Handedness and White Matter Networks

2020 ◽  
pp. 107385842093765
Author(s):  
Sanja Budisavljevic ◽  
Umberto Castiello ◽  
Chiara Begliomini

The development and persistence of laterality is a key feature of human motor behavior, with the asymmetry of hand use being the most prominent. The idea that asymmetrical functions of the hands reflect asymmetries in terms of structural and functional brain organization has been tested many times. However, despite advances in laterality research and increased understanding of this population-level bias, the neural basis of handedness remains elusive. Recent developments in diffusion magnetic resonance imaging enabled the exploration of lateralized motor behavior also in terms of white matter and connectional neuroanatomy. Despite incomplete and partly inconsistent evidence, structural connectivity of both intrahemispheric and interhemispheric white matter seems to differ between left and right-handers. Handedness was related to asymmetry of intrahemispheric pathways important for visuomotor and visuospatial processing (superior longitudinal fasciculus), but not to projection tracts supporting motor execution (corticospinal tract). Moreover, the interindividual variability of the main commissural pathway corpus callosum seems to be associated with handedness. The review highlights the importance of exploring new avenues for the study of handedness and presents the latest state of knowledge that can be used to guide future neuroscientific and genetic research.

2014 ◽  
Vol 21 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Matteo Pardini ◽  
Laura Bonzano ◽  
Maurizio Bergamino ◽  
Giulia Bommarito ◽  
Paola Feraco ◽  
...  

Objective: To evaluate the neural basis of subjective fatigue in subjects with multiple sclerosis (MS) using a connectionist framework. Methods: Seventy seven subjects with relapsing–remitting MS were recruited in the study and underwent subjective fatigue evaluations and a diffusion MRI scan. Firstly, local white matter Fractional Anisotropy values were correlated with subjective fatigue scores using a voxel-wise approach. The long-range loss of connectivity due to structural damage in the white matter voxels thus associated with subjective fatigue was then assessed using the Network Modification (NeMo) package. Results: A voxel-wise regression analysis with fatigue scores revealed a significant association between structural damage and fatigue levels in two discrete white matter clusters, both included in the left cingulate bundle. The connectivity analysis revealed that damage in these clusters was associated with loss of structural connectivity in the anterior and medial cingulate cortices, dorsolateral prefrontal areas and in the left caudate. Discussion: Our data point to the cingulum bundle and its projections as the key network involved in subjective fatigue perception in MS. More generally, these results suggest the potential of the connectionist framework to generate coherent models of the neural basis of complex symptomatology in MS.


e-Neuroforum ◽  
2016 ◽  
Vol 22 (2) ◽  
Author(s):  
N. Axmacher

AbstractDespite abundant knowledge on the neural basis of memory functions in the human brain, stimulus-specific memory traces- engrams-have long remained elusive. In this article, recent developments that start to shed light on the mechanisms underlying the formation, modification and potential degradation of engrams are reviewed. Stimulus-specific memory representations appear to occur at different levels of brain organization, from spike rates of individual cells via time-frequency signatures of small-scale neural networks to distributed activity patterns. However, memories undergo transformation whenever they are recalled. Thus, novel methodological approaches need to be employed in order to identify considerably modified engrams. Furthermore, engrams are impaired in a number of diseases involving memory dysfunction. This article is concluded with a description of recent translational work on altered content-specific memory representations in the context of Alzheimer’s disease.


2019 ◽  
Author(s):  
Henrietta Howells ◽  
Guglielmo Puglisi ◽  
Antonella Leonetti ◽  
Luca Vigano ◽  
Luca Fornia ◽  
...  

AbstractStrong right-hand preference on the population level is a uniquely human feature, although the neural basis for this is still not clearly defined. Recent behavioural and neuroimaging literature suggests that hand preference may be related to the orchestrated function and size of fronto-parietal white matter tracts bilaterally. Lesions to these tracts induced during tumour resection may provide an opportunity to test this hypothesis. In the present study, a cohort of seventeen neurosurgical patients with left hemisphere brain tumours were recruited to investigate whether resection of certain white matter tracts affects the choice of hand selected for the execution of a goal-directed task (assembly of jigsaw puzzles). Patients performed the puzzles, but also tests for basic motor ability, selective attention and visuo-constructional ability, preoperatively and one month after surgery. Diffusion tractography of fronto-parietal tracts (the superior longitudinal fasciculus) and the corticospinal tract were performed, to evaluate whether resection of tracts was significantly associated with changes in hand selection. A complementary atlas-based disconnectome analysis was also conducted. Results showed a shift in hand selection despite the absence of any motor or cognitive deficits, which was significantly associated with patients with frontal and parietal resections, compared with those with resections in other lobes. In particular, this effect was significantly associated with the resection of dorsal fronto-parietal white matter connections, but not with the ventral fronto-parietal tract. Dorsal white matter pathways contribute bilaterally, with specific lateralised competencies, to control of goal-directed hand movements. We show that unilateral lesions, by unbalancing the cooperation of the two hemispheres, can alter the choice of hand selected to accomplish movements.


