Subcortical hyperintensities in the cholinergic system are associated with improvements in executive function in older adults with coronary artery disease undergoing cardiac rehabilitation

Objective

Coronary artery disease (CAD) is frequently accompanied by white matter hyperintensities and executive dysfunction. Because acetylcholine is important in executive function, these symptoms may be exacerbated by subcortical hyperintensities (SH) located in cholinergic (CH) tracts. This study investigated the effects of SH on cognitive changes in CAD patients undergoing a 48‐week cardiac rehabilitation program.

Methods

Fifty patients (age 66.5 ± 7.1 years, 84% male) underwent the National Institute of Neurological Disorders and Stroke – Canadian Stroke Network neurocognitive battery at baseline and 48 weeks. Patients underwent a 48‐week cardiac program and completed neuroimaging at baseline. Subcortical hyperintensities in CH tracts were measured using Lesion Explorer. Repeated measures general linear models were used to examine interactions between SH and longitudinal cognitive outcomes, controlling for age, education, and max VO₂ change as a measure of fitness.

Results

In patients with SH in CH tracts, there was a significant interaction with the Trail Making Test (TMT) part A and part B over time. Patients without SH improved on average 16.6 and 15.0% on the TMT‐A and TMT‐B, respectively. Patients with SH on average showed no improvements in either TMT‐A or TMT‐B over time. There were no significant differences in other cognitive measures.

Conclusion

These results suggest that CAD patients with SH in CH tracts improve less than those without SH in CH tracts, over 48 weeks of cardiac rehabilitation. Thus, SH in CH tracts may contribute to longitudinal cognitive decline following a cardiac event and may represent a vascular risk factor of cognitive decline. © 2017 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons Ltd.     

Interaction Between Neuropsychiatric Symptoms and Cognitive Performance in Parkinson’s Disease: What Do Clinical and Neuroimaging Studies Tell Us?

Purpose of Review

Parkinson’s disease was studied for a long time from the prism of a motor impairment. Recent advances have outlined the importance of cognitive and neuropsychiatric symptoms (NPS) in the PD equation. This review concentrates on the present possibilities of using neuroimaging techniques in order to quantify the cognitive performance and NPS in PD patients.

Recent Findings

Mild cognitive impairment as well as many NPS have been acknowledged as important criteria for assessing the quality of life in patients with Parkinson’s disease and have been shown as potential factors in predicting further evolution of PD from a clinical perspective. Some NPS strongly influence cognition (depression, REM sleep behavior disorder), while others are less specifically associated with it (impulse control disorders). Neuroimaging techniques reported specific structural, functional, and metabolic brain changes that might be specific for each NPS type.

Summary

Recent neuroimaging advances report a strong interrelation between NPS and cognitive performance in PD. A special place for consideration is given to REM sleep behavior disorder, depression, and hallucinations. Nevertheless, some studies report distinct results, outlining that the neuroimaging acquisition and analysis techniques still have limitations and also likely represent the complexity of the manifestation of NPS in PD.

     

Motor network reorganization after motor imagery training in stroke patients with moderate to severe upper limb impairment

Background

Motor imagery training (MIT) has been widely used to improve hemiplegic upper limb function in stroke rehabilitation. The effectiveness of MIT is associated with the functional neuroplasticity of the motor network. Currently, brain activation and connectivity changes related to the motor recovery process after MIT are not well understood. Aim: We aimed to investigate the neural mechanisms of MIT in stroke rehabilitation through a longitudinal intervention study design with task-based functional magnetic resonance imaging (fMRI) analysis.

Methods

We recruited 39 stroke patients with moderate to severe upper limb motor impairment and randomly assigned them to either the MIT or control groups. Patients in the MIT group received 4 weeks of MIT therapy plus conventional rehabilitation, while the control group only received conventional rehabilitation. The assessment of Fugl-Meyer Upper Limb Scale (FM-UL) and Barthel Index (BI), and fMRI scanning using a passive hand movement task were conducted on all patients before and after treatment. The changes in brain activation and functional connectivity (FC) were analyzed. Pearson's correlation analysis was conducted to evaluate the association between neural functional changes and motor improvement.

