scholarly journals The role of probabilistic tractocraphy in the surgical treatment of deep seated brain tumors

2019 ◽  
Author(s):  
Dávid Kis
Keyword(s):  
Healthy Subjects ◽  
Tumor Resection ◽  
Brain Structures ◽  
Brain Regions ◽  
Probabilistic Tractography ◽  
Thalamic Nuclei ◽  
Descending Pathways ◽  
Tumor Patients ◽  
Mapping Techniques ◽  
Permanent Neurological Deficit

Surgery provides the best survival rate for brain tumor patients but the risk of severe permanent neurological deficit is high in case of deep-seated tumors involving eloquent regions. Advanced MRI-based brain mapping techniques, such as probabilistic tractography are capable to identify important white matter pathways and subcortical nuclei that are not visible on conventional MRI sequences. In this Ph.D thesis we examined if probabilistic tractography is suitable to identify important brain structures in tumor patients and healthy subjects in two distinct subcortical eloquent regions: 1, the thalamus and 2, the brainstem. As far as we know, no previous study has examined this question before. In thalamic tumor patients we used connectivity-based thalamic segmentation by probabilistic tractography to identify the border of the normal thalamus and the tumor and differentiate the thalamic nuclei. The same technique was applied to the brainstem in healthy subjects to segment the four main ascending-descending pathways, namely the corticospinal/corticobulbar, the frontopontine and the sensory pathways and the reticular formation. The method was applied in two representative brainstem tumor patients to demonstrate the clinical applicability of the technique. Our results showed that connectivity-based segmentation by probabilistic tractography of the thalamus and the brainstem is suitable for clinical use and can potentially lower the surgical risk of tumor resection in these delicate eloquent subcortical brain regions.

Developmental structure in brain evolution

2001 ◽  
Vol 24 (2) ◽  
pp. 263-278 ◽  
Author(s):  
Barbara L. Finlay ◽  
Richard B. Darlington ◽  
Nicholas Nicastro
Keyword(s):  
Large Scale ◽  
Mammalian Species ◽  
Brain Evolution ◽  
Brain Structures ◽  
Brain Regions ◽  
Structural Constraints ◽  
Thalamic Nuclei ◽  
Brain Expansion ◽  
A Minor ◽  
Selection Of

How does evolution grow bigger brains? It has been widely assumed that growth of individual structures and functional systems in response to niche-specific cognitive challenges is the most plausible mechanism for brain expansion in mammals. Comparison of multiple regressions on allometric data for 131 mammalian species, however, suggests that for 9 of 11 brain structures taxonomic and body size factors are less important than covariance of these major structures with each other. Which structure grows biggest is largely predicted by a conserved order of neurogenesis that can be derived from the basic axial structure of the developing brain. This conserved order of neurogenesis predicts the relative scaling not only of gross brain regions like the isocortex or mesencephalon, but also the level of detail of individual thalamic nuclei. Special selection of particular areas for specific functions does occur, but it is a minor factor compared to the large-scale covariance of the whole brain. The idea that enlarged isocortex could be a “spandrel,” a by-product of structural constraints later adapted for various behaviors, contrasts with approaches to selection of particular brain regions for cognitively advanced uses, as is commonly assumed in the case of hominid brain evolution.

Brain Mapping Techniques to Maximize Resection, Safety, and Seizure Control in Children with Brain Tumors

Neurosurgery ◽  
1989 ◽  
Vol 25 (5) ◽  
pp. 786-792 ◽  
Author(s):  
Mitchel S. Berger ◽  
Joseph Kincaid ◽  
George A. Ojemann ◽  
Ettore Lettich
Keyword(s):  
Brain Tumors ◽  
Brain Mapping ◽  
Seizure Control ◽  
Pediatric Population ◽  
Tumor Resection ◽  
Brain Regions ◽  
Subcortical Stimulation ◽  
Mapping Techniques ◽  
Supratentorial Brain Tumors ◽  
Language Cortex

Abstract Intraoperative brain mapping techniques were used to localize language cortex, sensorimotor pathways, and seizure foci in children with supratentorial brain tumors. The methods of direct cortical and subcortical stimulation, in addition to electrocorticography, enabled us to maximize tumor resection, minimize morbidity, and eradicate epileptogenic zones which were always adjacent to, but not involving, the tumor nidus. Language localization was found to be quite variable in the children tested and anatomically unpredictable based on the preoperative neurological or radiological examination. Physiological mapping techniques, therefore, appear to be safe, reliable, and very useful for operations on tumors located within or adjacent to eloquent brain regions in the pediatric population.

