Publications by authors named "Michael Esterman"

78 Publications

Evidence for a Specific Association Between Sustained Attention and Gait Speed in Middle-to-Older-Aged Adults.

Front Aging Neurosci 2021 5;13:703434. Epub 2021 Jul 5.

Boston Attention and Learning Laboratory (BALLAB), VA Boston Healthcare System, Boston, MA, United States.

Although cognitive decline has previously been associated with mobility limitations and frailty, the relationship between sustained attention and gait speed is incompletely characterized. To better quantify the specificity of the sustained attention and gait speed association, we examined the extent to which this relationship is unique rather than accounted for by executive functioning and physical health characteristics. 58 middle-to-older-aged community-dwelling adults without overt evidence of cognitive impairment (45-90 years old; 21 females) participated in the study. Each participant completed a 4-meter gait speed assessment and validated neuropsychological tests to examine various domains of executive functioning including working memory (i.e., Digit Span), inhibitory control (i.e., D-KEFS Color-Word Interference), and task switching (i.e., D-KEFS Number/Letter Switching). Multiple physical and vascular risk factors were also evaluated. Sustained attention was assessed using the gradual onset continuous performance task (gradCPT), a well-validated go/no-go sustained attention task. A series of linear regression models were used to examine how different aspects of cognition, including sustained attention and traditional measures of executive functioning, related to gait speed while controlling for a variety of physical and vascular risk factors. Among all predictors, gradCPT accuracy explained the most variance in gait speed ( = 0.19, < 0.001) and was the only significant predictor (β = 0.35, = 0.01) when accounting for executive functioning and other physical and vascular risk factors. The present results indicate that sustained attention may be uniquely sensitive and mechanistically linked to mobility limitations in middle-to-older adults.
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http://dx.doi.org/10.3389/fnagi.2021.703434DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8289388PMC
July 2021

Variable rather than extreme slow reaction times distinguish brain states during sustained attention.

Sci Rep 2021 Jul 21;11(1):14883. Epub 2021 Jul 21.

Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118, USA.

A common behavioral marker of optimal attention focus is faster responses or reduced response variability. Our previous study found two dominant brain states during sustained attention, and these states differed in their behavioral accuracy and reaction time (RT) variability. However, RT distributions are often positively skewed with a long tail (i.e., reflecting occasional slow responses). Therefore, a larger RT variance could also be explained by this long tail rather than the variance around an assumed normal distribution (i.e., reflecting pervasive response instability based on both faster and slower responses). Resolving this ambiguity is important for better understanding mechanisms of sustained attention. Here, using a large dataset of over 20,000 participants who performed a sustained attention task, we first demonstrated the utility of the exGuassian distribution that can decompose RTs into a strategy factor, a variance factor, and a long tail factor. We then investigated which factor(s) differed between the two brain states using fMRI. Across two independent datasets, results indicate unambiguously that the variance factor differs between the two dominant brain states. These findings indicate that 'suboptimal' is different from 'slow' at the behavior and neural level, and have implications for theoretically and methodologically guiding future sustained attention research.
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http://dx.doi.org/10.1038/s41598-021-94161-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8295386PMC
July 2021

Association between metabolic syndrome and resting-state functional brain connectivity.

Neurobiol Aging 2021 08 1;104:1-9. Epub 2021 Apr 1.

Neuroimaging Research for Veterans Center (NeRVe), Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.

The objective of this study is to examine whether metabolic syndrome (MetS), the clustering of 3 or more cardiovascular risk factors, disrupts the resting-state functional connectivity (FC) of the large-scale cortical brain networks. Resting-state functional magnetic resonance imaging data were collected from seventy-eight middle-aged and older adults living with and without MetS (27 MetS; 51 non-MetS). FC maps were derived from the time series of intrinsic activity in the large-scale brain networks by correlating the spatially averaged time series with all brain voxels using a whole-brain seed-based FC approach. Participants with MetS showed hyperconnectivity across the core brain regions with evidence of loss of modularity when compared with non-MetS individuals. Furthermore, patterns of higher between-network MetS-related effects were observed across most of the seed regions in both right and left hemispheres. These findings indicate that MetS is associated with altered intrinsic communication across core neural networks and disrupted between-network connections across the brain due to the co-occurring vascular risk factors in MetS.
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http://dx.doi.org/10.1016/j.neurobiolaging.2021.03.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8225583PMC
August 2021

Brain state-based detection of attentional fluctuations and their modulation.

Neuroimage 2021 08 18;236:118072. Epub 2021 Apr 18.

Department of Psychiatry, Boston University School of Medicine, Massachusetts, 02118. United States; Boston Attention and Learning Laboratory, VA Boston Healthcare System, Massachusetts,02130. United States; National Center for PTSD, VA Boston Healthcare System, Massachusetts, 02130. United States.

In the search for brain markers of optimal attentional focus, the mainstream approach has been to first define attentional states based on behavioral performance, and to subsequently investigate "neural correlates" associated with these performance variations. However, this approach constrains the range of contexts in which attentional states can be operationalized by relying on overt behavior, and assumes a one-to-one correspondence between behavior and brain state. Here, we reversed the logic of these previous studies and sought to identify behaviorally-relevant brain states based solely on brain activity, agnostic to behavioral performance. In four independent datasets, we found that the same two brain states were dominant during a sustained attention task. One state was behaviorally optimal, with higher accuracy and stability, but a greater tendency to mind wander (State1). The second state was behaviorally suboptimal, with lower accuracy and instability (State2). We further demonstrate how these brain states were impacted by motivation and attention-deficit/hyperactivity disorder (ADHD). Individuals with ADHD spent more time in suboptimal State2 and less time in optimal State1 than healthy controls. Motivation overcame the suboptimal behavior associated with State2. Our study provides compelling evidence for the existence of two attentional states from the sole viewpoint of brain activity.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118072DOI Listing
August 2021

Impaired executive function exacerbates neural markers of posttraumatic stress disorder.

Psychol Med 2021 Apr 21:1-14. Epub 2021 Apr 21.

National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA.

