Parcellation of left parietal tool representations by functional connectivity

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Tool manipulation integrates visual, conceptual, and motor information, largely involving the left parietal cortex.
• The precise integration mechanisms and neural representations within the parietal lobule are not fully understood.

Purpose of the Study:

• To investigate the functional organization and heterogeneity of tool representations in the left parietal cortex.
• To identify distinct subregions within the left parietal cortex based on their functional connectivity during tool processing.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used while participants viewed images of tools and animals.
• k-Means clustering of time series data parcellated left parietal cortex based on functional connectivity.
• Control analyses (Monte Carlo permutation tests) and hierarchical clustering were employed to validate the findings.

Main Results:

• Three distinct clusters were identified in the left parietal cortex with privileged functional connectivity to different brain regions involved in tool processing.
• An inferior parietal cluster connected with the ventral premotor cortex.
• An anterior intraparietal sulcus cluster connected with the medial fusiform gyrus, and a superior parietal cluster connected with dorsal occipital cortex.

Conclusions:

• The left parietal cortex exhibits significant functional heterogeneity in representing manipulable objects.
• This functional parcellation provides a framework for understanding the neural basis of upper limb apraxia.