The human frontal lobes and frontal network systems: an evolutionary, clinical, and treatment perspective

The Neurophysiological Effects of Theta Burst Stimulation as Measured by Electroencephalography: A Systematic Review

Theta burst stimulation (TBS) is a non-invasive brain stimulation technique that can modulate neural activity. The effect of TBS on regions beyond the motor cortex remains unclear. With increased interest in applying TBS to non-motor regions for research and clinical purposes, these effects must be understood and characterised. We synthesised the electrophysiological effects of a single session of TBS, as indexed by electroencephalography (EEG) and concurrent transcranial magnetic stimulation and EEG (TMS-EEG), in non-clinical participants. We reviewed 79 studies that administered either continuous TBS (cTBS) or intermittent TBS (iTBS) protocols. Broadly, cTBS suppressed and iTBS facilitated evoked response component amplitudes. Response to TBS as measured by spectral power and connectivity was much more variable. Variability increased in the presence of task stimuli. There was a large degree of heterogeneity in the research methodology across studies. Additionally, the effect of individual differences on TBS response is insufficiently investigated. Future research investigating the effects of TBS as measured by EEG must consider methodological and individual factors that may affect TBS outcomes.

Structure focused neurodegeneration convolutional neural network for modelling and classification of Alzheimer's disease

Alzheimer's disease (AD), the predominant form of dementia, is a growing global challenge, emphasizing the urgent need for accurate and early diagnosis. Current clinical diagnoses rely on radiologist expert interpretation, which is prone to human error. Deep learning has thus far shown promise for early AD diagnosis. However, existing methods often overlook focal structural atrophy critical for enhanced understanding of the cerebral cortex neurodegeneration. This paper proposes a deep learning framework that includes a novel structure-focused neurodegeneration CNN architecture named SNeurodCNN and an image brightness enhancement preprocessor using gamma correction. The SNeurodCNN architecture takes as input the focal structural atrophy features resulting from segmentation of brain structures captured through magnetic resonance imaging (MRI). As a result, the architecture considers only necessary CNN components, which comprises of two downsampling convolutional blocks and two fully connected layers, for achieving the desired classification task, and utilises regularisation techniques to regularise learnable parameters. Leveraging mid-sagittal and para-sagittal brain image viewpoints from the Alzheimer's disease neuroimaging initiative (ADNI) dataset, our framework demonstrated exceptional performance. The para-sagittal viewpoint achieved 97.8% accuracy, 97.0% specificity, and 98.5% sensitivity, while the mid-sagittal viewpoint offered deeper insights with 98.1% accuracy, 97.2% specificity, and 99.0% sensitivity. Model analysis revealed the ability of SNeurodCNN to capture the structural dynamics of mild cognitive impairment (MCI) and AD in the frontal lobe, occipital lobe, cerebellum, temporal, and parietal lobe, suggesting its potential as a brain structural change digi-biomarker for early AD diagnosis. This work can be reproduced using code we made available on GitHub.

Examining longitudinal associations between prenatal exposure to infections and child brain morphology

BACKGROUND

Maternal infection during pregnancy has been identified as a prenatal risk factor for the later development of psychopathology in exposed offspring. Neuroimaging data collected during childhood has suggested a link between prenatal exposure to maternal infection and child brain structure and function, potentially offering a neurobiological explanation for the emergence of psychopathology. Additionally, preclinical studies utilizing repeated measures of neuroimaging data suggest that effects of prenatal maternal infection on the offspring's brain may normalize over time (i.e., catch-up growth). However, it remains unclear whether exposure to prenatal maternal infection in humans is related to long-term differential neurodevelopmental trajectories. Hence, this study aimed to investigate the association between prenatal exposure to infections on child brain development over time using repeated measures MRI data.

METHODS

We leveraged data from a population-based cohort, Generation R, in which we examined prospectively assessed self-reported infections at each trimester of pregnancy (N = 2,155). We further used three neuroimaging assessments (at mean ages 8, 10 and 14) to obtain cortical and subcortical measures of the offspring's brain morphology with MRI. Hereafter, we applied linear mixed-effects models, adjusting for several confounding factors, to estimate the association of prenatal maternal infection with child brain development over time.

RESULTS

We found that prenatal exposure to infection in the third trimester was associated with a slower decrease in volumes of the pars orbitalis, rostral anterior cingulate and superior frontal gyrus, and a faster increase in the middle temporal gyrus. In the temporal pole we observed a divergent pattern, specifically showing an increase in volume in offspring exposed to more infections compared to a decrease in volume in offspring exposed to fewer infections. We further observed associations in other frontal and temporal lobe structures after exposure to infections in any trimester, though these did not survive multiple testing correction.

CONCLUSIONS

Our results suggest that prenatal exposure to infections in the third trimester may be associated with slower age-related growth in the regions: pars orbitalis, rostral anterior cingulate and superior frontal gyrus, and faster age-related growth in the middle temporal gyrus across childhood, suggesting a potential sensitive period. Our results might be interpreted as an extension of longitudinal findings from preclinical studies, indicating that children exposed to prenatal infections could exhibit catch-up growth. However, given the lack of differences in brain volume between various infection groups at baseline, there may instead be either a longitudinal deviation or a subtle temporal deviation. Subsequent well-powered studies that extend into the period of full brain development (∼25 years) are needed to confirm whether the observed phenomenon is indeed catch-up growth, a longitudinal deviation, or a subtle temporal deviation.

Cortical grey matter volume differences in children with developmental coordination disorder compared to typically developing children

Introduction

The cause of Developmental Coordination Disorder (DCD) is unknown, but neuroimaging evidence suggests that DCD may be related to altered brain development. Children with DCD show less structural and functional connectivity compared to typically developing (TD) children, but few studies have examined cortical volume in children with DCD. The purpose of this study was to investigate cortical grey matter volume using voxel-based morphometry (VBM) in children with DCD compared to TD children.

