Functional Anatomy of the Thalamus as a Model of Integrated Structural and Functional Connectivity of the Human Brain In Vivo

2014 ◽  
Vol 28 (4) ◽  
pp. 548-558 ◽  
Author(s):  
Chiara Mastropasqua ◽  
Marco Bozzali ◽  
Barbara Spanò ◽  
Giacomo Koch ◽  
Mara Cercignani
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Functional Anatomy

scholarly journals Genetically defined cellular correlates of the baseline brain MRI signal

2018 ◽  
Vol 115 (41) ◽  
pp. E9727-E9736 ◽  
Author(s):  
Jie Wen ◽  
Manu S. Goyal ◽  
Serguei V. Astafiev ◽  
Marcus E. Raichle ◽  
Dmitriy A. Yablonskiy
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Brain Activity ◽  
Brain Mri ◽  
Blood Oxygenation ◽  
Brain Atlas ◽  
Functional Connections ◽  
Fmri Signal ◽  
Useful Signal

fMRI revolutionized neuroscience by allowing in vivo real-time detection of human brain activity. While the nature of the fMRI signal is understood as resulting from variations in the MRI signal due to brain-activity-induced changes in the blood oxygenation level (BOLD effect), these variations constitute a very minor part of a baseline MRI signal. Hence, the fundamental (and not addressed) questions are how underlying brain cellular composition defines this baseline MRI signal and how a baseline MRI signal relates to fMRI. Herein we investigate these questions by using a multimodality approach that includes quantitative gradient recalled echo (qGRE), volumetric and functional connectivity MRI, and gene expression data from the Allen Human Brain Atlas. We demonstrate that in vivo measurement of the major baseline component of a GRE signal decay rate parameter (R2t*) provides a unique genetic perspective into the cellular constituents of the human cortex and serves as a previously unidentified link between cortical tissue composition and fMRI signal. Data show that areas of the brain cortex characterized by higher R2t* have high neuronal density and have stronger functional connections to other brain areas. Interestingly, these areas have a relatively smaller concentration of synapses and glial cells, suggesting that myelinated cortical axons are likely key cortical structures that contribute to functional connectivity. Given these associations, R2t* is expected to be a useful signal in assessing microstructural changes in the human brain during development and aging in health and disease.

scholarly journals 0147 Dynamic Alterations in Functional Connectivity Between Sleep- and Wake-Promoting Regions of the Human Brain at the Sleep Onset Period

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A58-A58
Author(s):  
T Ishii ◽  
T Koike ◽  
E Nakagawa ◽  
M Sumiya ◽  
N Sadato
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Transition Period ◽  
Sleep Stage ◽  
Sleep Onset ◽  
Sleep Stages ◽  
Alpha Power ◽  
Onset Period ◽  
The Brain

Abstract Introduction The sleep onset period, involving so-called stage N1 sleep largely, is characterized by a reduction in the amount of alpha activity compared to wakefulness. Various kinds of physiological and psychological changes are also apparent, such as slow eye movements, changes in muscle tonus, and the hypnagogic dream-like mentation. These phenomena are thought to be the reflection of dynamic alterations in the brain during the transition period, however, details of these changes have still been uncovered. Methods We aimed to investigate a dynamic shift in the brain connectivity at sleep onset using the method of EEG-fMRI simultaneous recording. Twenty-three healthy subjects participated. EEG/fMRI were recorded simultaneously during an hour’s nap in a 3T-MRI scanner and real-time monitoring of EEG was performed. To record the transition period between multiple times, an experimenter inside a scanner room touched a subject’s foot for inducing arousal when a shift to NREM sleep stage 1 was observed. EEG data were scored according to the AASM criteria. Based on sleep stages defined by polysomnographic findings, we investigated alterations in functional connectivity of sleep- and wake- promoting regions within the hypothalamus and other areas including the thalamus. Results Posterior alpha power showed significant positive correlation with BOLD signals in the anterior and medial dorsal thalamus. Connectivity between the thalamus and cortical regions reduced sharply in the descent to sleep stage. Meanwhile, BOLD signals of the sleep- and wake- promoting regions within the hypothalamus fluctuated with certain temporal lags from fluctuations of alpha rhythm at sleep onset. Conclusion Present findings provide preliminary evidence of dynamics of wake- and sleep- promoting regions in the human brain in vivo. Our data also support the hypothesis that reduced thalamocortical connectivity which limits the capacity to integrate information is associated with the transition of consciousness at sleep onset. Support None

scholarly journals Functional Connectivity of the Infant Human Brain

2016 ◽  
Vol 23 (2) ◽  
pp. 169-184 ◽  
Author(s):  
Wei Gao ◽  
Weili Lin ◽  
Karen Grewen ◽  
John H. Gilmore
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Brain Development ◽  
Human Life ◽  
Functional Brain ◽  
The Past ◽  
Human Brain Development ◽  
Infant Brain ◽  
Brain Functional Connectivity