Background: A major obstacle in understanding and treating posttraumatic stress disorder (PTSD) is its clinical and neurobiological heterogeneity. To address this barrier, the field has become increasingly interested in identifying subtypes of PTSD based on dysfunction in neural networks alongside cognitive impairments that may underlie the development and maintenance of symptoms. The current study aimed to determine if subtypes of PTSD, based on normative-based cognitive dysfunction across multiple domains, have unique neural network signatures.

Methods: In a sample of 271 veterans (90% male) that completed both neuropsychological testing and resting-state fMRI, two complementary, whole-brain functional connectivity analyses explored the link between brain functioning, PTSD symptoms, and cognition.

Results: At the network level, PTSD symptom severity was associated with reduced negative coupling between the limbic network (LN) and frontal-parietal control network (FPCN), driven specifically by the dorsolateral prefrontal cortex and amygdala Hubs of Dysfunction. Further, this relationship was uniquely moderated by executive function (EF). Specifically, those with PTSD and impaired EF had the strongest marker of LN-FPCN dysregulation, while those with above-average EF did not exhibit PTSD-related dysregulation of these networks.

Conclusion: These results suggest that poor executive functioning, alongside LN-FPCN dysregulation, may represent a neurocognitive subtype of PTSD.
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http://dx.doi.org/10.1017/S0033291721000842DOI Listing
April 2021

Prediction of stimulus-independent and task-unrelated thought from functional brain networks.

Nat Commun 2021 03 19;12(1):1793. Epub 2021 Mar 19.

Department of Psychology, Northeastern University, Boston, MA, USA.

Neural substrates of "mind wandering" have been widely reported, yet experiments have varied in their contexts and their definitions of this psychological phenomenon, limiting generalizability. We aimed to develop and test the generalizability, specificity, and clinical relevance of a functional brain network-based marker for a well-defined feature of mind wandering-stimulus-independent, task-unrelated thought (SITUT). Combining functional MRI (fMRI) with online experience sampling in healthy adults, we defined a connectome-wide model of inter-regional coupling-dominated by default-frontoparietal control subnetwork interactions-that predicted trial-by-trial SITUT fluctuations within novel individuals. Model predictions generalized in an independent sample of adults with attention-deficit/hyperactivity disorder (ADHD). In three additional resting-state fMRI studies (total n = 1115), including healthy individuals and individuals with ADHD, we demonstrated further prediction of SITUT (at modest effect sizes) defined using multiple trait-level and in-scanner measures. Our findings suggest that SITUT is represented within a common pattern of brain network interactions across time scales and contexts.
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http://dx.doi.org/10.1038/s41467-021-22027-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7979817PMC
March 2021

The missing role of gray matter in studying brain controllability.

Netw Neurosci 2021 1;5(1):198-210. Epub 2021 Mar 1.

Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany.

Brain controllability properties are normally derived from the white matter fiber tracts in which the neural substrate of the actual energy consumption, namely the gray matter, has been widely ignored. Here, we study the relationship between gray matter volume of regions across the whole cortex and their respective control properties derived from the structural architecture of the white matter fiber tracts. The data suggests that the ability of white fiber tracts to exhibit control at specific nodes not only depends on the connection strength of the structural connectome but additionally depends on gray matter volume at the host nodes. Our data indicate that connectivity strength and gray matter volume interact with respect to the brain's control properties. Disentangling effects of the regional gray matter volume and connectivity strength, we found that frontal and sensory areas play crucial roles in controllability. Together these results suggest that structural and regional properties of the white matter and gray matter provide complementary information in studying the control properties of the intrinsic structural and functional architecture of the brain.
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http://dx.doi.org/10.1162/netn_a_00174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7935040PMC
March 2021

Apolipoprotein E (APOE) ε4 moderates the relationship between c-reactive protein, cognitive functioning, and white matter integrity.

Brain Behav Immun 2021 07 23;95:84-95. Epub 2021 Feb 23.

National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA; Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA; Translational Research Center for TBI and Stress Disorders (TRACTS) and Geriatric Research Educational and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA, USA; Boston Attention and Learning Laboratory, VA Healthcare System, Boston, MA, USA.

Elevated serum C-reactive protein (CRP) and possessing an APOE ε4 allele are two of the most prominent risk factors for cognitive and neurological dysfunction in older adults, but little is known about the unique or cumulative effects of these risk factors in young-to-middle-aged adults. To further characterize these potential relationships, measures of cognition and microstructural white matter integrity were examined using data from a sample of 329 post-9/11 war veterans that was collected as part of a comprehensive evaluation that included assessment of neuropsychological functioning, MRI scanning, psychiatric diagnoses, health screening, markers of inflammation, and APOE genotypes. Hierarchical linear regression analyses revealed the CRP and APOE ε4 interaction was associated with global cognition (β = -0.633), executive functioning (β = -0.566), and global fractional anisotropy (β = -0.470), such that elevated CRP was associated with worse cognition and white matter integrity in APOE ε4 carriers. Diffusion tensor imaging (DTI) was used to determine if CRP × APOE ε4 presence was associated with regionally specific fractional anisotropy in white matter tracts. Tract-based spatial statistics revealed CRP × APOE ε4 presence was associated with fractional anisotropy in the corpus callosum, right superior longitudinal fasciculus, right posterior corona radiata, as well as the bilateral anterior and superior corona radiatas. This suggests that APOE ε4 carriers may be uniquely vulnerable to the potentially negative impact of elevated systematic inflammation to cognition and microstructural white matter integrity.
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http://dx.doi.org/10.1016/j.bbi.2021.02.016DOI Listing
July 2021

Apolipoprotein E (APOE) ε4 moderates the relationship between c-reactive protein, cognitive functioning, and white matter integrity.

Brain Behav Immun 2021 07 23;95:84-95. Epub 2021 Feb 23.

National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA; Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA; Translational Research Center for TBI and Stress Disorders (TRACTS) and Geriatric Research Educational and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA, USA; Boston Attention and Learning Laboratory, VA Healthcare System, Boston, MA, USA.