Methods

This cross-sectional study was part of a larger randomized-controlled trial (ClinicalTrials.gov ID: NCT02597751) that involved various MRI scans of children with/without DCD. This paper focuses on the anatomical scans, performing VBM of cortical grey matter volume in 30 children with DCD and 12 TD children. Preprocessing and VBM data analysis were conducted using the Computational Anatomy Tool Box-12 and a study-specific brain template. Differences between DCD and TD groups were assessed using a one-way ANOVA, controlling for total intracranial volume. Regression analyses examined if motor and/or attentional difficulties predicted grey matter volume. We used threshold-free cluster enhancement (5,000 permutations) and set an alpha level of 0.05. Due to the small sample size, we did not correct for multiple comparisons.

Results

Compared to the TD group, children with DCD had significantly greater grey matter in the left superior frontal gyrus. Lower motor scores (meaning greater impairment) were related to greater grey matter volume in left superior frontal gyrus, frontal pole, and right middle frontal gyrus. Greater grey matter volume was also significantly correlated with higher scores on the Conners 3 ADHD Index in the left superior frontal gyrus, superior parietal lobe, and precuneus. These results indicate that greater grey matter volume in these regions is associated with poorer motor and attentional skills.

Discussion

Greater grey matter volume in the left superior frontal gyrus in children with DCD may be a result of delayed or absent healthy cortical thinning, potentially due to altered synaptic pruning as seen in other neurodevelopmental disorders. These findings provide further support for the hypothesis that DCD is related to altered brain development.

Neuropsychological outcomes in patients with ruptured anterior communicating artery aneurysms treated by clipping versus coiling: a systematic review and meta-analysis

Ruptured anterior communicating artery (ACoA) aneurysms are frequently associated with neuropsychological deficits. This review aims to compare neuropsychological outcomes between surgical and endovascular approaches to ACoA. We systematically searched PubMed, Embase, and Web of Science for studies comparing the endovascular and surgical approaches to ruptured ACoA aneurysms. Outcomes of interest were the cognitive function, covered by memory, attention, intelligence, executive, and language domains, as well as motor and visual functions. Nine studies, comprising 524 patients were included. Endovascularly-treated patients showed better memory than those treated surgically (Standardized Mean Difference (SMD) = -2; 95% CI: -3.40 to -0.61; p < 0.01). Surgically clipped patients had poorer motor ability than those with coiling embolization (p = 0.01). Executive function (SMD = -0.20; 95% CI: -0.47 to 0.88; p = 0.55), language (SMD = -0.33; 95% CI: -0.95 to 0.30; p = 0.30), visuospatial function (SMD = -1.12; 95% CI: -2.79 to 0.56; p = 0.19), attention (SMD = -0.94; 95% CI: -2.79to 0.91; p = 0.32), intelligence (SMD = -0.25; 95% CI: -0.73 to 0.22; p = 0.30), and self-reported cognitive status (SMD = -0.51; 95% CI: -1.38 to 0.35; p = 0.25) revealed parity between groups. Patients with ACoA treated endovascularly had superior memory and motor abilities. Other cognitive domains, including executive function, language, visuospatial function, attention, intelligence and self-reported cognitive status revealed no statistically significant differences between the two approaches. Trial Registration PROSPERO (International Prospective Register of Systematic Reviews) CRD42023461283; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=461283.

Brain regions show different metabolic and protein arginine methylation phenotypes in frontotemporal dementias and Alzheimer's disease

Frontotemporal dementia (FTD) is a heterogeneous neurodegenerative disease with multiple histopathological subtypes. FTD patients share similar symptoms with Alzheimer's disease (AD). Hence, FTD patients are commonly misdiagnosed as AD, despite the consensus clinical diagnostic criteria. It is therefore of great clinical need to identify a biomarker that can distinguish FTD from AD and control individuals, and potentially further differentiate between FTD pathological subtypes. We conducted a metabolomic analysis on post-mortem human brain tissue from three regions: cerebellum, frontal cortex and occipital cortex from control, FTLD-TDP type A, type A-C9, type C and AD. Our results indicate that the brain subdivisions responsible for different functions show different metabolic patterns. We further explored the region-specific metabolic characteristics of different FTD subtypes and AD patients. Different FTD subtypes and AD share similar metabolic phenotypes in the cerebellum, but AD exhibited distinct metabolic patterns in the frontal and occipital regions compared to FTD. The identified brain region-specific metabolite biomarkers could provide a tool for distinguishing different FTD subtypes and AD and provide the first insights into the metabolic changes of FTLD-TDP type A, type A-C9, type C and AD in different regions of the brain. The importance of protein arginine methylation in neurodegenerative disease has come to light, so we investigated whether the arginine methylation level contributes to disease pathogenesis. Our findings provide new insights into the relationship between arginine methylation and metabolic changes in FTD subtypes and AD that could be further explored, to study the molecular mechanism of pathogenesis.

The Parietal Lobe in Alzheimer’s Disease and Blindness

The progressive aging of the population will notably increase the burden of those diseases which leads to a disabling situation, such as Alzheimer’s disease (AD) and ophthalmological diseases that cause a visual impairment (VI). Eye diseases that cause a VI raise neuroplastic processes in the parietal lobe. Meanwhile, the aforementioned lobe suffers a severe decline throughout AD. From this perspective, diving deeper into the particularities of the parietal lobe is of paramount importance. In this article, we discuss the functions of the parietal lobe, review the parietal anatomical and pathophysiological peculiarities in AD, and also describe some of the changes in the parietal region that occur after VI. Although the alterations in the hippocampus and the temporal lobe have been well documented in AD, the alterations of the parietal lobe have been less thoroughly explored. Recent neuroimaging studies have revealed that some metabolic and perfusion impairments along with a reduction of the white and grey matter could take place in the parietal lobe during AD. Conversely, it has been speculated that blinding ocular diseases induce a remodeling of the parietal region which is observable through the improvement of the integration of multimodal stimuli and in the increase of the volume of this cortical region. Based on current findings concerning the parietal lobe in both pathologies, we hypothesize that the increased activity of the parietal lobe in people with VI may diminish the neurodegeneration of this brain region in those who are visually impaired by oculardiseases.

