Specialized late cingulo-opercular network activation elucidates the mechanisms underlying decisions about ambiguity.

Cortical task control networks, including the cingulo-opercular (CO) network play a key role in decision-making across a variety of functional domains. In particular, the CO network functions in a performance reporting capacity that supports successful task performance, especially in response to errors and ambiguity. In two studies testing the contribution of the CO network to ambiguity processing, we presented a valence bias task in which masked clearly and ambiguously valenced emotional expressions were slowly revealed over several seconds. This slow reveal task design provides a window into the decision-making mechanisms as they unfold over the course of a trial. In the main study, the slow reveal task was administered to 32 young adults in the fMRI environment and BOLD time courses were extracted from regions of interest in three control networks. In a follow-up study, the task was administered to a larger, online sample (n = 81) using a more extended slow reveal design with additional unmasking frames. Positive judgments of surprised faces were uniquely accompanied by slower response times and strong, late activation in the CO network. These results support the initial negativity hypothesis, which posits that the default response to ambiguity is negative and positive judgments are associated with a more effortful controlled process, and additionally suggest that this controlled process is mediated by the CO network. Moreover, ambiguous trials were characterized by a second CO response at the end of the trial, firmly placing CO function late in the decision-making process.

Explicit and Implicit Emotion Processing in the Cerebellum: A Meta-analysis and Systematic Review.

The cerebellum's role in affective processing is increasingly recognized in the literature, but remains poorly understood, despite abundant clinical evidence for affective disruptions following cerebellar damage. To improve the characterization of emotion processing and investigate how attention allocation impacts this processing, we conducted a meta-analysis on task activation foci using GingerALE software. Eighty human neuroimaging studies of emotion including 2761 participants identified through Web of Science and ProQuest databases were analyzed collectively and then divided into two categories based on the focus of attention during the task: explicit or implicit emotion processing. The results examining the explicit emotion tasks identified clusters within the posterior cerebellar hemispheres (bilateral lobule VI/Crus I/II), the vermis, and left lobule V/VI that were likely to be activated across studies, while implicit tasks activated clusters including bilateral lobules VI/Crus I/II, right Crus II/lobule VIII, anterior lobule VI, and lobules I-IV/V. A direct comparison between these categories revealed five overlapping clusters in right lobules VI/Crus I/Crus II and left lobules V/VI/Crus I of the cerebellum common to both the explicit and implicit task contrasts. There were also three clusters activated significantly more for explicit emotion tasks compared to implicit tasks (right lobule VI, left lobule VI/vermis), and one cluster activated more for implicit than explicit tasks (left lobule VI). These findings support previous studies indicating affective processing activates both the lateral hemispheric lobules and the vermis of the cerebellum. The common and distinct activation of posterior cerebellar regions by tasks with explicit and implicit attention demonstrates the supportive role of this structure in recognizing, appraising, and reacting to emotional stimuli.

Reappraisal-related downregulation of amygdala BOLD activation occurs only during the late trial window.

During cognitive reappraisal, an individual reinterprets the meaning of an emotional stimulus to regulate the intensity of their emotional response. Prefrontal cortex activity has been found to support reappraisal and is putatively thought to downregulate the amygdala response to these stimuli. The timing of these regulation-related responses during the course of a trial, however, remains poorly understood. In the current fMRI study, participants were instructed to view or reappraise negative images and then rate how negative they felt following each image. The hemodynamic response function was estimated in 11 regions of interest for the entire time course of the trial including image viewing and rating. Notably, within the amygdala there was no evidence of downregulation in the early (picture viewing) window of the trial, only in the late (rating) window, which also correlated with a behavioral measure of reappraisal success. With respect to the prefrontal regions, some (e.g., inferior frontal gyrus) showed reappraisal-related activation in the early window, whereas others (e.g., middle frontal gyrus) showed increased activation primarily in the late window. These results highlight the temporal dynamics of different brain regions during emotion regulation and suggest that the amygdala response to negative images need not be immediately dampened to achieve successful cognitive reappraisal.

Reward-Based Learning and Emotional Habit Formation in the Cerebellum.