Elevated serum C-reactive protein (CRP) and possessing an APOE ε4 allele are two of the most prominent risk factors for cognitive and neurological dysfunction in older adults, but little is known about the unique or cumulative effects of these risk factors in young-to-middle-aged adults. To further characterize these potential relationships, measures of cognition and microstructural white matter integrity were examined using data from a sample of 329 post-9/11 war veterans that was collected as part of a comprehensive evaluation that included assessment of neuropsychological functioning, MRI scanning, psychiatric diagnoses, health screening, markers of inflammation, and APOE genotypes. Hierarchical linear regression analyses revealed the CRP and APOE ε4 interaction was associated with global cognition (β = -0.633), executive functioning (β = -0.566), and global fractional anisotropy (β = -0.470), such that elevated CRP was associated with worse cognition and white matter integrity in APOE ε4 carriers. Diffusion tensor imaging (DTI) was used to determine if CRP × APOE ε4 presence was associated with regionally specific fractional anisotropy in white matter tracts. Tract-based spatial statistics revealed CRP × APOE ε4 presence was associated with fractional anisotropy in the corpus callosum, right superior longitudinal fasciculus, right posterior corona radiata, as well as the bilateral anterior and superior corona radiatas. This suggests that APOE ε4 carriers may be uniquely vulnerable to the potentially negative impact of elevated systematic inflammation to cognition and microstructural white matter integrity.
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http://dx.doi.org/10.1016/j.bbi.2021.02.016DOI Listing
July 2021

Integration and segregation across large-scale intrinsic brain networks as a marker of sustained attention and task-unrelated thought.

Neuroimage 2021 04 6;229:117610. Epub 2021 Jan 6.

Department of Psychiatry, Boston University School of Medicine, United States; Boston Attention and Learning Laboratory, VA Boston Healthcare System, United States; National Center for PTSD, VA Boston Healthcare System, United States.

Sustained attention is a fundamental cognitive process that can be decoupled from distinct external events, and instead emerges from ongoing intrinsic large-scale network interdependencies fluctuating over seconds to minutes. Lapses of sustained attention are commonly associated with the subjective experience of mind wandering and task-unrelated thoughts. Little is known about how fluctuations in information processing underpin sustained attention, nor how mind wandering undermines this information processing. To overcome this, we used fMRI to investigate brain activity during subjects' performance (n=29) of a cognitive task that was optimized to detect and isolate continuous fluctuations in both sustained attention (via motor responses) and task-unrelated thought (via subjective reports). We then investigated sustained attention with respect to global attributes of communication throughout the functional architecture, i.e., by the segregation and integration of information processing across large scale-networks. Further, we determined how task-unrelated thoughts related to these global information processing markers of sustained attention. The results show that optimal states of sustained attention favor both enhanced segregation and reduced integration of information processing in several task-related large-scale cortical systems with concurrent reduced segregation and enhanced integration in the auditory and sensorimotor systems. Higher degree of mind wandering was associated with losses of the favored segregation and integration of specific subsystems in our sustained attention model. Taken together, we demonstrate that intrinsic ongoing neural fluctuations are characterized by two converging communication modes throughout the global functional architecture, which give rise to optimal and suboptimal attention states. We discuss how these results might potentially serve as neural markers for clinically abnormal attention. SIGNIFICANCE STATEMENT: Most of our brain activity unfolds in an intrinsic manner, i.e., is unrelated to immediate external stimuli or tasks. Here we use a gradual continuous performance task to map this intrinsic brain activity to both fluctuations of sustained attention and mind wandering. We show that optimal sustained attention is associated with concurrent segregation and integration of information processing within many large-scale brain networks, while task-unrelated thought is related to sub-optimal information processing in specific subsystems of this sustained attention network model. These findings provide a novel information processing framework for investigating the neural basis of sustained attention, by mapping attentional fluctuations to genuinely global features of intra-brain communication.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117610DOI Listing
April 2021

Evaluating the evidence for a neuroimaging subtype of posttraumatic stress disorder.

Sci Transl Med 2020 11;12(568)

Neuroimaging Research for Veterans (NeRVe) Center, VA Boston Healthcare System, Boston, MA 02130, USA.

A recent study used functional neuroimaging and cognitive tasks to identify posttraumatic stress disorder (PTSD) subtypes. Specifically, this study found that a subgroup of patients with verbal memory impairment had a unique neural signature, namely, decreased ventral attention network (VAN) resting-state functional connectivity, and these same individuals responded poorly to psychotherapy. Although this represents one of the first studies to propose a neurocognitive subtype of PTSD and has far-reaching translational potential, the generalizability and specificity of the observed neural network and cognitive domain remain unclear. We attempted to conceptually replicate and extend these findings in a similar cohort of combat-exposed veterans ( = 229) tested using a standardized battery of neuropsychological tests and a priori criteria for cognitive impairments. First, we conducted identical and complementary analyses to determine whether subjects with PTSD and neuropsychologically defined verbal memory deficits exhibited the VAN connectivity biomarker. Second, we examined whether cognitive deficits in other domains implicated in PTSD (executive functioning and attention) exhibited the VAN signature. Across multiple measures of verbal memory, we did not find that the subgroup of individuals with PTSD and memory impairments had lower VAN connectivity. However, a subgroup of individuals with PTSD and attentional impairments did have lower VAN connectivity, suggesting that the original subtype could have been related to attention and not memory impairments. Overall, our findings suggest that the previously identified memory-impaired PTSD subtype may not generalize. Further consideration of neuropsychological methods will be important for neurocognitive markers to be implemented clinically.
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http://dx.doi.org/10.1126/scitranslmed.aaz9343DOI Listing
November 2020

Apolipoprotein E () ε4 Status Moderates the Relationship Between Close-Range Blast Exposure and Cognitive Functioning.

J Int Neuropsychol Soc 2021 04 3;27(4):315-328. Epub 2020 Nov 3.

Translational Research Center for TBI and Stress Disorders (TRACTS) and Geriatric Research, Educational and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA02130, USA.

Objectives: Recent studies suggest that close-range blast exposure (CBE), regardless of acute concussive symptoms, may have negative long-term effects on brain health and cognition; however, these effects are highly variable across individuals. One potential genetic risk factor that may impact recovery and explain the heterogeneity of blast injury's long-term cognitive outcomes is the inheritance of an apolipoprotein (APOE) ε4 allele, a well-known genetic risk factor for Alzheimer's disease. We hypothesized that APOE ε4 carrier status would moderate the impact of CBE on long-term cognitive outcomes.

