Regional cerebellar volumetric correlates of manual motor and cognitive function

Motor development-focused exercise training enhances gross motor skills more effectively than ordinary physical activity in healthy preschool children: an updated meta-analysis

Purpose

The growth of certain human brain structures peaks at early ages, and complex motor interventions could positively facilitate this process. This study aims to offer an updated meta-analysis regarding the effectiveness of motor development-focused exercise training on gross motor skills in preschool children.

Methods

We searched English- and Chinese-language electronic databases as of March 2024. The main eligibility criteria were as follows: participants were healthy children aged 3 to 6 years old, and the experimental design was a randomized controlled trial, with the control arm participating in either free play or ordinary physical education curriculum. We conducted a Hartung-Knapp random-effects meta-analysis of the standardized mean difference for locomotor, object control, or gross motor quotient.

Results

The search identified 23 eligible studies, of which approximately 75% were considered to have a low risk of bias. Compared with active control, exercise training showed a large to very large effect size. Cohen's d values were 1.13, 1.55, and 1.53 for locomotor, object control, and gross motor quotient, respectively. From a probabilistic viewpoint, these effect sizes correspond to events that are "very likely to occur" and "almost sure to occur." Due to variations in intervention programs, all outcome measures showed high heterogeneity.

Conclusion

This updated meta-analysis offers a realistic synthesis of the current evidence, leading to the conclusion that targeted motor skill exercise training can almost certainly enhance preschool children's gross motor skills. Practical implications are discussed regarding the refinement of the instructional framework and the dissemination of these findings in preschool settings.

Morphological changes in the cerebellum during aging: evidence from convolutional neural networks and shape analysis

The morphology and function of the cerebellum are associated with various developmental disorders and healthy aging. Changes in cerebellar morphology during the aging process have been extensively investigated, with most studies focusing on changes in cerebellar regional volume. The volumetric method has been used to quantitatively demonstrate the decrease in the cerebellar volume with age, but it has certain limitations in visually presenting the morphological changes of cerebellar atrophy from a three-dimensional perspective. Thus, we comprehensively described cerebellar morphological changes during aging through volume measurements of subregions and shape analysis. This study included 553 healthy participants aged 20-80 years. A novel cerebellar localized segmentation algorithm based on convolutional neural networks was utilized to analyze the volume of subregions, followed by shape analysis for localized atrophy assessment based on the cerebellar thickness. The results indicated that out of the 28 subregions in the absolute volume of the cerebellum, 15 exhibited significant aging trends, and 16 exhibited significant sex differences. Regarding the analysis of relative volume, only 11 out of the 28 subregions of the cerebellum exhibited significant aging trends, and 4 exhibited significant sex differences. The results of the shape analysis revealed region-specific atrophy of the cerebellum with increasing age. Regions displaying more significant atrophy were predominantly located in the vermis, the lateral portions of bilateral cerebellar hemispheres, lobules I-III, and the medial portions of the posterior lobe. This atrophy differed between sexes. Men exhibited slightly more severe atrophy than women in most of the cerebellar regions. Our study provides a comprehensive perspective for observing cerebellar atrophy during the aging process.

Consensus Paper: Cerebellum and Ageing

Given the key roles of the cerebellum in motor, cognitive, and affective operations and given the decline of brain functions with aging, cerebellar circuitry is attracting the attention of the scientific community. The cerebellum plays a key role in timing aspects of both motor and cognitive operations, including for complex tasks such as spatial navigation. Anatomically, the cerebellum is connected with the basal ganglia via disynaptic loops, and it receives inputs from nearly every region in the cerebral cortex. The current leading hypothesis is that the cerebellum builds internal models and facilitates automatic behaviors through multiple interactions with the cerebral cortex, basal ganglia and spinal cord. The cerebellum undergoes structural and functional changes with aging, being involved in mobility frailty and related cognitive impairment as observed in the physio-cognitive decline syndrome (PCDS) affecting older, functionally-preserved adults who show slowness and/or weakness. Reductions in cerebellar volume accompany aging and are at least correlated with cognitive decline. There is a strongly negative correlation between cerebellar volume and age in cross-sectional studies, often mirrored by a reduced performance in motor tasks. Still, predictive motor timing scores remain stable over various age groups despite marked cerebellar atrophy. The cerebello-frontal network could play a significant role in processing speed and impaired cerebellar function due to aging might be compensated by increasing frontal activity to optimize processing speed in the elderly. For cognitive operations, decreased functional connectivity of the default mode network (DMN) is correlated with lower performances. Neuroimaging studies highlight that the cerebellum might be involved in the cognitive decline occurring in Alzheimer's disease (AD), independently of contributions of the cerebral cortex. Grey matter volume loss in AD is distinct from that seen in normal aging, occurring initially in cerebellar posterior lobe regions, and is associated with neuronal, synaptic and beta-amyloid neuropathology. Regarding depression, structural imaging studies have identified a relationship between depressive symptoms and cerebellar gray matter volume. In particular, major depressive disorder (MDD) and higher depressive symptom burden are associated with smaller gray matter volumes in the total cerebellum as well as the posterior cerebellum, vermis, and posterior Crus I. From the genetic/epigenetic standpoint, prominent DNA methylation changes in the cerebellum with aging are both in the form of hypo- and hyper-methylation, and the presumably increased/decreased expression of certain genes might impact on motor coordination. Training influences motor skills and lifelong practice might contribute to structural maintenance of the cerebellum in old age, reducing loss of grey matter volume and therefore contributing to the maintenance of cerebellar reserve. Non-invasive cerebellar stimulation techniques are increasingly being applied to enhance cerebellar functions related to motor, cognitive, and affective operations. They might enhance cerebellar reserve in the elderly. In conclusion, macroscopic and microscopic changes occur in the cerebellum during the lifespan, with changes in structural and functional connectivity with both the cerebral cortex and basal ganglia. With the aging of the population and the impact of aging on quality of life, the panel of experts considers that there is a huge need to clarify how the effects of aging on the cerebellar circuitry modify specific motor, cognitive, and affective operations both in normal subjects and in brain disorders such as AD or MDD, with the goal of preventing symptoms or improving the motor, cognitive, and affective symptoms.