There is growing evidence of the cerebellum's contribution to emotion processing from neuroimaging studies of healthy function and clinical studies of cerebellar patients. As demonstrated initially in the motor domain, one of the cerebellum's functions is to construct internal models of an individual's state and make predictions about how future behaviors will impact that state. By utilizing widespread connections with neocortex and subcortical regions such as the basal ganglia, the cerebellum can monitor and modulate precisely timed patterns of events using prediction and reward-based error feedback in a diverse range of tasks including auditory emotion prosody recognition. In coordination with a broader affective network, the cerebellum helps to select and refine emotional responses that are the most rewarded in a particular context, strengthening neural activity in relevant regions to form a representational chunk. This chunked set of affective stimuli, cognitive evaluations, and physiological responses subsequently can be enacted as a unitary response (i.e., an emotional habit) more quickly and with less attentional control than for a novel stimulus or goal-oriented action. Such emotional habits can allow for efficient, automatic, stimulus-triggered responses while maintaining the flexibility to adapt output when prediction errors signal a renewed need for cerebellar modification of cortical activity, or, conversely, may lead to behavioral or mood disorders when habitual responses persist despite negative consequences.

A novel computerized assessment of manual spatial exploration in unilateral spatial neglect.

Unilateral spatial neglect is a neuropsychological syndrome commonly observed after stroke and defined by the inability to attend or respond to contralesional stimuli. Typically, symptoms are assessed using clinical tests that rely upon visual/perceptual abilities. However, neglect may affect high-level representations controlling attention in other modalities as well. Here we developed a novel manual exploration test using a touch screen computer to quantify spatial search behaviour without visual input. Twelve chronic stroke patients with left neglect and 27 patients without neglect (based on clinical tests) completed our task. Four of the 12 "neglect" patients exhibited clear signs of neglect on our task as compared to "non-neglect" patients and healthy controls, and six other patients (from both groups) also demonstrated signs of neglect compared to healthy controls only. While some patients made asymmetrical responses on only one task, generally, patients with the strongest neglect performed poorly on multiple tasks. This suggests that representations associated with different modalities may be affected separately, but that severe forms of neglect are more likely related to damage in a common underlying representation. Our manual exploration task is easy to administer and can be added to standard neglect screenings to better measure symptom severity.

Regularized aggregation of statistical parametric maps.

Combining statistical parametric maps (SPM) from individual subjects is the goal in some types of group-level analyses of functional magnetic resonance imaging data. Brain maps are usually combined using a simple average across subjects, making them susceptible to subjects with outlying values. Furthermore, t tests are prone to false positives and false negatives when outlying values are observed. We propose a regularized unsupervised aggregation method for SPMs to find an optimal weight for aggregation, which aids in detecting and mitigating the effect of outlying subjects. We also present a bootstrap-based weighted t test using the optimal weights to construct an activation map robust to outlying subjects. We validate the performance of the proposed aggregation method and test using simulated and real data examples. Results show that the regularized aggregation approach can effectively detect outlying subjects, lower their weights, and produce robust SPMs.

Reduced Cognitive Control Demands after Practice of Saccade Tasks in a Trial Type Probability Manipulation.

Cognitive control is engaged to facilitate stimulus-response mappings for novel, complex tasks and supervise performance in unfamiliar, challenging contexts-processes supported by pFC, ACC, and posterior parietal cortex. With repeated task practice, however, the appropriate task set can be selected in a more automatic fashion with less need for top-down cognitive control and weaker activation in these brain regions. One model system for investigating cognitive control is the ocular motor circuitry underlying saccade production, with basic prosaccade trials (look toward a stimulus) and complex antisaccade trials (look to the mirror image location) representing low and high levels of cognitive control, respectively. Previous studies have shown behavioral improvements on saccade tasks after practice with contradictory results regarding the direction of functional MRI BOLD signal change. The current study presented healthy young adults with prosaccade and antisaccade trials in five mixed blocks with varying probability of each trial type (0%, 25%, 50%, 75%, or 100% anti vs. pro) at baseline and posttest MRI sessions. Between the scans, participants practiced either the specific probability blocks used during testing or only a general 100% antisaccade block. Results indicated an overall reduction in BOLD activation within pFC, ACC, and posterior parietal cortex and across saccade circuitry for antisaccade trials. The specific practice group showed additional regions including ACC, insula, and thalamus with an activation decrease after practice, whereas the general practice group showed a little change from baseline in those clusters. These findings demonstrate that cognitive control regions recruited to support novel task behaviors were engaged less after practice, especially with exposure to mixed task contexts rather than a novel task in isolation.

