The small world of the cerebral cortex

Area of Science:

• Neuroscience
• Computational Biology
• Graph Theory

Background:

• Structural connectivity of the cerebral cortex is extensively studied, particularly in primates.
• However, the fundamental organizational principles of connection patterns across brain areas, columns, and individual cells remain unclear.

Purpose of the Study:

• To characterize diverse cortical connectivity datasets using graph theory methods.
• To identify universal organizational principles in cortical connection patterns.

Main Methods:

• Application of graph theory to analyze cortical connection matrices.
• Measurement of global graph aspects: small structural motifs (e.g., cycles), local clustering, and average path length.
• Examination of both large-scale neuroanatomical and probabilistic connection matrices.

Main Results:

• All analyzed cortical connection matrices demonstrate "small-world" attributes.
• These attributes are characterized by high local clustering and short average path lengths between neuronal elements.
• Identified universal organizational features across different scales of cortical connectivity.

Conclusions:

• The "small-world" architecture is a fundamental organizational principle of the cerebral cortex.
• These findings provide insights into the functional brain anatomy and information processing capabilities of the cortex.