Sex Differences and Behavioral Associations with Typically Developing Pediatric Regional Cerebellar Gray Matter Volume

The cerebellum contributes to motor and higher-order control throughout neurodevelopment, with marked growth during childhood. Few studies have investigated differential associations of cerebellar morphometry with function in males and females. The present study examines sex differences in regional cerebellar gray matter volume (GMV) and the moderating effect of sex on the relationship between GMV and motor, cognitive, and emotional functions in a large cohort of typically developing (TD) children. Participants included 371 TD children (123 females, age 8-12 years). A convolutional neural network-based approach was employed for cerebellar parcellation. Volumes were harmonized using ComBat to adjust for hardware-induced variations. Regression analyses examined the effect of sex on GMV and whether sex moderated the relationship between GMV and motor, cognitive, and emotional functions. Males showed larger GMV in right lobules I-V, bilateral lobules VI, crus II/VIIb, and VIII, left lobule X, and vermis regions I-V and VIII-X. Greater motor function correlated with less vermis VI-VII GMV in females. Greater cognitive function correlated with greater left lobule VI GMV in females and less left lobule VI GMV in males. Finally, greater internalizing symptoms correlated with greater bilateral lobule IX GMV in females but less in males. These findings reveal sexually dimorphic patterns of cerebellar structure and associations with motor, cognitive, and emotional functions. Males generally show larger GMV than females. Larger GMV was associated with better cognitive functioning for females and better motor/emotional functioning for males.

The Cerebellum and Cognitive Function: Anatomical Evidence from a Transdiagnostic Sample

Multiple lines of evidence across human functional, lesion, and animal data point to a cerebellar role, in particular of crus I, crus II, and lobule VIIB, in cognitive function. However, a mapping of distinct facets of cognitive function to cerebellar structure is missing. We analyzed structural neuroimaging data from the Healthy Brain Network (HBN). Cerebellar parcellation was performed with a validated automated segmentation pipeline (CERES) and stringent visual quality check (n = 662 subjects retained from initial n = 1452). Canonical correlation analyses (CCA) examined regional gray matter volumetric (GMV) differences in association to cognitive function (quantified with NIH Toolbox Cognition domain, NIH-TB), accounting for psychopathology severity, age, sex, scan location, and intracranial volume. Multivariate CCA uncovered a significant correlation between two components entailing a latent cognitive canonical (NIH-TB subscales) and a brain canonical variate (cerebellar GMV and intracranial volume, ICV), surviving bootstrapping and permutation procedures. The components correspond to partly shared cerebellar-cognitive function relationship with a first map encompassing cognitive flexibility (r = 0.89), speed of processing (r = 0.65), and working memory (r = 0.52) associated with regional GMV in crus II (r = 0.57) and lobule X (r = 0.59) and a second map including the crus I (r = 0.49) and lobule VI (r = 0.49) associated with working memory (r = 0.51). We show evidence for a structural subspecialization of the cerebellum topography for cognitive function in a transdiagnostic sample.

The "Little Circles Test" (LCT): a dusted-off tool for assessing fine visuomotor function

BACKGROUND

The fine visuomotor function is commonly impaired in several neurological conditions. However, there is a scarcity of reliable neuropsychological tools to assess such a critical domain.

AIMS

The aim of this study is to explore the psychometric properties and provide normative data for the Visual-Motor Speed and Precision Test (VMSPT).

RESULTS

Our normative sample included 220 participants (130 females) aged 18-86 years (mean education = 15.24 years, SD = 3.98). Results showed that raw VMSPT scores were affected by higher age and lower education. No effect of sex or handedness was shown. Age- and education-based norms were provided. VMSPT exhibited weak-to-strong correlations with well-known neuropsychological tests, encompassing a wide range of cognitive domains of clinical relevance. By gradually intensifying the cognitive demands, the test becomes an indirect, performance-oriented measure of executive functioning. Finally, VMSPT seems proficient in capturing the speed-accuracy trade-off typically observed in the aging population.

CONCLUSIONS

This study proposes the initial standardization of a versatile, time-efficient, and cost-effective neuropsychological tool for assessing fine visuomotor coordination. We propose renaming the VMSPT as the more approachable "Little Circles Test" (LCT).

Disability and persistent motor deficits are linked to structural crossed cerebellar diaschisis in chronic stroke

Brain imaging has significantly contributed to our understanding of the cerebellum being involved in recovery after non-cerebellar stroke. Due to its connections with supratentorial brain networks, acute stroke can alter the function and structure of the contralesional cerebellum, known as crossed cerebellar diaschisis (CCD). Data on the spatially precise distribution of structural CCD and their implications for persistent deficits after stroke are notably limited. In this cross-sectional study, structural MRI and clinical data were analyzed from 32 chronic stroke patients, at least 6 months after the event. We quantified lobule-specific contralesional atrophy, as a surrogate of structural CCD, in patients and healthy controls. Volumetric data were integrated with clinical scores of disability and motor deficits. Diaschisis-outcome models were adjusted for the covariables age, lesion volume, and damage to the corticospinal tract. We found that structural CCD was evident for the whole cerebellum, and particularly for lobules V and VI. Lobule VI diaschisis was significantly correlated with clinical scores, that is, volume reductions in contralesional lobule VI were associated with higher levels of disability and motor deficits. Lobule V and the whole cerebellum did not show similar diaschisis-outcome relationships across the spectrum of the clinical scores. These results provide novel insights into stroke-related cerebellar plasticity and might thereby promote lobule VI as a key area prone to structural CCD and potentially involved in recovery and residual motor functioning.

Sex-dependent performance differences in curvilinear aiming arm movements in octogenarians

In an aging society, it is necessary to detect the cognitive decline of individuals at an early stage using simple measurement methods. This makes early health care possible for those affected. The aim of the study was to develop a classifier for cognitive state in older adults with and without mild cognitive impairment (MCI) based on kinematic parameters of linear and curvilinear aiming arm movements. In a group of 224 older adults over 80 years of age (cognitively healthy and MCI), the movement duration and intersegment intervals of linear and curvilinear arm movements of 20 cm were recorded. Movement duration was significantly longer in the curvilinear condition than in the straight movement, and MCI participants required significantly more time than cognitively healthy participants. Post-hoc analysis on the fluidity of movement in the curvilinear condition showed that MCI men had significantly longer inter-segmental intervals than non-MCI men. No difference was found in women. Based on the inter-segmental intervals, a simple classifier could be developed that correctly classified 63% of the men. In summary, aiming arm movements are only conditionally suitable as a classifier for cognitive states. For the construction of an ideal classifier, age-related degeneration of cortical and subcortical motor areas should be considered.

