Acquisitions with the spiral-in/out technique result in two separate image timeseries obtained during the spiral-in and spiral-out trajectory. In uniform brain regions the two components have comparable signal and BOLD contrast and can be averaged, but in regions compromised by susceptibility effects where both signal and noise can differ in the two images other combination methods may be more ...

Spontaneous slow oscillation-associated slow wave activity represents an internally generated state which is characterized by alternations of network quiescence and stereotypical episodes of neuronal activity - slow wave events. However, it remains unclear which macroscopic signal is related to these active periods of the slow wave rhythm. We used optic fiber-based calcium recordings of local n...

The blood oxygenation level-dependent (BOLD) functional MRI response to suppressive neural activity has not been tested on a fine spatial scale. Using Gabor patches placed in the near periphery, we precisely localized individual regions of interest in primary visual cortex and measured the response at a range of contrasts in two different contexts: with parallel and with orthogonal flanking Gab...

We have measured the relationship between image contrast, perceived contrast, and BOLD fMRI activity in human early visual areas, for natural, whitened, pink noise, and white noise images. As root-mean-square contrast increases, BOLD response to natural images is stronger and saturates more rapidly than response to the whitened images. Perceived contrast and BOLD fMRI responses are higher for p...

at 7T Dávid Z Balla, Rosa M Sanchez Panchuelo, Samuel J Wharton, Gisela E Hagberg, Klaus Scheffler, Susan T Francis, and Richard W Bowtell High-field MR Centre, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom, Department for Biomedical Magnetic Resonance Imaging, University of...

The blood-oxygen-level dependent (BOLD) signal in functional MRI (fMRI) reflects both neuronal activations and global physiological fluctuations. These physiological fluctuations can be attributed to physiological low frequency oscillations (pLFOs), respiration, and cardiac pulsation. With typical TR values, i.e., 2 s or longer, the high frequency physiological signals (i.e., from respiration a...

Volumetric Space–Time Structure of Physiological Noise in BOLD fMRI Arno Solin, Simo Särkkä, Aapo Nummenmaa, Aki Vehtari, Toni Auranen, Simo Vanni, and Fa-Hsuan Lin Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, Finland, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, Advanced Magnetic Imag...

Manuscript for The new handbook of multisensory processes, Barry Stein (Ed.).

Susceptibility-induced magnetic field gradients (SFGs) perpendicular to the slice plane often result in signal dropout in blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) experiments. Two-dimensional (2D) z-shim methods reduce these effects by acquiring multiple images with different slice refocusing gradient areas. In this work a 3D z-shim method is introdu...

BACKGROUND To what extent is activity of individual neurons coupled to the local field potential (LFP) and to blood-oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI)? This issue is of high significance for understanding brain function and for relating animal studies to fMRI, yet it is still under debate. RESULTS Here we report data from simultaneous recordings of...