The anatomy of the brain constrains its function

The human brain is one of the most complex and mysterious systems known to science. Despite the significant advances in neuroscience over the past few decades, our understanding of how the brain works remains limited. One of the key challenges in understanding brain function is determining its relationship with brain structure. However, a recent article published in Nature titled “Geometric Constraints on Human Brain Function” presents an innovative approach to understanding the complex interplay between brain structure and function.¹

The article argues that the physical architecture of the brain imposes geometric constraints on its function. Specifically, the authors propose that the arrangement and structure of neural connections play a vital role in determining the brain's functional capabilities. The article describes how the brain can be viewed as a network of interconnected nodes and edges, with the nodes representing neurons and the edges representing the connections between neurons.

The authors present several examples supporting this concept. They demonstrate how certain brain regions have higher degrees of connectivity, while others exhibit more localization of function. For instance, regions of the brain that are responsible for motor control have higher connectivity, while those that mediate sensory processing are more specialized.

The article also discusses how changes in connectivity due to disease or injury can lead to functional impairment. For example, an injury in the parietal cortex, which is involved in spatial awareness, can affect an individual's ability to navigate their surroundings. Similarly, changes in connectivity in the amygdala, which is involved in processing emotions, can cause mood disorders and anxiety.

Another interesting concept presented in the article is how the geometry of neural connections may be optimized for specific functions, such as object recognition or language processing. The authors propose that this optimization may be achieved through the connectivity of subnetworks with different geometries within the brain.

One of the strengths of the article is the use of mathematical models and simulations to test the proposed hypotheses. The authors developed a set of models that demonstrated how the geometry of neural connections affected brain function in different scenarios, such as the execution of motor tasks or the recognition of objects. These simulations provided evidence supporting the hypothesis that the brain's functional capabilities are determined, to some extent, by its physical geometry.

However, some limitations of the article should also be noted. First, the article relied heavily on mathematical modeling and simulation, which may not accurately reflect the complexity of the brain. Second, the study's focus on the physical structure of the brain may ignore the roles of other factors, such as genetic and environmental influences, in shaping brain function. Finally, while the article presents interesting hypotheses, further empirical research is needed to test them.

Nonetheless, the article remains an innovative and significant contribution to the field of neuroscience. It provides an exciting new way of conceptualizing the relationship between brain structure and function, and it raises intriguing questions for future research. Structure–function coupling refers to the relationship between the physical structure of a biological system and the functions it performs.² This understanding is essential for determining how variation in structure, whether caused by genetic or environmental factors, can impact function and ultimately contribute to disease. Individual differences in disease states can be significantly influenced by variation in structure–function coupling. For example, genetic mutations may alter the structure of a protein, potentially affecting its function and causing disease. Similarly, structural changes in tissues or organs (e.g., due to injury, aging, or environmental stressors) can disrupt normal function and contribute to disease development. Moreover, individual differences in structure–function coupling can influence how diseases manifest and progress in different individuals.³ This could explain why individuals with the same disease may exhibit different symptoms or respond differently to the same treatment.

One of the implications of the article's contribution to understanding the geometry of neural connections is the potential development of new treatments for neurological disorders. For example, if changes in connectivity patterns due to disease or injury can cause functional impairment, then interventions aimed at restoring the normal geometry of neural connections could be beneficial. Moreover, as the authors note, the principles underlying the brain's geometry and connectivity may inform the design of more robust and capable artificial intelligence (AI) systems.

Overall, “Geometric Constraints on Human Brain Function” presents a compelling and thought-provoking perspective on brain function. It provides evidence supporting the hypothesis that the brain's physical architecture plays an important role in determining its functional capabilities. While the study's limitations should be considered, it is an innovative and significant contribution to the field of neuroscience. Its findings could have significant implications for the development of new treatments for neurological disorders and the design of more advanced AI systems.

Haofuzi Zhang: Writing—original draft; writing—review & editing. Xiaofan Jiang: Writing—review & editing.

The authors declare that they have no competing interests.