Methods: To test this hypothesis, we examined 488 post-9/11 veterans who completed assessments of neuropsychological functioning, psychiatric diagnoses, history of blast exposure, military and non-military mild traumatic brain injuries (mTBIs), and available APOE genotypes. We separately examined the effects of CBE on attention, memory, and executive functioning in individuals with and without the APOE ε4 allele.

Results: As predicted, we observed a differential impact of CBE status on cognition as a function of APOE ε4 status, in which CBE ε4 carriers displayed significantly worse neuropsychological performance, specifically in the domain of memory. These results persisted after adjusting for clinical, demographic, and genetic factors and were not observed when examining other neurotrauma variables (i.e., lifetime or military mTBI, distant blast exposure), though these variables displayed similar trends.

Conclusions: These results suggest APOE ε4 carriers are more vulnerable to the impact of CBE on cognition and highlight the importance of considering genetic risk when studying cognitive effects of neurotrauma.
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http://dx.doi.org/10.1017/S1355617720001034DOI Listing
April 2021

Moderated mediation for exercise maintenance in pain and posttraumatic stress disorder: A randomized trial.

Health Psychol 2020 Sep;39(9):826-840

Women's Health Sciences Division, National Center for PTSD, Research Service, VA Boston Healthcare System.

This study utilizes the Science of Behavior Change (SOBC) experimental medicine approach to evaluate the effects of a 3-month, individually prescribed progressive exercise training program on neurobiological, cognitive and motivational mechanisms by which our exercise-training paradigm may foster exercise maintenance. We will investigate hypothesized relationships between exercise-training associated augmentation of neuropeptide Y (NPY) system function and improvements in self-regulation and reward sensitivity-cognitive control and motivational processes posited to promote self-efficacy and intrinsic motivation, which have been shown to predict exercise maintenance. This study will recruit Veterans with chronic low back pain and posttraumatic stress disorder (PTSD). Procedures include a baseline, acute cardiopulmonary exercise challenge assessment that will inform the exercise prescription for a 12-week progressive exercise training program comprised of three 45-minute aerobic exercise sessions per week-all of which will be supervised by an exercise physiologist. Additionally, a week-7 and week-14 exercise challenge assessment will track changes in NPY system function and the variables of interest. We hypothesize that increases in the capacity to release NPY in response to acute exercise testing will be associated with improvements in self-regulation and reward sensitivity, which will in turn be associated with self-efficacy and intrinsic motivation to maintain regular exercise. Ninety participants will be randomized either to the "active exercise training condition" or to the "wait list symptom monitoring condition". The study aims to demonstrate the feasibility of procedures and elucidate mechanisms relevant to developing individually prescribed, motivationally based exercise regimens to reduce negative consequences of PTSD and low back pain over the long-term. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
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http://dx.doi.org/10.1037/hea0000876DOI Listing
September 2020

Interpersonal early life trauma is associated with increased cerebral perfusion and poorer memory performance in post-9/11 veterans.

Neuroimage Clin 2020 1;28:102365. Epub 2020 Aug 1.

National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA; Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.

Background: Cerebral blood flow (CBF) is critically important in the overall maintenance of brain health, and disruptions in normal flow have been linked to the degradation of the brain's structural integrity and function. Recent studies have highlighted the potential role of CBF as a link between psychiatric disorders and brain integrity. Although interpersonal early life trauma (IP-ELT) is a risk factor for the development of psychiatric disorders and has been linked to disruptions in brain structure and function, the mechanisms through which IP-ELT alters brain integrity and development remain unclear. The goal of this study was to understand whether IP-ELT was associated with alterations in CBF assessed during adulthood. Further, because the cognitive implications of perfusion disruptions in IP-ELT are also unclear, this study sought to investigate the relationship between IP-ELT, perfusion, and cognition.

Methods: 179 Operations Enduring Freedom/Iraqi Freedom/New Dawn (OEF/OIF/OND) Veterans and military personnel completed pseudo-continuous arterial spin labeling (pCASL) imaging, clinical interviews, the Traumatic Life Events Questionnaire (TLEQ), and a battery of neuropsychological tests that were used to derive attention, memory, and executive function cognitive composite scores. To determine whether individuals were exposed to an IP-ELT, events on the TLEQ that specifically queried interpersonal trauma before the age of 18 were tallied for each individual. Analyses compared individuals who reported an interpersonal IP-ELT (IP-ELT+, n = 48) with those who did not (IP-ELT-, n = 131).

Results: Whole brain analyses revealed that IP-ELT+ individuals had significantly greater CBF in the right inferior/middle temporal gyrus compared to those in the IP-ELT- group, even after controlling for age, sex, and posttraumatic stress disorder (PTSD). Further, perfusion in the right inferior/middle temporal gyrus significantly mediated the relationship between IP-ELT and memory, not attention or executive function, such that those with an IP-ELT had greater perfusion, which, in turn, was associated with poorer memory. Examination of other clinical variables such as current PTSD diagnosis and severity as well as the interaction between IP-ELT and PTSD yielded no significant effects.

Conclusions: These results extend prior work demonstrating an association between ELT and cerebral perfusion by suggesting that increased CBF may be an important neural marker with cognitive implications in populations at risk for psychiatric disorders.
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http://dx.doi.org/10.1016/j.nicl.2020.102365DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417939PMC
June 2021

Early Adolescent Binge Drinking Increases Risk of Psychopathology in Post-9/11 Veterans and Mild Traumatic Brain Injury Exacerbates Symptom Severity.

Alcohol Alcohol 2021 Jan;56(1):116-124

Translational Research Center for TBI and Stress Disorders (TRACTS), VA Boston Healthcare System, 150 S. Huntington Avenue, Boston, MA 02130, USA.

Aims: To demonstrate that early adolescent binge drinking (BD) increases the risk for and/or severity of psychopathology in post-9/11 Veterans and determine if mild traumatic brain injury (mTBI) modifies risk.

