In this educational talk, I aim to highlight some of the main issues of high spatial resolution fMRI, geared towards best practice in imaging layers and columns in humans.
Subject summary: Over the past quarter century, functional Magnetic Resonance Imaging (fMRI) has quickly become one of the most powerful tools for investigating human neural processing. With the growing availability of ultra-high field scanners (UHF - i.e. >= 7 Tesla), and the development of more efficient hardware and software, researchers have been trading UHF related gains in signal-to-noise ratio (SNR) for higher spatial (e.g. 0.8 mm isotropic) resolution BOLD images. These high-resolution measurements can, at least in principle, provide the means to study some of the most fundamental units of neural computation: cortical layers and columns. UHF fMRI therefore provides the unique opportunity to investigate the organizing principles of the human cortex at the mesoscale level and, in doing so, to bridge the gap between invasive animal electrophysiology and non-invasive human neuroimaging. However, there remain a number of challenges in imaging layers and columns, including, but not limited to, low snr and doubts about the available spatial functional precision. In spite of the difficulties of such an endeavor, an increasing number of findings seem to support the feasibility of measuring fMRI activation profiles at different cortical depths and via the mapping of cortical columns. The aim of this talk will be to provide a brief overview of some of the main challenges of performing laminar and columnar fMRI, highlighting some of the strategies that can be adopted to tackle such problems.
Target Audience: This talk will benefit any researchers with some experience studying human neurocognitive functions using lower resolution fMRI, and who wish to begin using high resolution fMRI, such as 7 Tesla and above, to study human layers and columns.
Outcome/Objectives: The main objective of the current presentation is to render researchers who are beginning to venture in to the layer and columnar fMRI world aware of the main issues and challenges of this approach to studying the human brain at the mesoscale level.
Main Topics Covered: Content covered in this talk will review some of the fundamental challenges of layer fMRI, including: the trade-off between sensitivity and specificity; some preprocessing considerations to ensure minimizing imprecision in the estimation of cortical layers and columns; and analytical strategies that may help combat or attenuate some of these main difficulties.
Purpose: The purpose of the presentation is to build awareness among researchers who are newly experiencing, or considering delving into, the study of layer and columnar fMRI of some of the main challenges and limitations of this specific field. It will aim to provide a general overview of these details to allow the audience to explore further any one topic or problem of choice. Some of the main acquisition protocols are discussed in terms of their sensitivity vs specificity profiles. Examples of empirical applications to layers and columns are provided.

Acknowledgements

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