Brain phylogeny, ontogeny and dysfunction: integrating evolutionary, developmental and clinical perspectives in cognitive neuroscience

Objective: One of the most popular approaches in cognitive neuroscience has been to study the normal adult human brain. However, there are likely to be limits to the knowledge that can be obtained from such studies. If we assume that no single approach can ever provide us with knowledge of causative processes whereby the mind emerges from the brain, then we need to consider how to combine more disparate approaches. I aim to illustrate here how the parallel study of brain phylogeny, ontogeny and dysfunction may bring us towards an integrative understanding of fundamental aspects of cognitive neuroscience. Methods: A review of published literature in these research areas was carried out and representative articles selected. Results: Comparative approaches, utilizing the extraordinary behavioural abilities as well as the structural and functional variants that evolution has thrown up across diverse groups of species, can inform the core neural systems that may be necessary and sufficient to support specific cognitive processes. Similarly, detailed studies of human brain development, focusing on structural and functional maturation correlated with temporal mapping of cognitive processes as they come 'on-line', may provide unique mechanistic insights. Finally, the study of brain dysfunction in neurological and psychiatric disorders such as Huntington's disease, Alzheimer's disease, schizophrenia and depression, may have the beneficial side-effect of greatly enhancing our understanding of healthy brain function. Conclusion: Each approach has its own epistemological advantages and disadvantages, but combined they may lead to more sophisticated, and empirically testable, models. In this review, I outline evidence for their utility, illustrate the approaches using specific examples and suggest how new advances in fields such as genomics, neurophysiology and neuroimaging may provide unprecedented opportunities in cognitive neuroscience.