Modality-specific cognitive function of medial and lateral human Brodmann area 6

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Brodmann area 6 (BA6), traditionally viewed as a motor region, shows activity during complex cognitive tasks.
• The specific cognitive functions and specialization within BA6 remain largely unexplored.
• Previous findings are often attributed to underlying motor processes, questioning BA6's direct cognitive role.

Purpose of the Study:

• To investigate the structural-functional relationship of human BA6 in non-motor cognitive functions.
• To determine the functional relevance of BA6 in cognitive tasks using neuroimaging and stimulation.
• To elucidate the modality-specific roles within BA6 for cognitive operations.

Main Methods:

• Employed functional magnetic resonance imaging (fMRI) to observe brain activity during cognitive tasks.
• Utilized repetitive transcranial magnetic stimulation (rTMS) to probe the causal role of BA6 regions.
• Subjects performed mental-operation (MO) tasks involving serial updating of verbal (MO-v) and spatial (MO-s) representations.

Main Results:

• fMRI revealed increased activity in medial BA6 for MO-v and lateral BA6 for MO-s.
• rTMS applied to medial BA6 selectively impaired MO-v performance.
• rTMS applied to lateral BA6 selectively impaired MO-s performance, demonstrating a double dissociation.

Conclusions:

• Medial BA6 plays a critical role in updating verbal information.
• Lateral BA6 is essential for updating spatial information.
• These findings provide direct physiological evidence for modality-specific cognitive functions within human BA6.