Brain evolution

A neuroanatomical study of the brains of tool-using teleost fishes highlights the pallium and inferior lobe as the putative structures responsible for this behavior, and suggests that there are multiple ways of evolving tool-using brains.

As brain tissue is metabolically expensive, the evolutionary expansion of human brains required shifts in energy intake and metabolism. The External Fermentation Hypothesis proposes that a shift to consumption of externally fermented foods in human ancestors permitted a reduction in gut tissue required for internal fermentation, facilitating brain expansion.

In this Perspective, the authors illustrate how the use of companion animal models will provide insight into of the neurobiology of aging.

Recent advances in paleoneurology are collated together in this comprehensive review, linking neuroanatomy to genes and behavior. We provide guidance to the next generation of researchers to move the field forward.

High-resolution morphological reconstructions and computational models of cerebellar Purkinje cells (PCs) from humans and mice suggest that, while PCs in both species maintain similar spike discharge properties, human PCs developed more complex dendrites.

An evolutionary study in 34 primates provides evidence for a primate-general expansion of cerebellar crura I-II. Specifically, common accelerated scaling may directly explain previously reported high volumetric fractions of the human crura I-II.

Comparative fMRI in dogs and humans reveals functionally analogous body- and animacy responsive areas in the occipito-temporal lobe of both species and divergent neural representations of faces and conspecific bodies in dog olfactory regions.

Human and chimpanzee brain MRI scans reveal that the surface anatomy of the posteromedial cortex substantially differs between the species, which improves our understanding of the evolution of neuroanatomical-functional and neuroanatomical-behavioural relationships.

fMRI analysis of marmosets performing goal- or non-goal-directed grasping tasks suggests they share an action observation network similar to those observed in macaques and humans.

Cross-species analysis of brain mass and neuron number suggest that larger-brained species tend to shift towards more right-lateralized individuals, which should be considered in the context of the evolution of hemispheric asymmetries moving forward.

Like humans, marmoset caregivers exhibit individual parenting styles. Among these, infant tolerance is in part regulated by a subregion of the medial preoptic area enriched with calcitonin receptor-expressing neurons.

Integration of functional, structural, and neurochemical data proposes a framework to comprehensively understand the neural basis of attention across different species and neurological diseases.

Comparisons of frontoparietal connectivity between marmosets, rats and grey squirrels suggest the formation of a common frontoparietal network architecture among arboreal species (grey squirrels and marmosets) that might reflect convergent evolution.

Combined high-field MRI and DTI analyses in post-mortem mouse, marmoset, and human samples provide insight into the neural connections between nasal cavities and olfactory bulbs.

MRI and network modelling reveal correlation between the degree of involvement of the two corticospinal networks and the lateralization of handedness in humans.

Massen, Hartlieb, Martin et al. study the duration of yawns across mammals and birds to test the brain cooling hypothesis. Consistent with this hypothesis, their findings indicate that brain mass and neuron numbers influence yawn duration, and that mammals yawn longer than birds with similar brain and body masses.

Bertrand and colleagues use virtual endocasts from a variety of living and extinct rodent species to assess the effect of locomotion, body mass and phylogeny on the size of the brain and three of its components. Their findings indicate that arboreal and fossorial locomotor types correlate with differential expansion of the neocortex, petrosal lobules, and relative brain size.

Bibi and Tyler analyse the morphometric variation in the skulls of 96 species across Bovidae, using 3D geometric morphometrics and ecological variables. They show that ecological variables alone appear to have little connection to shape disparity in bovid skulls, instead discovering a deeply conserved association between size and shape that is linked to dietary selection.

The analysis of the schizophrenia polygenic load along the genomic Human Accelerated Regions (HARs) provides insight into the influence of early brain development regulation on the neuroanatomical changes associated with schizophrenia.

Comparative analysis of human, macaque and mouse function and genetic heterogeneity in the brain reveals links between gene expression and orderly topography of functional networks.

A genome-wide association study on MRI cerebellar volume in the UK Biobank cohort identifies 30 loci with genome-wide significance that might be relevant to brain structure and cognitive function.

Comparisons of fMRI data from humans and chimpanzees suggests that the Prefrontal extent of the Frontal Operculum region recently evolved in humans possibly in relation to the emergence of modern speech.

The brain size of carnivores has evolved to balance a trade-off between increased cognitive function and increased metabolic cost.