Opinion
Emerging from the bottleneck: benefits of the comparative approach to modern neuroscience

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Highlights

  • Neuroscience has historically exploited a wide diversity of animal taxa.

  • Over the past two decades research has focused on only a few model species.

  • Coalescence on a small number of model species comes with potential costs.

  • Comparative studies of non-model species can complement model species research.

Neuroscience has historically exploited a wide diversity of animal taxa. Recently, however, research has focused increasingly on a few model species. This trend has accelerated with the genetic revolution, as genomic sequences and genetic tools became available for a few species, which formed a bottleneck. This coalescence on a small set of model species comes with several costs that are often not considered, especially in the current drive to use mice explicitly as models for human diseases. Comparative studies of strategically chosen non-model species can complement model species research and yield more rigorous studies. As genetic sequences and tools become available for many more species, we are poised to emerge from the bottleneck and once again exploit the rich biological diversity offered by comparative studies.

Section snippets

Biological diversity as a resource for neuroscience

Model species such as the fruit fly (Drosophila melanogaster), the nematode ‘worm’ (Caenorhabditis. elegans), zebrafish (Danio rerio), the rat (Rattus rattus), and, most predominantly, the mouse (Mus musculus) have played an important role in biology. A given species may offer particular advantages for the study of a biological process, such as rapid embryonic development, accessible nervous systems, or ease of maintenance in the laboratory. The advantages of model species have become more

Potential limitations of the model species approach

Over the past 20 years or so, neuroscience and much of biology in general has coalesced from the traditional embrace of diverse species down to a small number of model species. There are various practical reasons for this process of concentration. Model species tend to be readily available, easily maintained in captivity, and are feasible to breed in large numbers. As a species becomes a well-established model for a research community, there is an exponential growth in the amount of available

Benefits of comparative approaches

Having discussed the potential limitations of the model species approach, we will consider the positive benefits of the comparative approach in which studies are designed to exploit species diversity in neural mechanisms.

A clear benefit is the potential for discovering novel adaptations that may have broad transformative impact. An example is the study of ongoing neurogenesis in adult brains. The addition of new neurons to the brain of adults of higher vertebrates was first suggested in the

Concluding comments: looking backward, looking forward

During the years when neuroscience was emerging as a distinct field of study, pioneering investigators worked on an eclectic variety of wild species, choosing the species for the question [5], rather than the question for the (model) species – as is too often the case now. Research on marine invertebrates, insects, fish, salamanders, frogs, turtles, chicks, and bats played a large role in developing this field. Pioneering neuroscientists and physiologists such as Ted Bullock, Steven Kuffler,

Acknowledgments

Our research is funded by the NIH (grants MH53032 and NS075331 to E.A.B.), the Department of Army (grant W911NF-14-1-0265 to H.H.Z.), a Carl Friedrich von Siemens Research Award from the Alexander von Humboldt Foundation (to H.H.Z.), and a traveling scientist award from the Virginia Merrill Bloedel Hearing Research Center at the University of Washington, Seattle (to H.H.Z.).

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