A case of spontaneous intracranial hypotension in a 45-year-old male with headache, behavior changes and altered mental status

Spontaneous intracranial hypotension is a rare disease that results from low cerebrospinal fluid (CSF) volume caused by leakage of CSF from the spine in the absence of lumbar puncture, spine surgery, or intervention. The most common presentation is the headache that is usually but not invariably orthostatic. The underlying pathology is a CSF leak resulting from dural weakness involving the nerve root sleeves, ventral dural tears associated with calcified disc herniations, or CSF venous fistula. In severe cases, neuropsychiatric symptoms and changes in mental status may develop. Some case reports also mention gait disturbances, slurred speech, and urinary incontinence. The constellation of neuropsychiatric symptoms similar to behavior variant frontotemporal dementia in the presence of "brain sag" on MRI is known as frontotemporal brain sagging syndrome, first described by Wicklund et al. (4). The disease presents a diagnostic challenge to the primary care physicians, who are the first to see these patients. Brain and spine imaging is key to diagnoses but requires a high index of suspicion, as very rarely are all classic findings of intracranial hypotension present in the same patient. Here we discuss a case of spontaneous intracranial hypotension in a 45-year-old male patient who presented with headache, drowsiness, incoherent speech, behavior symptoms, and altered mental status.

Can we rewire criminal mind via non-invasive brain stimulation of prefrontal cortex? Insights from clinical, forensic and social cognition studies

Non-compliance with social and legal norms and regulations represents a high burden for society. Social cognition deficits are frequently called into question to explain criminal violence and rule violations in individuals diagnosed with antisocial personality disorder (APD), borderline personality disorder (BPD), and psychopathy. In this article, we proposed to consider the potential benefits of non-invasive brain stimulation (NIBS) to rehabilitate forensic population. We focused on the effects of NIBS of the prefrontal cortex, which is central in social cognition, in modulating aggression and impulsivity in clinical disorders, as well as in forensic population. We also addressed the effect of NIBS on empathy, and theory of mind in non-clinical and/or prison population. The reviewed data provide promising evidence on the beneficial effect of NIBS on aggression/impulsivity dyscontrol and social cognitive functions, suggesting its relevance in promoting reintegration of criminals into society.

Cerebral blood flow self-regulation in depression

BACKGROUND

Depression is a common neuropsychiatric disease with a high prevalence rate. Sleep problems, memory decline, dizziness and headaches are the most common neurological symptoms in depressed patients. Abnormality of cerebral blood flow (CBF) has been observed in depressive patients, but those patients did not have intracranial structural damage. Both of those phenomena might be related to cerebral blood flow self-regulation (CBFSR: cerebral blood flow self-regulation). CBFSR can maintain CBF relatively stable in response to changes in neurological and metabolic factors. Therefore, this review aimed to discuss CBFSR in depression.

METHODS

We searched for keywords such as "depression", "cerebral blood flow", "cerebral autoregulation", "cerebrovascular reactivity" and the words related to depression. We analyzed whether there is a change in the CBFSR in depression, further explored whether there is a relationship between the pathogenesis of depression and the CBFSR, and discussed the possible mechanism of impaired CBFSR in patients with depression.

RESULTS

Discovered by the literature review, CBFSR is significantly impaired in depressed patients. The level of circulating markers of endothelial dysfunction, nitric oxide, inflammatory cytokines, glucocorticoid and monoamine neurotransmitters is mostly abnormal in depression, which affected the CBFSR to varying degrees.

LIMITATIONS

Limitations include the small number of direct studies about depression and CBFSR mechanisms.

CONCLUSION

CBFSR is impaired in depression. The underlying mechanisms include endothelial dysfunction, overactivation of microglia and changes of cytokines, hyperactivation of the HPA axis, increased oxidative stress, monoamine neurotransmitter disorders, etc. These deepened our understanding of the clinical symptoms of depressed patients.

Interrelationships between exercise, functional connectivity, and cognition among healthy adults: A systematic review

The main purpose of this systematic review was to examine past literature focusing on the potential relationship between exercise (or physical activity or cardiorespiratory fitness [CRF]) and functional brain connectivity in healthy adults. Among the studies meeting this purpose, we also evaluated studies investigating whether, and how, functional connectivity may influence the exercise-cognition relationship. A systematic review was employed through several electronic databases (PsychInfo, PubMed, and Google Scholar) in accordance with PRISMA guidelines. The literature search identified 656 records, and a total of 12 studies met the inclusion criteria. Among these 12 studies, there were 4, 7, and 1 study, respectively, examining the relationship between exercise and frontal lobe connectivity, temporal lobe connectivity, and whole-brain connectivity. Also, 7 studies examined the relationship between functional connectivity and cognitive performance across multiple brain regions as a function of exercise. Existing literature suggests that CRF, habitual physical activity, and varying intensities of acute exercise can strengthen functional connections among a wide variety of regions and subcortical structures of the human brain. These exercise-induced functional connectivity changes within and between specific brain structures/networks supporting cognitive processing may improve various domains of cognitive function. Given these complex associations, a thorough understanding of how functional connectivity plays a mediating role in the exercise-cognition interaction is needed in future studies.