scholarly journals An fMRI Study Using a Combined Task of Interval Discrimination and Oddball Could Reveal Common Brain Circuits of Cognitive Change

2021 ◽  
Vol 12 ◽  
Author(s):  
María Sol Garcés ◽  
Irene Alústiza ◽  
Anton Albajes-Eizagirre ◽  
Javier Goena ◽  
Patricio Molero ◽  
...  
Keyword(s):  
Cognitive Processes ◽  
Healthy Subjects ◽  
Functional Neuroimaging ◽  
Meta Analysis ◽  
Brain Structures ◽  
Cognitive Change ◽  
Brain Regions ◽  
Task Type ◽  
Meta Analyses ◽  
The Brain

Recent functional neuroimaging studies suggest that the brain networks responsible for time processing are involved during other cognitive processes, leading to a hypothesis that time-related processing is needed to perform a range of tasks across various cognitive functions. To examine this hypothesis, we analyze whether, in healthy subjects, the brain structures activated or deactivated during performance of timing and oddball-detection type tasks coincide. To this end, we conducted two independent signed differential mapping (SDM) meta-analyses of functional magnetic resonance imaging (fMRI) studies assessing the cerebral generators of the responses elicited by tasks based on timing and oddball-detection paradigms. Finally, we undertook a multimodal meta-analysis to detect brain regions common to the findings of the two previous meta-analyses. We found that healthy subjects showed significant activation in cortical areas related to timing and salience networks. The patterns of activation and deactivation corresponding to each task type partially coincided. We hypothesize that there exists a time and change-detection network that serves as a common underlying resource used in a broad range of cognitive processes.

scholarly journals High-fidelity transmission of high-frequency burst stimuli from peripheral nerve to thalamic nuclei in children with dystonia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Estefanía Hernandez-Martin ◽  
Enrique Arguelles ◽  
Yifei Zheng ◽  
Ruta Deshpande ◽  
Terence D. Sanger
Keyword(s):  
Deep Brain Stimulation ◽  
Peripheral Nerve ◽  
Brain Stimulation ◽  
High Frequency ◽  
Sensory Information ◽  
Brain Structures ◽  
High Fidelity ◽  
Thalamic Nuclei ◽  
Frequency Burst ◽  
Deep Brain

AbstractHigh-frequency peripheral nerve stimulation has emerged as a noninvasive alternative to thalamic deep brain stimulation for some patients with essential tremor. It is not known whether such techniques might be effective for movement disorders in children, nor is the mechanism and transmission of the peripheral stimuli to central brain structures understood. This study was designed to investigate the fidelity of transmission from peripheral nerves to thalamic nuclei in children with dystonia undergoing deep brain stimulation surgery. The ventralis intermediate (VIM) thalamus nuclei showed a robust evoked response to peripheral high-frequency burst stimulation, with a greatest response magnitude to intra-burst frequencies between 50 and 100 Hz, and reliable but smaller responses up to 170 Hz. The earliest response occurred at 12–15 ms following stimulation onset, suggesting rapid high-fidelity transmission between peripheral nerve and thalamic nuclei. A high-bandwidth, low-latency transmission path from peripheral nerve to VIM thalamus is consistent with the importance of rapid and accurate sensory information for the control of coordination and movement via the cerebello-thalamo-cortical pathway. Our results suggest the possibility of non-invasive modulation of thalamic activity in children with dystonia, and therefore the possibility that a subset of children could have beneficial clinical response without the need for invasive deep brain stimulation.

scholarly journals A Novel Language Paradigm for Intraoperative Language Mapping: Feasibility and Evaluation

2021 ◽  
Vol 10 (4) ◽  
pp. 655
Author(s):  
Katharina Rosengarth ◽  
Delin Pai ◽  
Frank Dodoo-Schittko ◽  
Katharina Hense ◽  
Teele Tamm ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Intraoperative Complications ◽  
Evaluation Study ◽  
Awake Craniotomy ◽  
Language Mapping ◽  
Tumor Patients ◽  
Language Functions ◽  
Before And After ◽  
Assessment Time ◽  
Neuropsychological Outcomes