2019 ◽  
Vol 1 (8) ◽  
pp. 42-50
Author(s):  
A. V. Budkevich ◽  
L. B. Ivanov ◽  
G. R. Novikova ◽  
G. M. Dzhanumova

According to the authors, rationing the age-related EEG parameters in children should be based on personal psychical characteristics. A comparative analysis of personal psychical characteristics and electroencephalographic data was carried out in 300 apparently healthy children aged 3-15 years. According to this principle, two subgroups of conditionally healthy children in each age group were singled out: 1) with an immature attention function and 2) with an increased anxious background that do not reach the pathological level. Registration and analysis of EEG was performed by the Neurokariograf computer complex (MBN, Moscow) using mathematical processing methods.The EEG interpretation was based on the principle of assessing the functional state of a child's brain using a three-component model according to: 1) wakefulness level and its dissociation, 2) severity of signs of the EEG neurotic pattern, 3) directionality of formation of traits of the system-functional brain organization (severity of signs functional hypofrontality).lt was found the presence of EEG signs was indicative of a lower level of wakefulness in children with an immature function of attention in all age groups, compared with the indicators of the average population of group and children with an increased background of anxiety. Children with an increased background of anxiety have a tendency to prevalence and excessive spatial synchronization of the alpha rhythm. ln healthy children, the fact of a decrease in wakefulness and the presence of signs of anxiety in the clinic and in EEG patterns indicates individual personalities and should not be considered as pathology.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Arian Ashourvan ◽  
Preya Shah ◽  
Adam Pines ◽  
Shi Gu ◽  
Christopher W. Lynn ◽  
...  

AbstractA major challenge in neuroscience is determining a quantitative relationship between the brain’s white matter structural connectivity and emergent activity. We seek to uncover the intrinsic relationship among brain regions fundamental to their functional activity by constructing a pairwise maximum entropy model (MEM) of the inter-ictal activation patterns of five patients with medically refractory epilepsy over an average of ~14 hours of band-passed intracranial EEG (iEEG) recordings per patient. We find that the pairwise MEM accurately predicts iEEG electrodes’ activation patterns’ probability and their pairwise correlations. We demonstrate that the estimated pairwise MEM’s interaction weights predict structural connectivity and its strength over several frequencies significantly beyond what is expected based solely on sampled regions’ distance in most patients. Together, the pairwise MEM offers a framework for explaining iEEG functional connectivity and provides insight into how the brain’s structural connectome gives rise to large-scale activation patterns by promoting co-activation between connected structures.


Author(s):  
Matthew Browne ◽  
Vijay Rawat ◽  
Catherine Tulloch ◽  
Cailem Murray-Boyle ◽  
Matthew Rockloff

Jurisdictions around the world have a self-declared mandate to reduce gambling-related harm. However, historically, this concept has suffered from poor conceptualisation and operationalisation. However, recent years have seen swift advances in measuring gambling harm, based on the principle of it being a quantifiable decrement to the health and wellbeing of the gambler and those connected to them. This review takes stock of the background and recent developments in harm assessment and summarises recent research that has validated and applied the Short Gambling Harms Screen and related instruments. We recommend that future work builds upon the considerable psychometric evidence accumulated for the feasibility of direct elicitation of harmful consequences. We also advocate for grounding harms measures with respect to scalar changes to public health utility metrics. Such an approach will avoid misleading pseudo-clinical categorisations, provide accurate population-level summaries of where the burden of harm is carried, and serve to integrate gambling research with the broader field of public health.


Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Edith Brignoni-Pérez ◽  
Maya Chan Morales ◽  
Virginia A. Marchman ◽  
Melissa Scala ◽  
Heidi M. Feldman ◽  
...  

Abstract Background Infants born very preterm (< 32 weeks gestational age (GA)) are at risk for developmental language delays. Poor language outcomes in children born preterm have been linked to neurobiological factors, including impaired development of the brain’s structural connectivity (white matter), and environmental factors, including decreased exposure to maternal speech in the neonatal intensive care unit (NICU). Interventions that enhance preterm infants’ exposure to maternal speech show promise as potential strategies for improving short-term health outcomes. Intervention studies have yet to establish whether increased exposure to maternal speech in the NICU offers benefits beyond the newborn period for brain and language outcomes. Methods This randomized controlled trial assesses the long-term effects of increased maternal speech exposure on structural connectivity at 12 months of age (age adjusted for prematurity (AA)) and language outcomes between 12 and 18 months of age AA. Study participants (N = 42) will include infants born very preterm (24–31 weeks 6/7 days GA). Newborns are randomly assigned to the treatment (n = 21) or standard medical care (n = 21) group. Treatment consists of increased maternal speech exposure, accomplished by playing audio recordings of each baby’s own mother reading a children’s book via an iPod placed in their crib/incubator. Infants in the control group have the identical iPod setup but are not played recordings. The primary outcome will be measures of expressive and receptive language skills, obtained from a parent questionnaire collected at 12–18 months AA. The secondary outcome will be measures of white matter development, including the mean diffusivity and fractional anisotropy derived from diffusion magnetic resonance imaging scans performed at around 36 weeks postmenstrual age during the infants’ routine brain imaging session before hospital discharge and 12 months AA. Discussion The proposed study is expected to establish the potential impact of increased maternal speech exposure on long-term language outcomes and white matter development in infants born very preterm. If successful, the findings of this study may help to guide NICU clinical practice for promoting language and brain development. This clinical trial has the potential to advance theoretical understanding of how early language exposure directly changes brain structure for later language learning. Trial registration NIH Clinical Trials (ClinicalTrials.gov) NCT04193579. Retrospectively registered on 10 December 2019.