Lesions in different prefrontal sectors are associated with different types of acquired personality disturbances

"Frontal lobe syndrome" is a term often used to describe a diverse array of personality disturbances following frontal lobe damage. This study's guiding premise was that greater neuroanatomical specificity could be achieved by evaluating specific types of personality disturbances following acquired frontal lobe lesions. We hypothesized that three acquired personality disturbances would be associated with lesion involvement of distinct sectors of the prefrontal cortex (PFC): 1) emotional-social disturbance and ventromedial PFC, 2) hypoemotional disturbance and dorsomedial PFC, and 3) dysexecutive and dorsolateral PFC. In addition, we hypothesized that distressed personality disturbance would not be associated with focal PFC lesions in any sector. Each hypothesis was pre-registered and tested in 182 participants with adult-onset, chronic, focal brain lesions studied with an observational, cross-sectional design. Pre- and postmorbid personality was assessed by informant-rating with the Iowa Scales of Personality Change, completed by a spouse or family member. Two complementary analytic approaches were employed: 1) a hypothesis-driven region-of-interest (ROI) regression analysis examining the associations of lesions in specific PFC sectors with acquired personality disturbances; 2) a data-driven multivariate lesion-behavior mapping analysis, which was not limited to pre-specified regions. Each hypothesis received some support: (i) Emotional/social personality disturbance was most strongly associated with ventromedial PFC lesions in both statistical approaches. (ii) Hypoemotional disturbance was associated with dorsomedial PFC lesions in the ROI analyses, without any significant lesion-symptom mapping associations. (iii) Dysexecutive personality disturbance was associated with bilateral dorsolateral PFC lesions and ventromedial PFC lesions; lesion-symptom mapping showed maximal association of executive dysfunction with damage of the right middle frontal gyrus within the dorsolateral PFC. (iv) Distressed personality disturbance was not associated with lesions in any PFC sector. Altogether, the findings can be interpreted to indicate that damage to different prefrontal sectors may disrupt different anatomical-functional systems and result in distinct personality disturbances.

Cognitive Impairment in People with Epilepsy

People with epilepsy frequently have cognitive impairment. The majority of cognitive problems is influenced by a variety of interlinked factors, including the early onset of epilepsy and the frequency, intensity and duration of seizures, along with the anti-epileptic drug treatment. With a systematic review, we investigate significant factors about the cognitive impairment in epilepsy. Most cognitive problems in adult people with epilepsy include memory, attention and executive function deficits. However, which cognitive area is mainly affected highly depends on the location of epileptic activity. Moreover, modifications in signalling pathways and neuronal networks have an essential role in both the pathophysiology of epilepsy and in the mechanism responsible for cognitive impairment. Additionally, studies have shown that the use of polytherapy in the treatment of epilepsy with anti-epileptic drugs (AEDs) heightens the risk for cognitive impairment. It can be challenging to distinguish the contribution of each factor, because they are often closely intertwined.

Brain Energy Metabolism in Two States of Mind Measured by Phosphorous Magnetic Resonance Spectroscopy

Introduction: Various functional neuroimaging studies help to better understand the changes in brain activity during meditation. The purpose of this study was to investigate how brain energy metabolism changes during focused attention meditation (FAM) state, measured by phosphorous magnetic resonance spectroscopy (³¹P-MRS).

Methods:³¹P-MRS imaging was carried out in 27 participants after 7 weeks of FAM training. Metabolite ratios and the absolute values of metabolites were assessed after meditation training in two MRI measurements, by comparing effects in a FAM state with those in a distinct focused attention awake state during a backwards counting task.

Results: The results showed decreased phosphocreatine/ATP (PCr/ATP), PCr/ inorganic phosphate (Pi), and intracellular pH values in the entire brain, but especially in basal ganglia, frontal lobes, and occipital lobes, and increased Pi/ATP ratio, cerebral Mg, and Pi absolute values were found in the same areas during FAM compared to the control focused attention awake state.

Conclusions: Changes in the temporal areas and basal ganglia may be interpreted as a higher energetic state induced by meditation, whereas the frontal and occipital areas showed changes that may be related to a down-regulation in ATP turnover, energy state, and oxidative capacity.

High Blood Lead Levels: An Increased Risk for Development of Brain Hyperintensities among Type 2 Diabetes Mellitus Patients

The current study was aimed to ascertain the effect of blood lead level on brain tissues in patients with type 2 diabetes. A total of 300 human participants ages 27 to 60 years with type 2 diabetes (n = 150) and healthy individuals (n = 150) were included in this study. The serum samples were used for measuring HbA1c and fasting blood glucose. Blood lead level was measured using flame atomic absorption spectrophotometer. Magnetic resonance imaging sub-analysis was used to assess the brain hyperintensities. Brain hyperintensities were found in 55% of patients with diabetes and 6% of non-diabetic control group subjects. The deep white matter hyperintensities were observed in 45% of diabetic patients, while the subcortical hyperintensities were noted in 10% of cases. Entorhinal cortex changes (31%) and hippocampus changes (42%) were noted in diabetic patients with brain hyperintensities. Diabetic patients with brain hyperintensities showed higher blood lead levels, HbA1c, and fasting blood sugar (p < 0.0001) as compared with healthy volunteers. A higher correlation (R² = 0.8922) was found between deep white matter hyperintensities' size and blood lead levels. In nutshell, persistence of high blood lead level in diabetic patients may progress to brain hyperintensities which may consequently lead to cognitive, behavioral changes and Alzheimer's disease.

Neuroimaging in infants with prenatal opioid exposure: Current evidence, recent developments and targets for future research

Prenatal opioid exposure (POE) has shown to be a risk factor for adverse long-term cognitive and behavioral outcomes in offspring. However, the neural mechanisms of these outcomes remain poorly understood. While preclinical and human studies suggest that these outcomes may be due to opioid-mediated changes in the fetal and early postnatal brain, other maternal, social, and environmental factors are also shown to play a role. Recent neuroimaging studies reveal brain alterations in children with POE. Early neuroimaging and novel methodology could provide an in vivo mechanistic understanding of opioid mediated alterations in developing brain. However, this is an area of ongoing research. In this review we explore recent imaging developments in POE, with emphasis on the neonatal and infant brain, and highlight some of the challenges of imaging the developing brain in this population. We also highlight evidence from animal models and imaging in older children and youth to understand areas where future research may be targeted in infants with POE.