Contextual effects on cognitive control and BOLD activation in single versus mixed saccade tasks.

The context or trial history of a task influences response efficiency in mixed paradigms based on cognitive control demands for task set selection. In the current study, the impact of context on prosaccade and antisaccade trials in single and mixed tasks was investigated with BOLD fMRI. Prosaccades require a look towards a newly appearing target, while antisaccades require cognitive control for prepotent response inhibition and generation of a saccade to the opposite location. Results indicated slower prosaccade reaction times and more antisaccade errors for switched than repeated or single trials, and slower antisaccade reaction times for single than mixed trials. BOLD activation was greater for the mixed than the single context in frontal eye fields and precuneus, while switch trials had greater activation than repeat trials in posterior parietal and middle occipital cortex. Greater antisaccade activation was observed overall in saccade circuitry, although effects were evident primarily for the mixed task when considered separately. Finally, an interaction was observed in superior frontal cortex, precuneus, anterior cingulate, and thalamus with strong responses for antisaccade switch trials in the latter two regions. Altogether this response pattern demonstrated the sensitivity of cognitive control to changing task conditions, especially due to task switching costs. Such context-specific differences highlight the importance of trial history when assessing cognitive control.

Modulation of cognitive control levels via manipulation of saccade trial-type probability assessed with event-related BOLD fMRI.

Cognitive control supports flexible behavior adapted to meet current goals and can be modeled through investigation of saccade tasks with varying cognitive demands. Basic prosaccades (rapid glances toward a newly appearing stimulus) are supported by neural circuitry, including occipital and posterior parietal cortex, frontal and supplementary eye fields, and basal ganglia. These trials can be contrasted with complex antisaccades (glances toward the mirror image location of a stimulus), which are characterized by greater functional magnetic resonance imaging (MRI) blood oxygenation level-dependent (BOLD) signal in the aforementioned regions and recruitment of additional regions such as dorsolateral prefrontal cortex. The current study manipulated the cognitive demands of these saccade tasks by presenting three rapid event-related runs of mixed saccades with a varying probability of antisaccade vs. prosaccade trials (25, 50, or 75%). Behavioral results showed an effect of trial-type probability on reaction time, with slower responses in runs with a high antisaccade probability. Imaging results exhibited an effect of probability in bilateral pre- and postcentral gyrus, bilateral superior temporal gyrus, and medial frontal gyrus. Additionally, the interaction between saccade trial type and probability revealed a strong probability effect for prosaccade trials, showing a linear increase in activation parallel to antisaccade probability in bilateral temporal/occipital, posterior parietal, medial frontal, and lateral prefrontal cortex. In contrast, antisaccade trials showed elevated activation across all runs. Overall, this study demonstrated that improbable performance of a typically simple prosaccade task led to augmented BOLD signal to support changing cognitive control demands, resulting in activation levels similar to the more complex antisaccade task.

Trial-type probability and task-switching effects on behavioral response characteristics in a mixed saccade task.

Eye movement circuitry involved in saccade production offers a model for studying cognitive control: visually guided prosaccades are stimulus-directed responses, while goal-driven antisaccades rely upon more complex control processes to inhibit the prepotent tendency to look toward a cue, transform its spatial location, and generate a volitional saccade in the opposite direction. By manipulating the relative probability of these saccade types, we measured participants' behavioral responses to different levels of implicit trial-type probability and task-switching demands in conditions with relatively long inter-trial fixation and trial-type cue lengths. Results indicated that when prosaccades were less probable in a run, more prosaccade errors were generated; however, for antisaccades, trial-type probability had no effect on the percent of correct responses. For reaction times, specifically in runs with a larger probability of antisaccade trials, latencies increased for both anti- and pro-saccades. Furthermore, task switching resulted in a lower percentage of correct responses on switched trials, but a prior antisaccade trial led to slower reaction times for both trial types (i.e., a task switch cost for prosaccades and switch benefit for antisaccades). These findings indicate that cognitive control demands and residual inhibition from antisaccades alter performance relative to trial-type probability and task switching within a run, with the prosaccade task showing greater susceptibility to the influence of a large probability of cognitively complex antisaccades.