Results

The MIT group achieved higher improvements in FM-UL and BI relative to the control group after the treatment. Passive movement of the affected hand evoked an abnormal bilateral activation pattern in both groups before intervention. A significant Group × Time interaction was found in the contralesional S1 and ipsilesional M1, showing a decrease of activation after intervention specifically in the MIT group, which was negatively correlated with the FM-UL improvement. FC analysis of the ipsilesional M1 displayed the motor network reorganization within the ipsilesional hemisphere, which correlated with the motor score changes.

Conclusions

MIT could help decrease the compensatory activation at both hemispheres and reshape the FC within the ipsilesional hemisphere along with functional recovery in stroke patients.     

Longitudinal associations between white matter maturation and cognitive development across early childhood

From birth to 5 years of age, brain structure matures and evolves alongside emerging cognitive and behavioral abilities. In relating concurrent cognitive functioning and measures of brain structure, a major challenge that has impeded prior investigation of their time‐dynamic relationships is the sparse and irregular nature of most longitudinal neuroimaging data. We demonstrate how this problem can be addressed by applying functional concurrent regression models (FCRMs) to longitudinal cognitive and neuroimaging data. The application of FCRM in neuroimaging is illustrated with longitudinal neuroimaging and cognitive data acquired from a large cohort (n = 210) of healthy children, 2–48 months of age. Quantifying white matter myelination by using myelin water fraction (MWF) as imaging metric derived from MRI scans, application of this methodology reveals an early period (200–500 days) during which whole brain and regional white matter structure, as quantified by MWF, is positively associated with cognitive ability, while we found no such association for whole brain white matter volume. Adjusting for baseline covariates including socioeconomic status as measured by maternal education (SES‐ME), infant feeding practice, gender, and birth weight further reveals an increasing association between SES‐ME and cognitive development with child age. These results shed new light on the emerging patterns of brain and cognitive development, indicating that FCRM provides a useful tool for investigating these evolving relationships.     

Changes in local and network brain activity after stereotactic thermocoagulation in patients with drug-resistant epilepsy

Objective

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) aims to reduce seizure frequency by modifying epileptogenic networks through local thermocoagulative lesions. Although RF-TC is hypothesized to functionally modify brain networks, reports of changes in functional connectivity (FC) following the procedure are missing. We evaluated, by means of SEEG recordings, whether variation in brain activity after RF-TC is related to clinical outcome.

Methods

Interictal SEEG recordings from 33 patients with drug-resistant epilepsy (DRE) were analyzed. Therapeutic response was defined as a >50% reduction in seizure frequency for at least 1 month following RF-TC. Local (power spectral density [PSD]) and FC changes were evaluated in 3-min segments recorded shortly before (baseline), shortly after, and 15 min after RF-TC. The PSD and FC strength values after thermocoagulation were compared with baseline as well as between the responder and nonresponder groups.

Results

In responders, we found a significant reduction in PSD after RF-TC in channels that were thermocoagulated for all frequency bands (p = .007 for broad, delta and theta, p <.001 for alpha and beta bands). However, we did not observe such PSD decrease in nonresponders. At the network level, nonresponders displayed a significant FC increase in all frequency bands except theta (broad, delta, beta band: p <.001; alpha band: p <.01), although responders showed a significant FC decrease in delta (p <.001) and alpha bands (p <.05). Nonresponders showed stronger FC changes with respect to responders exclusively in TC channels (broad, alpha, theta, beta: p >.05; delta: p = .001).

Significance

Thermocoagulation induces both local and network-related (FC) changes in electrical brain activity of patients with DRE lasting for at least 15 min. This study demonstrates that the observed short-term modifications in brain network and local activity significantly differ between responders and nonresponders and opens new perspectives for studying the longer-lasting FC changes after RF-TC.     

