[P3] Poster: Day 3

[P3-11] Sequential Brain Activity for subsecond-lagged Sensory and Motor events: Investigation using Temporal High-Resolution fMRI at 9.4 Tesla

*Nikolas Philipp Klein^1,2, Sebastian Mueller², Klaus Scheffler^2,3, Assaf Breska¹ (1. Research Group Cognitive Neuroscience of Dynamic Cognition, Max Planck Institute for Biological Cybernetics (Germany), 2. Department High-field Magnetic Resonance , Max Planck Institute for Biological Cybernetics (Germany), 3. Deparment of Biomedical Magnetic Resonance, Eberhard Karls University Tuebingen (Germany))

Keywords:

Fast fMRI,Delay encoding,Sequential brain activity

Temporal encoding and modulation in the subsecond is essential for visual perception and movement initiation, and relies on coordinated activity of the cerebellum, basal ganglia, and cortical regions. However, current research methods have significant limitations regarding generalizability, spatial- or temporal resolution, especially given the potential role of rapid neural dynamics in deep circuits. Here, we leveraged increased field strengths of 9.4 T to achieve both high temporal resolution (70 ms vol TR) and spatial resolution (1.5 mm isotropic voxel size), using a segmented 2D GRE EPI sequence based on [1], and tested the ability to detect sequential sub-second activations during a visual perception task with 500 ms delayed flickering checkerboard stimuli presented to the left and right lateral visual hemispheres. In the visual perception task the signal in the left and right lateral visual cortices showed periodic temporal behavior, tracking the temporal dynamics of the stimulus. A delay in the onset of the hemodynamic response function (HRF) matching the onset order of the visual stimuli is present at the majority (68 %) of all single trials in most participants, with the best participant having an accuracy of 100 % and the worst of 30 %. The feasibility of high temporal resolution fMRI in humans at 9.4 T to show temporal sequential activation in the visual cortex was shown. This method is currently being used in an ongoing study to investigate the sequential neuronal activation, ramping slope differences, and other neuronal correlates in the primary motor cortex and the supplementary motor area during movement initiation timing across different sub- and suprasecond intervals.
References[1] Stirnberg et al (2021). Magn. Reson. Med.