Hippocampal radiotherapy dose constraints for predicting long-term neurocognitive outcomes: mature data from a prospective trial in young patients with brain tumors

BACKGROUND

Hippocampus is considered to be the seat for neurocognitive functions. Avoidance of hippocampus during radiotherapy to brain may serve to preserve various domains of neurocognition. We aimed to derive radiotherapy dose constraints to hippocampi for preserving neurocognition in young patients with brain tumors by measuring various neurocognitive parameters.

METHODS

Forty-eight patients with residual/progressive benign or low-grade brain tumors treated with stereotactic conformal radiotherapy (SCRT) to a dose of 54 Gy in 30 fractions underwent prospective neuropsychological assessments at baseline before SCRT and at 6 months and 2, 3, 4, and 5 years. Hippocampi were drawn as per the Radiation Therapy Oncology Group atlas. Longitudinal change in intelligence quotient scores was correlated with hippocampal doses.

RESULTS

Mean volume of bilateral hippocampi was 4.35 cc (range: 2.12-8.41 cc). Craniopharyngioma was the commonest histologic subtype. A drop of >10% in mean full-scale intelligence quotient (FSIQ) scores at 3 and 5 years post SCRT was observed in patients in whom left hippocampus received a mean dose of 30.7 Gy (P = 0.04) and 31 Gy (P = 0.04), respectively. Mean performance quotient (PQ) scores dropped > 10% at 5 years when the left hippocampus received a dose of > 32 Gy (P = 0.03). There was no significant correlation of radiotherapy doses with verbal quotient, or with doses received by the right hippocampus. Multivariate analysis revealed young age (<13 y) and left hippocampus dose predicted for clinically relevant decline in certain neurocognitive domains.

CONCLUSIONS

A mean dose of ≤30 Gy to the left hippocampus as a dose constraint for preserving intelligence quotient is suggested.

KEY POINTS

1. Children and young adults with benign and low-grade gliomas survive long after therapy.2. Higher dose to the hippocampi may result in long-term neurocognitive impairment.3. Mean dose of <30 Gy to left hippocampus could be used as a pragmatic dose constraint to prevent long-term neurocognitive decline.

Value of the Frontal Assessment Battery Tool for Assessing the Frontal Lobe Function in Stroke Patients

OBJECTIVE

To examine the correlation between the Frontal Assessment Battery (FAB) test, which is used to assess the frontal lobe function, and anatomical lesions as well as the ability of the test to detect frontal lobe dysfunction.

METHODS

Records of stroke patients undergoing a FAB test and Mini-Mental State Examination (MMSE) were retrospectively reviewed. The patients were divided into three groups according to the lesions determined by an imaging study: frontal lobe cortex lesions, frontal subcortical circuit lesions, and other lesions. The FAB scores of the three groups were compared using the Kruskal-Wallis test. The validity of the FAB test to detect frontal lobe dysfunction was assessed by a comparison with the Computerized Neuropsychological Function Test (CNT) using the Spearman correlation coefficient. The correlation coefficients between the FAB test and MMSE were analyzed further based on the MMSE cutoff score.

RESULTS

Patients with frontal cortex lesions had significantly lower total and subtest scores according to the FAB test than the other patients. The FAB test correlated better with the CNT than the MMSE, particularly in the executive function and memory domains. A high MMSE score (r=0.435) indicated a lower correlation with the FAB test score than a low MMSE score (r=0.714).

CONCLUSION

The FAB test could differentiate frontal lobe lesions from others in stroke patients and showed a good correlation with the CNT. Moreover, the FAB test can be used in patients with high MMSE scores to detect frontal lobe dysfunction and determine the treatment strategies for stroke patients.

Cortical metabolic changes and clinical outcome in normal pressure hydrocephalus after ventriculoperitoneal shunt: Our preliminary results

INTRODUCTION

Our objective was to evaluate the cortical metabolic changes and clinical outcome in patients affected by idiopathic normal pressure hydrocephalus (iNPH) after a placement of ventriculoperitoneal (VP) shunt.

MATERIALS AND METHODS

10 patients affected by suspected iNPH underwent a CSF hydrodynamics evaluation based on a lumbar infusion test (LIT). The main selection criterion for surgery was based on intracranial elasticity (IE)>0.30. All subjects with an IE>0.30 underwent a PET scan with 18 fluorodeoxiglucose (¹⁸F-FDG) at baseline (PET1) and 1 month after surgery (PET2). Furthermore, the same patients were submitted to clinical evaluation before and 1 month after surgery through neuropsychological tests and gait analysis.

RESULTS

An overall number of 20 18F-FDG PET scans were performed in all the enrolled patients. As compared to PET1, PET2 showed an increase in glucose consumption in the left frontal and left parietal lobe in PET2 as compared to PET1 (P<.001). All the enrolled patients presented a significant increase in neuropsychological scores (i.e Frontal Assessment Battery and Montreal Cognitive Assessment) and have clinically improved at gait analysis. A significant correlation was found between the increase of cortical glucose consumption in the left parietal area and the cognitive improvement as detectable by neuropsychological assessment.

CONCLUSIONS

Improvement in 18F FDG PET glucose metabolism could be considered a useful imaging marker for the assessment of iNPH response to VP shunting.

