シンポジウム（Symposium）

Symposium Technological advances of ultra-high field MRI in Neuroscience and the future direction of laminar/columnar functional MRI シンポジウム脳神経科学における革新的超高磁場MRI技術の応用とlaminar/columnar fMRI技術への展望

7月27日（土）17:02～17:28　第6会場（朱鷺メッセ　2F　201A） 3S06e-1 超高磁場MRIによる脳微細構造と脳活動計測 Masaki Fukunaga（福永雅喜）^1,2 ¹生理学研究所システム脳科学心理生理学 ²総合研究大学院大学 The observation of the living body by the magnetic resonance imaging (MRI) depends on the spatial resolution and signal noise ratio (SNR), as well as relaxation time and contrast which is a tissue parameter. The advent of 7 tesla (T) ultra high field MR technology provides unprecedented capabilities for non-invasive imaging of human and animal model brain. This technical ability encompasses a range of functional and structural domains, as well as new opportunities for quantifying neurochemicals using spectroscopic techniques. In addition, increasing the static magnetic field strength promotes signal phase dispersion and shift. Predicted benefits included a stronger Blood Oxygenation Level Dependent (BOLD) effect which is used for detecting brain activity, improved signal and contrast-to-noise (CNR) ratio. By using optimal measurement techniques, improved CNR provides the delineation of the brain microstructure including laminar structure in cortex in vivo. In this talk, I'd like to present our experiences of 7T human brain imaging, especially in high resolution susceptibility imaging which delineate the intra cortical layered myelin distribution and some results of high resolution fMRI studies such as somatotopic mapping and its relation with myelin contrast in cortical gray matter.		7月27日（土）16:36～17:02　第6会場（朱鷺メッセ　2F　201A） 3S06e-2 Challenges and opportunities for laminar imaging using Gradient-echo BOLD signal Kamil Uludag（Uludag Kamil）^1,2 ¹Koerner Scientist in MR Imaging, Department of Medical Biohysics, University of Toronto ²Sungkyunkwan University, Department of Biomedical Engineering and Institute for Basic Science (IBS), Seobu-ro 2066, Jangan-gu, Suwon, Korea Ultra high-field MRI has, in the last years, rapidly grown from a niche technology primarily used by MRI physicist and engineers, to a widely used imaging approach to study brain structure and cognitive function. In particular, fMRI at field strengths 7T or larger allows to non-invasively map the mesoscopic organization of the human neocortex, bridging the gap between human cognitive neuroscience and invasive animal studies. However, data acquisition and analysis challenges for high-resolution fMRI remain, which hamper the direct interpretation of the measured fMRI signal in terms of layer- and columnar-specific neuronal activity. In this talk, I will give an overview of the main challenges for high-resolution fMRI and present possible solutions, namely on: a) the fMRI signal stems from changes in blood oxygenation mainly in the post-capillary vascular compartments, leading to contamination of the local layer-specific fMRI signal with non-local signal changes stemming from the lower cortical layers; and b) although fMRI is the non-invasive technique with the highest spatial resolution, the voxel size (e.g. 0.7-0.8 mm isotropic) still is large compared to the spatial dimensions of cortical layers and columns. In addition, I will provide an overview of recently published studies on cognitive neuroscience in humans using high-resolution fMRI, on a spatial scale only available thus far using invasive approaches in animals or patients.

