Normative Brain Size Variation and the Remodeling of Brain Shape in Humans

AbstractEvolutionary and developmental increases in primate brain size have been accompanied by systematic shifts in the proportionality of different primate brain systems. However, it remains unknown if and how brain patterning varies across the more than 2-fold inter-individual variation in brain size that occurs amongst typically-developing humans. Using in vivo neuroimaging data from 2 independent cohorts totaling nearly 3000 individuals, we find that larger-brained humans show preferential areal expansion within specific fronto-parietal cortical networks (default mode, dorsal attentional) and related subcortical regions, at the expense of primary sensory/motor systems. This targeted areal expansion recapitulates cortical remodeling across evolution, manifests by early childhood and is linked to molecular signatures of heightened metabolic cost. Our results define a new organizing principle in human brain patterning which governs the highly-coordinated remodeling of human brain shape as a function of naturally-occurring variations in brain size.One Sentence SummaryA hodologically and metabolically expensive brain network is preferentially expanded in larger-brained humans.

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Normative brain size variation and brain shape diversity in humans

Science ◽

10.1126/science.aar2578 ◽

2018 ◽

Vol 360 (6394) ◽

pp. 1222-1227 ◽

Cited By ~ 72

Author(s):

P. K. Reardon ◽

Jakob Seidlitz ◽

Simon Vandekar ◽

Siyuan Liu ◽

Raihaan Patel ◽

...

Keyword(s):

Brain Size ◽

Size Variation ◽

Metabolic Cost ◽

Brain Regions ◽

Brain Organization ◽

Neuroimaging Data ◽

Subcortical Regions ◽

Human Brains ◽

Brain Shape

Brain size variation over primate evolution and human development is associated with shifts in the proportions of different brain regions. Individual brain size can vary almost twofold among typically developing humans, but the consequences of this for brain organization remain poorly understood. Using in vivo neuroimaging data from more than 3000 individuals, we find that larger human brains show greater areal expansion in distributed frontoparietal cortical networks and related subcortical regions than in limbic, sensory, and motor systems. This areal redistribution recapitulates cortical remodeling across evolution, manifests by early childhood in humans, and is linked to multiple markers of heightened metabolic cost and neuronal connectivity. Thus, human brain shape is systematically coupled to naturally occurring variations in brain size through a scaling map that integrates spatiotemporally diverse aspects of neurobiology.

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Evolutionarily developed connections compromised in schizophrenia

10.1101/387506 ◽

2018 ◽

Cited By ~ 2

Author(s):

Martijn P. van den Heuvel ◽

Lianne H. Scholtens ◽

Siemon C. de Lange ◽

Rory Pijnenburg ◽

Wiepke Cahn ◽

...

Keyword(s):

Human Brain ◽

Genetic Basis ◽

Brain Connectivity ◽

Brain Evolution ◽

Brain Dysfunction ◽

Human Brain Evolution ◽

Evolutionary Changes ◽

Neuroimaging Data ◽

The Cost

AbstractThe genetic basis and uniquely human character of schizophrenia has led to the notion of human brain evolution to have resulted in vulnerability to the disorder. We examined schizophrenia-related changes in brain connectivity in the context of evolutionary changes in human brain wiring by comparingin-vivoneuroimaging data from humans, chimpanzees and macaque monkeys. We find that evolutionary changes in human connectome organization overlap with the pattern of schizophrenia-related changes in brain connectivity, with connections evolutionary enhanced in the human brain showing significantly more involvement in schizophrenia pathology than connections shared between humans and non-human primates (effects shown in three independent patient-control datasets). Our findings suggest that the evolution of brain wiring in support of complex brain function in humans may have come at the cost of an increased vulnerability to brain dysfunction in disease.

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Variation in the strength of allometry drives rates of evolution in primate brain shape

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.0807 ◽

2020 ◽

Vol 287 (1930) ◽

pp. 20200807 ◽

Cited By ~ 1

Author(s):

G. Sansalone ◽

K. Allen ◽

J. A. Ledogar ◽

S. Ledogar ◽

D. R. Mitchell ◽

...

Keyword(s):

Brain Size ◽

Three Dimensional ◽

Shape Evolution ◽

Evolutionary Time ◽

Primate Brain ◽

Rates Of Evolution ◽

Evolutionary Allometry ◽

The Relationship ◽

The Brain ◽

Brain Shape

Large brains are a defining feature of primates, as is a clear allometric trend between body mass and brain size. However, important questions on the macroevolution of brain shape in primates remain unanswered. Here we address two: (i), does the relationship between the brain size and its shape follow allometric trends and (ii), is this relationship consistent over evolutionary time? We employ three-dimensional geometric morphometrics and phylogenetic comparative methods to answer these questions, based on a large sample representing 151 species and most primate families. We found two distinct trends regarding the relationship between brain shape and brain size. Hominoidea and Cercopithecinae showed significant evolutionary allometry, whereas no allometric trends were discernible for Strepsirrhini, Colobinae or Platyrrhini. Furthermore, we found that in the taxa characterized by significant allometry, brain shape evolution accelerated, whereas for taxa in which such allometry was absent, the evolution of brain shape decelerated. We conclude that although primates in general are typically described as large-brained, strong allometric effects on brain shape are largely confined to the order's representatives that display more complex behavioural repertoires.

