Decoding Effector-Specific Parametric Grip-Force Anticipation From fMRI-Data
Guido Caccialupi1,2, Timo Torsten Schmidt1, Felix Blankenburg1,2
1Neurocomputation and Neuroimaging Unit (NNU), Freie Universität Berlin, Berlin, Germany.
Human Brain Mapping
|December 30, 2025
Summary
Brain regions like the intraparietal sulcus and lateral occipitotemporal cortex encode grip-force intensity in an effector-specific manner before motor cortex activation.
Area of Science:
- Neuroscience
- Motor Control
- Cognitive Neuroscience
Background:
- Motor planning involves neuronal representations of force and timing.
- Previous fMRI studies show premotor and parietal activity correlates with motor preparation parameters.
- The effector-specificity of these representations remains unclear.
Purpose of the Study:
- To investigate whether grip-force intensity is encoded in an effector-specific or effector-independent format in the brain.
- To identify brain regions involved in the parametric coding of grip-force during motor preparation.
Main Methods:
- Functional magnetic resonance imaging (fMRI) with time-resolved multivoxel pattern analysis (MVPA) and a searchlight approach.
- A delayed grip-force task with cued hand-use and mid-delay hand-switching.
- Cross-decoding analyses to assess effector-specificity.
Main Results:
- Above-chance decoding of grip-force intensity in contralateral intraparietal sulcus (IPS) and lateral occipitotemporal cortex (LOTC) during the first delay period.
- Decoding shifted to contralateral primary motor cortices (M1) during the second delay period.
- Systematic lateralization of decoding accuracy based on the cued hand indicated effector-specific coding.
Conclusions:
- Contralateral IPS and LOTCs encode effector-specific grip-force intensity information prior to M1.
- This suggests a transformation process where intended force is selected, maintained, and converted into movement plans.
- The findings highlight effector-specific neural representations during motor preparation.
