Neuroscience needs evolution

Abstract

The nervous system is a product of evolution. That is, it was constructed through a long series of modifications, within the strong constraints of heredity, and continuously subjected to intense selection pressures. As a result, the organization and functions of the brain are shaped by its history. We believe that this fact, underappreciated in contemporary systems neuroscience, offers an invaluable aid for helping us resolve the brain's mysteries. Indeed, we think that the consideration of evolutionary history ought to take its place alongside other intellectual tools used to understand the brain, such as behavioural experiments, studies of anatomical structure and functional characterization based on recordings of neural activity. In this introduction, we argue for the importance of evolution by highlighting specific examples of ways that evolutionary theory can enhance neuroscience. The rest of the theme issue elaborates this point, emphasizing the conservative nature of neural evolution, the important consequences of specific transitions that occurred in our history, and the ways in which considerations of evolution can shed light on issues ranging from specific mechanisms to fundamental principles of brain organization. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.

Color-biased regions in the ventral visual pathway are food-selective

“…Conway (2018) proposed a tripartite organization of the ventral visual pathway, consisting of parallel streams for faces, places, and color, based on the results of studies in both humans and macaques (Lafer-Sousa et al, 2016; Lafer-Sousa and Conway, 2013; Verhoef et al, 2015). Humans share a common ancestor with macaques 25 million years ago (Conway, 2018) and as the human brain is a product of evolution, it is important to consider these systems from an evolutionary perspective as this might inform key principles of cortical organization (Cisek and Hayden, 2021). Our present findings for humans do not change the proposed organization of the ventral visual pathway but rather replace the idea of color specialization with specialization for food.…”

Linking hubness, embryonic neurogenesis, transcriptomics and diseases in human brain networks

“…The general structure and functionality of the human brain and its embedded connectivity are the result of its developmental history, which is at the same time the product of evolution 5 . This way, the brain follows developmental instructions that decisively impact on the diversification of neural connections and their functions.…”

Thermotaxis in an apolar, non-neuronal animal

“…However, even at low gradient strengths, the organism is mostly able to detect the gradient. (See SI Fig.4 for the trajectories for trials with the three lowest Δ T that we tried, see SI Video 2 for video of trial with shallowest gradient) (d) We observe a drop in directionality index in organisms larger than 1.25 mm 2 .…”

“…For incremental values of L (window length - time is not fixed here, only the total distance traveled in each window) up to 2cm, < R 2 > was calculated as the averaged squared displacement between non-overlapping contours of length L. Then, the parameter L p was determined using a least regression fit in MATLAB. Then, plotting L against L p , we determined the window length L for which we get the longest persistence length.…”

“…It has been said that "nothing in neuroscience makes sense except in the light of behavior" 1 or "evolution". 2 How organisms integrate and transform sensory information into behavioral responses has both fascinated and confounded us since the days of Aristotle. Most behavioral responses in traditional biological model systems involve complex neuronal circuits.…”