Methods: Post-9/11 Veterans (n = 375) were classified into two groups: 57 Veterans with a history of early adolescent BD (E-BD; age of onset <15) and 318 who did not BD until age 15 or older (late-BD or L-BD; age of onset ≥15). History of military mTBI and mental health disorders were also assessed following military service.

Results: Logistic regression and analysis of variance (ANOVA) analyses revealed that the E-BD's had significantly higher prevalence of alcohol use disorders (AUDs) and more severe symptoms of AUD, substance use disorder (SUD), depression and stress. Two-way ANOVAs showed that history of military mTBI was differentially associated with posttraumatic stress disorder (PTSD) incidence and severity among Veterans who had engaged in early adolescent BD. Specifically, Veterans with a history of both early adolescent BD and military mTBI were at greater risk for a PTSD diagnosis and had more severe symptoms of PTSD than those with only a history of adolescent BD. The greater PTSD symptom severity in the comorbid group was driven by hyperarousal symptoms.

Conclusions: A history of BD during early adolescence is prevalent among Veterans and is related to higher risk for AUD and more severe AUD, SUD, mood and stress symptoms later in life. Veterans with early BD and military mTBI showed greater incidence and severity of PTSD, indicating that mTBI, a common comorbidity among post-9/11 Veterans, exacerbates risk.
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http://dx.doi.org/10.1093/alcalc/agaa075DOI Listing
January 2021

Childhood Adversity and Dimensional Variations in Adult Sustained Attention.

Front Psychol 2020 16;11:691. Epub 2020 Apr 16.

Department of Psychiatry, Harvard Medical School, Boston, MA, United States.

Background And Objective: Sustained attention is a transdiagnostic phenotype linked with most forms of psychopathology. We sought to understand factors that influence the development of sustained attention, by looking at the relationship between childhood adversity and adult sustained attention.

Participants Setting And Methods: Participants were 5,973 TestMyBrain.org visitors from English-speaking countries who completed a continuous performance task (gradCPT) of sustained attention and a childhood adversity questionnaire. We analyzed gradCPT performance using a signal detection approach.

Results: Discrimination ability (the main metric of performance on the gradCPT) was associated with total childhood adversity load, even when controlling for covariates related to age, gender, parental education, race, country of origin, and relative socioeconomic status (β = -0.079, = -0.032).

Conclusion: Our results demonstrate that attention differences related to childhood adversity exposure can (1) be measured using brief, performance-based measures of sustained attention, (2) persist into adulthood, and (3) be detected at the population level. These results, paired with the well-documented associations between sustained attention and psychopathology, indicate that sustained attention may be an important mechanism for understanding early influences on mental health.
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http://dx.doi.org/10.3389/fpsyg.2020.00691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180319PMC
April 2020

Electrophysiological dynamics of antagonistic brain networks reflect attentional fluctuations.

Nat Commun 2020 01 16;11(1):325. Epub 2020 Jan 16.

Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA, 94304, USA.

Neuroimaging evidence suggests that the default mode network (DMN) exhibits antagonistic activity with dorsal attention (DAN) and salience (SN) networks. Here we use human intracranial electroencephalography to investigate the behavioral relevance of fine-grained dynamics within and between these networks. The three networks show dissociable profiles of task-evoked electrophysiological activity, best captured in the high-frequency broadband (HFB; 70-170 Hz) range. On the order of hundreds of milliseconds, HFB responses peak fastest in the DAN, at intermediate speed in the SN, and slowest in the DMN. Lapses of attention (behavioral errors) are marked by distinguishable patterns of both pre- and post-stimulus HFB activity within each network. Moreover, the magnitude of temporally lagged, negative HFB coupling between the DAN and DMN (but not SN and DMN) is associated with greater sustained attention performance and is reduced during wakeful rest. These findings underscore the behavioral relevance of temporally delayed coordination between antagonistic brain networks.
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http://dx.doi.org/10.1038/s41467-019-14166-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6965628PMC
January 2020

Multiscale Dynamics of Spontaneous Brain Activity Is Associated With Walking Speed in Older Adults.

J Gerontol A Biol Sci Med Sci 2020 07;75(8):1566-1571

Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Roslindale, Massachusetts.

Background: In older adults, compromised white matter tract integrity within the brain has been linked to impairments in mobility. We contend that poorer integrity disrupts mobility by altering the processing of sensorimotor and cognitive and attentional resources in neural networks. The richness of information processing in a given network can be quantified by calculating the complexity of resting-state functional MRI time series. We hypothesized that (i) older adults with lower brain complexity, specifically within sensorimotor, executive, and attention networks, would exhibit slower walking speed and greater dual-task costs (ie, dual-task cost) and (ii) such complexity would mediate the effect of white matter integrity on these metrics of mobility.

Methods: Fifty-three older adults completed a walking assessment and a neuroimaging protocol. Brain complexity was quantified by calculating the multiscale entropy of the resting-state functional MRI signal within seven previously defined functional networks. The white matter integrity across structures of the corpus callosum was quantified using fractional anisotropy.

Results: Participants with lower resting-state complexity within the sensorimotor, executive, and attention networks walked more slowly under single- and dual-task (ie, walking while performing a serial-subtraction task) conditions (β > 0.28, p ≤ .01) and had a greater dual-task cost (β < -0.28, p < .04). Complexity in these networks mediated the influence of the corpus callosum genu on both single- (indirect effects > 0.15, 95% confidence intervals = 0.02-0.32) and dual-task walking speeds (indirect effects > 0.13, 95% confidence intervals = 0.02-0.33).

Conclusion: These results suggest that the multiscale dynamics of resting-state brain activity correlate with mobility and mediate the effect of the microstructural integrity in the corpus callosum genu on walking speed in older adults.
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http://dx.doi.org/10.1093/gerona/glz231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357585PMC
July 2020

Aberrant patterns of default-mode network functional connectivity associated with metabolic syndrome: A resting-state study.

Brain Behav 2019 12 30;9(12):e01333. Epub 2019 Sep 30.

Neuroimaging Research for Veterans Center (NeRVe), Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System, Boston, Massachusetts.

