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Venditti C, Baker J, Barton RA. Co-evolutionary dynamics of mammalian brain and body size. Nat Ecol Evol 2024:10.1038/s41559-024-02451-3. [PMID: 38977833 DOI: 10.1038/s41559-024-02451-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 05/29/2024] [Indexed: 07/10/2024]
Abstract
Despite decades of comparative studies, puzzling aspects of the relationship between mammalian brain and body mass continue to defy satisfactory explanation. Here we show that several such aspects arise from routinely fitting log-linear models to the data: the correlated evolution of brain and body mass is in fact log-curvilinear. This simultaneously accounts for several phenomena for which diverse biological explanations have been proposed, notably variability in scaling coefficients across clades, low encephalization in larger species and the so-called taxon-level problem. Our model implies a need to revisit previous findings about relative brain mass. Accounting for the true scaling relationship, we document dramatically varying rates of relative brain mass evolution across the mammalian phylogeny, and we resolve the question of whether there is an overall trend for brain mass to increase through time. We find a trend in only three mammalian orders, which is by far the strongest in primates, setting the stage for the uniquely rapid directional increase ultimately producing the computational powers of the human brain.
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Affiliation(s)
- Chris Venditti
- School of Biological Sciences, University of Reading, Reading, UK.
| | - Joanna Baker
- School of Biological Sciences, University of Reading, Reading, UK
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2
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Parkkinen S, Radua J, Andrews DS, Murphy D, Dell'Acqua F, Parlatini V. Cerebellar network alterations in adult attention-deficit/hyperactivity disorder. J Psychiatry Neurosci 2024; 49:E233-E241. [PMID: 38960626 PMCID: PMC11230668 DOI: 10.1503/jpn.230146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 03/07/2024] [Accepted: 05/22/2024] [Indexed: 07/05/2024] Open
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition that often persists into adulthood. Underlying alterations in brain connectivity have been identified but some relevant connections, such as the middle, superior, and inferior cerebellar peduncles (MCP, SCP, and ICP, respectively), have remained largely unexplored; thus, we sought to investigate whether the cerebellar peduncles contribute to ADHD pathophysiology among adults. METHODS We applied diffusion-weighted spherical deconvolution tractography to dissect the cerebellar peduncles of male adults with ADHD (including those who did or did not respond to methylphenidate, based on at least 30% symptom improvement at 2 months) and controls. We investigated differences in tract metrics between controls and the whole ADHD sample and between controls and treatment-response groups using sensitivity analyses. Finally, we analyzed the association between the tract metrics and cliniconeuropsychological profiles. RESULTS We included 60 participants with ADHD (including 42 treatment responders and 18 nonresponders) and 20 control participants. In the whole ADHD sample, MCP fractional anisotropy (FA; t 78 = 3.24, p = 0.002) and hindrance modulated orientational anisotropy (HMOA; t 78 = 3.01, p = 0.004) were reduced, and radial diffusivity (RD) in the right ICP was increased (t 78 = -2.84, p = 0.006), compared with controls. Although case-control differences in MCP FA and HMOA, which reflect white-matter microstructural organization, were driven by both treatment response groups, only responders significantly differed from controls in right ICP RD, which relates to myelination (t 60 = 3.14, p = 0.003). Hindrance modulated orientational anisotropy of the MCP was significantly positively associated with hyperactivity measures. LIMITATIONS This study included only male adults with ADHD. Further research needs to investigate potential sex- and development-related differences. CONCLUSION These results support the role of the cerebellar networks, especially of the MCP, in adult ADHD pathophysiology and should encourage further investigation. CLINICAL TRIAL REGISTRATION NCT03709940.
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Affiliation(s)
- Salla Parkkinen
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
| | - Joaquim Radua
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
| | - Derek S Andrews
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
| | - Declan Murphy
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
| | - Flavio Dell'Acqua
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
| | - Valeria Parlatini
- From the Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Andrews, Murphy, Dell'Acqua, Parlatini); the Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Parkkinen, Murphy, Dell'Acqua, Parlatini); the Institut d'Investigacions Biomèdiques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain (Radua); the Department of Psychiatry and Behavioral Sciences, The MIND Institute, University of California, Davis, Sacramento, CA, USA (Andrews); the Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Dell'Acqua); the NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK (Dell'Acqua); the School of Psychology, University of Southampton, Southampton, UK (Parlatini); the Solent NHS Trust, Southampton, UK (Parlatini)
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3
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Li S, Liu Y, DU X, Li G, Liao W. Nest complexity correlates with larger brain size but smaller body mass across bird species. Integr Zool 2024; 19:496-504. [PMID: 37378973 DOI: 10.1111/1749-4877.12744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Amniotes differ substantially in absolute and relative brain size after controlling for allometry, and numerous hypotheses have been proposed to explain brain size evolution. Brain size is thought to correlate with processing capacity and the brain's ability to support complex manipulation such as nest-building skills. The increased complexity of nest structure is supposed to be a measure of an ability to manipulate nesting material into the required shape. The degree of nest-structure complexity is also supposed to be associated with body mass, partly because small species lose heat faster and delicate and insulated nests are more crucial for temperature control of eggs during incubation by small birds. Here, we conducted comparative analyses to test these hypotheses by investigating whether the complexity of species-typical nest structure can be explained by brain size and body mass (a covariate also to control for allometric effects on brain size) across 1353 bird species from 147 families. Consistent with these hypotheses, our results revealed that avian brain size increases as the complexity of the nest structure increases after controlling for a significant effect of body size, and also that a negative relationship exists between nest complexity and body mass.
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Affiliation(s)
- Shaobin Li
- College of Life Science, Yangtze University, Jingzhou, China
| | - Yuxin Liu
- College of Life Science, Yangtze University, Jingzhou, China
| | - Xiaolong DU
- College of Life Science, Yangtze University, Jingzhou, China
| | - Guopan Li
- College of Life Science, Yangtze University, Jingzhou, China
| | - Wenbo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, China
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4
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Hirsch BT, Kays R, Alavi S, Caillaud D, Havmoller R, Mares R, Crofoot M. Smarter foragers do not forage smarter: a test of the diet hypothesis for brain expansion. Proc Biol Sci 2024; 291:20240138. [PMID: 38808448 DOI: 10.1098/rspb.2024.0138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/24/2024] [Indexed: 05/30/2024] Open
Abstract
A leading hypothesis for the evolution of large brains in humans and other species is that a feedback loop exists whereby intelligent animals forage more efficiently, which results in increased energy intake that fuels the growth and maintenance of large brains. We test this hypothesis for the first time with high-resolution tracking data from four sympatric, frugivorous rainforest mammal species (42 individuals) and drone-based maps of their predominant feeding trees. We found no evidence that larger-brained primates had more efficient foraging paths than smaller brained procyonids. This refutes a key assumption of the fruit-diet hypothesis for brain evolution, suggesting that other factors such as temporal cognition, extractive foraging or sociality have been more important for brain evolution.
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Affiliation(s)
- Ben T Hirsch
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- College of Science and Engineering, James Cook University, Townsville, Australia
| | - Roland Kays
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- North Carolina Museum of Natural Sciences, Raleigh, NC, USA
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
| | - Shauhin Alavi
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Konstanz, Germany
| | - Damien Caillaud
- Department of Anthropology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA
| | - Rasmus Havmoller
- Natural History Museum of Denmark, University of Copenhagen, Kobenhavn, Denmark
| | - Rafael Mares
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
| | - Margaret Crofoot
- Smithsonian Tropical Research Institute, Balboa, Republic of Panamá
- Natural History Museum of Denmark, University of Copenhagen, Kobenhavn, Denmark
- Department of Biology, University of Konstanz, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
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5
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Rickelton K, Zintel TM, Pizzollo J, Miller E, Ely JJ, Raghanti MA, Hopkins WD, Hof PR, Sherwood CC, Bauernfeind AL, Babbitt CC. Tempo and mode of gene expression evolution in the brain across primates. eLife 2024; 13:e70276. [PMID: 38275218 PMCID: PMC10876213 DOI: 10.7554/elife.70276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 01/25/2024] [Indexed: 01/27/2024] Open
Abstract
Primate evolution has led to a remarkable diversity of behavioral specializations and pronounced brain size variation among species (Barton, 2012; DeCasien and Higham, 2019; Powell et al., 2017). Gene expression provides a promising opportunity for studying the molecular basis of brain evolution, but it has been explored in very few primate species to date (e.g. Khaitovich et al., 2005; Khrameeva et al., 2020; Ma et al., 2022; Somel et al., 2009). To understand the landscape of gene expression evolution across the primate lineage, we generated and analyzed RNA-seq data from four brain regions in an unprecedented eighteen species. Here, we show a remarkable level of variation in gene expression among hominid species, including humans and chimpanzees, despite their relatively recent divergence time from other primates. We found that individual genes display a wide range of expression dynamics across evolutionary time reflective of the diverse selection pressures acting on genes within primate brain tissue. Using our samples that represent a 190-fold difference in primate brain size, we identified genes with variation in expression most correlated with brain size. Our study extensively broadens the phylogenetic context of what is known about the molecular evolution of the brain across primates and identifies novel candidate genes for the study of genetic regulation of brain evolution.