7月27日（土）17:54～18:20　第6会場（朱鷺メッセ　2F　201A） 3S06e-3 High-field high-resolution fMRI technology reveals information flow across cortical microcircuits of layers and columns. Renzo Huber（Huber Renzo）¹，Laurentius Huber（Huber Laurentius）^1,2 ¹University of Maastricht ²SFIM, LBC, NIMH, NIH Methodological advancements of functional Magnetic Resonance Imaging (fMRI) in recent years allow researchers to approach the mesoscopic spatial regime of cortical layers and cortical columns. This revolutionizes the ability to tackle cortical information processing within brain systems. In this symposium presentation, I will give an overview on the cutting-edge advancements in human high-field (7T), high-resolution fMRI. I will describe sensitivity and localization specificity challenges of sub-millimeter fMRI and how to overcome them with newly developed multi-contrast sequences and appropriate analysis methods. I will discuss how cutting-edge mesoscopic fMRI can be used to provide new insights on physiological and neural mechanisms at the laminar, and systems level to ultimately aid Neuroscientific insight. I will discuss neuroscientific applications of non-invasively extracting laminar and columnar information in humans with the focus on few neuroscientific areas: * I will discuss studies to map the directional functional connectivity in hierarchically organized brain areas in the visual system. As such, I will present latest results on the information flow between Thalamus, primary visual cortex, and area V5/MT. * I will discuss studies of generating a directional brain connectome atlas with resting-state layer-fMRI. * I will discuss studies of mapping the layer-dependent mechanisms of maintaining and manipulating mental information in dorsolateral prefrontal cortex during working memory tasks * I will discuss studies investigating afferent and efferent information flow in the motor system across layers and columns. References: * Huber, Finn, Handwerker ... Bandettini (2018). Unique functional digit representation in human motor cortex across columns and layers. In 48th Society for Neuroscience, p. 675.03. * Finn, Huber, Jangraw, and Bandettini (2018). Layer-dependent activity in human prefrontal cortex during working memory. BioRxiv 425249. * Huber, Tse, Wiggins, Ivanov (2018). Ultra-high resolution blood volume fMRI and BOLD fMRI in humans at 9.4T: Capabilities and challenges. Neuroimage in press. * Huber, Handwerker, Jangraw ... Bandettini (2017). High-resolution CBV-fMRI allows mapping of laminar activity and connectivity of cortical input and output in human M1. Neuron. * Huber, Uludag, and Moeller (2017). Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMRO2. Neuroimage, doi: 10.1016/j.neuroimage.2017.07		7月27日（土）17:28～17:54　第6会場（朱鷺メッセ　2F　201A） 3S06e-4 高空間分解能fMRIによるヒト体性感覚野の機能的役割の検討 Yinghua Yu（于英花）^1,2,3，Laurentius Huber（Huber Laurentius）^3,4，Jiajia Yang（Yang Jiajia）^1,3，Peter A Bandettini（Bandettini A Peter）³ ¹岡山大学　大学院ヘルスシステム統合科学研究科 ²日本学術振興会、東京、日本 ³アメリカ国立衛生研究所, メリーランド州ベセスダ,アメリカ ⁴University of Maastricht, Maastricht, Netherlands When humans touch an object, their brains represent the inputs from sensory receptors and continuously update them based on their expectations. This mechanism of tactile sensory encoding rests on hierarchically related prediction errors that are calculated by the predictive feedback and actual sensory input. Making sense of such cortical systems requires measurements of columnar/laminar activity in the human brain. In recent years, there have been several highly publicized studies showing the value of high-field (7 Tesla), high-resolution fMRI for human neuroscience. With recent advancements high-field fMRI allows researchers to approach the spatial scale of cortical layers and cortical columns. In this symposium presentation, I will give an overview of our recent challenges and findings in the human somatosensory cortex (S1) by using high-resolution (0.7 mm) blood-oxygen-level-dependent (BOLD) and vascular-space-occupancy (VASO) fMRI at 7T. First, I will present and discuss our latest results on human area 3b of S1 receives cutaneous input from slow-adapting (SA) and rapidly adapting (RA) cutaneous receptors in a columnar manner. Second, I will present and discuss our latest results on layer-specific activation of sensory input and predictive feedback in area 3b. Third, I will discuss how the prediction error activity changes across layers in area 3b. Then, I will conclude recent findings and descript how these finding will help us to understand the mechanism of tactile sensory processing. Finally, I will point out our future challenges.