Introduction: Metabolic syndrome (MetS) is a clustering of three or more cardiovascular risk factors (RF), including hypertension, obesity, high cholesterol, or hyperglycemia. MetS and its component RFs are more prevalent in older age, and can be accompanied by alterations in brain structure. Studies have shown altered functional connectivity (FC) in samples with individual RFs as well as in clinical populations that are at higher risk to develop MetS. These studies have indicated that the default mode network (DMN) may be particularly vulnerable, yet little is known about the overall impact of MetS on FC in this network.

Methods: In this study, we evaluated the integrity of FC to the DMN in participants with MetS relative to non-MetS individuals. Using a seed-based connectivity analysis approach, resting-state functional MRI (fMRI) data were analyzed, and the FC measures among the DMN seed (isthmus of the cingulate) and rest of the brain voxels were estimated.

Results: Participants with MetS demonstrated reduced positive connectivity between the DMN seed and left superior frontal regions, and reduced negative connectivity between the DMN seed and left superior parietal, left postcentral, right precentral, right superior temporal and right superior parietal regions, after accounting for age- and sex-effects.

Conclusions: Our results suggest that MetS is associated with alterations in FC between the DMN and other regions of the brain. Furthermore, these results indicate that the overall burden of vascular RFs associated with MetS may, in part, contribute to the pathophysiology underlying aberrant FC in the DMN.
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http://dx.doi.org/10.1002/brb3.1333DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6908882PMC
December 2019

Motor-Cognitive Neural Network Communication Underlies Walking Speed in Community-Dwelling Older Adults.

Front Aging Neurosci 2019 16;11:159. Epub 2019 Jul 16.

Neuroimaging Research for Veterans (NeRVe) Center, VA Boston Healthcare System, Boston, MA, United States.

While walking was once thought to be a highly automated process, it requires higher-level cognition with older age. Like other cognitive tasks, it also becomes further challenged with increased cognitive load (e.g., the addition of an unrelated dual task) and often results in poorer performance (e.g., slower speed). It is not well known, however, how intrinsic neural network communication relates to walking speed, nor to this "cost" to gait performance; i.e., "dual-task cost (DTC)." The current study investigates the relationship between network connectivity, using resting-state functional MRI (rs-fMRI), and individual differences in older adult walking speed. Fifty participants (35 females; 84 ± 4.5 years) from the MOBILIZE Boston Study cohort underwent an MRI protocol and completed a gait assessment during two conditions: walking quietly at a preferred pace and while concurrently performing a serial subtraction task. Within and between neural network connectivity measures were calculated from rs-fMRI and were correlated with walking speeds and the DTC (i.e., the percent change in speed between conditions). Among the rs-fMRI correlates, faster walking was associated with increased connectivity between motor and cognitive networks and decreased connectivity between limbic and cognitive networks. Smaller DTC was associated with increased connectivity within the motor network and increased connectivity between the ventral attention and executive networks. These findings support the importance of both motor network integrity as well as inter-network connectivity amongst higher-level cognitive networks in older adults' ability to maintain mobility, particularly under dual-task (DT) conditions.
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http://dx.doi.org/10.3389/fnagi.2019.00159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6647911PMC
July 2019

Trauma-related psychiatric and behavioral conditions are uniquely associated with sustained attention dysfunction.

Neuropsychology 2019 Jul 30;33(5):711-724. Epub 2019 May 30.

Translational Research Center for TBI and Stress Disorders.

Objective: It is increasingly recognized that trauma victims, particularly Veterans, have co-occurring psychological and physical conditions that impact cognition, especially the domains of sustained attention and executive functioning. Although previous work has generally attempted to isolate the unique cognitive effects of common combat-related comorbidities, less work has been done to examine how these conditions co-occur, and whether unique cognitive signatures accompany certain clinical combinations.

Method: To address this gap, we examined how several deployment-related conditions were associated with performance on a well-validated measure of sustained attention (i.e., gradual onset continuous performance task [gradCPT]) and a battery of standard neuropsychological measures in 123 Veterans from the Translational Research Center for TBI and Stress Disorders. Initially, a Principal component analysis was conducted to investigate how comorbid conditions grouped together.

Results: Several sustained attention measures from the gradCPT were differentially associated with four unique combinations of trauma-related pathology. Specifically, a somatic component representing the combination of current pain, sleep disturbance, and mild traumatic brain injury was associated with a higher rate of failures of attentional engagement. On the other hand, a comorbid posttraumatic stress disorder (PTSD) and mood disorder component (moodPTSD), as well as a substance use disorder component, were associated with higher rates of inhibitory control failures. Increased attentional instability was associated with moodPTSD as well as an anxiety disorder component. In contrast, the cognitive effects of deployment-related trauma were not observed on standard neuropsychological measures.

Conclusion: These findings suggest that unique combinations of trauma-related pathology have dissociable effects on sustained attentional control. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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http://dx.doi.org/10.1037/neu0000525DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6912598PMC
July 2019

Metabolic risk in older adults is associated with impaired sustained attention.

Neuropsychology 2019 Oct 16;33(7):947-955. Epub 2019 May 16.

Geriatric Research, Education, & Clinical Center (GRECC).

Objective: Metabolic syndrome (MetS), the presence of three or more cardiovascular risk factors, has been associated with subtle and diffuse neural compromise but has not been consistently associated with cognitive dysfunction. Sustained attention is a fundamental cognitive operation that relies on multiple brain networks and is impaired in a broad array of neurologic conditions. We examined whether a well-validated measure of sustained attention would be sensitive to vascular risk, as compared with more standard neuropsychological measures of attention and executive functioning.

Method: We assessed vascular risk factors (VRFs; blood pressure, waist circumference, cholesterol, glucose, and triglycerides) in 93 middle-to-older aged adults (45-75 years). MetS was defined based on current guidelines from the National Cholesterol Education Program Adult Training Program (NCEP ATP III). Participants were grouped according to number of VRFs: high risk (MetS; 3+ VRFs; = 32), medium risk (1 or 2 VRFs; = 35), and low risk (0 VRFs; = 26). All participants underwent a neuropsychological battery of tests measuring executive functioning. Participants also performed the gradual-onset continuous performance task (gradCPT), a measure of sustained attention.