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Affiliation(s)
- Katherine Rickelton
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Biology Graduate Program, University of Massachusetts AmherstAmherstUnited States
| | - Trisha M Zintel
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Biology Graduate Program, University of Massachusetts AmherstAmherstUnited States
| | - Jason Pizzollo
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Biology Graduate Program, University of Massachusetts AmherstAmherstUnited States
| | - Emily Miller
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
| | - John J Ely
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington UniversityWashingtonUnited States
- MAEBIOS Epidemiology UnitAlamogordoUnited States
| | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State UniversityKentUnited States
| | - William D Hopkins
- Department of Comparative Medicine, Michale E. Keeling Center for Comparative Medicine,The University of Texas M D Anderson Cancer CentreBastropUnited States
| | - Patrick R Hof
- New York Consortium in Evolutionary PrimatologyNew YorkUnited States
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington UniversityWashingtonUnited States
| | - Amy L Bauernfeind
- Department of Neuroscience, Washington University School of MedicineSt. LouisUnited States
- Department of Anthropology, Washington University in St. LouisSt. LouisUnited States
| | - Courtney C Babbitt
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
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6
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Martín-González E, Prados-Pardo Á, Sawiak SJ, Dalley JW, Padro D, Ramos-Cabrer P, Mora S, Moreno-Montoya M. Mapping the neuroanatomical abnormalities in a phenotype of male compulsive rats. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2023; 19:19. [PMID: 37932782 PMCID: PMC10626819 DOI: 10.1186/s12993-023-00221-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 10/28/2023] [Indexed: 11/08/2023]
Abstract
Compulsivity is considered a transdiagnostic dimension in obsessive-compulsive and related disorders, characterized by heterogeneous cognitive and behavioral phenotypes associated with abnormalities in cortico-striatal-thalamic-cortical circuitry. The present study investigated the structural morphology of white and gray matter in rats selected for low- (LD) and high- (HD) compulsive drinking behavior on a schedule-induced polydipsia (SIP) task. Regional brain morphology was assessed using ex-vivo high-resolution magnetic resonance imaging (MRI). Voxel-based morphometry of segmented MRI images revealed larger white matter volumes in anterior commissure and corpus callosum of HD rats compared with LD rats. HD rats also showed significantly larger regional volumes of dorsolateral orbitofrontal cortex, striatum, amygdala, hippocampus, midbrain, sub-thalamic nucleus, and cerebellum. By contrast, the medial prefrontal cortex was significantly smaller in HD rats compared with LD rats with no significant group differences in whole brain, ventricular, or cerebrospinal fluid volumes. These findings show that limbic cortico-basal ganglia structures implicated in impulse control disorders are distinct in rats that are vulnerable to develop compulsive behavior. Such abnormalities may be relevant to the etiology of compulsive disorders in humans.
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Affiliation(s)
- Elena Martín-González
- Department of Psychology and Health Research Centre (CEINSA), University of Almería, Carretera de Sacramento s/n, 04120, Almería, Spain
| | - Ángeles Prados-Pardo
- Department of Psychology and Health Research Centre (CEINSA), University of Almería, Carretera de Sacramento s/n, 04120, Almería, Spain
| | - Stephen J Sawiak
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Jeffrey W Dalley
- Department of Psychology, University of Cambridge, Cambridge, UK
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Daniel Padro
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramón 182, 20014, Donostia-San Sebastián, Spain
| | - Pedro Ramos-Cabrer
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramón 182, 20014, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Santiago Mora
- Department of Neuroscience, University of Copenhagen Panum Institute, Copenhagen, Denmark
| | - Margarita Moreno-Montoya
- Department of Psychology and Health Research Centre (CEINSA), University of Almería, Carretera de Sacramento s/n, 04120, Almería, Spain.
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Heuer K, Traut N, de Sousa AA, Valk SL, Clavel J, Toro R. Diversity and evolution of cerebellar folding in mammals. eLife 2023; 12:e85907. [PMID: 37737580 PMCID: PMC10617990 DOI: 10.7554/elife.85907] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 09/22/2023] [Indexed: 09/23/2023] Open
Abstract
The process of brain folding is thought to play an important role in the development and organisation of the cerebrum and the cerebellum. The study of cerebellar folding is challenging due to the small size and abundance of its folia. In consequence, little is known about its anatomical diversity and evolution. We constituted an open collection of histological data from 56 mammalian species and manually segmented the cerebrum and the cerebellum. We developed methods to measure the geometry of cerebellar folia and to estimate the thickness of the molecular layer. We used phylogenetic comparative methods to study the diversity and evolution of cerebellar folding and its relationship with the anatomy of the cerebrum. Our results show that the evolution of cerebellar and cerebral anatomy follows a stabilising selection process. We observed two groups of phenotypes changing concertedly through evolution: a group of 'diverse' phenotypes - varying over several orders of magnitude together with body size, and a group of 'stable' phenotypes varying over less than 1 order of magnitude across species. Our analyses confirmed the strong correlation between cerebral and cerebellar volumes across species, and showed in addition that large cerebella are disproportionately more folded than smaller ones. Compared with the extreme variations in cerebellar surface area, folial anatomy and molecular layer thickness varied only slightly, showing a much smaller increase in the larger cerebella. We discuss how these findings could provide new insights into the diversity and evolution of cerebellar folding, the mechanisms of cerebellar and cerebral folding, and their potential influence on the organisation of the brain across species.
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Affiliation(s)
- Katja Heuer
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
| | - Nicolas Traut
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
| | | | - Sofie Louise Valk
- Otto Hahn Group Cognitive Neurogenetics, Max Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
- Institute of Neuroscience and Medicine, Brain & Behaviour (INM-7), Research Centre Jülich, FZ JülichJülichGermany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Julien Clavel
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNAVilleurbanneFrance
| | - Roberto Toro
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
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8
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Zeiträg C, Reber SA, Osvath M. Gaze following in Archosauria-Alligators and palaeognath birds suggest dinosaur origin of visual perspective taking. SCIENCE ADVANCES 2023; 9:eadf0405. [PMID: 37205749 DOI: 10.1126/sciadv.adf0405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/17/2023] [Indexed: 05/21/2023]
Abstract
Taking someone else's visual perspective marks an evolutionary shift in the formation of advanced social cognition. It enables using others' attention to discover otherwise hidden aspects of the surroundings and is foundational for human communication and understanding of others. Visual perspective taking has also been found in some other primates, a few songbirds, and some canids. However, despite its essential role for social cognition, visual perspective taking has only been fragmentedly studied in animals, leaving its evolution and origins uncharted. To begin to narrow this knowledge gap, we investigated extant archosaurs by comparing the neurocognitively least derived extant birds-palaeognaths-with the closest living relatives of birds, the crocodylians. In a gaze following paradigm, we showed that palaeognaths engage in visual perspective taking and grasp the referentiality of gazes, while crocodylians do not. This suggests that visual perspective taking originated in early birds or nonavian dinosaurs-likely earlier than in mammals.
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Affiliation(s)
- Claudia Zeiträg
- Department of Philosophy and Cognitive Science, Lund University, Lund, Sweden
| | - Stephan A Reber
- Department of Philosophy and Cognitive Science, Lund University, Lund, Sweden
| | - Mathias Osvath
- Department of Philosophy and Cognitive Science, Lund University, Lund, Sweden
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Abstract
Large brains provide adaptive cognitive benefits but require unusually high, near-constant energy inputs and become fully functional well after their growth is completed. Consequently, young of most larger-brained endotherms should not be able to independently support the growth and development of their own brains. This paradox is solved if the evolution of extended parental provisioning facilitated brain size evolution. Comparative studies indeed show that extended parental provisioning coevolved with brain size and that it may improve immature survival. The major role of extended parental provisioning supports the idea that the ability to sustain the costs of brains limited brain size evolution.