Long‐term neurobiological consequences of early postnatal hCMV‐infection in former preterms

Early postnatal infection with human cytomegalovirus (hCMV) may contribute to an adverse cognitive outcome in early preterm‐born children (PT). We here set out to explore whether long‐term neurobiological consequences of such an infection are detectable using fMRI in children and adolescents who were born very preterm and who either did (PT_hCMV+) or did not (PT_hCMV?) suffer from an early postnatal hCMV‐infection, when compared with typically developing healthy control (HC) subjects. Overall, data from 71 children and adolescents could be included, 34 PT (of which 15 were PT _hCMV+ and 19 were PT _hCMV?) and 37 HC. Using a recently established “dual use” fMRI task, we investigated language and visuospatial functions. There were significant activation differences in the left hippocampus (PT > HC and PT_hCMV+ > HC), and in the right anterior cingulate cortex (PT_hCMV? > PT_hCMV+) when performing the language task. Surprisingly, only a small region in the occipital cortex showed a significant activation difference (HC > PT _HCMV?) when performing the visuospatial task. Targeted analyses revealed differences in gray matter volume, but not density, in several brain regions. Our results suggest that long‐term neurobiological consequences of an early postnatal hCMV infection are detectable even in older children and adolescents formerly born very preterm, compatible with a higher effort when performing a cognitive task. This suggests that measures to prevent such an infection are warranted. Furthermore, an interrelation of brain structure and function was detected that may constitute a severe confound when using fMRI to compare structurally differing groups. Hum Brain Mapp 35:2594–2606, 2014. © 2013 Wiley Periodicals, Inc.     

NT-proBNP and changes in cognition and global brain structure: The Rotterdam Study

Objective

To investigate the association between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and changes in cognition and global brain structure.

Methods

In the Rotterdam Study, baseline NT-proBNP was assessed at baseline from 1997 to 2008. Between 1997 and 2016, participants without dementia or stroke at baseline (n = 9566) had repeated cognitive tests (every 3–6 years) for global cognitive function, executive cognitive function, fine manual dexterity, and memory. Magnetic resonance imaging of the brain was performed repeatedly at re-examination visits between 2005 and 2015 for 2607 participants to obtain brain volumes, focal brain lesions, and white matter microstructural integrity as measures of brain structure.

Results

Among 9566 participants (mean age 65.1 ± 9.8 years), 5444 (56.9%) were women, and repeated measures of cognition were performed during a median follow-up time of 5.5 (range 1.1–17.9) years, of whom 2607 participants completed at least one brain imaging scan. Higher levels of NT-proBNP were associated with a faster decline of scores in the global cognitive function (p value = 0.003) and the Word-Fluency test (p value = 0.003) but were not related to a steeper deterioration in brain volumes, global fractional anisotropy, and mean diffusivity, as indicators of white matter microstructural integrity, or focal brain lesions.

Conclusions

Higher baseline NT-proBNP levels were associated with a faster decline in cognition; however, no association with global brain structure was found.     

Age and sex differentially shape brain networks in Parkinson's disease

Aims

Age and sex are important individual factors modifying the clinical symptoms of patients with Parkinson's disease (PD). Our goal is to evaluate the effects of age and sex on brain networks and clinical manifestations of PD patients.

Methods

Parkinson's disease participants (n = 198) receiving functional magnetic resonance imaging from Parkinson's Progression Markers Initiative database were investigated. Participants were classified into lower quartile group (age rank: 0%~25%), interquartile group (age rank: 26%~75%), and upper quartile group (age rank: 76%~100%) according to their age quartiles to examine how age shapes brain network topology. The differences of brain network topological properties between male and female participants were also investigated.

Results

Parkinson's disease patients in the upper quartile age group exhibited disrupted network topology of white matter networks and impaired integrity of white matter fibers compared to lower quartile age group. In contrast, sex preferentially shaped the small-world topology of gray matter covariance network. Differential network metrics mediated the effects of age and sex on cognitive function of PD patients.

Conclusion

Age and sex have diverse effects on brain structural networks and cognitive function of PD patients, highlighting their roles in the clinical management of PD.     

Enhanced rostral anterior cingulate cortex activation during cognitive control is related to orbitofrontal volume reduction in unipolar depression

Objective

In patients with major depressive disorder (MDD), enhanced activation of the rostral anterior cingulate cortex (rACC) during conflict resolution has been demonstrated with the use of functional magnetic resonance imaging (fMRI), which suggests dysregulation of the affective compartment of the ACC associated with error monitoring and cognitive control. Moreover, several previous studies have reported disrupted structural integrity in limbic brain areas and the orbitofrontal cortex in MDD. However, the relation between structural and functional alterations remains unclear. Therefore, the present study sought to investigate whether structural brain aberrations in terms of grey matter decreases directly in the medial frontal regions or in anatomically closely connected areas might be related to our previously reported functional alterations.