Improved frontoparietal white matter integrity in overweight children is associated with attendance at an after-school exercise program.

Aerobic fitness is associated with white matter integrity (WMI) in adults as measured by diffusion tensor imaging (DTI). This study examined the effect of an 8-month exercise intervention on WMI in children. Participants were 18 sedentary, overweight (BMI≥85th percentile) 8- to 11-year-old children (94% Black), randomly assigned to either an aerobic exercise (n=10) or sedentary attention control group (n=8). Each group was offered an instructor-led after-school program every school day for approximately 8 months. Before and after the program, all subjects participated in DTI scans. Tractography was conducted to isolate the superior longitudinal fasciculus and investigate whether the exercise intervention affected WMI in this region. There was no group by time interaction for WMI in the superior longitudinal fasciculus. There was a group by time by attendance interaction, however, such that higher attendance at the exercise intervention, but not the control intervention, was associated with increased WMI. Heart rate and the total dose of exercise correlated with WMI changes in the exercise group. In the overall sample, increased WMI was associated with improved scores on a measure of attention and improved teacher ratings of executive function. This study indicates that participating in an exercise intervention improves WMI in children as compared to a sedentary after-school program.

A More Connected Future: How Social Connection, Interdisciplinary Approaches, and New Technology Will Shape the Affective Science of Loneliness, a Commentary on the Special Issue.

The recent Special Issue of Affective Science considered "The Future of Affective Science," offering new directions for the field. One recurring theme was the need to consider the social nature of emotional experiences. In this article, we take an interdisciplinary approach toward studies of social connection that builds upon current theoretical foundations to address an important public health issue - loneliness. Loneliness is an affective state that is characterized by feelings of isolation and has widespread adverse effects on mental and physical health. Recent studies have established links between loneliness, social connection, and well-being, but most of this work has been siloed in separate fields. We bridge these themes, leveraging advances in technology, such as artificial intelligence-based voice assistants (e.g., Alexa), to illuminate new avenues for detecting and intervening against loneliness "in the wild." Recognizing the power of connection among individuals as social beings and among researchers with shared goals, affective science can advance our understanding of loneliness and provide tangible benefits to society at large.

Affective flexibility as a developmental building block of cognitive reappraisal: An fMRI study.

Cognitive reappraisal is a form of emotion regulation that involves reinterpreting the meaning of a stimulus, often to downregulate one's negative affect. Reappraisal typically recruits distributed regions of prefrontal and parietal cortex to generate new appraisals and downregulate the emotional response in the amygdala. In the current study, we compared reappraisal ability in an fMRI task with affective flexibility in a sample of children and adolescents (ages 6-17, N = 76). Affective flexibility was defined as variability in valence interpretations of ambiguous (surprised) facial expressions from a second behavioral task. Results demonstrated that age and affective flexibility predicted reappraisal ability, with an interaction indicating that flexibility in children (but not adolescents) supports reappraisal success. Using a region of interest-based analysis of participants' BOLD time courses, we also found dissociable reappraisal-related brain mechanisms that support reappraisal success and affective flexibility. Specifically, late increases in middle prefrontal cortex activity supported reappraisal success and late decreases in amygdala activity supported flexibility. Together, these results suggest that our novel measure of affective flexibility - the ability to see multiple interpretations of an ambiguous emotional cue - may represent part of the developmental building blocks of cognitive reappraisal ability.

Task-irrelevant emotional faces impact BOLD responses more for prosaccades than antisaccades in a mixed saccade fMRI task.