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10
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Gräßle T, Crockford C, Eichner C, Girard‐Buttoz C, Jäger C, Kirilina E, Lipp I, Düx A, Edwards L, Jauch A, Kopp KS, Paquette M, Pine K, Haun DBM, McElreath R, Anwander A, Gunz P, Morawski M, Friederici AD, Weiskopf N, Leendertz FH, Wittig RM, Albig K, Amarasekaran B, Angedakin S, Anwander A, Aschoff D, Asiimwe C, Bailanda L, Beehner JC, Belais R, Bergman TJ, Blazey B, Bernhard A, Bock C, Carlier P, Chantrey J, Crockford C, Deschner T, Düx A, Edwards L, Eichner C, Escoubas G, Ettaj M, Fedurek P, Flores K, Francke R, Friederici AD, Girard‐Buttoz C, Fortun JG, GoneBi ZB, Gräßle T, Gruber‐Dujardin E, Gunz P, Hartel J, Haun DBM, Henshall M, Hobaiter C, Hofman N, Jaffe JE, Jäger C, Jauch A, Kahemere S, Kirilina E, Klopfleisch R, Knauf‐Witzens T, Kopp KS, Kouima GLM, Lange B, Langergraber K, Lawrenz A, Leendertz FH, Lipp I, Liptovszky M, Theron TL, Lumbu CP, Nzassi PM, Mätz‐Rensing K, McElreath R, McLennan M, Mezö Z, Moittie S, Møller T, Morawski M, Morgan D, Mugabe T, Muller M, Müller M, Njumboket I, Olofsson‐Sannö K, Ondzie A, Otali E, Paquette M, Pika S, Pine K, Pizarro A, Pléh K, Rendel J, Reichler‐Danielowski S, Robbins MM, Forero AR, Ruske K, Samuni L, Sanz C, Schüle A, Schwabe I, Schwalm K, Speede S, Southern L, Steiner J, Stidworthy M, Surbeck M, Szentiks C, Tanga T, Ulrich R, Unwin S, van de Waal E, Walker S, Weiskopf N, Wibbelt G, Wittig RM, Wood K, Zuberbühler K. Sourcing high tissue quality brains from deceased wild primates with known socio‐ecology. Methods Ecol Evol 2023. [DOI: 10.1111/2041-210x.14039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Tobias Gräßle
- Epidemiology of highly pathogenic microorganisms Robert Koch‐Institute Berlin Germany
- Helmholtz Institute for One Health Greifswald Germany
| | - Catherine Crockford
- Ape Social Mind Lab Institute of Cognitive Science Marc Jeannerod, UMR 5229, CNRS Lyon France
- Department of Human Behavior, Ecology and Culture Max Planck Institute for Evolutionary Anthropology Leipzig Germany
- Taï Chimpanzee Project Centre Suisse de Recherches Scientifiques en Côte d'Ivoire Abidjan Ivory Coast
| | - Cornelius Eichner
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Cédric Girard‐Buttoz
- Ape Social Mind Lab Institute of Cognitive Science Marc Jeannerod, UMR 5229, CNRS Lyon France
- Department of Human Behavior, Ecology and Culture Max Planck Institute for Evolutionary Anthropology Leipzig Germany
- Taï Chimpanzee Project Centre Suisse de Recherches Scientifiques en Côte d'Ivoire Abidjan Ivory Coast
| | - Carsten Jäger
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- Paul Flechsig Institute ‐ Center of Neuropathology and Brain Research, Faculty of Medicine Universität Leipzig Germany
| | - Evgeniya Kirilina
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- Center for Cognitive Neuroscience Berlin Freie Universität Berlin Berlin Germany
| | - Ilona Lipp
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Ariane Düx
- Epidemiology of highly pathogenic microorganisms Robert Koch‐Institute Berlin Germany
- Helmholtz Institute for One Health Greifswald Germany
| | - Luke Edwards
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Anna Jauch
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Kathrin S. Kopp
- Department of Comparative Cultural Psychology Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Michael Paquette
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Kerrin Pine
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Daniel B. M. Haun
- Department of Comparative Cultural Psychology Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Richard McElreath
- Department of Human Behavior, Ecology and Culture Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Alfred Anwander
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Philipp Gunz
- Department of Human Evolution Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Markus Morawski
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- Paul Flechsig Institute ‐ Center of Neuropathology and Brain Research, Faculty of Medicine Universität Leipzig Germany
| | - Angela D. Friederici
- Department of Neuropsychology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
| | - Nikolaus Weiskopf
- Department of Neurophysics Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences Leipzig University Leipzig Germany
| | - Fabian H. Leendertz
- Epidemiology of highly pathogenic microorganisms Robert Koch‐Institute Berlin Germany
- Helmholtz Institute for One Health Greifswald Germany
| | - Roman M. Wittig
- Ape Social Mind Lab Institute of Cognitive Science Marc Jeannerod, UMR 5229, CNRS Lyon France
- Department of Human Behavior, Ecology and Culture Max Planck Institute for Evolutionary Anthropology Leipzig Germany
- Taï Chimpanzee Project Centre Suisse de Recherches Scientifiques en Côte d'Ivoire Abidjan Ivory Coast
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11
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Neuron numbers link innovativeness with both absolute and relative brain size in birds. Nat Ecol Evol 2022; 6:1381-1389. [PMID: 35817825 DOI: 10.1038/s41559-022-01815-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 05/19/2022] [Indexed: 12/31/2022]
Abstract
A longstanding issue in biology is whether the intelligence of animals can be predicted by absolute or relative brain size. However, progress has been hampered by an insufficient understanding of how neuron numbers shape internal brain organization and cognitive performance. On the basis of estimations of neuron numbers for 111 bird species, we show here that the number of neurons in the pallial telencephalon is positively associated with a major expression of intelligence: innovation propensity. The number of pallial neurons, in turn, is greater in brains that are larger in both absolute and relative terms and positively covaries with longer post-hatching development periods. Thus, our analyses show that neuron numbers link cognitive performance to both absolute and relative brain size through developmental adjustments. These findings help unify neuro-anatomical measures at multiple levels, reconciling contradictory views over the biological significance of brain expansion. The results also highlight the value of a life history perspective to advance our understanding of the evolutionary bases of the connections between brain and cognition.
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12
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Schumacher EL, Carlson BA. Convergent mosaic brain evolution is associated with the evolution of novel electrosensory systems in teleost fishes. eLife 2022; 11:74159. [PMID: 35713403 PMCID: PMC9333993 DOI: 10.7554/elife.74159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 06/16/2022] [Indexed: 11/16/2022] Open
Abstract
Brain region size generally scales allometrically with brain size, but mosaic shifts in brain region size independent of brain size have been found in several lineages and may be related to the evolution of behavioral novelty. African weakly electric fishes (Mormyroidea) evolved a mosaically enlarged cerebellum and hindbrain, yet the relationship to their behaviorally novel electrosensory system remains unclear. We addressed this by studying South American weakly electric fishes (Gymnotiformes) and weakly electric catfishes (Synodontis spp.), which evolved varying aspects of electrosensory systems, independent of mormyroids. If the mormyroid mosaic increases are related to evolving an electrosensory system, we should find similar mosaic shifts in gymnotiforms and Synodontis. Using micro-computed tomography scans, we quantified brain region scaling for multiple electrogenic, electroreceptive, and non-electrosensing species. We found mosaic increases in cerebellum in all three electrogenic lineages relative to non-electric lineages and mosaic increases in torus semicircularis and hindbrain associated with the evolution of electrogenesis and electroreceptor type. These results show that evolving novel electrosensory systems is repeatedly and independently associated with changes in the sizes of individual major brain regions independent of brain size, suggesting that selection can impact structural brain composition to favor specific regions involved in novel behaviors. Larger animals tend to have larger brains and smaller animals tend to have smaller ones. However, some species do not fit the pattern that would be expected based on their body size. This variation between species can also apply to individual brain regions. This may be due to evolutionary forces shaping the brain when favouring particular behaviours. However, it is difficult to directly link changes in species behaviour and variations in brain structure. One way to understand the impact of evolutionary adaptations is to study species that have developed new behaviours and compare them to related ones that lack such a behaviour. An opportunity to do this lies in the ability of several species of fish to produce and sense electric fields in water. While this system is not found in most fish, it has evolved multiple times independently in distantly-related lineages. Schumacher and Carlson examined whether differences in the size of brains and individual regions between species were associated with the evolution of electric field generation and sensing. Micro-computed tomography, or μCT, scans of the brains of multiple fish species revealed that the species that can produce electricity – also known as ‘electrogenic’ species’ – have more similar brain structures to each other than to their close relatives that lack this ability. The brain regions involved in producing and detecting electrical charges were larger in these electrogenic fish. This similarity was apparent despite variations in how total brain size has evolved with body size across species. These results demonstrate how evolutionary forces acting on particular behaviours can lead to predictable changes in brain structure. Understanding how and why brains evolve will allow researchers to better predict how species’ brains and behaviours may adapt as human activities alter their environments.
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Affiliation(s)
- Erika L Schumacher
- Department of Biology, Washington University in St. Louis, St. Louis, United States
| | - Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, United States
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13
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Ash H, Chang A, Ortiz RJ, Kulkarni P, Rauch B, Colman R, Ferris CF, Ziegler TE. Structural and functional variations in the prefrontal cortex are associated with learning in pre-adolescent common marmosets (Callithrix jacchus). Behav Brain Res 2022; 430:113920. [PMID: 35595058 PMCID: PMC9362994 DOI: 10.1016/j.bbr.2022.113920] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 04/06/2022] [Accepted: 05/04/2022] [Indexed: 12/27/2022]
Abstract
There is substantial evidence linking the prefrontal cortex (PFC) to a variety of cognitive abilities, with adolescence being a critical period in its development. In the current study, we investigated the neural basis of differences in learning in pre-adolescent common marmosets. At 8 months old, marmosets were given anatomical and resting state MRI scans (n=24). At 9 months old, association learning and inhibitory control was tested using a 'go/no go' visual discrimination (VD) task. Marmosets were grouped into 'learners' (n=12) and 'non-learners' (n=12), and associations between cognitive performance and sub-regional PFC volumes, as well as PFC connectivity patterns, were investigated. 'Learners' had significantly (p<0.05) larger volumes of areas 11, 25, 47 and 32 than 'non-learners', although 'non-learners' had significantly larger volumes of areas 24a and 8v than 'learners'. There was also a significant correlation between average % correct responses to the 'punished' stimulus and volume of area 47. Further, 'non-learners' had significantly greater global PFC connections, as well as significantly greater numbers of connections between the PFC and basal ganglia, cerebellum and hippocampus, compared to 'non-learners'. These results suggest that larger sub-regions of the orbitofrontal cortex and ventromedial PFC, as well more refined PFC connectivity patterns to other brain regions associated with learning, may be important in successful response inhibition. This study therefore offers new information on the neurodevelopment of individual differences in cognition during pre-adolescence in non-human primates.