Methods

A sample of 16 female, drug-free patients with an acute episode of MDD and 16 healthy control subjects matched for age, sex and education were examined with structural high-resolution T₁-weighted MRI; fMRI images were obtained in the same session.

Results

Voxel-based morphometry (VBM) revealed grey matter decreases in the orbitofrontal and subgenual cortex, in the hippocampus-amygdala complex and in the middle frontal gyrus. The relative hyperactivation of the rACC in terms of inability to deactivate this region during the Stroop Color-Word Test showed an inverse correlation with grey matter reduction in the orbitofrontal cortex.

Conclusion

The present study provides strong evidence for an association between structural alterations in the orbitofrontal cortex and disturbed functional activation in the emotional compartment of the ACC in patients with MDD during cognitive control.Medical subject headings: magnetic resonance imaging, depressive disorder, depression     

Looking into cognitive impairment in primary‐progressive multiple sclerosis

Background and purpose

Cognitive impairment in primary‐progressive multiple sclerosis (PP‐MS) is correlated with global brain atrophy. Unfortunately, brain volume computation requires processing resources that are not widely available in clinical practice. Therefore, we decided to test the predictive role of retinal atrophy metrics on cognitive decline, applying them as a proxy of gray matter atrophy in PP‐MS.

Methods

Twenty‐five patients with PP‐MS completed the Brief International Cognitive Assessment for Multiple Sclerosis and underwent spectral‐domain optical coherence tomography (OCT) and 3.0‐T magnetic resonance imaging. We tested, through a stepwise logistic regression, whether OCT metrics [retinal nerve fiber layer, ganglion cell + inner plexiform layer (GCIPL) and total macular volume] predicted cognitive impairment and explored the role of gray matter atrophy in mediating these correlations.

Results

Among OCT metrics, only GCIPL was associated with cognitive impairment (r_p = 0.448, P = 0.036) and predictive of objective cognitive impairment (Wald [1] = 4.40, P = 0.036). Controlling for demographics, normalized brain volume and thalamic volume were correlated with GCIPL (r_p = 0.427, P = 0.047 and r_p = 0.674, P = 0.001, respectively) and cognitive scores (r_p = 0.593, P = 0.004 and r_p = 0.501, P = 0.017, respectively), with thalamic volume nearly mediating the association between GCIPL and cognition (Sobel z = 1.86, P = 0.063).

Conclusions

The GCIPL thickness is a suitable measure of neurodegeneration. In comparison with brain atrophy, GCIPL offers higher histopathological specificity, being a pure correlate of neuronal loss, and may be a non‐invasive, easy‐to‐perform way to quantitatively evaluate and monitor neuronal loss related to cognitive impairment in PP‐MS.     

Altered Spinal Cord Functional Connectivity Associated with Parkinson's Disease Progression

Background

Parkinson's disease (PD) has traditionally been viewed as an α-synucleinopathy brain pathology. Yet evidence based on postmortem human and animal experimental models indicates that the spinal cord may also be affected.

Objective

Functional magnetic resonance imaging (fMRI) seems to be a promising candidate to better characterize spinal cord functional organization in PD patients.

Methods

Resting-state spinal fMRI was performed in 70 PD patients and 24 age-matched healthy controls, the patients being divided into three groups based on their motor symptom severity: PD_low (n = 24), PD_med (n = 22), and PD_adv (n = 24) groups. A combination of independent component analysis (ICA) and a seed-based approach was applied.

Results

When pooling all participants, the ICA revealed distinct ventral and dorsal components distributed along the rostro-caudal axis. This organization was highly reproducible within subgroups of patients and controls. PD severity, assessed by Unified Parkinson's Disease Rating Scale (UPDRS) scores, was associated with a decrease in spinal functional connectivity (FC). Notably, we observed a reduced intersegmental correlation in PD as compared to controls, the latter being negatively associated with patients' upper-limb UPDRS scores (P = 0.0085). This negative association between FC and upper-limb UPDRS scores was significant between adjacent C4–C5 (P = 0.015) and C5–C6 (P = 0.20) cervical segments, levels associated with upper-limb functions.

