Decoding Effector-Specific Parametric Grip-Force Anticipation From fMRI-Data

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.