Plastic frontal pole cortex structure related to individual persistence for goal achievement

Persistent goal-directed behaviours result in achievements in many fields. However, the underlying neural mechanisms of persistence and the methods that enhance the neuroplasticity underlying persistence, remain unclear. We here demonstrate that the structural properties of the frontal pole cortex (FPC) before tasks contain information that can classify Achievers and Non-achievers (goal-directed persistence) participating in three tasks that differ in time scale (hours to months) and task domains (cognitive, language, and motor learning). We also found that most Achievers exhibit experience-dependent neuroplastic changes in the FPC after completing language and motor learning tasks. Moreover, we confirmed that a coaching strategy that used subgoals modified goal-directed persistence and increased the likelihood of becoming an Achiever. Notably, we discovered that neuroplastic changes in the FPC were facilitated by the subgoal strategy, suggesting that goal-striving, using effective coaching, optimizes the FPC for goal persistence.

Hosoda et al. study the neurobiological underpinnings of goal pursuit and persistence. They use MRI data and identify areas in the frontal pole cortex that could predict performance on various tasks. They also show that coaching results in neuroplastic remodeling that increases the likelihood of goal persistence.

Alcohol and Parasomnias: The Statistical Evaluation of the Parasomnia Defense in Sexual Assault, Where Alcohol is Involved

Sleep sex may be a defense for alleged sexual assault. The International Classification of Sleep Disorders (ICSD3) states: "Disorders of arousal should not be diagnosed in the presence of alcohol intoxication… The former [alcohol blackouts] are exponentially more prevalent." A panel member of ICSD3, quoting ICSD3 asserts: "alcohol intoxication should rule out a sleep-walking defense". This implies extremely strong support for a prosecution hypothesis (H_p ) over a defense hypothesis (H_d ). I use Bayesian methodology to evaluate the evidential probity of alcohol intoxication. The likelihood ratio, LR, measures the amplification of prior odds of guilt, LR = Posterior odds of guilt after considering alcohol intoxication /Prior odds of guilt before considering alcohol intoxication . By Bayes' theorem, LR = p ( alcohol intoxication, given H p ) / p ( alcohol intoxication, given H d ) . I use data from cross-sectional studies of sexual assault and prevalence of alcohol use, in college students, with data from longitudinal studies, and data from the epidemiology of parasomnias to evaluate LR (alcohol). LR ~1.5 or 5, depending whether alcohol does, or does not, increase the risk of parasomnias. The proposition of extremely strong support for H_p implies a LR ~1,000,000, so the proposition in ICSD3 is not supported by formal analysis. The statistical reasoning in ICSD3 is unclear. There appears to be inversion of the Bayesian conditional (confusing intoxication given assault, and assault given intoxication) and failure to evaluate alcohol intoxication in H_d . Similar statistical errors in R. v Sally Clark are discussed. The American Academy of Sleep Medicine should review the statistical methodology in ICSD3.

Moral conduct and social behavior

Over the past 150 years, the frontal lobes (FLs) have been implicated in the neural mediation of both normal and abnormal moral conduct and social behavior (MCSB). Despite the remarkable advances that have permeated this period up to the present, a comprehensive account of the neural underpinnings of MCSB has stubbornly defied the best minds of psychology, psychiatry, and neurology. The goal of this chapter is to review a few practical and conceptual achievements that have proved heuristically valuable as an impetus for further advance of knowledge. In virtually all cases in which MCSB was compromised by brain damage, the injuries were located (i) in the prefrontal cortices, (ii) in their connections with the temporal poles and anterior insula, or (iii) in related subcortical structures and pathways, such as the thalamic dorsomedial nucleus or the anterior thalamic radiation. The clinicoanatomic associations among these structures originated the "frontal network systems" concept, which satisfactorily explains the occurrence of classical FL syndromes in patients with lesions outside the prefrontal cortices. Overall, clinicoanatomic observational studies and experimental evidence from patients with acquired sociopathy/psychopathy indicate that abnormalities of MCSB are the final common pathway of single or mixed impairments of subordinate psychologic and neural domains that support MCSB. Independent studies on normal volunteers concur with this view, indicating that MCSB is shaped by the dynamic interplay of subordinate psychologic domains, such as moral sensitivity and judgment, and their neural correlates.

Differential associations of neurobehavioral traits and cognitive ability to academic achievement in higher education

BACKGROUND

People vary between each other on several neurobehavioral traits, which may have implications for understanding academic achievement.

METHODS

University-level Psychology or Engineering students were assessed for neurobehavioral traits, intelligence, and current psychological distress. Scores were compared with their grade point average (GPA) data.

RESULTS

Factors associated with higher GPA differed markedly between groups. For Engineers, intelligence, but not neurobehavioral traits or psychological distress, was a strong correlate of grades. For Psychologists, grades were not correlated with intelligence but they were with the neurobehavioral traits of executive dysfunction, disinhibition, apathy, and positive schizotypy. However, only the latter two were associated independently of psychological distress. Additionally, higher mixed-handedness was associated with higher GPA in the combined sample.

CONCLUSIONS

Neurological factors (i.e., neurobehavioral traits and intelligence), are differentially associated with university-level grades, depending on the major studied. However, mixed-handedness may prove to be a better general predictor of academic performance across disciplines.

Associations Between Altered Cerebral Activity Patterns and Psychosocial Disorders in Patients With Psychogenic Erectile Dysfunction: A Mediation Analysis of fMRI

Previous studies had illustrated the significant neural pathological changes in patients with psychogenic erectile dysfunction (pED), while few works focused on the neural underpinning of the psychosocial status in patients with pED. This study aimed to investigate the associations among the altered cerebral activity patterns, impaired erectile function, and the disrupted psychosocial status in patients with pED. Thirty-two patients with pED and 28 healthy controls (HCs) were included. The amplitude of low-frequency fluctuations (ALFF), region-of-interest-based functional connectivity (FC), as well as Pearson correlation analyses and mediation analyses between neuroimaging outcomes and clinical outcomes were performed. Compared to HCs, patients with pED manifested lower erectile function, disrupted psychosocial status, as well as decreased ALFF in the left dorsolateral prefrontal cortex (dlPFC) and reduced FC between the left dlPFC and left angular gyrus, and left posterior cingulate cortex (PCC) and precuneus, which belonged to the default mode network (DMN). Moreover, both the ALFF of the left dlPFC and FC between the left dlPFC and left PCC and precuneus were significantly correlated with the sexual function and psychosocial status in patients with pED. The disrupted psychosocial status mediated the influence of atypical FC between dlPFC and DMN on decreased erectile function. This study widened our understanding of the important role of psychosocial disorders in pathological neural changes in patients with pED.

