Brain activity during predictable and unpredictable weight changes when lifting objects

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• Humans adapt grip force based on object weight through sensorimotor memory.
• Anticipatory force programming relies on stored representations of object weight.

Purpose of the Study:

• To investigate the neural mechanisms underlying sensorimotor memory updating during object manipulation.
• To identify brain regions involved in adapting to predictable and unpredictable weight changes.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to record brain activity in healthy subjects.
• Participants performed repetitive lifting tasks with constant, regular, or irregular object weight changes.
• Brain activations were analyzed by contrasting different weight change conditions.

Main Results:

• Activations were observed in the right inferior frontal gyrus (area 44), left parietal operculum, and right supramarginal gyrus.
• The right inferior frontal cortex showed stronger activation during irregular weight changes compared to regular changes.
• These findings suggest a role for fronto-parietal circuits in updating sensorimotor memories and executing corrective actions.

Conclusions:

• The updating of sensorimotor memory representations is associated with neural activity in fronto-parietal circuits.
• Corrective reactions to unexpected object weight changes involve these same neural circuits.
• These brain regions are crucial for adapting motor control to varying object properties.