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Affiliation(s)
- Hayley Ash
- Wisconsin National Primate Research Center, University of Wisconsin, Madison WI.
| | - Arnold Chang
- Center for Translational NeuroImaging, Northeastern University, Boston MA
| | - Richard J Ortiz
- Center for Translational NeuroImaging, Northeastern University, Boston MA; Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces NM
| | - Praveen Kulkarni
- Center for Translational NeuroImaging, Northeastern University, Boston MA
| | - Beth Rauch
- Department of Medical Physics, University of Wisconsin, Madison WI
| | - Ricki Colman
- Wisconsin National Primate Research Center, University of Wisconsin, Madison WI; Department of Cell and Regenerative Biology, University of Wisconsin, Madison WI
| | - Craig F Ferris
- Center for Translational NeuroImaging, Northeastern University, Boston MA
| | - Toni E Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin, Madison WI
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14
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Domestication effects on social information transfer in chickens. Anim Cogn 2022; 25:1473-1478. [PMID: 35507205 PMCID: PMC9652291 DOI: 10.1007/s10071-022-01628-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/30/2022] [Accepted: 04/17/2022] [Indexed: 11/28/2022]
Abstract
Red junglefowl (RJF), ancestor of all domesticated chickens, is a highly social, omnivorous bird species, presumably with a capacity for social information sharing. During domestication, birds have been selected to live in large, dynamic groups, and this may have affected their social cognition. Here, we studied social information transfer in female RJF and domesticated White Leghorn (WL) chickens. Individuals were trained to open a puzzle-box feeder by pecking a lid and we then recorded the behaviour towards the same puzzle-box feeder for birds that had either observed the trained individual (“guided”) or saw the puzzle-box feeder for the first time (“naïve”). WL were considerably faster in approaching the feeder regardless of prior demonstration and pecked more at it. Both breeds were significantly faster to approach the puzzle-box feeder and pecked more after prior demonstration, but the effects were significantly stronger in WL. We conclude that both RJF and WL can utilize social information to address a novel problem, but during domestication this ability appears to have increased. The effects can be an effect of either social learning or stimulus enhancement. Some caution in this conclusion is necessary since we tested relatively few WL. Furthermore, possible confounding explanations include higher fearfulness in RJF and different effects of dominance interactions between demonstrators and observers.
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15
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Quan P, He L, Mao T, Fang Z, Deng Y, Pan Y, Zhang X, Zhao K, Lei H, Detre JA, Kable JW, Rao H. Cerebellum Anatomy Predicts Individual Risk-taking Behavior and Risk Tolerance. Neuroimage 2022; 254:119148. [PMID: 35346839 DOI: 10.1016/j.neuroimage.2022.119148] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/09/2022] [Accepted: 03/24/2022] [Indexed: 11/30/2022] Open
Abstract
Human risk tolerance is highly idiosyncratic and individuals often show distinctive preferences when faced with similar risky situations. However, the neural underpinnings of individual differences in risk-taking remain unclear. Here we combined structural and perfusion MRI and examined the associations between brain anatomy and individual risk-taking behavior/risk tolerance in a sample of 115 healthy participants during the Balloon Analogue Risk Task, a well-established sequential risky decision paradigm. Both whole brain and region-of-interest analyses showed that the left cerebellum gray matter volume (GMV) has a strong association with individual risk-taking behavior and risk tolerance, outperforming the previously reported associations with the amygdala and right posterior parietal cortex (PPC) GMV. Left cerebellum GMV also accounted for risk tolerance and risk-taking behavior changes with aging. However, regional cerebral blood flow (CBF) provided no additional predictive power. These findings suggest a novel cerebellar anatomical contribution to individual differences in risk tolerance. Further studies are necessary to elucidate the underestimated important role of cerebellum in risk-taking.
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Affiliation(s)
- Peng Quan
- Research Center for Quality of Life and Applied Psychology, Guangdong Medical University, Dongguan, China; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lisheng He
- SILC Business School, Shanghai University, Shanghai, China
| | - Tianxin Mao
- Center for Magnetic Resonance Imaging Research & Key Laboratory of Applied Brain and Cognitive Sciences, School of Business and Management, Shanghai International Studies University, Shanghai, China; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhuo Fang
- Center for Magnetic Resonance Imaging Research & Key Laboratory of Applied Brain and Cognitive Sciences, School of Business and Management, Shanghai International Studies University, Shanghai, China; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yao Deng
- Center for Magnetic Resonance Imaging Research & Key Laboratory of Applied Brain and Cognitive Sciences, School of Business and Management, Shanghai International Studies University, Shanghai, China; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yu Pan
- Center for Magnetic Resonance Imaging Research & Key Laboratory of Applied Brain and Cognitive Sciences, School of Business and Management, Shanghai International Studies University, Shanghai, China
| | - Xiaocui Zhang
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ke Zhao
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hui Lei
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph W Kable
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hengyi Rao
- Center for Magnetic Resonance Imaging Research & Key Laboratory of Applied Brain and Cognitive Sciences, School of Business and Management, Shanghai International Studies University, Shanghai, China; Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.
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16
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Abstract
The evolution of brain processing capacity has traditionally been inferred from data on brain size. However, similarly sized brains of distantly related species can differ in the number and distribution of neurons, their basic computational units. Therefore, a finer-grained approach is needed to reveal the evolutionary paths to increased cognitive capacity. Using a new, comprehensive dataset, we analyzed brain cellular composition across amniotes. Compared to reptiles, mammals and birds have dramatically increased neuron numbers in the telencephalon and cerebellum, which are brain parts associated with higher cognition. Astoundingly, a phylogenetic analysis suggests that as few as four major changes in neuron–brain scaling in over 300 million years of evolution pave the way to intelligence in endothermic land vertebrates. Reconstructing the evolution of brain information-processing capacity is paramount for understanding the rise of complex cognition. Comparative studies of brain evolution typically use brain size as a proxy. However, to get a less biased picture of the evolutionary paths leading to high cognitive power, we need to compare brains not by mass but by numbers of neurons, which are their basic computational units. This study reconstructs the evolution of brains across amniotes by directly analyzing neuron numbers by using the largest dataset of its kind and including essential data on reptiles. We show that reptiles have not only small brains relative to body size but also low neuronal densities, resulting in average neuron numbers over 20 times lower than those in birds and mammals of similar body size. Amniote brain evolution is characterized by the following four major shifts in neuron–brain scaling. The most dramatic increases in brain neurons occurred independently with the appearance of birds and mammals, resulting in convergent neuron scaling in the two endotherm lineages. The other two major increases in the number of neurons happened in core land birds and anthropoid primates, which are two groups known for their cognitive prowess. Interestingly, relative brain size is associated with relative neuronal cell density in reptiles, birds, and primates but not in other mammals. This has important implications for studies using relative brain size as a proxy when looking for evolutionary drivers of animal cognition.
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17
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DeCasien AR, Barton RA, Higham JP. Understanding the human brain: insights from comparative biology. Trends Cogn Sci 2022; 26:432-445. [DOI: 10.1016/j.tics.2022.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/27/2022] [Accepted: 02/08/2022] [Indexed: 02/08/2023]
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18
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Lingam M. The Possible Role of Body Temperature in Modulating Brain and Body Sizes in Hominin Evolution. Front Psychol 2022; 12:774683. [PMID: 35222146 PMCID: PMC8866639 DOI: 10.3389/fpsyg.2021.774683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Many models have posited that the concomitant evolution of large brains and body sizes in hominins was constrained by metabolic costs. In such studies, the impact of body temperature has arguably not been sufficiently addressed despite the well-established fact that the rates of most physiological processes are manifestly temperature-dependent. Hence, the potential role of body temperature in regulating the number of neurons and body size is investigated by means of a heuristic quantitative model. It is suggested that modest deviations in body temperature (i.e., by a couple of degrees Celsius) might allow for substantive changes in brain and body parameters. In particular, a higher body temperature may prove amenable to an increased number of neurons, a higher brain-to-body mass ratio and fewer hours expended on feeding activities, while the converse could apply when the temperature is lowered. Future studies should, therefore, endeavor to explore and incorporate the effects of body temperature in metabolic theories of hominin evolution, while also integrating other factors such as foraging efficiency, diet, and fire control in tandem.
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Affiliation(s)
- Manasvi Lingam
- Department of Aerospace, Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL, United States
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19
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Barrett L, Henzi SP, Barton RA. Experts in action: why we need an embodied social brain hypothesis. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200533. [PMID: 34957849 PMCID: PMC8710874 DOI: 10.1098/rstb.2020.0533] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The anthropoid primates are known for their intense sociality and large brain size. The idea that these might be causally related has given rise to a large body of work testing the 'social brain hypothesis'. Here, the emphasis has been placed on the political demands of social life, and the cognitive skills that would enable animals to track the machinations of other minds in metarepresentational ways. It seems to us that this position risks losing touch with the fact that brains primarily evolved to enable the control of action, which in turn leads us to downplay or neglect the importance of the physical body in a material world full of bodies and other objects. As an alternative, we offer a view of primate brain and social evolution that is grounded in the body and action, rather than minds and metarepresentation. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.