Pathways of Prevention: A Scoping Review of Dietary and Exercise Interventions for Neurocognition

Alzheimer's disease and related dementias (ADRD) represent an increasingly urgent public health concern, with an increasing number of baby boomers now at risk. Due to a lack of efficacious therapies among symptomatic older adults, an increasing emphasis has been placed on preventive measures that can curb or even prevent ADRD development among middle-aged adults. Lifestyle modification using aerobic exercise and dietary modification represents one of the primary treatment modalities used to mitigate ADRD risk, with an increasing number of trials demonstrating that exercise and dietary change, individually and together, improve neurocognitive performance among middle-aged and older adults. Despite several optimistic findings, examination of treatment changes across lifestyle interventions reveals a variable pattern of improvements, with large individual differences across trials. The present review attempts to synthesize available literature linking lifestyle modification to neurocognitive changes, outline putative mechanisms of treatment improvement, and discuss discrepant trial findings. In addition, previous mechanistic assumptions linking lifestyle to neurocognition are discussed, with a focus on potential solutions to improve our understanding of individual neurocognitive differences in response to lifestyle modification. Specific recommendations include integration of contemporary causal inference approaches for analyzing parallel mechanistic pathways and treatment-exposure interactions. Methodological recommendations include trial multiphase optimization strategy (MOST) design approaches that leverage individual differences for improved treatment outcomes.

Cortical network fingerprints predict deep brain stimulation outcome in dystonia

BACKGROUND

Deep brain stimulation (DBS) is an effective evidence-based therapy for dystonia. However, no unequivocal predictors of therapy responses exist. We investigated whether patients optimally responding to DBS present distinct brain network organization and structural patterns.

METHODS

From a German multicenter cohort of 82 dystonia patients with segmental and generalized dystonia who received DBS implantation in the globus pallidus internus, we classified patients based on the clinical response 3 years after DBS. Patients were assigned to the superior-outcome group or moderate-outcome group, depending on whether they had above or below 70% motor improvement, respectively. Fifty-one patients met MRI-quality and treatment response requirements (mean age, 51.3 ± 13.2 years; 25 female) and were included in further analysis. From preoperative MRI we assessed cortical thickness and structural covariance, which were then fed into network analysis using graph theory. We designed a support vector machine to classify subjects for the clinical response based on individual gray-matter fingerprints.

RESULTS

The moderate-outcome group showed cortical atrophy mainly in the sensorimotor and visuomotor areas and disturbed network topology in these regions. The structural integrity of the cortical mantle explained about 45% of the DBS stimulation amplitude for optimal response in individual subjects. Classification analyses achieved up to 88% of accuracy using individual gray-matter atrophy patterns to predict DBS outcomes.

CONCLUSIONS

The analysis of cortical integrity, informed by group-level network properties, could be developed into independent predictors to identify dystonia patients who benefit from DBS. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

The association between frontal lobe perfusion and depressive symptoms in later life

BACKGROUND

Deficits in frontal lobe perfusion have been demonstrated in late-life depression; however, studies to date have generally involved small numbers, used neuroimaging rather than bedside testing and have not controlled for important covariates.AimsWe aimed to examine the association between depressive symptoms and frontal lobe perfusion during standing, in a large cohort of community-dwelling older people.

METHOD

Participants aged ≥50 years underwent continuous measurement of orthostatic blood pressure by finometry, and frontal lobe perfusion by near-infrared spectroscopy. Depressive symptoms were assessed by the eight-item Centre for Epidemiological Studies Depression Scale. Real-time frontal lobe cerebral oxygenation was measured by the Portalite System, detecting changes in frontal lobe perfusion and reporting a tissue saturation index score.

RESULTS

Almost 8% (209 out of 2616) had clinically significant depressive symptoms. Multilevel models demonstrated a significantly lower tissue saturation index in participants with depressive symptoms at both 60 and 90 s post-stand, with coefficients of -0.43 (95% CI -0.63 to -0.22) and -0.37 (95% CI -0.57 to -0.16), respectively. Controlling for relevant covariates did not significantly attenuate these associations. After addition of systolic blood pressure this association was no longer significant, suggesting lower blood pressure may modify this relationship.

CONCLUSIONS

This study demonstrates that lower frontal lobe perfusion, related to lower values of baseline systolic blood pressure, is associated with clinically significant depressive symptoms in a cohort of community-dwelling older people. Given the recognised longitudinal association between lower blood pressure and depression in older people, this may represent a potential therapeutic target for prevention of incident depression.Declaration of interestNone.

Executive functions

Executive functions (EFs) include high-order cognitive abilities such as working memory, inhibitory control, cognitive flexibility, planning, reasoning, and problem solving. EFs enable humans to achieve goals, adapt to novel everyday life situations, and manage social interactions. Traditionally EFs have been associated with frontal lobe functioning. More recent evidence shows that posterior and subcortical regions also play a crucial role in EF processing, especially in the integration of sensory information and emotion. This chapter reviews the variety of EFs and their neural underpinning, based on lesion mapping and neuroimaging studies, as well as the evidence for rehabilitation interventions, neuropsychological assessment based on standard and ecologically valid tests, development, and genetic predisposition for recovery of executive functions after brain injury. Taken together, the EFs are critical for unique human abilities and more careful analyses of their subcomponents may help the development of targeted translational interventions to improve them.

