Proprioceptive engagement of the human cerebellum studied with 7T-fMRI.

Proprioception, the process of perceiving our bodies in space, is a key aspect of self-perception. The cerebellar cortex is believed to play a critical role in proprioception. However, our understanding of the functional involvement of the cerebellum in proprioception remains limited due to the intricate, thin, and highly folded structure of the human cerebellar cortex, which is more challenging to resolve using in-vivo MRI compared to the cerebral cortex.

Contextual responses drive a unique laminar signature in human V1.

Neuronal populations in visual cortex integrate stimulus-driven input from the retina with contextual input from neighboring neurons, each targeting distinct cortical layers. Using line-scanning fMRI with precise targeting, we recorded depth-resolved responses in human visual cortex to stimuli tailored to each participant's population receptive field (pRF) of the target patch. Stimuli in the center of the pRF evoked increasing responses toward the pial surface with a small peak at middle depths, consistent with feedforward input.

Easy-to-use shims for human brain imaging at 7 T.

Purpose: field inhomogeneity is a common problem in high field brain MRI (  T). Parallel-transmit methods that adjust the field channelwise often require valuable scan time. Group-optimized phase shims are presented to increase or attenuate the field in specific brain regions, omitting personalized calibrations and potentially enabling reduced FOV acquisitions or artifact reduction.

Compressed Sensing-Accelerated Free-Breathing Liver MRI at 7 T.

Ultra-high field MRI facilitates imaging at high spatial resolutions, which may become important for detailed anatomical and pathological assessment of the human liver. Therefore, we aimed to advance structural liver imaging at 7 T by implementing a high-resolution, phase-shimmed, free-breathing liver scan. Six healthy participants underwent liver MRI scans at 7 T, utilizing an eight-channel parallel transmission system for phase shimming.

High-Resolution 3D Turbo Spin-Echo Wrist MRI at 7T Accelerated by Compressed Sensing.

This study aimed to obtain high-resolution 3D isotropic turbo spin-echo (TSE) wrist MRI acquisitions at 7T, with and without fat suppression, facilitated by compressed-sensing (CS) acceleration. In 16 healthy subjects, fat-suppressed (FS) and nonfat-suppressed (NFS) TSE wrist images were obtained. The protocol consisted of a SENSE-accelerated scan, with an isotropic voxel size of 0.

Does the Cortical-Depth Dependence of the Hemodynamic Response Function Differ Between Age Groups?

Functional magnetic resonance imaging (fMRI) is a widely used tool to investigate the functional brain responses in living humans. Valid comparisons of fMRI results depend on consistency of the blood-oxygen-level-dependent (BOLD) hemodynamic response function (HRF). Although common statistical approaches assume a single HRF across the entire brain, the HRF differs across individuals, regions of the brain, and cortical depth.

Structural connectivity of thalamic subnuclei in major depressive disorder: An ultra-high resolution diffusion MRI study at 7-Tesla.

Background: The thalamus serves as a central relay station within the brain, and thalamic connectional anomalies are increasingly thought to be present in major depressive disorder (MDD). However, the use of conventional MRI scanners and acquisition techniques has prevented a thorough examination of the thalamus and its subnuclear connectional profile. We combined ultra-high field diffusion MRI acquired at 7.

Hippocampal, thalamic, and amygdala subfield morphology in major depressive disorder: an ultra-high resolution MRI study at 7-Tesla.

Morphological changes in the hippocampal, thalamic, and amygdala subfields have been suggested to form part of the pathophysiology of major depressive disorder (MDD). However, the use of conventional MRI scanners and acquisition techniques has prevented in-depth examinations at the subfield level, precluding a fine-grained understanding of these subfields and their involvement in MDD pathophysiology. We uniquely employed ultra-high field MRI at 7.

Advancing 7T perfusion imaging by pulsed arterial spin labeling: Using a parallel transmit coil for enhanced labeling robustness and temporal SNR.

Non-invasive perfusion imaging by Arterial spin labeling (ASL) can be advantageous at Ultra-high field (UHF) MRI, since the image SNR and the T1 relaxation time both increase with the static field. However, ASL implementation, especially at 7T, is not trivial. Especially for ASL, UHF MRI comes with many challenges, mainly due to B1+ inhomogeneities.

7-Tesla Magnetic Resonance Imaging Scanning in Deep Brain Stimulation for Parkinson's Disease: Improving Visualization of the Dorsolateral Subthalamic Nucleus.