The assessment of executive functions to test the integrity of the nigrostriatal network: A pilot study

Background

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by motor and non-motor symptoms. The latter mainly include affective, sleep, and cognitive deficits. Non-demented PD patients often demonstrate impairments in several executive domains following neuropsychological evaluation. The current pilot study aims at assessing the discriminatory power of the Frontal Assessment Battery-15 (FAB15) in differentiating (i) non-demented PD patients and healthy controls and (ii) PD patients with more and less pronounced motor symptoms.

Methods

Thirty-nine non-demented early-stage PD patients in the “on” dopamine state (26 females, mean age = 64.51 years, SD = 6.47, mean disease duration = 5.49 years, SD = 2.28) and 39 healthy participants (24 females, mean age = 62.60 years, SD = 5.51) were included in the study. All participants completed the FAB15. Motor symptoms of PD patients were quantified via the Unified Parkinson’s Disease Rating Scale-Part III (UPDRS-Part III) and Hoehn and Yahr staging scale (H&Y).

Results

The FAB15 score, adjusted according to normative data for sex, age, and education, proved to be sufficiently able to discriminate PD patients from healthy controls (AUC = 0.69 [95% CI 0.60–0.75], SE = 0.06, p = 0.04, optimal cutoff = 11.29). Conversely, the battery lacked sufficient discriminative capability to differentiate PD patients based on the severity of motor symptoms.

Conclusion

The FAB15 may be a valid tool for distinguishing PD patients from healthy controls. However, it might be less sensitive in identifying clinical phenotypes characterized by visuospatial impairments resulting from posteroparietal and/or temporal dysfunctions. In line with previous evidence, the battery demonstrated to be not expendable in the clinical practice for monitoring the severity of PD-related motor symptoms.

Associations of baseline and longitudinal change in cerebellum volume with age-related changes in verbal learning and memory

The cerebellum is involved in higher-order cognitive functions, e.g., learning and memory, and is susceptible to age-related atrophy. Yet, the cerebellum's role in age-related cognitive decline remains largely unknown. We investigated cross-sectional and longitudinal associations between cerebellar volume and verbal learning and memory. Linear mixed effects models and partial correlations were used to examine the relationship between changes in cerebellum volumes (total cerebellum, cerebellum white matter [WM], cerebellum hemisphere gray matter [GM], and cerebellum vermis subregions) and changes in verbal learning and memory performance among 549 Baltimore Longitudinal Study of Aging participants (2,292 visits). All models were adjusted by baseline demographic characteristics (age, sex, race, education), and APOE e4 carrier status. In examining associations between change with change, we tested an additional model that included either hippocampal (HC), cuneus, or postcentral gyrus (PoCG) volumes to assess whether cerebellar volumes were uniquely associated with verbal learning and memory. Cross-sectionally, the association of baseline cerebellum GM and WM with baseline verbal learning and memory was age-dependent, with the oldest individuals showing the strongest association between volume and performance. Baseline volume was not significantly associated with change in learning and memory. However, analysis of associations between change in volumes and changes in verbal learning and memory showed that greater declines in verbal memory were associated with greater volume loss in cerebellum white matter, and preserved GM volume in cerebellum vermis lobules VI-VII. The association between decline in verbal memory and decline in cerebellar WM volume remained after adjustment for HC, cuneus, and PoCG volume. Our findings highlight that associations between cerebellum volume and verbal learning and memory are age-dependent and regionally specific.

The impact of aging on morphometric changes in the cerebellum: A voxel-based morphometry study

Introduction

Aging influences the morphology of the central nervous system. While several previous studies focused on morphometric changes of the supratentorial parts, investigations on age-related cerebellar changes are rare. The literature concerning the morphological changes in the cerebellum is heterogenous depending (i) on the methods used (cerebellar analysis in the context of a whole brain analysis or specific methods for a cerebellar analysis), (ii) the life span that was investigated, and (iii) the analytic approach (i.e., using linear or non-linear methods).

Methods

We fill this research gap by investigating age-dependent cerebellar changes in the aging process occurring before the age of 70 in healthy participants, using non-linear methods and the spatially unbiased infratentorial template (SUIT) toolbox which is specifically developed to examine the cerebellum. Furthermore, to derive an overview of the possible behavioral correlates, we relate our findings to functional maps of the cerebellum. Twenty-four older participants (mean age 64.42 years, SD ± 4.8) and 25 younger participants (mean age 24.6 years, SD ± 2.14) were scanned using a 3 T-MRI, and the resulting data were processed using a SUIT.

Results

Gray matter (GM) volume loss was found in older participants in three clusters in the right cerebellar region, namely crus I/II and lobule VI related to the frontoparietal network, with crus I being functionally related to the default-mode network and lobule VI extending into vermis VIIa related to the ventral-attention-network.

Discussion

Our results underline an age-related decline in GM volume in the right cerebellar regions that are functionally predominantly related to non-motor networks and cognitive tasks regions of the cerebellum before the age of 70.

A Comprehensive Analysis of Cerebellar Volumes in the 22q11.2 Deletion Syndrome

BACKGROUND

The presence of a 22q11.2 microdeletion (22q11.2 deletion syndrome [22q11DS]) ranks among the greatest known genetic risk factors for the development of psychotic disorders. There is emerging evidence that the cerebellum is important in the pathophysiology of psychosis. However, there is currently limited information on cerebellar neuroanatomy in 22q11DS specifically.

METHODS

High-resolution 3T magnetic resonance imaging was acquired in 79 individuals with 22q11DS and 70 typically developing control subjects (N = 149). Lobar and lobule-level cerebellar volumes were estimated using validated automated segmentation algorithms, and subsequently group differences were compared. Hierarchical clustering, principal component analysis, and graph theoretical models were used to explore intercerebellar relationships. Cerebrocerebellar structural connectivity with cortical thickness was examined via linear regression models.

RESULTS

Individuals with 22q11DS had, on average, 17.3% smaller total cerebellar volumes relative to typically developing subjects (p < .0001). The lobules of the superior posterior cerebellum (e.g., VII and VIII) were particularly affected in 22q11DS. However, all cerebellar lobules were significantly smaller, even after adjusting for total brain volumes (all cerebellar lobules p < .0002). The superior posterior lobule was disproportionately associated with cortical thickness in the frontal lobes and cingulate cortex, brain regions known be affected in 22q11DS. Exploratory analyses suggested that the superior posterior lobule, particularly Crus I, may be associated with psychotic symptoms in 22q11DS.

CONCLUSIONS

The cerebellum is a critical but understudied component of the 22q11DS neuroendophenotype.