(1) Background—Mapping language using direct cortical stimulation (DCS) during an awake craniotomy is difficult without using more than one language paradigm that particularly follows the demand of DCS by not exceeding the assessment time of 4 s to prevent intraoperative complications. We designed an intraoperative language paradigm by combining classical picture naming and verb generation, which safely engaged highly relevant language functions. (2) Methods—An evaluation study investigated whether a single trial of the language task could be performed in less than 4 s in 30 healthy subjects and whether the suggested language paradigm sufficiently pictured the cortical language network using functional magnetic resonance imaging (fMRI) in 12 healthy subjects. In a feasibility study, 24 brain tumor patients conducted the language task during an awake craniotomy. The patients’ neuropsychological outcomes were monitored before and after surgery. (3) Results—The fMRI results in healthy subjects showed activations in a language-associated network around the (left) sylvian fissure. Single language trials could be performed within 4 s. Intraoperatively, all tumor patients showed DCS-induced language errors while conducting the novel language task. Postoperatively, mild neuropsychological impairments appeared compared to the presurgical assessment. (4) Conclusions—These data support the use of a novel language paradigm that safely monitors highly relevant language functions intraoperatively, which can consequently minimize negative postoperative neuropsychological outcomes.

scholarly journals Astrocytes and neurons share region-specific transcriptional signatures that confer regional identity to neuronal reprogramming

2021 ◽  
Vol 7 (15) ◽  
pp. eabe8978
Author(s):  
Álvaro Herrero-Navarro ◽  
Lorenzo Puche-Aroca ◽  
Verónica Moreno-Juan ◽  
Alejandro Sempere-Ferràndez ◽  
Ana Espinosa ◽  
...  
Keyword(s):  
Molecular Diversity ◽  
Regional Identity ◽  
Brain Regions ◽  
Molecular Signature ◽  
Specific Gene ◽  
Thalamic Nuclei ◽  
Brain Repair ◽  
Cell Diversity ◽  
Regional Specificity ◽  
Epigenetic Signatures

Neural cell diversity is essential to endow distinct brain regions with specific functions. During development, progenitors within these regions are characterized by specific gene expression programs, contributing to the generation of diversity in postmitotic neurons and astrocytes. While the region-specific molecular diversity of neurons and astrocytes is increasingly understood, whether these cells share region-specific programs remains unknown. Here, we show that in the neocortex and thalamus, neurons and astrocytes express shared region-specific transcriptional and epigenetic signatures. These signatures not only distinguish cells across these two brain regions but are also detected across substructures within regions, such as distinct thalamic nuclei, where clonal analysis reveals the existence of common nucleus-specific progenitors for neurons and astrocytes. Consistent with their shared molecular signature, regional specificity is maintained following astrocyte-to-neuron reprogramming. A detailed understanding of these regional-specific signatures may thus inform strategies for future cell-based brain repair.

scholarly journals Dissociable Mechanisms of Verbal Working Memory Revealed through Multivariate Lesion Mapping

2019 ◽  
Vol 30 (4) ◽  
pp. 2542-2554 ◽  
Author(s):  
Maryam Ghaleh ◽  
Elizabeth H Lacey ◽  
Mackenzie E Fama ◽  
Zainab Anbari ◽  
Andrew T DeMarco ◽  
...  
Keyword(s):  
Working Memory ◽  
Spatial Working Memory ◽  
Superior Temporal Gyrus ◽  
Verbal Working Memory ◽  
Brain Structures ◽  
Brain Regions ◽  
Task Demands ◽  
Auditory Information ◽  
Verbal Information ◽  
Task Conditions

Abstract Two maintenance mechanisms with separate neural systems have been suggested for verbal working memory: articulatory-rehearsal and non-articulatory maintenance. Although lesion data would be key to understanding the essential neural substrates of these systems, there is little evidence from lesion studies that the two proposed mechanisms crucially rely on different neuroanatomical substrates. We examined 39 healthy adults and 71 individuals with chronic left-hemisphere stroke to determine if verbal working memory tasks with varying demands would rely on dissociable brain structures. Multivariate lesion–symptom mapping was used to identify the brain regions involved in each task, controlling for spatial working memory scores. Maintenance of verbal information relied on distinct brain regions depending on task demands: sensorimotor cortex under higher demands and superior temporal gyrus (STG) under lower demands. Inferior parietal cortex and posterior STG were involved under both low and high demands. These results suggest that maintenance of auditory information preferentially relies on auditory-phonological storage in the STG via a nonarticulatory maintenance when demands are low. Under higher demands, sensorimotor regions are crucial for the articulatory rehearsal process, which reduces the reliance on STG for maintenance. Lesions to either of these regions impair maintenance of verbal information preferentially under the appropriate task conditions.

scholarly journals Chronic Alcohol Use Induces Molecular Genetic Changes in the Dorsomedial Thalamus of People with Alcohol-Related Disorders

2021 ◽  
Vol 11 (4) ◽  
pp. 435
Author(s):  
Andreas-Christian Hade ◽  
Mari-Anne Philips ◽  
Ene Reimann ◽  
Toomas Jagomäe ◽  
Kattri-Liis Eskla ◽  
...  
Keyword(s):  
Alcohol Use ◽  
Molecular Genetic ◽  
Brain Structures ◽  
Thalamic Nuclei ◽  
Genetic Changes ◽  
Molecular Changes ◽  
Gabaergic Neurotransmission ◽  
And Control ◽  
Upregulated Genes