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Affiliation(s)
- Louise Barrett
- Department of Psychology, University of Lethbridge, Lethbridge, Canada
| | - S. Peter Henzi
- Department of Psychology, University of Lethbridge, Lethbridge, Canada
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20
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Bryer MAH, Koopman SE, Cantlon JF, Piantadosi ST, MacLean EL, Baker JM, Beran MJ, Jones SM, Jordan KE, Mahamane S, Nieder A, Perdue BM, Range F, Stevens JR, Tomonaga M, Ujfalussy DJ, Vonk J. The evolution of quantitative sensitivity. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200529. [PMID: 34957840 PMCID: PMC8710878 DOI: 10.1098/rstb.2020.0529] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The ability to represent approximate quantities appears to be phylogenetically widespread, but the selective pressures and proximate mechanisms favouring this ability remain unknown. We analysed quantity discrimination data from 672 subjects across 33 bird and mammal species, using a novel Bayesian model that combined phylogenetic regression with a model of number psychophysics and random effect components. This allowed us to combine data from 49 studies and calculate the Weber fraction (a measure of quantity representation precision) for each species. We then examined which cognitive, socioecological and biological factors were related to variance in Weber fraction. We found contributions of phylogeny to quantity discrimination performance across taxa. Of the neural, socioecological and general cognitive factors we tested, cortical neuron density and domain-general cognition were the strongest predictors of Weber fraction, controlling for phylogeny. Our study is a new demonstration of evolutionary constraints on cognition, as well as of a relation between species-specific neuron density and a particular cognitive ability. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.
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Affiliation(s)
- Margaret A H Bryer
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Department of Psychology, University of California-Berkeley, Berkeley, CA 94720, USA
| | - Sarah E Koopman
- School of Psychology and Neuroscience, University of St. Andrews, St Andrews KY16 9AJ, UK
| | - Jessica F Cantlon
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Steven T Piantadosi
- Department of Psychology, University of California-Berkeley, Berkeley, CA 94720, USA
| | - Evan L MacLean
- School of Anthropology, University of Arizona, Tucson, AZ 85719, USA.,College of Veterinary Medicine, University of Arizona, Tucson, AZ 85719, USA
| | - Joseph M Baker
- Center for Interdisciplinary Brain Sciences Research, Division of Brain Sciences, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Michael J Beran
- Department of Psychology and Language Research Center, Georgia State University, Atlanta, GA 30302, USA
| | - Sarah M Jones
- Psychology Program, Berea College, Berea, KY 40403, USA
| | - Kerry E Jordan
- Department of Psychology, Utah State University, Logan, UT 84322, USA
| | - Salif Mahamane
- Behavioral and Social Sciences Department, Western Colorado University, Gunnison, CO 81231, USA
| | - Andreas Nieder
- Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Bonnie M Perdue
- Department of Psychology, Agnes Scott College, Decatur, GA 30030, USA
| | - Friederike Range
- Domestication Lab, Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Savoyenstrasse 1a, Vienna 1160, Austria
| | - Jeffrey R Stevens
- Department of Psychology and Center for Brain, Biology and Behavior, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | | | - Dorottya J Ujfalussy
- MTA-ELTE Comparative Ethology Research Group, Eötvös Loránd University of Sciences (ELTE), Budapest 1117, Hungary.,Department of Ethology, Eötvös Loránd University of Sciences (ELTE), Budapest 1117, Hungary
| | - Jennifer Vonk
- Department of Psychology, Oakland University, Rochester, MI 48309, USA
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21
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Current and Future Perspectives of the Cerebellum in Affective Neuroscience. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1378:303-313. [DOI: 10.1007/978-3-030-99550-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Adamaszek M, Cattaneo Z, Ciricugno A, Chatterjee A. The Cerebellum and Beauty: The Impact of the Cerebellum in Art Experience and Creativity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1378:213-233. [DOI: 10.1007/978-3-030-99550-8_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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23
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Cerebellum and Emotion Recognition. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1378:41-51. [DOI: 10.1007/978-3-030-99550-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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24
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Bernard JA. Understanding cerebellar function through network perspectives: A review of resting-state connectivity of the cerebellum. PSYCHOLOGY OF LEARNING AND MOTIVATION 2022. [DOI: 10.1016/bs.plm.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Gabriel R. Affect, Belief, and the Arts. Front Psychol 2021; 12:757234. [PMID: 34925160 PMCID: PMC8674731 DOI: 10.3389/fpsyg.2021.757234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/01/2021] [Indexed: 11/13/2022] Open
Abstract
The cultural project is a therapeutic melding of emotion, symbols, and knowledge. In this paper, I describe how spiritual emotions engendered through encounters in imaginative culture enable fixation of metaphysical beliefs. Evolved affective systems are domesticated through the social practices of imaginative culture so as to adapt people to live in culturally defined cooperative groups. Conditioning, as well as tertiary-level cognitive capacities such as symbols and language are enlisted to bond groups through the imaginative formats of myth and participatory ritual. These cultural materializations can be shared by communities both synchronically and diachronically in works of art. Art is thus a form of self-knowledge that equips us with a motivated understanding of ourselves in the world. In the sacred state produced through the arts and in religious acts, the sense of meaning becomes noetically distinct because affect infuses the experience of immanence, and one's memory of it, with salience. The quality imbued thereby makes humans attentive to subtle signs and broad “truths.” Saturated by emotions and the experience of alterity in the immanent encounter of imaginative culture, information made salient in the sacred experience can become the basis for belief fixation. Using examples drawn from mimetic arts and arts of immanence, I put forward a theory about how sensible affective knowledge is mediated through affective systems, direct perception, and the imagination.
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Affiliation(s)
- Rami Gabriel
- Research Group in Mind, Science, and Culture, Department of History, Humanities, and Social Sciences, Columbia College Chicago, Chicago, IL, United States
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26
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Chambers HR, Heldstab SA, O’Hara SJ. Why big brains? A comparison of models for both primate and carnivore brain size evolution. PLoS One 2021; 16:e0261185. [PMID: 34932586 PMCID: PMC8691615 DOI: 10.1371/journal.pone.0261185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 11/24/2021] [Indexed: 11/19/2022] Open
Abstract
Despite decades of research, much uncertainty remains regarding the selection pressures responsible for brain size variation. Whilst the influential social brain hypothesis once garnered extensive support, more recent studies have failed to find support for a link between brain size and sociality. Instead, it appears there is now substantial evidence suggesting ecology better predicts brain size in both primates and carnivores. Here, different models of brain evolution were tested, and the relative importance of social, ecological, and life-history traits were assessed on both overall encephalisation and specific brain regions. In primates, evidence is found for consistent associations between brain size and ecological factors, particularly diet; however, evidence was also found advocating sociality as a selection pressure driving brain size. In carnivores, evidence suggests ecological variables, most notably home range size, are influencing brain size; whereas, no support is found for the social brain hypothesis, perhaps reflecting the fact sociality appears to be limited to a select few taxa. Life-history associations reveal complex selection mechanisms to be counterbalancing the costs associated with expensive brain tissue through extended developmental periods, reduced fertility, and extended maximum lifespan. Future studies should give careful consideration of the methods chosen for measuring brain size, investigate both whole brain and specific brain regions where possible, and look to integrate multiple variables, thus fully capturing all of the potential factors influencing brain size.
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Affiliation(s)
- Helen Rebecca Chambers
- School of Science, Engineering & Environment, University of Salford, Salford, Greater Manchester, United Kingdom
| | | | - Sean J. O’Hara
- School of Science, Engineering & Environment, University of Salford, Salford, Greater Manchester, United Kingdom
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27
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28
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Day LB, Helmhout W, Pano G, Olsson U, Hoeksema JD, Lindsay WR. Correlated evolution of acrobatic display and both neural and somatic phenotypic traits in manakins (Pipridae). Integr Comp Biol 2021; 61:1343-1362. [PMID: 34143205 DOI: 10.1093/icb/icab139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 12/22/2022] Open
Abstract
Brightly colored manakin (Aves: Pipridae) males are known for performing acrobatic displays punctuated by non-vocal sounds (sonations) in order to attract dull colored females. The complexity of the display sequence and assortment of display elements involved (e.g., sonations, acrobatic maneuvers, and cooperative performances) varies considerably across manakin species. Species-specific display elements coevolve with display-distinct specializations of the neuroanatomical, muscular, endocrine, cardiovascular, and skeletal systems in the handful of species studied. Conducting a broader comparative study, we previously found positive associations between display complexity and both brain mass and body mass across 8 manakin genera, indicating selection for neural and somatic expansion to accommodate display elaboration. Whether this gross morphological variation is due to overall brain and body mass expansion (concerted evolution) versus size increases in only functionally relevant brain regions and growth of particular body ("somatic") features (mosaic evolution) remains to be explored. Here we test the hypothesis that cross-species variation in male brain mass and body mass is driven by mosaic evolution. We predicted positive associations between display complexity and variation in the volume of the cerebellum and sensorimotor arcopallium, brain regions which have roles in sensorimotor processes, and learning and performance of precisely timed and sequenced thoughts and movements, respectively. In contrast, we predicted no associations between the volume of a limbic arcopallial nucleus or a visual thalamic nucleus and display complexity as these regions have no-specific functional relationship to display behavior. For somatic features, we predicted that the relationship between body mass and complexity would not include contributions of tarsus length based on a recent study suggesting selection on tarsus length is less labile than body mass. We tested our hypotheses in males from 12 manakin species and a closely related flycatcher. Our analyses support mosaic evolution of neural and somatic features functionally relevant to display and indicate sexual selection for acrobatic complexity may increase the capacity for procedural learning via cerebellar enlargement and maneuverability via a reduction in tarsus length in species with lower overall complexity scores.