Age-volume associations in cerebellar lobules by sex and reproductive stage

The cerebellum has established associations with motor function and a well-recognized role in cognition. In advanced age, cognitive and motor impairments contribute to reduced quality of life and are more common. Regional cerebellar volume is associated with performance across these domains and sex hormones may influence this volume. Examining sex differences in regional cerebellar volume in conjunction with age, and in the context of reproductive stage stands to improve our understanding of cerebellar aging and pathology. Data from 508 healthy adults (ages 18-88; 47% female) from the Cambridge Centre for Ageing and Neuroscience database were used here. CERES was used to assess lobular volume in T1-weighted images. We examined sex differences in adjusted regional cerebellar volume while controlling for age. A subgroup of participants (n = 370, 50% female) was used to assess group differences in female reproductive stages as compared to age-matched males. Sex differences in adjusted volume were seen across most anterior and posterior cerebellar lobules. Most of these lobules had significant linear relationships with age in males and females. While there were no interactions between sex and reproductive stage groups, exploratory analyses in females alone revealed multiple regional differences by reproductive stage. We found sex differences in volume across much of the cerebellum, linear associations with age, and did not find an interaction for sex and reproductive stage on regional cerebellar volume. Longitudinal investigation into hormonal influences on cerebellar structure and function is warranted as hormonal changes with menopause may impact cerebellar volume over time.

Specific brain gray matter volume changes in pediatric complete spinal cord injury without fracture or dislocation using voxel-based morphometry analysis: Preliminary Results

This study aims to investigate the brain gray matter volume (GMV) alterations of pediatric complete thoracolumbar spinal cord injury without fracture or dislocation (SCIWOFD) using voxel-based morphometry (VBM) analysis and assess the sensitive neuroimaging biomarkers which may be surrogate targets to enhance brain plasticity. A total of 52 pediatric subjects (age range, 6-12 years), including 25 pediatric SCIWOFD patients and 27 typically developing (TD) children were recruited. Independent two-sample t test was performed to assess between-group differences of brain GMV. Partial correlation analyses were performed to explore the correlations between GMV values and ISNCSCI scores, age at the time of injury, time after initial SCI. Receiver operating characteristic (ROC) analysis was performed to compute the sensitivity and specificity of the imaging biomarkers for pediatric SCIWOFD diagnosis. As the results, pediatric SCIWOFD patients showed significantly decreased GMV of bilateral Cerebellum lobule VIII, right middle occipital gyrus (MOG) and putamen (PUT), left pallidum (PAL) and thalamus (THA), and increased GMV of Vermis_III, right Cerebellum lobule VI and SupraMarginal gyrus (SMG). Additionally, GMV of left PAL and right PUT were negatively correlated with the pinprick/light touch sensory scores in pediatric SCIWOFD patients. Finally, when using the GMV values of left PAL and right PUT in combination as the predictor, area under the curve (AUC) reached the highest, of 0.93. These findings provided evidence that the brain undergoes GMV changes following pediatric SCIWOFD, which may suggest important targets for functional remodeling after SCI in children and provide valuable information for the development of novel and effective rehabilitation therapies in the future.

Structural cerebellar reserve positively influences outcome after severe stroke

The concept of brain reserve capacity positively influencing the process of recovery after stroke has been continuously developed in recent years. Global measures of brain health have been linked with a favourable outcome. Numerous studies have evidenced that the cerebellum is involved in recovery after stroke. However, it remains an open question whether characteristics of cerebellar anatomy, quantified directly after stroke, might have an impact on subsequent outcome after stroke. Thirty-nine first-ever ischaemic non-cerebellar stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Structural images were used for volumetric analyses of distinct cerebellar regions. Ordinal logistic regression analyses were conducted to associate cerebellar volumes with functional outcome 3-6 months after stroke, operationalized by the modified Rankin Scale. Larger volumes of cerebellar lobules IV, VI, and VIIIB were positively correlated with favourable outcome, independent of the severity of initial impairment, age, and lesion volume (P < 0.01). The total cerebellar volume did not exhibit a significant structure-outcome association. The present study reveals that pre-stroke anatomy of distinct cerebellar lobules involved in motor and cognitive functioning might be linked to outcome after acute non-cerebellar stroke, thereby promoting the emerging concepts of structural brain reserve for recovery processes after stroke.

The Differences in Structure and Function of the Cerebellum Between Cantonese-Mandarin Bilinguals and Mandarin Monolinguals: a Multi-model MRI Study

The effects of the long-term bilingual experience on structure and function of the cerebellum remain unclear. To explore whether there are differences in cerebellar gray matter structure between Cantonese-Mandarin bilinguals and Mandarin monolinguals and whether these different cerebellar structures have different resting-state functional connectivity (RSFC) with the cerebrum between the two groups, 30 Cantonese-Mandarin bilingual and 30 Mandarin monolingual college students were scanned by the T1-weighted magnetic resonance imaging (MRI) and resting-state functional MRI. Voxel-based morphology (VBM) analysis and RSFC analysis were used to analyze the cerebellar gray matter volume (GMV) and cerebellar-cerebro functional connectivity, respectively. Correlation analysis was performed between GMV/RSFC and the rapid automatized naming (RAN) and cognitive control. Compared to Mandarin monolinguals, Cantonese-Mandarin bilinguals showed larger GMV in bilateral cerebellar inferior posterior lobe (including bilateral VIIIa, VIIIb,IX, and right X, Vermis VIIIb, and Vermis IX) and a significant increase in RSFC coupling of the right inferior cerebellar posterior lobe with orbital part of left inferior frontal gyrus (IFG). In addition, there was a positive correlation between average response time (RT) of Mandarin alphanumeric RAN and RSFC between the right inferior posterior lobe of cerebellum and left IFG of all participants. The long-term Cantonese-Mandarin bilingual experience can increase the GMV of the bilateral cerebellar inferior posterior lobe and the RSFC between the right inferior cerebellar posterior lobe with orbital part of left inferior frontal gyrus (IFG).

Don't forget the little brain: A framework for incorporating the cerebellum into the understanding of cognitive aging

With the rapidly growing population of older adults, an improved understanding of brain and cognitive aging is critical, given the impacts on health, independence, and quality of life. To this point, we have a well-developed literature on the cortical contributions to cognition in advanced age. However, while this work has been foundational for our understanding of brain and behavior in older adults, subcortical contributions, particularly those from the cerebellum, have not been integrated into these models and frameworks. Incorporating the cerebellum into models of cognitive aging is an important step for moving the field forward. There has also been recent interest in this structure in Alzheimer's dementia, indicating that such work may be beneficial to our understanding of neurodegenerative disease. Here, I provide an updated overview of the cerebellum in advanced age and propose that it serves as a critical source of scaffolding or reserve for cortical function. Age-related impacts on cerebellar function further impact cortical processing, perhaps resulting in many of the activation patterns commonly seen in aging.

