Complexity affects regional cerebral blood flow change during sequential finger movements

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Understanding the neural basis of complex motor sequences is crucial for cognitive neuroscience.
• Sequential finger movements involve intricate coordination and planning.
• Previous research has identified brain regions involved in simple motor tasks, but less is known about complex sequences.

Purpose of the Study:

• To identify brain regions activated during complex sequential finger movements.
• To investigate how brain activation patterns change with increasing movement sequence complexity.
• To explore the roles of specific brain areas in motor sequence storage and execution.

Main Methods:

• Positron emission tomography (PET) was used to measure regional cerebral blood flow (rCBF).
• Participants performed auditory-cued sequential finger movements of the right hand with varying complexity (sequence length).
• Brain activation was analyzed across four conditions of differing sequence complexity.

Main Results:

• Bilateral primary sensorimotor areas, left ventral premotor cortex, posterior supplementary motor area, right superior cerebellum, and left putamen were consistently activated.
• Right dorsal premotor cortex and right precuneus showed increased rCBF with higher sequence complexity.
• Left inferior parietal lobule showed decreased rCBF as complexity increased, potentially indicating suppression of unused systems.

Conclusions:

• Complex sequential finger movements recruit a distinct set of brain areas beyond those for simple movements.
• The dorsal premotor cortex and precuneus are involved in storing and producing motor sequences in spatial working memory.
• The findings suggest a dynamic interplay between different brain regions, including suppression of irrelevant systems, during complex motor tasks.