NSF Workshop Report: Discovering General Principles of Nervous System Organization by Comparing Brain Maps across Species

Abstract

Efforts to understand nervous system structure and function have received new impetus from the federal Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. Comparative analyses can contribute to this effort by leading to the discovery of general principles of neural circuit design, information processing, and gene-structure-function relationships that are not apparent from studies on single species. We here propose to extend the comparative approach to nervous system ‘maps' comprising molecular, anatomical, and physiological data. This research will identify which neural features are likely to generalize across species, and which are unlikely to be broadly conserved. It will also suggest causal relationships between genes, development, adult anatomy, physiology, and, ultimately, behavior. These causal hypotheses can then be tested experimentally. Finally, insights from comparative research can inspire and guide technological development. To promote this research agenda, we recommend that teams of investigators coalesce around specific research questions and select a set of ‘reference species' to anchor their comparative analyses. These reference species should be chosen not just for practical advantages, but also with regard for their phylogenetic position, behavioral repertoire, well-annotated genome, or other strategic reasons. We envision that the nervous systems of these reference species will be mapped in more detail than those of other species. The collected data may range from the molecular to the behavioral, depending on the research question. To integrate across levels of analysis and across species, standards for data collection, annotation, archiving, and distribution must be developed and respected. To that end, it will help to form networks or consortia of researchers and centers for science, technology, and education that focus on organized data collection, distribution, and training. These activities could be supported, at least in part, through existing mechanisms at NSF, NIH, and other agencies. It will also be important to develop new integrated software and database systems for cross-species data analyses. Multidisciplinary efforts to develop such analytical tools should be supported financially. Finally, training opportunities should be created to stimulate multidisciplinary, integrative research into brain structure, function, and evolution.

The Utility of DiceCT Imaging for High-Throughput Comparative Neuroanatomical Studies

“…Specimens were subsequently prepared using Nissl staining, fluorescent immunohistochemical staining, and diceCT imaging. As a result of these efforts, there is a clear pathway to accessing potentially large numbers of specimens from remote locations for neuroanatomical research, expanding the potential breadth of comparative brain, spinal cord, and peripheral nerve studies [Striedter et al, 2014].…”

Convergent evolution of neural systems in ctenophores

“…The reconstruction of the origins of neural systems requires a careful selection of reference species (Striedter et al, 2014). We can set the stage in this direction starting from the enigmatic Ctenophora.…”

Applying gene regulatory network logic to the evolution of social behavior

“…Furthermore, behavioral biologists, neuroendocrinologists, and neuroanatomists need to continue to champion comparative approaches and emphasize the value of studying multiple species in an evolutionary context (28). First, having such a broad perspective will ensure that the most sophisticated technologies can be used to answer important biological questions in a wider range of species.…”