Results: There was a significant main effect of VRF group on sustained attention performance; participants with lower vascular risk were better able to sustain attention. No significant effects were detected on standard neuropsychological tests of executive function.

Conclusion: Our results suggest that the gradCPT is sensitive to the potentially negative effects of MetS on subtle aspects of neurocognitive functioning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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http://dx.doi.org/10.1037/neu0000554DOI Listing
October 2019

Models of sustained attention.

Curr Opin Psychol 2019 10 13;29:174-180. Epub 2019 Mar 13.

Boston Attention and Learning Laboratory, VA Boston Healthcare System, United States.

Attention is not constant, but fluctuates from moment-to-moment. Multiple neurocognitive factors contribute to these fluctuations, acting to help us get 'in the zone' as well as pulling us away from this optimal and fleeting state. Models of arousal, mind wandering, cognitive resource allocation, and effort have consequences for this fundamental process. Integrating these models with an understanding of how attentional fluctuations impact information processing-from stimulus to motor representations-will help to reveal the causes and consequences of these fluctuations. This integrated perspective has implications for a range of clinical populations and cognitive processes that rely on attention.
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http://dx.doi.org/10.1016/j.copsyc.2019.03.005DOI Listing
October 2019

Individual differences in sustained attention are associated with cortical thickness.

Hum Brain Mapp 2019 08 13;40(11):3243-3253. Epub 2019 Apr 13.

Translational Research Center for TBI and Stress Disorders (TRACTS), VA RR&D TBI National Research Center, VA Boston Healthcare System, Boston, Massachusetts.

Several studies have examined how individual differences in sustained attention relate to functional brain measures (e.g., functional connectivity), but far fewer studies relate sustained attention ability, or cognition in general, to individual differences in cortical structure. Functional magnetic resonance imaging meta-analyses and patient work have highlighted that frontoparietal regions, lateralized to the right hemisphere, are critical for sustained attention, though recent work implicates a broader expanse of brain regions. The current study sought to determine if and where variation in cortical thickness is significantly associated with sustained attention performance. Sustained attention was measured using the gradual onset continuous performance task and the Test of Variables of Attention in 125 adult Veteran participants after acquiring two high-resolution structural MRI scans. Whole-brain vertex-wise analyses of the cortex demonstrated that better sustained attention was associated with increased thickness in visual, somatomotor, frontal, and parietal cortices, especially in the right hemisphere. Network-based analyses revealed relationships between sustained attention and cortical thickness in the dorsal attention, ventral attention, somatomotor, and visual networks. These results indicate cortical thickness in multiple regions and networks is associated with sustained attention, and add to the growing knowledge of how structural MRI can help explain individual differences in cognition.
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http://dx.doi.org/10.1002/hbm.24594DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865816PMC
August 2019

Clinically significant cognitive dysfunction in OEF/OIF/OND veterans: Prevalence and clinical associations.

Neuropsychology 2019 May 4;33(4):534-546. Epub 2019 Apr 4.

Translational Research Center for TBI and Stress Disorders, VA RR&D TBI Center of Excellence, VA Boston Healthcare System.

Objective: Cognitive performance in trauma-exposed populations, such as combat Veterans, has been shown to be worse than in nonexposed peers. However, cognitive performance has typically been within the normal range (within 1 SD of normative mean), and the prevalence of clinically significant cognitive dysfunction (i.e., performance more than 1 SD below the mean on multiple measures in a domain) in younger adults with trauma exposure remains unknown. The objective of our study was to measure this.

Method: We applied Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) cutoffs for clinically significant cognitive dysfunction (>1 SD below the mean in multiple measures within a domain) in the domains of memory, executive function, and attention to a sample of combat-exposed Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND; N = 368, mean age = 31.7 years, 90% men) Veterans. We then compared psychiatric, physiological, and neural measures, as well as functional outcomes, between those with and without cognitive dysfunction.

Results: Veterans with cognitive dysfunction (n = 129, 35.1%) had lower premorbid reading ability and more severe psychological distress, including increased anxiety, depression, posttraumatic stress disorder (PTSD), sleep difficulties, pain, and alcohol consumption. Those with cognitive dysfunction also had worse functional outcomes, with mild but significant disability. In contrast, we found associations between outcome and age, traumatic brain injury, physiological and neural measures to be weak or not significant.

Conclusions: Together, this suggests that premorbid abilities and trauma-related psychological symptoms contribute significantly to cognitive dysfunction in OEF/OIF/OND Veterans, and that neurological insult and aging may play less of a role. Cognitive dysfunction may be at least partially ameliorated by treating trauma-related symptoms. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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http://dx.doi.org/10.1037/neu0000529DOI Listing
May 2019

Reward Ameliorates Posttraumatic Stress Disorder-Related Impairment in Sustained Attention.

Chronic Stress (Thousand Oaks) 2018 Jan-Dec;2. Epub 2018 Nov 26.

Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.

Background: Posttraumatic stress disorder is associated with impairments in a fundamental cognitive process important for a variety of social and occupational tasks. To date, however, the precise nature of these impairments and the posttraumatic stress disorder symptoms associated with them have not been well understood.

Methods: Using a well-characterized sample of returning United States military OEF/OIF/OND Veterans who varied in posttraumatic stress disorder symptoms, we employed a validated sustained attention paradigm designed to probe fluctuations across two attentional states characterized by prior research, including a peak state termed "in the zone" and a less efficient, more error-prone state termed "out of the zone." Rewarded and nonrewarded conditions were employed to examine whether motivating strong task performance could ameliorate sustained attention deficits. Analyses examined associations between attentional state, availability of reward, and posttraumatic stress disorder symptoms.

Results: Results indicated that, consistent with prior findings, higher levels of posttraumatic stress disorder symptoms were broadly associated with impaired task performance. This impairment was driven largely by performance deficits during individuals' optimal ("in the zone") attentional state, and follow-up analyses indicated that the performance deficit was primarily associated with anhedonia and emotional numbing symptoms. However, the deficit was partially ameliorated when better performance was rewarded.

Conclusion: Our results provide a more complex understanding of the sustained attention deficits associated with posttraumatic stress disorder and suggest that external incentives may help to enhance sustained attention performance for affected individuals.
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http://dx.doi.org/10.1177/2470547018812400DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6350805PMC
November 2018

The attentional repulsion effect and relative size judgments.