Differential Relationships Between Brain Structure and Dual Task Walking in Young and Older Adults

Almost 25% of all older adults experience difficulty walking. Mobility difficulties for older adults are more pronounced when they perform a simultaneous cognitive task while walking (i.e., dual task walking). Although it is known that aging results in widespread brain atrophy, few studies have integrated across more than one neuroimaging modality to comprehensively examine the structural neural correlates that may underlie dual task walking in older age. We collected spatiotemporal gait data during single and dual task walking for 37 young (18–34 years) and 23 older adults (66–86 years). We also collected T₁-weighted and diffusion-weighted MRI scans to determine how brain structure differs in older age and relates to dual task walking. We addressed two aims: (1) to characterize age differences in brain structure across a range of metrics including volumetric, surface, and white matter microstructure; and (2) to test for age group differences in the relationship between brain structure and the dual task cost (DTcost) of gait speed and variability. Key findings included widespread brain atrophy for the older adults, with the most pronounced age differences in brain regions related to sensorimotor processing. We also found multiple associations between regional brain atrophy and greater DTcost of gait speed and variability for the older adults. The older adults showed a relationship of both thinner temporal cortex and shallower sulcal depth in the frontal, sensorimotor, and parietal cortices with greater DTcost of gait. Additionally, the older adults showed a relationship of ventricular volume and superior longitudinal fasciculus free-water corrected axial and radial diffusivity with greater DTcost of gait. These relationships were not present for the young adults. Stepwise multiple regression found sulcal depth in the left precentral gyrus, axial diffusivity in the superior longitudinal fasciculus, and sex to best predict DTcost of gait speed, and cortical thickness in the superior temporal gyrus to best predict DTcost of gait variability for older adults. These results contribute to scientific understanding of how individual variations in brain structure are associated with mobility function in aging. This has implications for uncovering mechanisms of brain aging and for identifying target regions for mobility interventions for aging populations.

Finger Tapping as a Biomarker to Classify Cognitive Status in 80+-Year-Olds

This study examined the association between finger tapping and cognitive function in a group of 225 elderly participants (116 males; age 79–92 years; M = 82.5; SD = 2.4). Finger tapping was assessed in two conditions: self-selected pace and fast pace. Based on cognitive assessments, including the MoCA and CERA-NP test battery, participants were classified as cognitively healthy individuals (CHI), participants with mild cognitive impairments (MCI), and those with possible MCI (pMCI). Results of the analyses show significant differences between groups, sex and the group × sex interaction in four parameters for the self-selected pace condition and eight parameters for the fast pace condition. These parameters were used for classification by means of linear discriminant analysis (LDA). The first LDA component showed significant differences between CHI and pMCI and between CHI and MCI. Furthermore, the second LDA component showed significant differences between CHI and pMCI as well as between pMCI and MCI. Nevertheless, the algorithm correctly classified only 50% of participants, regardless of group, suggesting that tapping parameters are only partially useful for classification in early stages of dementia. We discuss these findings in terms of the diadochokinetic nature of finger tapping as associated with the age-related degeneration of cortical and subcortical motor areas.

Cerebellar Dentate Connectivity across Adulthood: A Large-Scale Resting State Functional Connectivity Investigation

Cerebellar contributions to behavior in advanced age are of interest and importance, given its role in motor and cognitive performance. There are differences and declines in cerebellar structure in advanced age and cerebellar resting state connectivity is lower. However, the work on this area to date has focused on the cerebellar cortex. The deep cerebellar nuclei provide the primary cerebellar inputs and outputs to the cortex, as well as the spinal and vestibular systems. Dentate networks can be dissociated such that the dorsal region is associated with the motor cortex, whereas the ventral aspect is associated with the prefrontal cortex. However, whether dentato-thalamo-cortical networks differ across adulthood remains unknown. Here, using a large adult sample (n = 590) from the Cambridge Center for Ageing and Neuroscience, we investigated dentate connectivity across adulthood. We replicated past work showing dissociable resting state networks in the dorsal and ventral aspects of the dentate. In both seeds, we demonstrated that connectivity is lower with advanced age, indicating that connectivity differences extend beyond the cerebellar cortex. Finally, we demonstrated sex differences in dentate connectivity. This expands our understanding of cerebellar circuitry in advanced age and underscores the potential importance of this structure in age-related performance differences.

Increased volumes of lobule VI in a valproic acid model of autism are associated with worse set-shifting performance in male Long-Evan rats

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a skewed sex-based diagnostic ratio. While males are at a higher risk for ASD, it is critical to understand the neurobiology of the disorder to develop better treatments for both males and females. Our prior work has demonstrated that VPA (valproic acid) treated offspring had impaired performance on an attentional set-shifting task. The current study used MRI and regions of interest analyses to measure the volumes of cerebellar subregions in VPA and controls rats that had participated in the attentional set-shifting task. VPA males had significantly more volume in lobule VI compared to male controls. VPA female rats had significantly less volume in lobules I, IV and X compared to female controls. In addition, it was revealed that decreases in volume for VPA females was associated with worse performance. Males with increases in lobule VI were also impaired on the set-shifting task. Similar volumetric differences within the cerebellum have been observed in humans with ASD, which suggests that the VPA model is capturing some of the same brain changes observed in humans with ASD, and that these changes in volume may be impacting cognition.

Dependence and reduced motor function in heart failure: future directions for well-being

While patients with heart failure experience a wide range of symptoms, evidence is mounting that patients with heart failure suffer from reduced functional independence. Given that the number of patients with heart failure is rising and considering the adverse outcomes of reduced functional independence, understanding the underlying mechanisms of reduced functionality in patients with heart failure is of increasing importance. Yet, little information exists on how heart failure negatively affects functional independence, including motor function. This article summarizes reports of reduced independence and highlights its significant adverse outcomes in the patients with heart failure. Finally, this article discusses potential causes of reduced independence based on existing reports of impaired central and peripheral nervous systems in the patients with heart failure. Overall, the article provides a solid foundation for future studies investigating motor impairments in patients with heart failure. Such studies may lead to advances in treatment and prevention of reduced independence associated with heart failure, which ultimately contribute to the well-being of patients with heart failure.

