Journal Article

7T Spin-echo BOLD fMRI enhances spatial specificity in the human motor cortex during finger movement tasks

Kim, Dongho, Eun, Seulgi, Han, SoHyun, Cho, HyungJoon, Kim, Seong-Gi

2025

Overview

•High-resolution 7T SE-BOLD fMRI was employed to observe fine-scale structures in M1.•SE-BOLD fMRI showed higher spatial specificity compared to GE-BOLD fMRI, providing non-invasive evidence of fine-grained organizational patterns.•An MR-compatible data glove was used to record hand motion in real-time during fMRI acquisition. The human primary motor cortex (M1) follows a well-established somatotopic organization, yet finer-scale representations, such as mirrored finger maps, have remained difficult to resolve non-invasively. To investigate movement representations in an action-based framework rather than a strictly somatotopic layout, we conducted both conventional gradient-echo (GE) and highly specific spin-echo (SE) BOLD fMRI at 7 T with 1 mm isotropic resolution. Subjects performed 1-Hz visually-instructed thumb–index finger or thumb–ring finger opposition tasks, and their finger movements were recorded using an MR-compatible data glove to verify proper task performance. In each subject, the activated M1 region spanning multiple slices was subdivided into ten columns along a medial-to-lateral axis. Finger dominance (index vs. ring) was determined within each column. In GE-BOLD fMRI, two distinct tasks exhibited similar activation patterns across columns, reflecting its limited ability to resolve columnar activation differences due to contamination from draining vein effects. In contrast, SE-BOLD fMRI revealed alternating task dominance across columns, demonstrating higher spatial specificity compared to GE-BOLD. By integrating SE-BOLD fMRI, but not GE-BOLD, with behavioral data, we present a more accurate mesoscopic mapping of motor activity in individual subjects. These findings provide non-invasive evidence of fine-grained motor organization, demonstrating the utility of SE-BOLD contrast for mapping mesoscopic representations.

• Publisher: Elsevier Inc,Elsevier Limited,Elsevier
• Subject: Adult / Brain Mapping - methods / Cortex (motor) / Cortical Columnar Specificity / Dominance / Experiments / Female / Finger / Fingers - physiology / Functional magnetic resonance imaging / Hand motion measurement / Humans / Linens / Magnetic Resonance Imaging - methods / Male / Mapping / Mesoscopic fMRI / Motor activity / Motor Cortex - physiology / Motor cortex organization / Movement - physiology / Radiology/Diagnostic Imaging / Spin-echo BOLD (SE-BOLD) / Young Adult