Cognitive control allows individuals to flexibly and efficiently perform tasks by attending to relevant stimuli while inhibiting distraction from irrelevant stimuli. The antisaccade task assesses cognitive control by requiring participants to inhibit a prepotent glance towards a peripheral stimulus and generate an eye movement to the mirror image location. This task can be administered with various contextual manipulations to investigate how factors such as trial timing or emotional content interact with cognitive control. In the current study, 26 healthy adults completed a mixed antisaccade and prosaccade fMRI task that included task irrelevant emotional faces and gap/overlap timing. The results showed typical antisaccade and gap behavioral effects with greater BOLD activation in frontal and parietal brain regions for antisaccade and overlap trials. Conversely, there were no differences in behavior based on the emotion of the task irrelevant face, but trials with neutral faces had greater activation in widespread visual regions than trials with angry faces, particularly for prosaccade and overlap trials. Together, these effects suggest that a high level of cognitive control and inhibition was required throughout the task, minimizing the impact of the face presentation on saccade behavior, but leading to increased attention to the neutral faces on overlap prosaccade trials when both the task cue (look towards) and emotion stimulus (neutral, non-threatening) facilitated disinhibition of visual processing.

Real-time fMRI and EEG neurofeedback: A perspective on applications for the rehabilitation of spatial neglect.

Spatial neglect is a neuropsychological syndrome characterized by a failure to orient, perceive, and act toward the contralesional side of the space after brain injury. Neglect is one of the most frequent and disabling neuropsychological syndromes following right-hemisphere damage, often persisting in the chronic phase and responsible for a poor functional outcome at hospital discharge. Different rehabilitation approaches have been proposed over the past 60 years, with a variable degree of effectiveness. In this point-of-view article, we describe a new rehabilitation technique for spatial neglect that directly targets brain activity and pathological physiological processes: namely, neurofeedback (NFB) with real-time brain imaging methodologies. In recent proof-of-principle studies, we have demonstrated the potential of this rehabilitation technique. Using real-time functional MRI (rt-fMRI) NFB in chronic neglect, we demonstrated that patients are able to upregulate their right visual cortex activity, a response that is otherwise reduced due to losses in top-down attentional signals. Using real-time electroencephalography NFB in patients with acute or chronic condition, we showed successful regulation with partial restoration of brain rhythm dynamics over the damaged hemisphere. Both approaches were followed by mild, but encouraging, improvement in neglect symptoms. NFB techniques, by training endogenous top-down modulation of attentional control on sensory processing, might induce sustained changes at both the neural and behavioral levels, while being non-invasive and safe. However, more properly powered clinical studies with control groups and longer follow-up are needed to fully establish the effectiveness of the techniques, identify the most suitable candidates, and determine how the techniques can be optimized or combined in the context of rehabilitation.

The basal ganglia and the cerebellum in human emotion.

The basal ganglia (BG) and the cerebellum historically have been relegated to a functional role in producing or modulating motor output. Recent research, however, has emphasized the importance of these subcortical structures in multiple functional domains, including affective processes such as emotion recognition, subjective feeling elicitation and reward valuation. The pathways through the thalamus that connect the BG and cerebellum directly to each other and with extensive regions of the cortex provide a structural basis for their combined influence on limbic function. By regulating cortical oscillations to guide learning and strengthening rewarded behaviors or thought patterns to achieve a desired goal state, these regions can shape the way an individual processes emotional stimuli. This review will discuss the basic structure and function of the BG and cerebellum and propose an updated view of their functional role in human affective processing.

Differential parietal activations for spatial remapping and saccadic control in a visual memory task.

Remapping is a process that updates visual information in internal spatial representations across eye movements, allowing for stable perception of the environment. Previous work has demonstrated visual remapping activity in parietal cortex during saccades, but it remains unclear whether remapping is triggered by overt saccades only (or by attentional shifts also), and whether it engages parietal areas only (or other cortical areas). Here, we used fMRI to investigate spatial remapping during two visuospatial memory tasks requiring either overt (accompanied by a saccade) or covert (with central fixation) attention shifts to peripheral distracters. Participants had to remember the position and color of a lateralized dot during a saccade or attention shift, requiring them to update the dot position in memory, and then indicate if a second dot matched the first. Differential activation patterns were observed within parietal cortex as a function of the different visual, motor, and interhemispheric remapping demands in the saccade task, presumably mediating the maintenance of spatial position in perceptual and motor maps. Remapping engaged parietal areas adjacent to, but not overlapping with, those activated by saccade execution, while it did not engage the frontal eye fields, pointing to distinct neural substrates for ocular motor and spatial updating processes. No differential activation related to remapping was found during the covert attention shift task, suggesting that this condition did not necessitate the same remapping as the saccade condition. Overall these results further elucidate the mechanisms of spatial remapping in human parietal cortex and their relationship with attention processing and ocular motor behavior, with implications for understanding visuospatial attention deficits in hemispatial neglect.

