The Evolutionary Development of the Brain As It Pertains to Neurosurgery.

Background Neuroanatomists have long been fascinated by the complex topographic organization of the cerebrum. We examined historical and modern phylogenetic theories pertaining to microneurosurgical anatomy and intrinsic brain tumor development. Methods Literature and history related to the study of anatomy, evolution, and tumor predilection of the limbic and paralimbic regions were reviewed. We used vertebrate histological cross-sections, photographs from Albert Rhoton Jr.'s dissections, and original drawings to demonstrate the utility of evolutionary temporal causality in understanding anatomy. Results Phylogenetic neuroanatomy progressed from the substantial works of Alcmaeon, Herophilus, Galen, Vesalius, von Baer, Darwin, Felsenstein, Klingler, MacLean, and many others. We identified two major modern evolutionary theories: "triune brain" and topological phylogenetics. While the concept of "triune brain" is speculative and highly debated, it remains the most popular in the current neurosurgical literature. Phylogenetics inspired by mathematical topology utilizes computational, statistical, and embryological data to analyze the temporal transformations leading to three-dimensional topographic anatomy. These transformations have shaped well-defined surgical planes, which can be exploited by the neurosurgeon to access deep cerebral targets. The microsurgical anatomy of the cerebrum and the limbic system is redescribed by incorporating the dimension of temporal causality. Yasargil's anatomical classification of glial tumors can be revisited in light of modern phylogenetic cortical categorization. Conclusion Historical and modern topological phylogenetic notions provide a deeper understanding of neurosurgical anatomy and approaches to the limbic and paralimbic regions. However, many questions remain unanswered and further research is needed to elucidate the anatomical pathology of intrinsic brain tumors.