Large-scale network connectivity as a predictor of age: Evidence across the adult lifespan from the Cam-CAN data set.

Changes in brain connectivity patterns as a function of age have been recently proposed to underlie differences in cognitive abilities between young and older adults. These shifts track patterns of increased functional coupling between the executive control network (ECN)-a network of prefrontal and parietal areas that is broadly implicated in externally directed attention and cognitive control-and default mode network (DMN) regions-most commonly associated with internally directed cognitive activity. Although age-related changes in ECN-DMN coupling are well characterized, the contributions of the salience network are less clear. Furthermore, given the salience network's crucial role in arbitrating ECN-DMN functional connectivity, it is important to understand its contribution throughout the adult lifespan. Here, we used the data from a large cohort (N = 547) of participants from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) database (18-88 years old) to investigate first whether resting-state ECN-DMN functional connectivity predicts age. We further examined how connectivity between ECN, DMN, and salience network regions impacts the hypothesized age-related increased connectivity between ECN and DMN areas. Multiple regression analyses revealed that connectivity between dorsolateral and ventromedial prefrontal cortex and parietal regions, including the precuneus, accounted for a significant portion of age variability and that the inclusion of connectivity between orbitofrontal insula, anterior insula, and anterior cingulate regions of the salience network improved the models' explanatory power. Additional age cohort analyses further highlighted that these relationships vary across the lifespan. We discuss how these findings expand on our current understanding of the variations in large-scale intrinsic network connectivity as a function of healthy aging. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The cingulate cortex and spatial neglect.

Spatial neglect is asymmetric attention, orienting, and action causing functional disability. It is linked to higher-order cortical sensory processing; however, spatial motor "Aiming" processing is critical to fundamental, adaptive environmental movement and daily life function. The cingulate cortex, in particular the anterior cingulate and anterior midcingulate cortex, is strongly linked to spatial Aiming deficits and likely to predict daily life disability in spatial neglect. The authors review the impact and mechanisms of spatial neglect and then describe specific symptoms associated with spatial neglect that are theoretically linked to cingulate cortical functions or associated with lesions extending to cingulate regions in a well-characterized spatial neglect cohort. The treatment implications for a link between cingulate cortex spatial Aiming neglect and therapies that improve spatial action, arousal, and persistence are discussed. Clinicians may want to consider theoretically motivated treatments targeted at specific symptoms as well as use treatments supported for spatial neglect based on unselected and uncharacterized groups.

Post-traumatic stress symptoms are associated with better performance on a delayed match-to-position task.

Many individuals with posttraumatic stress disorder (PTSD) report experiencing frequent intrusive memories of the original traumatic event (e.g., flashbacks). These memories can be triggered by situations or stimuli that reflect aspects of the trauma and may reflect basic processes in learning and memory, such as generalization. It is possible that, through increased generalization, non-threatening stimuli that once evoked normal memories become associated with traumatic memories. Previous research has reported increased generalization in PTSD, but the role of visual discrimination processes has not been examined. To investigate visual discrimination in PTSD, 143 participants (Veterans and civilians) self-assessed for symptom severity were grouped according to the presence of severe PTSD symptoms (PTSS) vs. few/no symptoms (noPTSS). Participants were given a visual match-to-sample pattern separation task that varied trials by spatial separation (Low, Medium, High) and temporal delays (5, 10, 20, 30 s). Unexpectedly, the PTSS group demonstrated better discrimination performance than the noPTSS group at the most difficult spatial trials (Low spatial separation). Further assessment of accuracy and reaction time using diffusion drift modeling indicated that the better performance by the PTSS group on the hardest trials was not explained by slower reaction times, but rather a faster accumulation of evidence during decision making in conjunction with a reduced threshold, indicating a tendency in the PTSS group to decide quickly rather than waiting for additional evidence to support the decision. This result supports the need for future studies examining the precise role of discrimination and generalization in PTSD, and how these cognitive processes might contribute to expression and maintenance of PTSD symptoms.

Which perseverative behaviors are symptoms of spatial neglect?

Spatial neglect is a characterized by a failure to attend or make movements towards left-sided stimuli. Common paper-and-pencil tasks to diagnose spatial neglect are sensitive to perseverative errors, including additional marks over already cancelled targets and "scribbling" out a target. Here, we examine whether functionally distinct perseverative behaviors are related to spatial neglect. Line cancellation tasks of 45 healthy controls and 220 right-hemisphere stroke survivors were examined for recurrent marks (RM) and continuous marks (CM) perseverations. We found that RM perseveration correlated with neglect severity, while CM perseveration did not. Examination of lesion profiles for the two groups indicated distinct anatomical correlates, with RM lesions overlapping regions implicated in spatial neglect including the rolandic operculum, superior temporal gyrus, and inferior parietal lobule.

