Laminar fMRI: Applications for cognitive neuroscience

Abstract

Highlights Recent developments in high spatial resolution fMRI allow for functional imaging of human cortical layers (laminar fMRI)  Feedforward and feedback responses can be dissociated by their laminar profiles  In vivo measurements of feedforward and feedback responses in humans with laminar fMRI have many, far-reaching applications for cognitive neuroscience  We review recent laminar fMRI studies, and several areas of cognitive neuroscience that stand to benefit from this exciting technological development AbstractThe cortex is a massively recurrent network, characterised by feedforward and feedback connections between brain areas as well as lateral connections within an area. areas at a more fine-grained level than previously possible in the human species. In this review,we highlight recent studies that successfully used laminar fMRI to isolate layer-specific feedback responses in human sensory cortex. In addition, we review several areas of cognitive neuroscience that stand to benefit from this new technological development, highlighting contemporary hypotheses that yield testable predictions for laminar fMRI. We hope to encourage researchers with the opportunity to embrace this development in fMRI research, as we expect that many future advancements in our current understanding of human brain function will be gained from measuring lamina-specific brain responses.

Emergence of symmetry selectivity in the visual areas of the human brain: fMRI responses to symmetry presented in both frontoparallel and slanted planes

“…However, if retinal structure is sufficient to extract symmetry from slanted planes then we would expect similar feedforward and feedback processes to be invoked independent of stimulus slant and task. To help answer these questions future investigations could draw from studies that have used transcranial magnetic stimulation (TMS) (Bona et al, 2014;Maus, Ward, Nijhawan, & Whitney, 2013;Wokke, Vandenbroucke, Scholte, & Lamme, 2012), and imaging of the laminar structure of visual cortex (Kok, Bains, van Mourik, Norris, & de Lange, 2016;Lawrence, Formisano, Muckli, & de Lange, 2017). Indeed, estimates of slant from disparity and texture cues have been found to be combined in V3B (Murphy et al, 2013), making this a candidate area for future TMS studies.…”

Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

“…Our paradigm relates to amodal completion where the subjects do not directly 479 perceive, but rather infer a presence of the continued stimulus behind the occluder, from knowledge about 480 natural objects and scenes. Filling-in (modal completion) and inference (amodal completion) may have 481 different neuronal processes, discussed, for example, in Lawrence et al (2017). 482…”

Ultra-high resolution blood volume fMRI and BOLD fMRI in humans at 9.4 T: Capabilities and challenges

“…The cortical grey matter (GM) ribbon consists of up to six of these histologically-defined cortical layers with thicknesses usually between 0.2 mm and 1 mm (Brodmann, 1909). Mapping the brain activity across the cortical layers and their differential functional connectivity to distant brain areas is highly valuable for human cognitive research (Lawrence et al, 2017; Stephan et al, 2017) and has the potential to become a valuable tool in clinical psychiatry. As such, many current theories of psychiatric and neurological diseases stress that they are primarily related to disorders of neural circuits (Gordon, 2016).…”