Functional Connectivity Changes in Behavioral, Semantic, and Nonfluent Variants of Frontotemporal Dementia

Frontotemporal dementia (FTD) affects behavior, language, and personality. This study aims to explore functional connectivity changes in three FTD variants: behavioral (bvFTD), semantic (svPPA), and nonfluent variant (nfvPPA). Seventy-six patients diagnosed with FTD by international criteria and thirty-two controls were investigated. Functional connectivity from resting functional magnetic resonance imaging (fMRI) was estimated for the whole brain. Two types of analysis were done: network basic statistic and topological measures by graph theory. Several hubs in the limbic system and basal ganglia were compromised in the behavioral variant apart from frontal networks. Nonfluent variants showed a major disconnection with respect to the behavioral variant in operculum and parietal inferior. The global efficiency had lower coefficients in nonfluent variants than behavioral variants and controls. Our results support an extensive disconnection among frontal, limbic, basal ganglia, and parietal hubs.

The Evolutionary Theory of Depression

The evolutionary success of Homo sapiens is attributed to the following two factors: the upright body posture (which freed our hands and allowed unconstrained operation of various objects) and intensive development of the frontal lobes, mainly the Broca area of the brain. Underlining the uniqueness of the human brain, we often forget about the fact that the frontal lobes – the most developed part of the brain – are at the same time our greatest weakness, exposed to the action of damaging factors in our evolving environment. Is depression the cost of evolution?

A T1 and DTI fused 3D corpus callosum analysis in MCI subjects with high and low cardiovascular risk profile

Understanding the extent to which vascular disease and its risk factors are associated with prodromal dementia, notably Alzheimer's disease (AD), may enhance predictive accuracy as well as guide early interventions. One promising avenue to determine this relationship consists of looking for reliable and sensitive in-vivo imaging methods capable of characterizing the subtle brain alterations before the clinical manifestations. However, little is known from the imaging perspective about how risk factors such as vascular disease influence AD progression. Here, for the first time, we apply an innovative T1 and DTI fusion analysis of 3D corpus callosum (CC) on mild cognitive impairment (MCI) populations with different levels of vascular profile, aiming to de-couple the vascular factor in the prodromal AD stage. Our new fusion method successfully increases the detection power for differentiating MCI subjects with high from low vascular risk profiles, as well as from healthy controls. MCI subjects with high and low vascular risk profiles showed differed alteration patterns in the anterior CC, which may help to elucidate the inter-wired relationship between MCI and vascular risk factors.

Mechanisms of radiotherapy-associated cognitive disability in patients with brain tumours

Standard treatment of primary and metastatic brain tumours includes high-dose megavoltage-range radiation to the cranial vault. About half of patients survive >6 months, and many attain long-term control or cure. However, 50-90% of survivors exhibit disabling cognitive dysfunction. The radiation-associated cognitive syndrome is poorly understood and has no effective prevention or long-term treatment. Attention has primarily focused on mechanisms of disability that appear at 6 months to 1 year after radiotherapy. However, recent studies show that CNS alterations and dysfunction develop much earlier following radiation exposure. This finding has prompted the hypothesis that subtle early forms of radiation-induced CNS damage could drive chronic pathophysiological processes that lead to permanent cognitive decline. This Review presents evidence of acute radiation-triggered CNS inflammation, injury to neuronal lineages, accessory cells and their progenitors, and loss of supporting structure integrity. Moreover, injury-related processes initiated soon after irradiation could synergistically alter the signalling microenvironment in progenitor cell niches in the brain and the hippocampus, which is a structure critical to memory and cognition. Progenitor cell niche degradation could cause progressive neuronal loss and cognitive disability. The concluding discussion addresses future directions and potential early treatments that might reverse degenerative processes before they can cause permanent cognitive disability.

Onset of psychosis at age 81? With regard to frontal lobe syndromes

When the frontal lobe of the brain is affected important behavioral changes may occur mainly at the level of executive functioning, i.e., planning, decision-making, judgment and self-perception. However, the behavioral changes may be of different nature with marked indifference and apathy. We report a clinical case of an 81-year-old patient with sudden onset of behavioral changes that were initially interpreted as an acute confusional episode of infectious etiology, but actually they were due to an ischemic lesion in the frontal lobe.

How to build up the actionable knowledge base: the role of 'best fit' framework synthesis for studies of improvement in healthcare

Increasing recognition of the role and value of theory in improvement work in healthcare offers the prospect of capitalising upon, and consolidating, actionable lessons from synthesis of improvement projects and initiatives. We propose that informed use of theory can (i) provide a mechanism by which to collect and organise data from a body of improvement work, (ii) offer a framework for analysis and identification of lessons learnt and (iii) facilitate an evaluation of the feasibility, effectiveness and acceptability of improvement programmes. Improvement practitioners can benefit from using an underpinning external structure as a lens by which to examine the specific achievements of their own projects alongside comparable initiatives led by others. We demonstrate the utility of a method known as ‘best fit framework synthesis’ (BFFS) in offering a ubiquitous and versatile means by which to collect, analyse and evaluate improvement work in healthcare. First reported in 2011, BFFS represents a pragmatic, flexible approach to integrating theory with findings from practice. A deductive phase, where a review team seeks to accommodate a substantial part of the data, is followed by an inductive phase, in which the team explores data not accommodated by the framework. We explore the potential for BFFS within improvement work by drawing upon the evidence synthesis methodology literature and practical examples of improvement work reported in BMJ Quality and Safety (2011–2015). We suggest four variants of BFFS that may have particular value in synthesising a body of improvement work. We conclude that BFFS, alongside other approaches that seek to optimise the contribution of theory to improvement work, represents one important enabling mechanism by which to establish the rigour and scientific credentials of the emerging discipline of ‘improvement science’.