Evaluating the Specificity of Cognitive Control Deficits in Schizophrenia Using Antisaccades, Functional Magnetic Resonance Imaging, and Healthy Individuals With Poor Cognitive Control.

Cognitive control impairments in schizophrenia (SZ) can be evaluated using antisaccade tasks and functional magnetic resonance imaging (fMRI). Studies, however, often compare people with SZ to high performing healthy people, making it unclear if antisaccade-related disruptions are specific to the disease or due to generalized deficits in cognitive control. We included two healthy comparison groups in addition to people with SZ: healthy people with high cognitive control (HCC), who represent a more typical comparison group, and healthy people with low cognitive control (LCC), who perform similarly on antisaccade measures as people with SZ. Using two healthy comparison groups may help determine which antisaccade-related deficits are specific to SZ (distinguish SZ from LCC and HCC groups) and which are due to poor cognitive control (distinguish the LCC and SZ groups from the HCC group). People with SZ and healthy people with HCC or LCC performed an antisaccade task during fMRI acquisition. LCC and SZ groups showed under-activation of saccade circuitry. SZ-specific disruptions were observed in the left superior temporal gyrus and insula during error trials (suppression of activation in the SZ group compared to the LCC and HCC group). Differences related to antisaccade errors may distinguish people with SZ from healthy people with LCC.

Microstructural differences in visual white matter tracts in people with aniridia.

Aniridia is a panocular disorder characterized chiefly by iris hypoplasia. Most cases result from mutations of the PAX6 gene, which is important in both eye and brain development. In addition to ocular alterations, differences in global brain volume and functional connectivity have been reported in humans with aniridia. Understanding neural alterations in aniridia may require examination of possible differences in white matter structure, as few studies have assessed white matter in this population. The current study utilized diffusion-weighted imaging to assess white matter structure in 11 people with aniridia and 11 healthy comparison participants, matched for sex and age. A map of the local connectome was calculated to compare quantitative anisotropy (QA), an index of white matter tract density, in all white matter voxels, revealing subcomponents of white matter tracts with differing QA between people with aniridia and healthy comparisons. The analysis indicated that QA was lower for people with aniridia in portions of bilateral optic tract [t(20)=-4.23, P=0.001, d=-1.80], bilateral optic radiation [t(20)=-4.06, P=0.001, d=-1.73], forceps major [t(20)=-3.65, P=0.002, d=-1.55], bilateral superior longitudinal fasciculus [left: t(20)=-3.15, P=0.005, d=-1.34; right, t(20)=-4.28, P<0.001, d=-1.83], and right posterior corona radiata [t(20)=-3.19, P=0.006, d=-1.36]. These differences demonstrate that white matter structure is altered in people with aniridia in both visual tracts and associated posterior visual pathways.

Structural brain abnormalities in 12 persons with aniridia.

Background: Aniridia is a disorder predominately caused by heterozygous loss-of-function mutations of the PAX6 gene, which is a transcriptional regulator necessary for normal eye and brain development.  The ocular abnormalities of aniridia have been well characterized, but mounting evidence has implicated brain-related phenotypes as a prominent feature of this disorder as well.  Investigations using neuroimaging in aniridia patients have shown reductions in discrete brain structures and changes in global grey and white matter.  However, limited sample sizes and substantive heterogeneity of structural phenotypes in the brain remain a challenge.  Methods: Here, we examined brain structure in a new population sample in an effort to add to the collective understanding of anatomical abnormalities in aniridia.  The current study used 3T magnetic resonance imaging to acquire high-resolution structural data in 12 persons with aniridia and 12 healthy demographically matched comparison subjects.  Results: We examined five major structures: the anterior commissure, the posterior commissure, the pineal gland, the corpus callosum, and the optic chiasm.  The most consistent reductions were found in the anterior commissure and the pineal gland; however, abnormalities in all of other structures examined were present in at least one individual.  Conclusions: Our results indicate that the anatomical abnormalities in aniridia are variable and largely individual-specific.  These findings suggest that future studies investigate this heterogeneity further, and that normal population variation should be considered when evaluating structural abnormalities.