Conclusions

The present study provides the first evidence of spinal cord FC changes in PD and opens new avenues for the effective diagnosis and therapeutic strategies in PD. This underscores how spinal cord fMRI can serve as a powerful tool to characterize, in vivo, spinal circuits for a variety of neurological diseases. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

Basal Forebrain Atrophy,Cortical Thinning,and Amyloid-β Status in Parkinson's disease-Related Cognitive Decline

Background

Degeneration of the cortically-projecting cholinergic basal forebrain (cBF) is a well-established pathologic correlate of cognitive decline in Parkinson's disease (PD). In Alzheimer's disease (AD) the effect of cBF degeneration on cognitive decline was found to be mediated by parallel atrophy of denervated cortical areas.

Objectives

To examine whether the association between cBF degeneration and cognitive decline in PD is mediated by parallel atrophy of cortical areas and whether these associations depend on the presence of comorbid AD pathology.

Methods

We studied 162 de novo PD patients who underwent serial 3 T magnetic resonance imaging scanning (follow-up: 2.33 ± 1.46 years) within the Parkinson's Progression Markers Initiative. cBF volume and regional cortical thickness were automatically calculated using established procedures. Individual slopes of structural brain changes and cognitive decline were estimated using linear-mixed models. Associations between longitudinal cBF degeneration, regional cortical thinning, and cognitive decline were assessed using regression analyses and mediation effects were assessed using nonparametric bootstrap. Complementary analyses assessed the effect of amyloid-β biomarker positivity on these associations.

Results

After controlling for global brain atrophy, longitudinal cBF degeneration was highly correlated with faster cortical thinning (P_FDR < 0.05), and thinning in cBF-associated cortical areas mediated the association between cBF degeneration and cognitive decline (r_cBF-MoCA = 0.30, P < 0.001). Interestingly, both longitudinal cBF degeneration and its association with cortical thinning were largely independent of amyloid-β status.

Conclusions

cBF degeneration in PD is linked to parallel thinning of cortical target areas, which mediate the effect on cognitive decline. These associations are independent of amyloid-β status, indicating that they reflect proper features of PD pathophysiology. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

Increased brain connectivity and activation after cognitive rehabilitation in Parkinson’s disease: a randomized controlled trial

Cognitive rehabilitation programs have demonstrated efficacy in improving cognitive functions in Parkinson’s disease (PD), but little is known about cerebral changes associated with an integrative cognitive rehabilitation in PD. To assess structural and functional cerebral changes in PD patients, after attending a three-month integrative cognitive rehabilitation program (REHACOP). Forty-four PD patients were randomly divided into REHACOP group (cognitive rehabilitation) and a control group (occupational therapy). T1-weighted, diffusion weighted and functional magnetic resonance images (fMRI) during resting-state and during a memory paradigm (with learning and recognition tasks) were acquired at pre-treatment and post-treatment. Cerebral changes were assessed with repeated measures ANOVA 2 × 2 for group x time interaction. During resting-state fMRI, the REHACOP group showed significantly increased brain connectivity between the left inferior temporal lobe and the bilateral dorsolateral prefrontal cortex compared to the control group. Moreover, during the recognition fMRI task, the REHACOP group showed significantly increased brain activation in the left middle temporal area compared to the control group. During the learning fMRI task, the REHACOP group showed increased brain activation in the left inferior frontal lobe at post-treatment compared to pre-treatment. No significant structural changes were found between pre- and post-treatment. Finally, the REHACOP group showed significant and positive correlations between the brain connectivity and activation and the cognitive performance at post-treatment. This randomized controlled trial suggests that an integrative cognitive rehabilitation program can produce significant functional cerebral changes in PD patients and adds evidence to the efficacy of cognitive rehabilitation programs in the therapeutic approach for PD.     

Quantitative microstructural cerebral changes in neurofibromatosis type 1

Objectives

To evaluate microstructural cerebral changes in children with neurofibromatosis type 1 (NF1) based on T₂ relaxation time measurements at 3Tesla.