Infancy is a critical and immensely important period in human brain development. Subtle changes during this stage may be greatly amplified with the unfolding of different developmental processes, exerting far-reaching consequences. Studies of the structure and behavioral manifestations of the infant brain are fruitful. However, the specific functional brain mechanisms that enable the execution of different behaviors remained elusive until the advent of functional connectivity fMRI (fcMRI), which provides an unprecedented opportunity to probe the infant functional brain development in vivo. Since its inception, a burgeoning field of infant brain functional connectivity study has emerged and thrived during the past decade. In this review, we describe (1) findings of normal development of functional connectivity networks and their relationships to behaviors and (2) disruptions of the normative functional connectivity development due to identifiable genetic and/or environmental risk factors during the first 2 years of human life. Technical considerations of infant fcMRI are also provided. It is our hope to consolidate previous findings so that the field can move forward with a clearer picture toward the ultimate goal of fcMRI-based objective methods for early diagnosis/identification of risks and evaluation of early interventions to optimize developing functional connectivity networks in this critical developmental window.

In Vivo 1H MR Spectroscopic Imaging of Human Brain

1994 ◽  
Vol 31 (2) ◽  
pp. 185
Author(s):  
Yong Whee Bahk ◽  
Kyung Sub Shinn ◽  
Tae Suk Suh ◽  
Bo Young Choe ◽  
Kyo Ho Choi
Keyword(s):  
Human Brain ◽  
Spectroscopic Imaging ◽  
Mr Spectroscopic Imaging

scholarly journals Diffusion MRI microstructure models with in vivo human brain Connectome data: results from a multi-group comparison

2017 ◽  
Vol 30 (9) ◽  
pp. e3734 ◽  
Author(s):  
Uran Ferizi ◽  
Benoit Scherrer ◽  
Torben Schneider ◽  
Mohammad Alipoor ◽  
Odin Eufracio ◽  
...  
Keyword(s):  
Human Brain ◽  
Diffusion Mri ◽  
Group Comparison ◽  
Brain Connectome

scholarly journals O-012 Evidence of arterial collapse in a human brain model and in-vivo with aspiration thrombectomy

2021 ◽  
Author(s):  
Y Liu ◽  
D Gebrezgiabhier ◽  
J Arturo Larco ◽  
S Madhani ◽  
A Shahid ◽  
...  
Keyword(s):  
Human Brain ◽  
Aspiration Thrombectomy

scholarly journals Role of SHH in Patterning Human Pluripotent Cells towards Ventral Forebrain Fates

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 914
Author(s):  
Melanie V. Brady ◽  
Flora M. Vaccarino
Keyword(s):  
Stem Cell ◽  
Human Brain ◽  
Human Development ◽  
Disease Modeling ◽  
Model Systems ◽  
Advantages And Disadvantages ◽  
Technical Ability ◽  
Cellular Phenotypes

The complexities of human neurodevelopment have historically been challenging to decipher but continue to be of great interest in the contexts of healthy neurobiology and disease. The classic animal models and monolayer in vitro systems have limited the types of questions scientists can strive to answer in addition to the technical ability to answer them. However, the tridimensional human stem cell-derived organoid system provides the unique opportunity to model human development and mimic the diverse cellular composition of human organs. This strategy is adaptable and malleable, and these neural organoids possess the morphogenic sensitivity to be patterned in various ways to generate the different regions of the human brain. Furthermore, recapitulating human development provides a platform for disease modeling. One master regulator of human neurodevelopment in many regions of the human brain is sonic hedgehog (SHH), whose expression gradient and pathway activation are responsible for conferring ventral identity and shaping cellular phenotypes throughout the neural axis. This review first discusses the benefits, challenges, and limitations of using organoids for studying human neurodevelopment and disease, comparing advantages and disadvantages with other in vivo and in vitro model systems. Next, we explore the range of control that SHH exhibits on human neurodevelopment, and the application of SHH to various stem cell methodologies, including organoids, to expand our understanding of human development and disease. We outline how this strategy will eventually bring us much closer to uncovering the intricacies of human neurodevelopment and biology.

Sign in / Sign up

Export Citation Format

Share Document