Neuroanatomical norms in the UK Biobank: The impact of allometric scaling, sex, and age

Few neuroimaging studies are sufficiently large to adequately describe population‐wide variations. This study's primary aim was to generate neuroanatomical norms and individual markers that consider age, sex, and brain size, from 629 cerebral measures in the UK Biobank (N = 40,028). The secondary aim was to examine the effects and interactions of sex, age, and brain allometry—the nonlinear scaling relationship between a region and brain size (e.g., total brain volume)—across cerebral measures. Allometry was a common property of brain volumes, thicknesses, and surface areas (83%) and was largely stable across age and sex. Sex differences occurred in 67% of cerebral measures (median |β| = .13): 37% of regions were larger in males and 30% in females. Brain measures (49%) generally decreased with age, although aging effects varied across regions and sexes. While models with an allometric or linear covariate adjustment for brain size yielded similar significant effects, omitting brain allometry influenced reported sex differences in variance. Finally, we contribute to the reproducibility of research on sex differences in the brain by replicating previous studies examining cerebral sex differences. This large‐scale study advances our understanding of age, sex, and brain allometry's impact on brain structure and provides data for future UK Biobank studies to identify the cerebral regions that covary with specific phenotypes, independently of sex, age, and brain size.

Time spent on the smartphone does not relate to manual dexterity in young adults

Background

The Grooved Pegboard Test (GPT) is widely adopted to evaluate manual dexterity, it presents normative data but the test is influenced by different factors. The influence of time spent on smartphones has not been considered before, for this reason, the objective of this study was to evaluate if smartphone use influences the time to complete the GPT. A total of 38 (21 women; 17 men) young adults 20.7 (1.5) years participated in the study. The time spent on the smartphones during the last seven days was recorded through the device itself and the GPT performance was measured. A correlation analysis between the time spent on the smartphone and GPT was performed while the t-test was adopted to evaluate gender differences.

Results

No statistically significant differences were detected between men and women in the time to complete the GPT (p = 0.20) and in the time spent on the smartphone (p = 0.87). The GPT and the time spent using the smartphone were not correlated (r = 0.044, p = 0.78).

Conclusion

The time spent on the smartphone by young adults does not influence the time to complete the GPT, indicating that smartphone use does not influence measures of manual dexterity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-021-00639-y.

Differential vulnerability of the cerebellum in healthy ageing and Alzheimer's disease

Recent findings challenge the prior notion that the cerebellum remains unaffected by Alzheimer's disease (AD). Yet, it is unclear whether AD exacerbates age-related cerebellar grey matter decline or engages distinct structural and functional territories. We performed a meta-analysis of cerebellar grey matter loss in normal ageing and AD. We mapped voxels with structural decline onto established brain networks, functional parcellations, and along gradients that govern the functional organisation of the cerebellum. Importantly, these gradients track continuous changes in cerebellar specialisation providing a more nuanced measure of the functional profile of regions vulnerable to ageing and AD. Gradient 1 progresses from motor to cognitive territories; Gradient 2 isolates attentional processing; Gradient 3 captures lateralisation differences in cognitive functions. We identified bilateral and right-lateralised posterior cerebellar atrophy in ageing and AD, respectively. Age- and AD-related structural decline only showed partial spatial overlap in right lobule VI/Crus I. Despite the seemingly distinct patterns of AD- and age-related atrophy, the functional profiles of these regions were similar. Both participate in the same macroscale networks (default mode, frontoparietal, attention), support executive functions and language processing, and did not exhibit a difference in relative positions along Gradients 1 or 2. However, Gradient 3 values were significantly different in ageing vs. AD, suggesting that the roles of left and right atrophied cerebellar regions exhibit subtle functional differences despite their membership in similar macroscale networks. These findings provide an unprecedented characterisation of structural and functional differences and similarities in cerebellar grey matter loss between normal ageing and AD.

Shaky scaffolding: Age differences in cerebellar activation revealed through activation likelihood estimation meta-analysis

Cognitive neuroscience research has provided foundational insights into aging, but has focused primarily on the cerebral cortex. However, the cerebellum is subject to the effects of aging. Given the importance of this structure in the performance of motor and cognitive tasks, cerebellar differences stand to provide critical insights into age differences in behavior. However, our understanding of cerebellar functional activation in aging is limited. Thus, we completed a meta‐analysis of neuroimaging studies across task domains. Unlike in the cortex where an increase in bilateral activation is seen during cognitive task performance with advanced age, there is less overlap in cerebellar activation across tasks in older adults (OAs) relative to young. Conversely, we see an increase in activation overlap in OAs during motor tasks. We propose that this is due to inputs for comparator processing in the context of control theory (cortical and spinal) that may be differentially impacted in aging. These findings advance our understanding of the aging mind and brain.

Longitudinal analysis of regional cerebellum volumes during normal aging

Some cross-sectional studies suggest reduced cerebellar volumes with aging, but there have been few longitudinal studies of age changes in cerebellar subregions in cognitively healthy older adults. In this work, 2,023 magnetic resonance (MR) images of 822 cognitively normal participants from the Baltimore Longitudinal Study of Aging (BLSA) were analyzed. Participants ranged in age from 50 to 95 years (mean 70.7 years) at the baseline assessment. Follow-up intervals were 1-9 years (mean 3.7 years) for participants with two or more visits. We used a recently developed cerebellum parcellation algorithm based on convolutional neural networks to divide the cerebellum into 28 subregions. Linear mixed effects models were applied to the volume of each cerebellar subregion to investigate cross-sectional and longitudinal age effects, as well as effects of sex and their interactions, after adjusting for intracranial volume. Our findings suggest spatially varying atrophy patterns across the cerebellum with respect to age and sex both cross-sectionally and longitudinally.

Automatic cerebellum anatomical parcellation using U-Net with locally constrained optimization

The cerebellum plays a central role in sensory input, voluntary motor action, and many neuropsychological functions and is involved in many brain diseases and neurological disorders. Cerebellar parcellation from magnetic resonance images provides a way to study regional cerebellar atrophy and also provides an anatomical map for functional imaging. In a recent comparison, a multi-atlas approach proved to be superior to other parcellation methods including some based on convolutional neural networks (CNNs) which have a considerable speed advantage. In this work, we developed an alternative CNN design for cerebellar parcellation, yielding a method that achieves the leading performance to date. The proposed method was evaluated on multiple data sets to show its broad applicability, and a Singularity container has been made publicly available.