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Affiliation(s)
- Lainy B Day
- Department of Biology, University of Mississippi, 30 University Avenue, University, MS 38677, USA.,Neuroscience Minor, University of Mississippi, 30 University Avenue, University, MS 38677, USA
| | - Wilson Helmhout
- Neuroscience Minor, University of Mississippi, 30 University Avenue, University, MS 38677, USA
| | - Glendin Pano
- Neuroscience Minor, University of Mississippi, 30 University Avenue, University, MS 38677, USA
| | - Urban Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18, SE-413-90 Gothenburg, Sweden.,Gothenburg Global Biodiversity Centre, Box 461, SE-405 30 Gothenburg, Sweden
| | - Jason D Hoeksema
- Department of Biology, University of Mississippi, 30 University Avenue, University, MS 38677, USA
| | - Willow R Lindsay
- Department of Biology, University of Mississippi, 30 University Avenue, University, MS 38677, USA.,Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18, SE-413-90 Gothenburg, Sweden.,Gothenburg Global Biodiversity Centre, Box 461, SE-405 30 Gothenburg, Sweden
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29
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Abstract
The endocast was paid great attention in the study of human brain evolution. However, compared to that of the cerebrum, the cerebellar lobe is poorly studied regarding its morphology, function, and evolutionary changes in the process of human evolution. In this study, we define the major axis and four measurements to inspect possible asymmetric patterns within the genus Homo. Results show that significant asymmetry is only observed for the cerebellar length in modern humans and is absent in Homo erectus and Neanderthals. The influence of occipital petalia is obscure due to the small sample size for H. erectus and Neanderthals, while it has a significant influence over the asymmetries of cerebellar height and horizontal orientation in modern humans. Although the length and height of the Neanderthal cerebellum are comparable to that of modern humans, its sagittal orientation is closer to that of H. erectus, which is wider than that of modern humans. The cerebellar morphological difference between Neanderthals and modern humans is suggested to be related to high cognitive activities, such as social factors and language ability.
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30
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Asano R. The evolution of hierarchical structure building capacity for language and music: a bottom-up perspective. Primates 2021; 63:417-428. [PMID: 33839984 PMCID: PMC9463250 DOI: 10.1007/s10329-021-00905-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 03/26/2021] [Indexed: 12/27/2022]
Abstract
A central property of human language is its hierarchical structure. Humans can flexibly combine elements to build a hierarchical structure expressing rich semantics. A hierarchical structure is also considered as playing a key role in many other human cognitive domains. In music, auditory-motor events are combined into hierarchical pitch and/or rhythm structure expressing affect. How did such a hierarchical structure building capacity evolve? This paper investigates this question from a bottom-up perspective based on a set of action-related components as a shared basis underlying cognitive capacities of nonhuman primates and humans. Especially, I argue that the evolution of hierarchical structure building capacity for language and music is tractable for comparative evolutionary study once we focus on the gradual elaboration of shared brain architecture: the cortico-basal ganglia-thalamocortical circuits for hierarchical control of goal-directed action and the dorsal pathways for hierarchical internal models. I suggest that this gradual elaboration of the action-related brain architecture in the context of vocal control and tool-making went hand in hand with amplification of working memory, and made the brain ready for hierarchical structure building in language and music.
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Affiliation(s)
- Rie Asano
- Systematic Musicology, Institute of Musicology, University of Cologne, Cologne, Germany.
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31
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Abstract
Our current understanding of manipulation is based on primate hands, resulting in a detailed but narrow perspective of ways to handle objects. Although most other animals lack hands, they are still capable of flexible manipulation of diverse objects, including food and nest materials, and depend on dexterity in object handling to survive and reproduce. Birds, for instance, use their bills and feet to forage and build nests, while insects carry food and construct nests with their mandibles and legs. Bird bills and insect mandibles are much simpler than a primate hand, resembling simple robotic grippers. A better understanding of manipulation in these and other species would provide a broader comparative perspective on the origins of dexterity. Here we contrast data from primates, birds and insects, describing how they sense and grasp objects, and the neural architectures that control manipulation. Finally, we outline techniques for collecting comparable manipulation data from animals with diverse morphologies and describe the practical applications of studying manipulation in a wide range of species, including providing inspiration for novel designs of robotic manipulators.
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Affiliation(s)
- Shoko Sugasawa
- Centre for Biological Diversity, Harold Mitchell Building, School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
| | - Barbara Webb
- School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh EH8 9AB, UK
| | - Susan D Healy
- Centre for Biological Diversity, Harold Mitchell Building, School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
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32
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Breen AJ, Sugasawa S, Healy SD. Manipulative and Technological Skills Do Not Require a Slow Life History. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.635802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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33
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Katajamaa R, Wright D, Henriksen R, Jensen P. Cerebellum size is related to fear memory and domestication of chickens. Biol Lett 2021; 17:20200790. [PMID: 33529547 DOI: 10.1098/rsbl.2020.0790] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Red Junglefowl (Gallus gallus) were selected for divergent levels of fear of humans during eight generations, causing the selection lines to differ in fear levels as well as in the proportional brain and cerebellum masses. Birds from the two lines were then crossed to obtain an F3 intercross in order to study the correlations between brain mass and fear learning. We exposed 105 F3-animals individually to a fear habituation and memory test at 8 days of age, where the reactions to repeated light flashes were assessed on 2 consecutive days. After culling, the absolute and relative sizes of each of four brain regions were measured. Stepwise regression was used to analyse the effects of the size of each brain region on habituation and memory. There were no effects of any brain region on the habituation on day one. However, birds with a larger absolute size of cerebellum had significantly reduced reactions to the fearful stimuli on day two, indicating a better memory of the stimuli. No other regions had significant effects. We conclude that increased cerebellum size may have been important in facilitating chicken domestication, allowing them to adapt to a life with humans.
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Affiliation(s)
| | - Dominic Wright
- IFM-Biology, Linköping University, 581 83 Linköping, Sweden
| | - Rie Henriksen
- IFM-Biology, Linköping University, 581 83 Linköping, Sweden
| | - Per Jensen
- IFM-Biology, Linköping University, 581 83 Linköping, Sweden
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34
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Cabrera-Álvarez MJ, Clayton NS. Neural Processes Underlying Tool Use in Humans, Macaques, and Corvids. Front Psychol 2020; 11:560669. [PMID: 33117228 PMCID: PMC7561402 DOI: 10.3389/fpsyg.2020.560669] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 08/31/2020] [Indexed: 11/25/2022] Open
Abstract
It was thought that tool use in animals is an adaptive specialization. Recent studies, however, have shown that some non-tool-users, such as rooks and jays, can use and manufacture tools in laboratory settings. Despite the abundant evidence of tool use in corvids, little is known about the neural mechanisms underlying tool use in this family of birds. This review summarizes the current knowledge on the neural processes underlying tool use in humans, macaques and corvids. We suggest a possible neural network for tool use in macaques and hope this might inspire research to discover a similar brain network in corvids. We hope to establish a framework to elucidate the neural mechanisms that supported the convergent evolution of tool use in birds and mammals.
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Affiliation(s)
| | - Nicola S Clayton
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
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35
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Miquel M, Gil-Miravet I, Guarque-Chabrera J. The Cerebellum on Cocaine. Front Syst Neurosci 2020; 14:586574. [PMID: 33192350 PMCID: PMC7641605 DOI: 10.3389/fnsys.2020.586574] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/29/2020] [Indexed: 12/30/2022] Open
Abstract
The traditional cerebellum’s role has been linked to the high computational demands for sensorimotor control. However, several findings have pointed to its involvement in executive and emotional functions in the last decades. First in 2009 and then, in 2016, we raised why we should consider the cerebellum when thinking about drug addiction. A decade later, mounting evidence strongly suggests the cerebellar involvement in this disorder. Nevertheless, direct evidence is still partial and related mainly to drug-induced reward memory, but recent results about cerebellar functions may provide new insights into its role in addiction. The present review does not intend to be a compelling revision on available findings, as we did in the two previous reviews. This minireview focuses on specific findings of the cerebellum’s role in drug-related reward memories and the way ahead for future research. The results discussed here provide grounds for involving the cerebellar cortex’s apical region in regulating behavior driven by drug-cue associations. They also suggest that the cerebellar cortex dysfunction may facilitate drug-induced learning by increasing glutamatergic output from the deep cerebellar nucleus (DCN) to the ventral tegmental area (VTA) and neural activity in its projecting areas.
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Affiliation(s)
- Marta Miquel
- Área de Psicobiología, Universitat Jaume I, Castellón de la Plana, Spain
| | - Isis Gil-Miravet
- Área de Psicobiología, Universitat Jaume I, Castellón de la Plana, Spain
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36
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Complex Economic Behavior Patterns Are Constructed from Finite, Genetically Controlled Modules of Behavior. Cell Rep 2020; 28:1814-1829.e6. [PMID: 31412249 PMCID: PMC7476553 DOI: 10.1016/j.celrep.2019.07.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 02/22/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022] Open
Abstract
Complex ethological behaviors could be constructed from finite modules that are reproducible functional units of behavior. Here, we test this idea for foraging and develop methods to dissect rich behavior patterns in mice. We uncover discrete modules of foraging behavior reproducible across different strains and ages, as well as nonmodular behavioral sequences. Modules differ in terms of form, expression frequency, and expression timing and are expressed in a probabilistically determined order. Modules shape economic patterns of feeding, exposure, activity, and perseveration responses. The modular architecture of foraging changes developmentally, and different developmental, genetic, and parental effects are found to shape the expression of specific modules. Dissecting modules from complex patterns is powerful for phenotype analysis. We discover that both parental alleles of the imprinted Prader-Willi syndrome gene Magel2 are functional in mice but regulate different modules. Our study found that complex economic patterns are built from finite, genetically controlled modules. The principles and mechanisms involved in constructing complex behavior patterns are not well defined. Stacher Hörndli et al. find that complex foraging patterns in mice are constructed from finite modules, defined as significantly reproducible behavioral sequences. Modules are expressed in a probabilistically defined order to construct complex patterns and controlled by genetic mechanisms.