Assessing viewer-centered and stimulus-centered spatial bias: The 3s spreadsheet test version 1.

The 3s Spreadsheet Test (3S Test) is a cancellation test with high stimulus density and low target-to-distractor ratio, to assess stimulus-centered and viewer-centered spatial neglect. Twenty-five stroke survivors with left-sided neglect and 68 age-matched healthy controls took the 3S Test. Patients also took the Apples Test, a validated cancellation test. No patient's accuracy on the 3S Test was in the normal range. A total of 91.7% of the patients had an abnormal start; 52.6% of the patients took abnormally long time to complete the 3S Test. The 3S and Apples Tests agreed poorly on both the viewer-centered and stimulus-centered neglect classifications (κ = .25 and .05, respectively), but consistently identified 8 of the 25 patients (32%) as having both forms of neglect while each isolated form of neglect was present in one patient (4%). Lesion data were consistent with previous studies. These findings suggest that the 3S Test is a sensitive cancellation test for assessing viewer-centered and stimulus-centered spatial neglect. We are currently developing the 3S Test version 2 to refine the test stimuli and the scoring procedure.

Cerebellar response to familiar and novel stimuli: An fMRI study.

Historically known for its key contribution to motor behavior, the cerebellum continues to break boundaries. Researchers have demonstrated the cerebellum also plays a role in learning, memory, and more recent evidence for contributions in language, attention, working memory, emotions, and social processes. Here, we present a study that adds to the list of nonmotor processes of the cerebellum. We used images of faces and outdoor scenes to examine the cerebellar response to familiar and novel stimuli. Participants were familiarized with a subset of stimuli, and then underwent functional MRI (fMRI) where they were presented with the previously stimuli and new stimuli while making "old" and "new" judgment. In a familiar versus novel contrast, familiar stimuli (faces and scenes combined) activated bilateral regions of the cerebellum including I-IV, V, VI, Crus I, and Crus II. When separated by type, familiar faces had greater activation of bilateral I-IV than novel faces. These results demonstrate the cerebellar role in determining familiarity and contribute to continuing research supporting cerebellar contributions to nonmotor processes. (PsycINFO Database Record

Individual differences in resting-state functional connectivity with the executive network: support for a cerebellar role in anxiety vulnerability.

This study characterized cerebellar connectivity with executive intrinsic functional connectivity networks. Using seed regions at the right and left dorsolateral prefrontal cortices (dlPFC) and right orbital frontoinsula, we measured resting-state brain connectivity in healthy college-aged participants. Based on the previous research demonstrating a relationship between the cerebellum and self-report measures of behavioral inhibition, we assessed individual differences in connectivity between groups. Overall, intrinsic activity in cerebellar lobule VIII was significantly correlated with the executive network and cerebellar Crus I with the salience network. Between-group comparisons indicated stronger cerebellar connectivity with the executive network in behaviorally inhibited individuals. Intrinsic activity in Crus I, a region previously implicated in non-motor cerebellar functions, significantly correlated with intrinsic activity in the right dlPFC seed region. These findings support a growing number of studies demonstrating cerebellar influence on higher cognitive processes, extending this relationship to individual differences in anxiety vulnerability.

Facilitated acquisition of eyeblink conditioning in those vulnerable to anxiety disorders.

Behavioral inhibition (BI) increases vulnerability to develop anxiety disorders and is typified by avoidance and withdrawal from novel objects, people, and situations. The present study considered the relationship between BI and temperamental risk factors, such as trait anxiety and acquisition rate of a classically conditioned eyeblink response. One-hundred seventy-four healthy undergraduate students (mean age 20.3 years, 71.8% female) were given the State-Trait Anxiety Inventory and a battery of self-report measures of BI consisting of the Adult and Retrospective Measures of Behavioral Inhibition (AMBI/RMBI) and the Concurrent and Retrospective Self Report of Inhibition (CSRI/RSRI). Participants then underwent standard delay classical eyeblink conditioning consisting of 45 trials with a 500-ms CS overlapping and co-terminating with a 10-ms airpuff US. Individuals with higher scores on the AMBI and Trait Anxiety Inventory, but not the other measures, showed faster acquisition of a conditioned eyeblink response than individuals with lower scores. Results support a relationship between facilitated acquisition of inter-stimulus relationships and risk for anxiety, and suggest that some measures assessing anxiety vulnerability better capture this relationship than others.