviors in dynamic environments, especially in conditions of uncertainty. However, it is unclear how agency judgments are made in ambiguous situations where self-agency and non-self-agency are both possible. Agency attribution is thus thought to require higher-order neurocognitive processes that integrate several possibilities. Furthermore, neural activity specific to self-attribution, as compared with non-self-attribution, may reflect higher-order critical operations that contribute to constructions of self-consciousness. Based on these assumptions, the present study focused on agency judgments under ambiguous conditions and examined the neural correlates of this operation with functional magnetic resonance imaging. Participants performed a simple but demanding agency-judgment task, which required them to report on whether they attributed their own action as the cause of a visual stimulus change. The temporal discrepancy between the participant’s action and the visual events was adaptively set to be maximally ambiguous for each individual on a trial-by-trial basis. Comparison with results for a control condition revealed that the judgment of agency was associated with activity in lateral temporo-parietal areas, medial frontal areas, the dorsolateral prefrontal area, and frontal operculum/insula regions. However, most of these areas did not differentiate between self- and non-self-attribution. Instead, self-attribution was associated with activity in posterior midline areas, including the precuneus and posterior cingulate cortex. These results suggest that deliberate self-attribution of an external event is principally associated with activity in posterior midline structures, which is imperative for self-consciousness.
Independent versus interdependent self-construal is a concept that reflects how people perceive the relationship between self and other people, which has been extensively examined across disciplines. However, little evidence on the whole-brain functional connectivity pattern of independent versus interdependent self-construal has been reported. Here, in a sample of 51 healthy participants, we used resting-state fMRI and voxel-based functional connectivity analysis [i.e., Functional connectivity strength (FCS) and seed-based functional connectivity (FC)] by measuring the temporal correlation of blood oxygen level-dependent signals between spatially separate brain regions to investigate the neural mechanism of independent versus interdependent self-construal. First, we found that FCS of bilateral posterior cingulate cortex and precuneus, and left inferior frontal gyrus were positively correlated with the independent versus interdependent score. Seed-based functional connectivity analysis with these three regions as seeds revealed that, functional connectivity within default mode network and executive control network was positively correlated with the independent versus interdependent score. Negative correlation with independent versus interdependent score was shown in the connections between default mode network and executive control regions. Taking together, our results provide a comprehensive functional connectivity architecture of the independent versus interdependent self-construal and advance the understanding of the interplay between culture, mind and brain.
The default mode network (DMN) is typically associated with off-task internal mentation, or with goal-oriented tasks that require self-referential processing such as autobiographical planning. However, recent reports suggest a broader involvement of the DMN in higher cognitive processing. In line with this view, we report global connectivity changes centred on the main DMN hubs of precuneus and posterior cingulate cortex during an fMRI-based visuospatial version of the Tower of London planning task. Importantly, functional connectivity of these regions and the left caudate shows a significant relationship with faster reaction time to correct responses only during the high-demand planning condition, thus offering further evidence for the DMN’s engagement during visuospatial planning. The results of this study not only provide robust evidence against the widely held notion of DMN disengagement during goal-oriented, attention-demanding, externally-directed tasks, but also support its involvement in a broader cognitive context with a memory-related role that extends beyond self-referential, internally-directed mentation.
Older adults often display postoperative cognitive decline (POCD) after surgery, yet it is unclear to what extent functional connectivity (FC) alterations may underlie these deficits. We examined for postoperative voxel-wise FC changes in response to increased working memory load demands in cardiac surgery patients and nonsurgical controls.
Mindfulness refers to attending to moment-to-moment experiences with acceptance and no judgment. Several scales have been developed to quantify different components of mindfulness. The Mindful Attention Awareness Scale (MAAS) is particularly sensitive to trait mindfulness and is proposed to measure the attentional component of mindfulness. The purpose of the current study was to identify the neural correlates of the MAAS in four resting state networks related to attention-the default mode network (DMN), the salience network (SN), and the left and right central executive network (lCEN and rCEN). Thirty-two university students naïve to mindfulness completed the MAAS and later underwent a resting state functional magnetic resonance imaging scan. Resting state data were analyzed using an independent component analysis; the scores from the MAAS were co-varied to the connectivity maps in an analysis of co-variance. The results indicate that variations in MAAS scores correlated with variations in functional connectivity patterns in resting state networks. Specifically, within the SN and CEN, the MAAS was negatively correlated with functional connectivity in the precuneus, even though the precuneus is a key component of the DMN. Negative correlations in the DMN between the MAAS and the insula and in the SN between the MAAS and the posterior cingulate cortex were also observed. These results suggest MAAS scores (1) are correlated with the functional connectivity of several brain structures related to attention, and (2) involve cross-network functional connectivity.
Predicting and processing the sensory consequences of one’s own actions is essential to enable successful interactions with the environment. Previous studies have suggested that the angular gyrus detects discrepancies between predicted and actual action consequences, at least for unimodal feedback. However, most actions lead to multisensory consequences, raising the question whether previous models can sufficiently explain action-outcome processing. Here, we investigated neural comparator processes during detection of delays between action and unimodal or bimodal consequences in human subjects with fMRI, using parametric and connectivity analyses. Participants had to perform button presses, which led to the presentation of either a dot on the screen, a tone, or both, presented with a variable delay after the button press. Participants were asked to judge whether there was a delay between action and feedback. Activity in the angular gyrus correlated positively with delay for both visual, auditory, and audio-visual action consequences. Furthermore, the angular gyrus was functionally connected with midline structures such as the posterior cingulate cortex and precuneus in all conditions. Our results show that the angular gyrus is (1) a supramodal area, sensitive to delays in multiple modalities, and (2) functionally connected with self-referential areas during delay detection of both unimodal and bimodal action consequences. Overall, our results suggest that the angular gyrus functions as a mediator between perception and interpretation, and that this process is remarkably similar for unimodal and bimodal action consequences.
We examined the neurobiological basis of temporal resetting, an aspect of temporal order memory, using a version of the delayed-match-to-multiple-sample task. While in an fMRI scanner, participants evaluated whether an item was novel or whether it had appeared before or after a reset event that signified the start of a new block of trials. Participants responded “old” to items that were repeated within the current block and “new” to both novel items and items that had last appeared before the reset event (pseudonew items). Medial-temporal, prefrontal, and occipital regions responded to absolute novelty of the stimulus-they differentiated between novel items and previously seen items, but not between old and pseudonew items. Activation for pseudonew items in the frontopolar and parietal regions, in contrast, was intermediate between old and new items. The posterior cingulate cortex extending to precuneus was the only region that showed complete temporal resetting, and its activation reflected whether an item was new or old according to the task instructions regardless of its familiarity. There was also a significant Condition (old/pseudonew) × Familiarity (second/third presentations) interaction effect on behavioral and neural measures. For pseudonew items, greater familiarity decreased response accuracy, increased RTs, increased ACC activation, and increased functional connectivity between ACC and the left frontal pole. The reverse was observed for old items. On the basis of these results, we propose a theoretical framework in which temporal resetting relies on an episodic retrieval network that is modulated by cognitive control and conflict resolution.