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Feature Article: A Connectomic Hypothesis for the Hominization of the Brain

Cerebral Cortex ◽

10.1093/cercor/bhaa365 ◽

2020 ◽

Author(s):

Jean-Pierre Changeux ◽

Alexandros Goulas ◽

Claus C Hilgetag

Keyword(s):

Human Brain ◽

Cognitive Abilities ◽

Brain Size ◽

Brain Connectivity ◽

Feature Article ◽

Primate Brain ◽

Gene Level ◽

Small Set ◽

The Brain ◽

Human Specific

Abstract Cognitive abilities of the human brain, including language, have expanded dramatically in the course of our recent evolution from nonhuman primates, despite only minor apparent changes at the gene level. The hypothesis we propose for this paradox relies upon fundamental features of human brain connectivity, which contribute to a characteristic anatomical, functional, and computational neural phenotype, offering a parsimonious framework for connectomic changes taking place upon the human-specific evolution of the genome. Many human connectomic features might be accounted for by substantially increased brain size within the global neural architecture of the primate brain, resulting in a larger number of neurons and areas and the sparsification, increased modularity, and laminar differentiation of cortical connections. The combination of these features with the developmental expansion of upper cortical layers, prolonged postnatal brain development, and multiplied nongenetic interactions with the physical, social, and cultural environment gives rise to categorically human-specific cognitive abilities including the recursivity of language. Thus, a small set of genetic regulatory events affecting quantitative gene expression may plausibly account for the origins of human brain connectivity and cognition.

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In Vivo 1H MR Spectroscopic Imaging of Human Brain

Journal of the Korean Radiological Society ◽

10.3348/jkrs.1994.31.2.185 ◽

1994 ◽

Vol 31 (2) ◽

pp. 185

Author(s):

Yong Whee Bahk ◽

Kyung Sub Shinn ◽

Tae Suk Suh ◽

Bo Young Choe ◽

Kyo Ho Choi

Keyword(s):

Human Brain ◽

Spectroscopic Imaging ◽

Mr Spectroscopic Imaging

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In vivo magnetic resonance imaging and 31P spectroscopy of large human brain tumours at 1.5 tesla

Acta Radiologica ◽

10.3109/02841858809171216 ◽

1988 ◽

Vol 29 (1) ◽

pp. 77-82 ◽

Cited By ~ 3

Author(s):

C. Thomsen ◽

K. E. Jensen ◽

E. Achten ◽

O. Henriksen

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Human Brain ◽

Brain Tumours ◽

Resonance Imaging ◽

Human Brain Tumours

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Fear-induced brain activations distinguish anxious and trauma-exposed brains

Translational Psychiatry ◽

10.1038/s41398-020-01193-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhenfu Wen ◽

Marie-France Marin ◽

Jennifer Urbano Blackford ◽

Zhe Sage Chen ◽

Mohammed R. Milad

Keyword(s):

Neural Network ◽

Fear Conditioning ◽

Psychiatric Diagnosis ◽

Data Analytics ◽

Conditioned Fear ◽

Brain Regions ◽

Brain Network ◽

Neuroimaging Data ◽

Task Irrelevant ◽

Translational Models

AbstractTranslational models of fear conditioning and extinction have elucidated a core neural network involved in the learning, consolidation, and expression of conditioned fear and its extinction. Anxious or trauma-exposed brains are characterized by dysregulated neural activations within regions of this fear network. In this study, we examined how the functional MRI activations of 10 brain regions commonly activated during fear conditioning and extinction might distinguish anxious or trauma-exposed brains from controls. To achieve this, activations during four phases of a fear conditioning and extinction paradigm in 304 participants with or without a psychiatric diagnosis were studied. By training convolutional neural networks (CNNs) using task-specific brain activations, we reliably distinguished the anxious and trauma-exposed brains from controls. The performance of models decreased significantly when we trained our CNN using activations from task-irrelevant brain regions or from a brain network that is irrelevant to fear. Our results suggest that neuroimaging data analytics of task-induced brain activations within the fear network might provide novel prospects for development of brain-based psychiatric diagnosis.

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In vivo proton magnetic resonance spectroscopy studies of human brain

Magnetic Resonance Imaging ◽

10.1016/0730-725x(91)90415-i ◽

1991 ◽

Vol 9 (3) ◽

pp. 303-308 ◽

Cited By ~ 64

Author(s):

P.A. Narayana ◽

D. Johnston ◽

D.P. Flamig

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Human Brain ◽

Proton Magnetic Resonance ◽

Proton Magnetic Resonance Spectroscopy ◽

Resonance Spectroscopy ◽

Spectroscopy Studies

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Different environmental variables predict body and brain size evolution in Homo

Nature Communications ◽

10.1038/s41467-021-24290-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Manuel Will ◽

Mario Krapp ◽

Jay T. Stock ◽

Andrea Manica

Keyword(s):

Environmental Factors ◽

Cognitive Abilities ◽

Net Primary Productivity ◽

Brain Size ◽

Environmental Influence ◽

Size Variation ◽

Evolutionary Pattern ◽

Statistical Framework ◽

Size Evolution ◽

Major Predictor

AbstractIncreasing body and brain size constitutes a key macro-evolutionary pattern in the hominin lineage, yet the mechanisms behind these changes remain debated. Hypothesized drivers include environmental, demographic, social, dietary, and technological factors. Here we test the influence of environmental factors on the evolution of body and brain size in the genus Homo over the last one million years using a large fossil dataset combined with global paleoclimatic reconstructions and formalized hypotheses tested in a quantitative statistical framework. We identify temperature as a major predictor of body size variation within Homo, in accordance with Bergmann’s rule. In contrast, net primary productivity of environments and long-term variability in precipitation correlate with brain size but explain low amounts of the observed variation. These associations are likely due to an indirect environmental influence on cognitive abilities and extinction probabilities. Most environmental factors that we test do not correspond with body and brain size evolution, pointing towards complex scenarios which underlie the evolution of key biological characteristics in later Homo.

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