Cerebellar Contribution to Motor and Non-motor Functions in Parkinson's Disease: A Meta-Analysis of fMRI Findings

Background: Parkinson's disease (PD) results in both motor and non-motor symptoms. Traditionally, the underlying mechanism of PD has been linked to neurodegeneration of the basal ganglia. Yet it does not adequately account for the non-motor symptoms of the disease, suggesting that other brain regions may be involved. One such region is the cerebellum, which is known to be involved, together with the basal ganglia, in both motor and non-motor functions. Many studies have found the cerebellum to be hyperactive in PD patients, a finding that is seldom discussed in detail, and warrants further examination. The current study thus aims to examine quantitively the current literature on the cerebellar involvement in both motor and non-motor functioning in PD. Methods: A meta-analysis of functional neuroimaging literature was conducted with Seed-based D mapping. Only the studies testing functional activation in response to motor and non-motor paradigms in PD and healthy controls (HC) were included in the meta-analysis. Separate analyses were conducted by including only studies with non-motor paradigms, as well as meta-regressions with UPDRS III scores and disease duration. Results: A total of 57 studies with both motor and non-motor paradigms fulfilled our inclusion criteria and were included in the meta-analysis, which revealed hyperactivity in Crus I-II and vermal III in PD patients compared to HC. An analysis including only studies with cognitive paradigms revealed a cluster of increased activity in PD patients encompassing lobule VIIB and VIII. Another meta-analysis including the only 20 studies that employed motor paradigms did not reveal any significant group differences. However, a descriptive analysis of these studies revealed that 60% of them reported cerebellar hyperactivations in PD and included motor paradigm with significant cognitive task demands, as opposed to 40% presenting the opposite pattern and using mainly force grip tasks. The meta-regression with UPDRS III scores found a negative association between motor scores and activation in lobule VI and vermal VII-VIII. No correlation was found with disease duration. Discussion: The present findings suggest that one of the main cerebellar implications in PD is linked to cognitive functioning. The negative association between UPDRS scores and activation in regions implicated in motor functioning indicate that there is less involvement of these areas as the disease severity increases. In contrast, the lack of correlation with disease duration seems to indicate that the cerebellar activity may be a compensatory mechanism to the dysfunctional basal ganglia, where certain sub-regions of the cerebellum are employed to cope with motor demands. Yet future longitudinal studies are needed to fully address this possibility.

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the "cerebellar cognitive affective syndrome" ("CCAS") or "Schmahmann syndrome." Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion-affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

Single session high definition transcranial direct current stimulation to the cerebellum does not impact higher cognitive function

The prefrontal cortex is central to higher order cognitive function. However, the cerebellum, generally thought to be involved in motor control and learning, has also been implicated in higher order cognition. Recent work using transcranial direct current stimulation (tDCS) provides some support for right cerebellar involvement in higher order cognition, though the results are mixed, and often contradictory. Here, we used cathodal high definition tDCS (HD-tDCS) over the right cerebellum to assess the impact of HD-tDCS on modulating cognitive performance. We predicted that stimulation would result in performance decreases, which would suggest that optimal cerebellar function is necessary for cognitive performance, much like the prefrontal cortex. That is, it is not simply a structure that lends support to complete difficult tasks. While the expected cognitive behavioral effects were present, we did not find effects of stimulation. This has broad implications for cerebellar tDCS research, particularly for those who are interested in using HD-tDCS as a way of examining cerebellar function. Further implications, limitations, and future directions are discussed with particular emphasis on why null findings might be critical in developing a clear picture of the effects of tDCS on the cerebellum.

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the "cerebellar cognitive affective syndrome" ("CCAS") or "Schmahmann syndrome." Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion-affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

Cerebellar Lobules Optimal Stimulation (CLOS): A Computational Pipeline to Optimize Cerebellar Lobule-Specific Electric Field Distribution

Objective

Cerebellar transcranial direct current stimulation (ctDCS) is challenging due to the complexity of the cerebellar structure which is reflected by the well-known variability in ctDCS effects. Therefore, our objective is to present a freely available computational modeling pipeline for cerebellar lobules’ optimal stimulation (CLOS).

Methods

CLOS can optimize lobule-specific electric field distribution following finite element analysis (FEA) using freely available computational modeling pipelines. We modeled published ctDCS montages with 5 cm × 5 cm anode placed 3 cm lateral to inion, and the same sized cathode was placed on the: (1) contralateral supra-orbital area (called Manto montage), and (2) buccinators muscle (called Celnik montage). Also, a published (3) 4×1 HD-ctDCS electrode montage was modeled. We also investigated the effects of the subject-specific head model versus Colin 27 average head model on lobule-specific electric field distribution. Three-way analysis of variance (ANOVA) was used to determine the effects of lobules, montage, and head model on the electric field distribution. The differences in lobule-specific electric field distribution across different freely available computational pipelines were also evaluated using subject-specific head model. We also presented an application of our computational pipeline to optimize a ctDCS electrode montage to deliver peak electric field at the cerebellar lobules VII-IX related to ankle function.

Results

Eta-squared effect size after three-way ANOVA for electric field strength was 0.05 for lobule, 0.00 for montage, 0.04 for the head model, 0.01 for lobule^∗montage interaction, 0.01 for lobule^∗ head model interaction, and 0.00 for montage^∗head model interaction. The electric field strength of both the Celnik and the Manto montages affected the lobules Crus I/II, VIIb, VIII, and IX of the targeted cerebellar hemisphere where Manto montage had a spillover to the contralateral cerebellar hemisphere. The 4×1 HD-ctDCS montage primarily affected the lobules Crus I/II of the targeted cerebellar hemisphere. All three published ctDCS montages were found to be not optimal for ankle function (lobules VII-IX), so we presented a novel HD-ctDCS electrode montage.

Discussion

Our freely available CLOS pipeline can be leveraged to optimize electromagnetic stimulation to target cerebellar lobules related to different cognitive and motor functions.

Visuospatial imagery in healthy individuals with different hypnotizability levels

Hypnotizability is a psychophysiological trait associated with morpho-functional brain differences. Since also cerebellar peculiarities have been reported in individuals with different hypnotizability levels and the cerebellar function is relevant to spatial imagery, the present study was aimed at investigating possible hypnotizability-related differences in the ability of spatial imagery. Highly (highs, N = 31), low (lows, N = 17) and medium (mediums, N = 16) hypnotizable participants (classified by Stanford Hypnotic Susceptibility Scale, form A) of both genders were submitted to a test of mental rotation, which requires the integrity of both executive and cerebellar structures. In order to disentangle the role of the cerebellum from that of executive circuits as much as possible, visuospatial and verbal working memory tests, which mainly reflect executive processes, were also performed. Healthy highs exhibited higher scores of mental rotation ability compared to mediums in the absence of significant differences in visual-spatial and verbal working memory. Lows reported intermediate scores not significantly different from both highs' and mediums'. Different cognitive strategies were observed in the three groups as the correlations between mental rotation, visuospatial and verbal working memory were different in highs, mediums and lows. In conclusion, present findings represent the first report of hypnotizability-related differences in a mental rotation task, which is relevant to several cognitive functions.