Limbic grey matter changes in early Parkinson's disease

The purpose of this study was to investigate local and network‐related changes of limbic grey matter in early Parkinson's disease (PD) and their inter‐relation with non‐motor symptom severity. We applied voxel‐based morphometric methods in 538 T1 MRI images retrieved from the Parkinson's Progression Markers Initiative website. Grey matter densities and cross‐sectional estimates of age‐related grey matter change were compared between subjects with early PD (n = 366) and age‐matched healthy controls (n = 172) within a regression model, and associations of grey matter density with symptoms were investigated. Structural brain networks were obtained using covariance analysis seeded in regions showing grey matter abnormalities in PD subject group. Patients displayed focally reduced grey matter density in the right amygdala, which was present from the earliest stages of the disease without further advance in mild‐moderate disease stages. Right amygdala grey matter density showed negative correlation with autonomic dysfunction and positive with cognitive performance in patients, but no significant interrelations were found with anxiety scores. Patients with PD also demonstrated right amygdala structural disconnection with less structural connectivity of the right amygdala with the cerebellum and thalamus but increased covariance with bilateral temporal cortices compared with controls. Age‐related grey matter change was also increased in PD preferentially in the limbic system. In conclusion, detailed brain morphometry in a large group of early PD highlights predominant limbic grey matter deficits with stronger age associations compared with controls and associated altered structural connectivity pattern. This provides in vivo evidence for early limbic grey matter pathology and structural network changes that may reflect extranigral disease spread in PD. Hum Brain Mapp 38:3566–3578, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.     

Neural correlates of formal thought disorder: An activation likelihood estimation meta‐analysis

Formal thought disorder (FTD) refers to a psychopathological dimension characterized by disorganized and incoherent speech. Whether symptoms of FTD arise from aberrant processing in language‐related regions or more general cognitive networks, however, remains debated. Here, we addressed this question by a quantitative meta‐analysis of published functional neuroimaging studies on FTD. The revised Activation Likelihood Estimation (ALE) algorithm was used to test for convergent aberrant activation changes in 18 studies (30 experiments) investigating FTD, of which 17 studies comprised schizophrenia patients and one study healthy subjects administered to S‐ketamine. Additionally, we analyzed task‐dependent and task‐independent (resting‐state) functional connectivity (FC) of brain regions showing convergence in activation changes. Subsequent functional characterization was performed for the initial clusters and the delineated connectivity networks by reference to the BrainMap database. Consistent activation changes were found in the left superior temporal gyrus (STG) and two regions within the left posterior middle temporal gyrus (p‐MTG), ventrally (vp‐MTG) and dorsally (dp‐MTG). Functional characterization revealed a prominent functional association of ensuing clusters from our ALE meta‐analysis with language and speech processing, as well as auditory perception in STG and with social cognition in dp‐MTG. FC analysis identified task‐dependent and task‐independent networks for all three seed regions, which were mainly related to language and speech processing, but showed additional involvement in higher order cognitive functions. Our findings suggest that FTD is mainly characterized by abnormal activation in brain regions of the left hemisphere that are associated with language and speech processing, but also extend to higher order cognitive functions. Hum Brain Mapp 38:4946–4965, 2017. © 2017 Wiley Periodicals, Inc.     

Transcranial direct current stimulation combined with cognitive training for the treatment of Parkinson Disease: A randomized,placebo-controlled study

Background

A number of non-motor symptoms occurs in Parkinson Disease (PD), cognitive decline and mood disturbances representing the most prevalent.Recent studies reported that cognitive training could potentially help to attenuate cognitive deficits in patients with PD and several researches demonstrated a beneficial effect of active transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (anode over left dorsolateral prefrontal cortex, cathode over right supraorbital area) on cognitive deficits and mood disturbances.

Recognition of Human Emotions from Cerebral Blood Flow Changes in the Frontal Region: A Study with Event‐Related Near‐Infrared Spectroscopy

ABSTRACT

BACKGROUNDS AND PURPOSE

The aim of this study is to develop a near‐infrared spectroscopy (NIRS)‐based system that recognizes pleasant and unpleasant human emotions based on cerebral blood flow (CBF) in order to understand the minds of patients whose brain function is severely impaired. The forehead region is easily accessible to NIRS measurements, whereas the role of the anterior prefrontal cortex (PFC) in the processing of emotion remains to be elucidated.