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37
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Abdallah M, Farrugia N, Chirokoff V, Chanraud S. Static and dynamic aspects of cerebro-cerebellar functional connectivity are associated with self-reported measures of impulsivity: A resting-state fMRI study. Netw Neurosci 2020; 4:891-909. [PMID: 33615095 PMCID: PMC7888486 DOI: 10.1162/netn_a_00149] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 05/13/2020] [Indexed: 01/21/2023] Open
Abstract
Human and animal brain studies bring converging evidence of a possible role for the cerebellum and the cerebro-cerebellar system in impulsivity. However, the precise nature of the relation between cerebro-cerebellar coupling and impulsivity is far from understood. Characterizing functional connectivity (FC) patterns between large-scale brain networks that mediate different forms of impulsivity, and the cerebellum may improve our understanding of this relation. Here, we analyzed static and dynamic features of cerebro-cerebellar FC using a highly sampled resting-state functional magnetic resonance imaging (rs-fMRI) dataset and tested their association with two widely used self-reports of impulsivity: the UPPS-P impulsive behavior scale and the behavioral inhibition/approach systems (BIS/BAS) in a large group of healthy subjects (N = 134, ≈ 1 hr of rs-fMRI/subject). We employed robust data-driven techniques to identify cerebral and cerebellar resting-state networks and extract descriptive summary measures of static and dynamic cerebro-cerebellar FC. We observed evidence linking BIS, BAS, sensation seeking, and lack of premeditation to the total strength and temporal variability of FC within networks connecting regions of the prefrontal cortex, precuneus, posterior cingulate cortex, basal ganglia, and thalamus with the cerebellum. Overall, our findings improve the existing knowledge of the neural correlates of impulsivity and the behavioral correlates of the cerebro-cerebellar system.
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Affiliation(s)
- Majd Abdallah
- Aquitaine Institute of Cognitive and Integrative Neuroscience, UMR CNRS 5287, University of Bordeaux, France
| | - Nicolas Farrugia
- Electronics Department Lab STICC, IMT Atlantique, UMR CNRS 6285, Brest, France
| | - Valentine Chirokoff
- Aquitaine Institute of Cognitive and Integrative Neuroscience, UMR CNRS 5287, University of Bordeaux, France
| | - Sandra Chanraud
- Aquitaine Institute of Cognitive and Integrative Neuroscience, UMR CNRS 5287, University of Bordeaux, France
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38
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Corbey R. Baldwin effects in early stone tools. Evol Anthropol 2020; 29:237-244. [PMID: 32835429 PMCID: PMC7693078 DOI: 10.1002/evan.21864] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/17/2020] [Accepted: 07/31/2020] [Indexed: 11/07/2022]
Abstract
A sizeable dataset comprising millions of lithic artifacts sampling over two million years of early paleolithic tool technology from Africa and Eurasia is now available. The widespread presupposition of an exclusively cultural, that is, socially learned, nature of early stone tools from at least Acheulean times onwards has been challenged by researchers who hypothesize that these tools, a crucial element of early hominin survival strategies, may partly have been under genetic control, next to the effects of various other determinants. The discussion this hypothesis has sparked off in the present journal is here explored somewhat further, focusing on the Baldwin effect.
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Affiliation(s)
- Raymond Corbey
- Faculty of Archaeology, Leiden University, Leiden, The Netherlands
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39
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DeCasien AR, Higham JP. Relative Cerebellum Size Is Not Sexually Dimorphic across Primates. BRAIN, BEHAVIOR AND EVOLUTION 2020; 95:93-101. [PMID: 32791505 DOI: 10.1159/000509070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/02/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Substantive sex differences in behavior and cognition are found in humans and other primates. However, potential sex differences in primate neuroanatomy remain largely unexplored. Here, we investigate sex differences in the relative size of the cerebellum, a region that has played a major role in primate brain evolution and that has been associated with cognitive abilities that may be subject to sexual selection in primates. METHODS We compiled individual volumetric and sex data from published data sources and used MCMC generalized linear mixed models to test for sex effects in relative cerebellar volume while controlling for phylogenetic relationships between species. Given that the cerebellum is a functionally heterogeneous structure involved in multiple complex cognitive processes that may be under selection in males or females within certain species, and that sexual selection pressures vary so greatly across primate species, we predicted there would be no sex difference in the relative size of the cerebellum across primates. RESULTS Our results support our prediction, suggesting there is no consistent sex difference in relative cerebellum size. CONCLUSION This work suggests that the potential for sex differences in relative cerebellum size has been subject to either developmental constraint or lack of consistent selection pressures, and highlights the need for more individual-level primate neuroanatomical data to facilitate intra- and inter-specific study of brain sexual dimorphism.
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Affiliation(s)
- Alex R DeCasien
- Department of Anthropology, New York University, New York, New York, USA, .,New York Consortium in Evolutionary Primatology, New York, New York, USA,
| | - James P Higham
- Department of Anthropology, New York University, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA
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40
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Pargeter J, Khreisheh N, Shea JJ, Stout D. Knowledge vs. know-how? Dissecting the foundations of stone knapping skill. J Hum Evol 2020; 145:102807. [DOI: 10.1016/j.jhevol.2020.102807] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 10/24/2022]
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41
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Uomini N, Fairlie J, Gray RD, Griesser M. Extended parenting and the evolution of cognition. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190495. [PMID: 32475334 DOI: 10.1098/rstb.2019.0495] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Traditional attempts to understand the evolution of human cognition compare humans with other primates. This research showed that relative brain size covaries with cognitive skills, while adaptations that buffer the developmental and energetic costs of large brains (e.g. allomaternal care), and ecological or social benefits of cognitive abilities, are critical for their evolution. To understand the drivers of cognitive adaptations, it is profitable to consider distant lineages with convergently evolved cognitions. Here, we examine the facilitators of cognitive evolution in corvid birds, where some species display cultural learning, with an emphasis on family life. We propose that extended parenting (protracted parent-offspring association) is pivotal in the evolution of cognition: it combines critical life-history, social and ecological conditions allowing for the development and maintenance of cognitive skillsets that confer fitness benefits to individuals. This novel hypothesis complements the extended childhood idea by considering the parents' role in juvenile development. Using phylogenetic comparative analyses, we show that corvids have larger body sizes, longer development times, extended parenting and larger relative brain sizes than other passerines. Case studies from two corvid species with different ecologies and social systems highlight the critical role of life-history features on juveniles' cognitive development: extended parenting provides a safe haven, access to tolerant role models, reliable learning opportunities and food, resulting in higher survival. The benefits of extended juvenile learning periods, over evolutionary time, lead to selection for expanded cognitive skillsets. Similarly, in our ancestors, cooperative breeding and increased group sizes facilitated learning and teaching. Our analyses highlight the critical role of life-history, ecological and social factors that underlie both extended parenting and expanded cognitive skillsets. This article is part of the theme issue 'Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals'.
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Affiliation(s)
- Natalie Uomini
- Department of Linguistic and Cultural Evolution, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, Jena, Germany
| | | | - Russell D Gray
- Department of Linguistic and Cultural Evolution, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, Jena, Germany.,School of Psychology, University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand
| | - Michael Griesser
- State Key Laboratory of Biocontrol, Department of Ecology and School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.,Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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42
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Fernandes HB, Peñaherrera-Aguirre M, Woodley of Menie MA, Figueredo AJ. Macroevolutionary patterns and selection modes for general intelligence (G) and for commonly used neuroanatomical volume measures in primates. INTELLIGENCE 2020. [DOI: 10.1016/j.intell.2020.101456] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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43
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Tamura M. Extractive foraging on hard‐shelled walnuts and variation of feeding techniques in wild Japanese macaques (
Macaca fuscata
). Am J Primatol 2020; 82:e23130. [DOI: 10.1002/ajp.23130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Masaya Tamura
- Laboratory of Human Evolution Studies, Graduate School of ScienceKyoto University Kyoto Japan
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44
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Shilton D, Breski M, Dor D, Jablonka E. Human Social Evolution: Self-Domestication or Self-Control? Front Psychol 2020; 11:134. [PMID: 32116937 PMCID: PMC7033472 DOI: 10.3389/fpsyg.2020.00134] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/17/2020] [Indexed: 01/02/2023] Open
Abstract
The self-domestication hypothesis suggests that, like mammalian domesticates, humans have gone through a process of selection against aggression - a process that in the case of humans was self-induced. Here, we extend previous proposals and suggest that what underlies human social evolution is selection for socially mediated emotional control and plasticity. In the first part of the paper we highlight general features of human social evolution, which, we argue, is more similar to that of other social mammals than to that of mammalian domesticates and is therefore incompatible with the notion of human self-domestication. In the second part, we discuss the unique aspects of human evolution and propose that emotional control and social motivation in humans evolved during two major, partially overlapping stages. The first stage, which followed the emergence of mimetic communication, the beginnings of musical engagement, and mimesis-related cognition, required socially mediated emotional plasticity and was accompanied by new social emotions. The second stage followed the emergence of language, when individuals began to instruct the imagination of their interlocutors, and to rely even more extensively on emotional plasticity and culturally learned emotional control. This account further illustrates the significant differences between humans and domesticates, thus challenging the notion of human self-domestication.