2021 ◽  
Vol 11 (5) ◽  
pp. 632
Author(s):  
Valentina Pacella ◽  
Giuseppe Kenneth Ricciardi ◽  
Silvia Bonadiman ◽  
Elisabetta Verzini ◽  
Federica Faraoni ◽  
...  

The anarchic hand syndrome refers to an inability to control the movements of one’s own hand, which acts as if it has a will of its own. The symptoms may differ depending on whether the brain lesion is anterior, posterior, callosal or subcortical, but the relative classifications are not conclusive. This study investigates the role of white matter disconnections in a patient whose symptoms are inconsistent with the mapping of the lesion site. A repeated neuropsychological investigation was associated with a review of the literature on the topic to identify the frequency of various different symptoms relating to this syndrome. Furthermore, an analysis of the neuroimaging regarding structural connectivity allowed us to investigate the grey matter lesions and white matter disconnections. The results indicated that some of the patient’s symptoms were associated with structures that, although not directly damaged, were dysfunctional due to a disconnection in their networks. This suggests that the anarchic hand may be considered as a disconnection syndrome involving the integration of multiple antero-posterior, insular and interhemispheric networks. In order to comprehend this rare syndrome better, the clinical and neuroimaging data need to be integrated with the clinical reports available in the literature on this topic.


Author(s):  
Eberhard Passarge

AbstractGenetics evolved as a field of science after 1900 with new theories being derived from experiments obtained in fruit flies, bacteria, and viruses. This personal account suggests that the origins of human genetics can best be traced to the years 1949 to 1959. Several genetic scientific advances in genetics in 1949 yielded results directly relating to humans for the first time, except for a few earlier observations. In 1949 the first textbook of human genetics was published, the American Journal of Human Genetics was founded, and in the previous year the American Society of Human Genetics. In 1940 in Britain a textbook entitled Introduction to Medical Genetics served as a foundation for introducing genetic aspects into medicine. The introduction of new methods for analyzing chromosomes and new biochemical assays using cultured cells in 1959 and subsequent years revealed that many human diseases, including cancer, have genetic causes. It became possible to arrive at a precise cause-related genetic diagnosis. As a result the risk of occurrence or re-occurrence of a disease within a family could be assessed correctly. Genetic counseling as a new concept became a basis for improved patient care. Taken together the advances in medically orientated genetic research and patient care since 1949 have resulted in human genetics being both, a basic medical and a basic biological science. Prior to 1949 genetics was not generally viewed in a medical context. Although monogenic human diseases were recognized in 1902, their occurrence and distribution were considered mainly at the population level.


2019 ◽  
Vol 12 ◽  
pp. 175628641984344 ◽  
Author(s):  
Martin Gorges ◽  
Hans-Peter Müller ◽  
Inga Liepelt-Scarfone ◽  
Alexander Storch ◽  
Richard Dodel ◽  
...  

Background: The nonmotor symptom spectrum of Parkinson’s disease (PD) includes progressive cognitive decline mainly in late stages of the disease. The aim of this study was to map the patterns of altered structural connectivity of patients with PD with different cognitive profiles ranging from cognitively unimpaired to PD-associated dementia. Methods: Diffusion tensor imaging and neuropsychological data from the observational multicentre LANDSCAPE study were analyzed. A total of 134 patients with PD with normal cognitive function (56 PD-N), mild cognitive impairment (67 PD-MCI), and dementia (11 PD-D) as well as 72 healthy controls were subjected to whole-brain-based fractional anisotropy mapping and covariance analysis with cognitive performance measures. Results: Structural data indicated subtle changes in the corpus callosum and thalamic radiation in PD-N, whereas severe white matter impairment was observed in both PD-MCI and PD-D patients including anterior and inferior fronto-occipital, uncinate, insular cortices, superior longitudinal fasciculi, corona radiata, and the body of the corpus callosum. These regional alterations were demonstrated for PD-MCI and were more pronounced in PD-D. The pattern of involved regions was significantly correlated with the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) total score. Conclusions: The findings in PD-N suggest impaired cross-hemispherical white matter connectivity that can apparently be compensated for. More pronounced involvement of the corpus callosum as demonstrated for PD-MCI together with affection of fronto-parieto-temporal structural connectivity seems to lead to gradual disruption of cognition-related cortico-cortical networks and to be associated with the onset of overt cognitive deficits. The increase of regional white matter damage appears to be associated with the development of PD-associated dementia.


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