Atten Percept Psychophys 2019 Feb;81(2):442-461

GRECC & Research Services, Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA, USA.

Rapid shifts of involuntary attention have been shown to induce mislocalizations of nearby objects. One pattern of mislocalization, termed the Attentional Repulsion Effect (ARE), occurs when the onset of peripheral pre-cues lead to perceived shifts of subsequently presented stimuli away from the cued location. While the standard ARE configuration utilizes vernier lines, to date, all previous ARE studies have only assessed distortions along one direction and tested one spatial dimension (i.e., position or shape). The present study assessed the magnitude of the ARE using a novel stimulus configuration. Across three experiments participants judged which of two rectangles on the left or right side of the display appeared wider or taller. Pre-cues were used in Experiments 1 and 2. Results show equivalent perceived expansions in the width and height of the pre-cued rectangle in addition to baseline asymmetries in left/right relative size under no-cue conditions. Altering cue locations led to shifts in the perceived location of the same rectangles, demonstrating distortions in perceived shape and location using the same stimuli and cues. Experiment 3 demonstrates that rectangles are perceived as larger in the periphery compared to fixation, suggesting that eye movements cannot account for results from Experiments 1 and 2. The results support the hypothesis that the ARE reflects a localized, symmetrical warping of visual space that impacts multiple aspects of spatial and object perception.
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http://dx.doi.org/10.3758/s13414-018-1612-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760903PMC
February 2019

Compromised prefrontal structure and function are associated with slower walking in older adults.

Neuroimage Clin 2018 10;20:620-626. Epub 2018 Aug 10.

Institute for Aging Research, Hebrew SeniorLife, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States; Beth Israel Deaconess Medical Center, Boston, MA, United States.

Our previous work demonstrates that reduced activation of the executive network is associated with slow walking speed in a cohort of older adults from the MOBILIZE Boston Study. However, the influence of underlying white matter integrity on the activation of this network and walking speed is unknown. Thus, we used diffusion-weighted imaging and fMRI during an n-back task to assess associations between executive network structure, function, and walking speed. Whole-brain tract-based spatial statistics (TBSS) were used to identify regions of white matter microstructural integrity that were associated with walking speed. The integrity of these regions was then entered into multiple regression models to predict task performance and executive network activation during the n-back task. Among the significant associations of FA with walking speed, we observed the anterior thalamic radiation and superior longitudinal fasciculus were further associated with both n-back response speed and executive network activation. These findings suggest that subtle damage to frontal white matter may contribute to altered executive network activation and slower walking in older adults.
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http://dx.doi.org/10.1016/j.nicl.2018.08.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6125763PMC
January 2019

Attentional Fluctuations Influence the Neural Fidelity and Connectivity of Stimulus Representations.

J Cogn Neurosci 2018 09 13;30(9):1209-1228. Epub 2018 Jul 13.

VA Boston Healthcare System.

Attention is thought to facilitate both the representation of task-relevant features and the communication of these representations across large-scale brain networks. However, attention is not "all or none," but rather it fluctuates between stable/accurate (in-the-zone) and variable/error-prone (out-of-the-zone) states. Here we ask how different attentional states relate to the neural processing and transmission of task-relevant information. Specifically, during in-the-zone periods: (1) Do neural representations of task stimuli have greater fidelity? (2) Is there increased communication of this stimulus information across large-scale brain networks? Finally, (3) can the influence of performance-contingent reward be differentiated from zone-based fluctuations? To address these questions, we used fMRI and representational similarity analysis during a visual sustained attention task (the gradCPT). Participants ( n = 16) viewed a series of city or mountain scenes, responding to cities (90% of trials) and withholding to mountains (10%). Representational similarity matrices, reflecting the similarity structure of the city exemplars ( n = 10), were computed from visual, attentional, and default mode networks. Representational fidelity (RF) and representational connectivity (RC) were quantified as the interparticipant reliability of representational similarity matrices within (RF) and across (RC) brain networks. We found that being in the zone was characterized by increased RF in visual networks and increasing RC between visual and attentional networks. Conversely, reward only increased the RC between the attentional and default mode networks. These results diverge with analogous analyses using functional connectivity, suggesting that RC and functional connectivity in tandem better characterize how different mental states modulate the flow of information throughout the brain.
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http://dx.doi.org/10.1162/jocn_a_01306DOI Listing
September 2018

Sensitivity to stimulus similarity is associated with greater sustained attention ability.

Atten Percept Psychophys 2018 08;80(6):1390-1408

Boston Attention and Learning Laboratory, VA Boston Healthcare System, Boston, MA, 02130, USA.

Sustained attention is critical for tasks where perceptual information must be continuously processed, like reading or driving; however, the cognitive processes underlying sustained attention remain incompletely characterized. In the experiments that follow, we explore the relationship between sustaining attention and the contents and maintenance of task-relevant features in an attentional template. Specifically, we administered the gradual onset continuous performance task (gradCPT), a sensitive measure of sustained attention, to a large web-based sample (N>20,000) and a smaller laboratory sample for validation and extension. The gradCPT requires participants to respond to most stimuli (city scenes - 90 %) and withhold to rare target images (mountain scenes - 10 %). By using stimulus similarity to probe the representational content of task-relevant features-assuming either exemplar- or category-based feature matching-we predicted that RTs for city stimuli that were more "mountain-like" would be slower and "city-like" mountain stimuli would elicit more erroneous presses. We found that exemplar-based target-nontarget (T-N) similarity predicted both RTs and erroneous button presses, suggesting a stimulus-specific feature matching process was adopted. Importantly, individual differences in the degree of sensitivity to these similarity measures correlated with conventional measures of attentional ability on the gradCPT as well as another CPT that is perceptually less demanding. In other words, individuals with greater sustained attention ability (assessed by two tasks) were more likely to be influenced by stimulus similarity on the gradCPT. These results suggest that sustained attention facilitates the construction and maintenance of an attentional template that is optimal for a given task.
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http://dx.doi.org/10.3758/s13414-018-1504-0DOI Listing
August 2018
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