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Affiliation(s)
- Dor Shilton
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University, Tel-Aviv, Israel
| | - Mati Breski
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University, Tel-Aviv, Israel
| | - Daniel Dor
- The Department of Communication, Tel-Aviv University, Tel-Aviv, Israel
| | - Eva Jablonka
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University, Tel-Aviv, Israel
- Centre for Philosophy of Natural and Social Science (CPNSS), London School of Economics, London, United Kingdom
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45
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Němec P, Osten P. The evolution of brain structure captured in stereotyped cell count and cell type distributions. Curr Opin Neurobiol 2020; 60:176-183. [PMID: 31945723 PMCID: PMC7191610 DOI: 10.1016/j.conb.2019.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022]
Abstract
The stereotyped features of brain structure, such as the distribution, morphology and connectivity of neuronal cell types across brain areas, are those most likely to explain the remarkable capacity of the brain to process information and govern behaviors. Recent advances in anatomical methods, including the simple but versatile isotropic fractionator and several whole-brain labeling, clearing and microscopy methods, have opened the door to an exciting new era in comparative brain anatomy, one that has the potential to transform our understanding of the brain structure-function relationship by representing the evolution of brain complexity in quantitative anatomical features shared across species and species-specific or clade-specific. Here we discuss these methods and their application to mapping brain cell count and cell type distributions-two particularly powerful neural correlates of vertebrate cognitive and behavioral capabilities.
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Affiliation(s)
- Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic.
| | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11743, USA.
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46
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Stairways to the brain: Transcutaneous spinal direct current stimulation (tsDCS) modulates a cerebellar-cortical network enhancing verb recovery. Brain Res 2020; 1727:146564. [DOI: 10.1016/j.brainres.2019.146564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/01/2019] [Accepted: 11/19/2019] [Indexed: 12/17/2022]
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47
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Powell LE, Barton RA, Street SE. Maternal investment, life histories and the evolution of brain structure in primates. Proc Biol Sci 2019; 286:20191608. [PMID: 31530145 PMCID: PMC6784728 DOI: 10.1098/rspb.2019.1608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/15/2019] [Indexed: 12/16/2022] Open
Abstract
Life history is a robust correlate of relative brain size: larger-brained mammals and birds have slower life histories and longer lifespans than smaller-brained species. The cognitive buffer hypothesis (CBH) proposes an adaptive explanation for this relationship: large brains may permit greater behavioural flexibility and thereby buffer the animal from unpredictable environmental challenges, allowing for reduced mortality and increased lifespan. By contrast, the developmental costs hypothesis (DCH) suggests that life-history correlates of brain size reflect the extension of maturational processes needed to accommodate the evolution of large brains, predicting correlations with pre-adult life-history phases. Here, we test novel predictions of the hypotheses in primates applied to the neocortex and cerebellum, two major brain structures with distinct developmental trajectories. While neocortical growth is allocated primarily to pre-natal development, the cerebellum exhibits relatively substantial post-natal growth. Consistent with the DCH, neocortical expansion is related primarily to extended gestation while cerebellar expansion to extended post-natal development, particularly the juvenile period. Contrary to the CBH, adult lifespan explains relatively little variance in the whole brain or neocortex volume once pre-adult life-history phases are accounted for. Only the cerebellum shows a relationship with lifespan after accounting for developmental periods. Our results substantiate and elaborate on the role of maternal investment and offspring development in brain evolution, suggest that brain components can evolve partly independently through modifications of distinct developmental phases, and imply that environmental input during post-natal maturation may be particularly crucial for the development of cerebellar function. They also suggest that relatively extended post-natal maturation times provide a developmental mechanism for the marked expansion of the cerebellum in the apes.
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Affiliation(s)
- Lauren E. Powell
- Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK
| | | | - Sally E. Street
- Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK
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48
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DeCasien AR, Higham JP. Primate mosaic brain evolution reflects selection on sensory and cognitive specialization. Nat Ecol Evol 2019; 3:1483-1493. [PMID: 31548648 DOI: 10.1038/s41559-019-0969-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 07/26/2019] [Indexed: 02/06/2023]
Abstract
The mammalian brain is composed of numerous functionally distinct structures that vary in size within and between clades, reflecting selection for sensory and cognitive specialization. Primates represent a particularly interesting case in which to examine mosaic brain evolution since they exhibit marked behavioural variation, spanning most social structures, diets and activity periods observed across mammals. Although studies have consistently demonstrated a trade-off between visual and olfactory specialization in primates, studies of some regions (for example, the neocortex) have produced conflicting results. Here, we analyse the socioecological factors influencing the relative size of 33 brain regions, using updated statistical techniques and data from more species and individuals than previous studies. Our results confirm that group-living species and those with high-quality diets have expanded olfactory or visual systems, depending on whether they are nocturnal or diurnal. Conversely, regions associated with spatial memory are expanded in solitary species and those with low-quality diets, suggesting a trade-off between visual processing and spatial memory. Contrary to previous work, we show that diet quality predicts relative neocortex size at least as well as, if not better than, social complexity. Overall, our results demonstrate that primate brain structure is largely driven by selection on sensory and cognitive specializations that develop in response to divergent socioecological niches.
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Affiliation(s)
- Alex R DeCasien
- Department of Anthropology, New York University, New York, NY, USA. .,New York Consortium in Evolutionary Primatology, New York, NY, USA.
| | - James P Higham
- Department of Anthropology, New York University, New York, NY, USA.,New York Consortium in Evolutionary Primatology, New York, NY, USA
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49
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Muller AS, Montgomery SH. Co-evolution of cerebral and cerebellar expansion in cetaceans. J Evol Biol 2019; 32:1418-1431. [PMID: 31507000 PMCID: PMC6916408 DOI: 10.1111/jeb.13539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/27/2019] [Indexed: 12/23/2022]
Abstract
Cetaceans possess brains that rank among the largest to have ever evolved, either in terms of absolute mass or relative to body size. Cetaceans have evolved these huge brains under relatively unique environmental conditions, making them a fascinating case study to investigate the constraints and selection pressures that shape how brains evolve. Indeed, cetaceans have some unusual neuroanatomical features, including a thin but highly folded cerebrum with low cortical neuron density, as well as many structural adaptations associated with acoustic communication. Previous reports also suggest that at least some cetaceans have an expanded cerebellum, a brain structure with wide‐ranging functions in adaptive filtering of sensory information, the control of motor actions, and cognition. Here, we report that, relative to the size of the rest of the brain, both the cerebrum and cerebellum are dramatically enlarged in cetaceans and show evidence of co‐evolution, a pattern of brain evolution that is convergent with primates. However, we also highlight several branches where cortico‐cerebellar co‐evolution may be partially decoupled, suggesting these structures can respond to independent selection pressures. Across cetaceans, we find no evidence of a simple linear relationship between either cerebrum and cerebellum size and the complexity of social ecology or acoustic communication, but do find evidence that their expansion may be associated with dietary breadth. In addition, our results suggest that major increases in both cerebrum and cerebellum size occurred early in cetacean evolution, prior to the origin of the major extant clades, and predate the evolution of echolocation.
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Affiliation(s)
| | - Stephen Hugh Montgomery
- Department of Zoology, University of Cambridge, Cambridge, UK.,School of Biological Sciences, University of Bristol, Bristol, UK
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50
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Marhounová L, Kotrschal A, Kverková K, Kolm N, Němec P. Artificial selection on brain size leads to matching changes in overall number of neurons. Evolution 2019; 73:2003-2012. [PMID: 31339177 PMCID: PMC6772110 DOI: 10.1111/evo.13805] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 12/16/2022]
Abstract
Neurons are the basic computational units of the brain, but brain size is the predominant surrogate measure of brain functional capacity in comparative and cognitive neuroscience. This approach is based on the assumption that larger brains harbor higher numbers of neurons and their connections, and therefore have a higher information-processing capacity. However, recent studies have shown that brain mass may be less strongly correlated with neuron counts than previously thought. Till now, no experimental test has been conducted to examine the relationship between evolutionary changes in brain size and the number of brain neurons. Here, we provide such a test by comparing neuron number in artificial selection lines of female guppies (Poecilia reticulata) with >15% difference in relative brain mass and numerous previously demonstrated cognitive differences. Using the isotropic fractionator, we demonstrate that large-brained females have a higher overall number of neurons than small-brained females, but similar neuronal densities. Importantly, this difference holds also for the telencephalon, a key region for cognition. Our study provides the first direct experimental evidence that selection for brain mass leads to matching changes in number of neurons and shows that brain size evolution is intimately linked to the evolution of neuron number and cognition.
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Affiliation(s)
- Lucie Marhounová
- Department of Zoology, Faculty of ScienceCharles University12844PragueCzech Republic
| | - Alexander Kotrschal
- Behavioural Ecology GroupDepartment of Animal Sciences6708wdWageningenNetherlands
- Department of Zoology/EthologyStockholm University10691StockholmSweden
| | - Kristina Kverková
- Department of Zoology, Faculty of ScienceCharles University12844PragueCzech Republic
| | - Niclas Kolm
- Department of Zoology/EthologyStockholm University10691StockholmSweden
| | - Pavel Němec
- Department of Zoology, Faculty of ScienceCharles University12844PragueCzech Republic
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