Exercise effects on bed rest-induced brain changes

PURPOSE

Spaceflight negatively affects sensorimotor behavior; exercise mitigates some of these effects. Head down tilt bed rest (HDBR) induces body unloading and fluid shifts, and is often used to investigate spaceflight effects. Here, we examined whether exercise mitigates effects of 70 days HDBR on the brain and if fitness and brain changes with HDBR are related.

METHODS

HDBR subjects were randomized to no-exercise (n = 5) or traditional aerobic and resistance exercise (n = 5). Additionally, a flywheel exercise group was included (n = 8). Exercise protocols for exercise groups were similar in intensity, therefore these groups were pooled in statistical analyses. Pre and post-HDBR MRI (structure and structural/functional connectivity) and physical fitness measures (lower body strength, muscle cross sectional area, VO2 max, body composition) were collected. Voxel-wise permutation analyses were used to test group differences in brain changes, and their associations with fitness changes.

RESULTS

Comparisons of exercisers to controls revealed that exercise led to smaller fitness deterioration with HDBR but did not affect brain volume or connectivity. Group comparisons showed that exercise modulated post-HDBR recovery of brain connectivity in somatosensory regions. Posthoc analysis showed that this was related to functional connectivity decrease with HDBR in non-exercisers but not in exercisers. Correlational analyses between fitness and brain changes showed that fitness decreases were associated with functional connectivity and volumetric increases (all r >.74), potentially reflecting compensation. Modest brain changes or even decreases in connectivity and volume were observed in subjects who maintained or showed small fitness gains. These results did not survive Bonferroni correction, but can be considered meaningful because of the large effect sizes.

CONCLUSION

Exercise performed during HDBR mitigates declines in fitness and strength. Associations between fitness and brain connectivity and volume changes, although unadjusted for multiple comparisons in this small sample, suggest that supine exercise reduces compensatory HDBR-induced brain changes.

Cerebellar atrophy in different subtypes of Parkinson's disease

BACKGROUND

To investigate, using Magnetic Resonance Imaging (MRI) and voxel-based morphometry (VBM), morphometric changes of cerebellum in Parkinson's disease with different motor and affective subtypes.

METHODS

Fifty-four patients with idiopathic Parkinson's disease (PD) were classified into tremor-predominant-PD (PDT) (n = 37) and akinetic/rigidity-predominant-PD (PDAR) (n = 17). Moreover, PD groups were divided into four affective subtypes, including depressive but not anxious PD (dPD, n = 5), anxious but not depressive PD (aPD, n = 8), comorbid depressive and anxious PD (coPD, n = 8), and PD patients without depressive or anxious symptoms (nPD, n = 33). They were additionally compared at a group level with thirty-nine normal controls (NCs). An analysis of covariance followed by post hoc tests was performed to examine the alterations of cerebellar grey matter volume (GMV) in different groups of PD.

RESULTS

Compared with NCs, PD showed grey matter (GM) atrophy in the right Crus II, pyramis, culmen, the right lobules IV, and V, and the left lobule VI. PDT, PDAR and NCs did not differ in the volume of the cerebellum. Relative to nPD group, dPD group exhibited GMV reduction in the left Crus I, while aPD group showed GMV reduction in the tonsil and the right lobule VIII. The GM atrophy was also found in the coPD group compared to NCs, including the tonsil, the left lobule VIII, the right lobule VI, the left Crus I, and vermis IV, and V. There was a significant negative correlation between the Hamilton Rating Scale for Depression (HAMD) score and the right lobule IX volume, and a significant negative correlation between the Hamilton Rating Scale for Anxiety (HAMA) score and the right lobule VIII volume.

CONCLUSIONS

These findings suggest that cerebellar changes are involved in PD. It also supports a possible role of the cerebellum in the depressive and anxious symptoms in PD.

Functional topography of the human cerebellum

Accumulating evidence points to a critical role for the human cerebellum in both motor and nonmotor behaviors. A core tenet of this new understanding of cerebellar function is the existence of functional subregions within the cerebellum that differentially support motor, cognitive, and affective behaviors. This cerebellar functional topography - based on converging evidence from neuroanatomic, neuroimaging, and clinical studies - is evident in both adult and pediatric populations. The sensorimotor homunculi in the anterior lobe and lobule VIII established in early tract tracing and electrophysiologic studies are evident in both task-based and resting-state human functional imaging studies. In patients, damage to the anterior cerebellum, extending into medial lobule VI, is associated with the cerebellar motor syndrome. The cerebellar posterior lobe, including vermal and hemispheric regions of lobules VI and VII, is reciprocally interconnected with cerebral association and paralimbic cortices. Resting-state and task-based neuroimaging studies show functional activation patterns in these regions during higher-level cognitive tasks, and lesions of the posterior cerebellum lead to the cerebellar cognitive affective/Schmahmann syndrome with its characteristic intellectual and emotional impairments. The existence of cerebellar connectional and functional topography provides the critical anatomic substrate for a cerebellar role in both motor and nonmotor functions. It also establishes a framework for interpreting cerebellar activation patterns, cognitive and behavioral outcomes following cerebellar damage, and the cerebellar structural and functional differences reported in a range of neurodevelopmental and neuropsychiatric disorders.

Clinical Phenotype of Depression Affects Interleukin-6 Synthesis

Major depressive disorder (MDD) is not a single disease, but a number of various ailments that form one entity. Psychomotor retardation, anhedonia, sleep disorders, an increased suicide risk, and anxiety are the main symptoms that often define the clinical diagnosis of depression. Interleukin-6 (IL-6), as one of the proinflammatory cytokines, seems to be overexpressed during certain mental disorders, including MDD. Overexpression of IL-6 in depression is thought to be a factor associated with bad prognosis and worse disease course. IL-6 may directly affect brain functioning and production of neurotransmitters; moreover, its concentration is correlated with certain clinical symptoms within the wide range of depressive symptomatology. Furthermore, there is a strong correlation between IL-6 synthesis and psychosomatic functioning of the patient. This article discusses potential sources and significance of IL-6 in the pathogenesis of depression.