METHODS

Initially, using event‐related NIRS we examined changes in oxygenated hemoglobin (oxy‐Hb) as an indicator of regional CBF changes, which reflect brain activity directly related to emotions, but not to cognitive operations in the anterior frontal regions, during viewing affective pictures. The event‐related potentials (ERPs), systemic blood pressure, and pulse rate were also measured simultaneously.

RESULTS

The event‐related analysis of changes in oxy‐Hb for a 6 s‐picture presentation period showed that very unpleasant emotion was accompanied by an increase in oxy‐Hb in the bilateral ventrolateral PFCs, while very pleasant emotion was accompanied by a decrease in oxy‐Hb in the left dorsolateral PFC. There were no significant differences in either ERPs or autonomic nervous system activities between the two emotional states.

CONCLUSION

These findings suggest the possibility of recognizing patients’ emotions from CBF changes.

     

Longitudinal increases in structural connectome segregation and functional connectome integration are associated with better recovery after mild TBI

Traumatic brain injury damages white matter pathways that connect brain regions, disrupting transmission of electrochemical signals and causing cognitive and emotional dysfunction. Connectome‐level mechanisms for how the brain compensates for injury have not been fully characterized. Here, we collected serial MRI‐based structural and functional connectome metrics and neuropsychological scores in 26 mild traumatic brain injury subjects (29.4 ± 8.0 years, 20 males) at 1 and 6 months postinjury. We quantified the relationship between functional and structural connectomes using network diffusion (ND) model propagation time, a measure that can be interpreted as how much of the structural connectome is being utilized for the spread of functional activation, as captured via the functional connectome. Overall cognition showed significant improvement from 1 to 6 months (t₂₅ = ?2.15, p = .04). None of the structural or functional global connectome metrics was significantly different between 1 and 6 months, or when compared to 34 age‐ and gender‐matched controls (28.6 ± 8.8 years, 25 males). We predicted longitudinal changes in overall cognition from changes in global connectome measures using a partial least squares regression model (cross‐validated R² = .27). We observe that increased ND model propagation time, increased structural connectome segregation, and increased functional connectome integration were related to better cognitive recovery. We interpret these findings as suggesting two connectome‐based postinjury recovery mechanisms: one of neuroplasticity that increases functional connectome integration and one of remote white matter degeneration that increases structural connectome segregation. We hypothesize that our inherently multimodal measure of ND model propagation time captures the interplay between these two mechanisms.     

BDNF and BMI effects on brain structures of bipolar offspring: results from the global mood and brain science initiative

Objective

To compare brain‐derived neurotrophic factor (BDNF) levels between offspring of individuals with bipolar disorders (BD) and healthy controls (HCs) and investigate the effects of BDNF levels and body mass index (BMI) on brain structures.

Method

Sixty‐seven bipolar offspring and 45 HCs were included (ages 8‐28). Structural images were acquired using 3.0 Tesla magnetic resonance imaging. Serum BDNF levels were measured using enzyme‐linked immunosorbent assay. Multivariate and univariate analyses of covariance were conducted.

Results

Significantly higher BDNF levels were observed among bipolar offspring, relative to HCs (P > 0.025). Offspring status moderated the association between BDNF and BMI (F₁=4.636, P = 0.034). After adjustment for relevant covariates, there was a trend for a significant interaction of group and BDNF on neuroimaging parameters (Wilks’λ F_56,94=1.463, P = 0.052), with significant effects on cerebellar white matter and superior and middle frontal regions. Brain volume and BDNF were positively correlated among HCs and negatively correlated among bipolar offspring. Interactions between BDNF and BMI on brain volumes were non‐significant among HCs (Wilks’λ F_28,2=2.229, P = 0.357), but significant among bipolar offspring (Wilks’λ F_28,12=2.899, P = 0.028).

Conclusion

Offspring status and BMI moderate the association between BDNF levels and brain structures among bipolar offspring, underscoring BDNF regulation and overweight/obesity as key moderators of BD pathogenesis.