The Mediodorsal (MD) thalamus that represents a fundamental subcortical relay has been underrepresented in the studies focusing on the molecular changes in the brains of subjects with alcohol use disorder (AUD). In the current study, MD thalamic regions from AUD subjects and controls were analyzed with Affymetrix Clariom S human microarray. Long-term alcohol use induced a significant (FDR ≤ 0.05) upregulation of 2802 transcripts and downregulation of 1893 genes in the MD thalamus of AUD subjects. A significant upregulation of GRIN1 (glutamate receptor NMDA type 1) and FTO (alpha-ketoglutarate dependent dioxygenase) was confirmed in western blot analysis. Immunohistochemical staining revealed similar heterogenous distribution of GRIN1 in the thalamic nuclei of both AUD and control subjects. The most prevalent functional categories of upregulated genes were related to glutamatergic and GABAergic neurotransmission, cellular metabolism, and neurodevelopment. The prevalent gene cluster among down-regulated genes was immune system mediators. Forty-two differentially expressed genes, including FTO, ADH1B, DRD2, CADM2, TCF4, GCKR, DPP6, MAPT and CHRH1, have been shown to have strong associations (FDR p < 10−8) with AUD or/and alcohol use phenotypes in recent GWA studies. Despite a small number of subjects, we were able to detect robust molecular changes in the mediodorsal thalamus caused by alcohol emphasizing the importance of deeper brain structures such as diencephalon, in the development of AUD-related dysregulation of neurocircuitry.

Sleep Duration, Sleep Apnea, and Gray Matter Volume

2021 ◽  
pp. 089198872098891
Author(s):  
Regina Eun Young Kim ◽  
Robert Douglas Abbott ◽  
Soriul Kim ◽  
Robert Joseph Thomas ◽  
Chang-Ho Yun ◽  
...  
Keyword(s):  
Sleep Apnea ◽  
Sleep Duration ◽  
Gray Matter ◽  
Gray Matter Volume ◽  
Brain Structures ◽  
Brain Regions ◽  
Population Based ◽  
Older Individuals ◽  
Bootstrap Sampling ◽  
Matter Volume

This study aimed to evaluate the effect of sleep duration on brain structures in the presence versus absence of sleep apnea in middle-aged and older individuals. The study investigated a population-based sample of 2,560 individuals, aged 49-80 years. The presence of sleep apnea and self-reported sleep duration were examined in relation to gray matter volume (GMV) in total and lobar brain regions. We identified ranges of sleep duration associated with maximal GMV using quadratic regression and bootstrap sampling. A significant quadratic association between sleep duration and GMV was observed in total and lobar brain regions of men with sleep apnea. In the fully adjusted model, optimal sleep durations associated with peak GMV between brain regions ranged from 6.7 to 7.0 hours. Shorter and longer sleep durations were associated with lower GMV in total and 4 sub-regions of the brain in men with sleep apnea.

Intranasal administration of mitochondria improves spatial memory in olfactory bulbectomized mice

2021 ◽  
pp. 153537022110568
Author(s):  
Natalia V Bobkova ◽  
Daria Y Zhdanova ◽  
Natalia V Belosludtseva ◽  
Nikita V Penkov ◽  
Galina D Mironova
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Spatial Memory ◽  
Intranasal Administration ◽  
Brain Structures ◽  
Brain Regions ◽  
Dependent Manner ◽  
Behavioral Experiments ◽  
Hippocampal Cell Culture ◽  
The Brain

Here, we found that functionally active mitochondria isolated from the brain of NMRI donor mice and administrated intranasally to recipient mice penetrated the brain structures in a dose-dependent manner. The injected mitochondria labeled with the MitoTracker Red localized in different brain regions, including the neocortex and hippocampus, which are responsible for memory and affected by degeneration in patients with Alzheimer's disease. In behavioral experiments, intranasal microinjections of brain mitochondria of native NMRI mice improved spatial memory in the olfactory bulbectomized (OBX) mice with Alzheimer’s type degeneration. Control OBX mice demonstrated loss of spatial memory tested in the Morris water maze. Immunocytochemical analysis revealed that allogeneic mitochondria colocalized with the markers of astrocytes and neurons in hippocampal cell culture. The results suggest that a non-invasive route intranasal administration of mitochondria may be a promising approach to the treatment of neurodegenerative diseases characterized, like Alzheimer's disease, by mitochondrial dysfunction.

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