Background: Identifying the dorsolateral subthalamic nucleus (STN) for deep brain stimulation (DBS) in Parkinson's disease (PD) can be challenging due to the size and double-oblique orientation. Since 2015 we implemented 7-Tesla T2 weighted magnetic resonance imaging (7 T T2) for improving visualization and targeting of the dorsolateral STN. We describe the changes in surgical planning and outcome since implementation of 7 T T2 for DBS in PD.

The cerebellum during provocation and aggressive behaviour: A 7 T fMRI study.

Increasing empirical evidence points towards the involvement of the cerebellum in anger and aggressive behaviour. However, human functional neuroimaging studies so far have emphasised the involvement of subcortical and cortical regions, rather than examining the contributions of the cerebellum. In the present study, 7 T functional magnetic resonance imaging (fMRI) was used to assess cerebellar activation during provocation and aggressive behaviour elicited by the Point Subtraction Aggression Paradigm in 29 healthy adult volunteers.

A 7T interleaved fMRS and fMRI study on visual contrast dependency in the human brain.

Functional magnetic resonance spectroscopy (fMRS) is a non-invasive technique for measuring dynamic changes in neurometabolites. While previous studies have observed concentration changes in metabolites during neural activation, the relationship between neurometabolite response and stimulus intensity and timing requires further investigation. To address this, we conducted an interleaved fMRS and functional magnetic resonance imaging (fMRI) experiment using a visual stimulus with varying contrast levels.

A selection and targeting framework of cortical locations for line-scanning fMRI.

Depth-resolved functional magnetic resonance imaging (fMRI) is an emerging field growing in popularity given the potential of separating signals from different computational processes in cerebral cortex. Conventional acquisition schemes suffer from low spatial and temporal resolutions. Line-scanning methods allow depth-resolved fMRI by sacrificing spatial coverage to sample blood oxygenated level-dependent (BOLD) responses at ultra-high temporal and spatial resolution.

Combining arterial blood contrast with BOLD increases fMRI intracortical contrast.

BOLD fMRI is widely applied in human neuroscience but is limited in its spatial specificity due to a cortical-depth-dependent venous bias. This reduces its localization specificity with respect to neuronal responses, a disadvantage for neuroscientific research. Here, we modified a submillimeter BOLD protocol to selectively reduce venous and tissue signal and increase cerebral blood volume weighting through a pulsed saturation scheme (dubbed Arterial Blood Contrast) at 7 T.

Towards functional spin-echo BOLD line-scanning in humans at 7T.

Objective: Neurons cluster into sub-millimeter spatial structures and neural activity occurs at millisecond resolutions; hence, ultimately, high spatial and high temporal resolutions are required for functional MRI. In this work, we implemented a spin-echo line-scanning (SELINE) sequence to use in high spatial and temporal resolution fMRI.

Materials And Methods: A line is formed by simply rotating the spin-echo refocusing gradient to a plane perpendicular to the excited slice and by removing the phase-encoding gradient.

Improved Selectivity in 7 T Digit Mapping Using VASO-CBV.

Functional magnetic resonance imaging (fMRI) at Ultra-high field (UHF, ≥ 7 T) benefits from significant gains in the BOLD contrast-to-noise ratio (CNR) and temporal signal-to-noise ratio (tSNR) compared to conventional field strengths (3 T). Although these improvements enabled researchers to study the human brain to unprecedented spatial resolution, the blood pooling effect reduces the spatial specificity of the widely-used gradient-echo BOLD acquisitions. In this context, vascular space occupancy (VASO-CBV) imaging may be advantageous since it is proposed to have a higher spatial specificity than BOLD.

Robust high spatio-temporal line-scanning fMRI in humans at 7T using multi-echo readouts, denoising and prospective motion correction.

Background: Functional magnetic resonance imaging (fMRI), typically using blood oxygenation level-dependent (BOLD) contrast weighted imaging, allows the study of brain function with millimeter spatial resolution and temporal resolution of one to a few seconds. At a mesoscopic scale, neurons in the human brain are spatially organized in structures with dimensions of hundreds of micrometers, while they communicate at the millisecond timescale. For this reason, it is important to develop an fMRI method with simultaneous high spatial and temporal resolution.

Auditory timing-tuned neural responses in the human auditory cortices.

Perception of sub-second auditory event timing supports multisensory integration, and speech and music perception and production. Neural populations tuned for the timing (duration and rate) of visual events were recently described in several human extrastriate visual areas. Here we ask whether the brain also contains neural populations tuned for auditory event timing, and whether these are shared with visual timing.