scholarly journals Human-Specific Genes, Cortical Progenitor Cells, and Microcephaly

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1209
Author(s):  
Michael Heide ◽  
Wieland B. Huttner
Keyword(s):  
Cerebral Cortex ◽  
Cognitive Abilities ◽  
Functional Role ◽  
Brain Size ◽  
Cortical Development ◽  
Specific Gene ◽  
The Past ◽  
The Brain ◽  
Cortical Progenitor ◽  
Human Specific

Over the past few years, human-specific genes have received increasing attention as potential major contributors responsible for the 3-fold difference in brain size between human and chimpanzee. Accordingly, mutations affecting these genes may lead to a reduction in human brain size and therefore, may cause or contribute to microcephaly. In this review, we will concentrate, within the brain, on the cerebral cortex, the seat of our higher cognitive abilities, and focus on the human-specific gene ARHGAP11B and on the gene family comprising the three human-specific genes NOTCH2NLA, -B, and -C. These genes are thought to have significantly contributed to the expansion of the cerebral cortex during human evolution. We will summarize the evolution of these genes, as well as their expression and functional role during human cortical development, and discuss their potential relevance for microcephaly. Furthermore, we will give an overview of other human-specific genes that are expressed during fetal human cortical development. We will discuss the potential involvement of these genes in microcephaly and how these genes could be studied functionally to identify a possible role in microcephaly.

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

2020 ◽  
Author(s):  
Jean-Pierre Changeux ◽  
Alexandros Goulas ◽  
Claus C Hilgetag
Keyword(s):  
Human Brain ◽  
Cognitive Abilities ◽  
Brain Size ◽  
Brain Connectivity ◽  
Feature Article ◽  
Primate Brain ◽  
Gene Level ◽  
Small Set ◽  
The Brain ◽  
Human Specific

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

scholarly journals New human-specific brain landmark: The depth asymmetry of superior temporal sulcus

2015 ◽  
Vol 112 (4) ◽  
pp. 1208-1213 ◽  
Author(s):  
François Leroy ◽  
Qing Cai ◽  
Stephanie L. Bogart ◽  
Jessica Dubois ◽  
Olivier Coulon ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Autistic Spectrum Disorder ◽  
Right Hemisphere ◽  
Human Subjects ◽  
Superior Temporal Sulcus ◽  
Mr Images ◽  
Human Cerebral Cortex ◽  
The Right ◽  
The Brain ◽  
Human Specific

Identifying potentially unique features of the human cerebral cortex is a first step to understanding how evolution has shaped the brain in our species. By analyzing MR images obtained from 177 humans and 73 chimpanzees, we observed a human-specific asymmetry in the superior temporal sulcus at the heart of the communication regions and which we have named the “superior temporal asymmetrical pit” (STAP). This 45-mm-long segment ventral to Heschl’s gyrus is deeper in the right hemisphere than in the left in 95% of typical human subjects, from infanthood till adulthood, and is present, irrespective of handedness, language lateralization, and sex although it is greater in males than in females. The STAP also is seen in several groups of atypical subjects including persons with situs inversus, autistic spectrum disorder, Turner syndrome, and corpus callosum agenesis. It is explained in part by the larger number of sulcal interruptions in the left than in the right hemisphere. Its early presence in the infants of this study as well as in fetuses and premature infants suggests a strong genetic influence. Because this asymmetry is barely visible in chimpanzees, we recommend the STAP region during midgestation as an important phenotype to investigate asymmetrical variations of gene expression among the primate lineage. This genetic target may provide important insights regarding the evolution of the crucial cognitive abilities sustained by this sulcus in our species, namely communication and social cognition.

scholarly journals The Effects of Domestication on the Brain and Behavior of the Chicken in the Light of Evolution

2021 ◽  
pp. 1-15
Author(s):  
Julia Mehlhorn ◽  
Svenja Caspers
Keyword(s):  
Evolutionary Theory ◽  
Artificial Selection ◽  
Brain Size ◽  
Domestic Chicken ◽  
Brain Morphology ◽  
Long Period ◽  
The Past ◽  
Brain And Behavior ◽  
And Behavior ◽  
The Brain

The avian class is characterized by particularly strong variability in their domesticated species. With more than 250 breeds and highly efficient commercial lines, domestic chickens represent the outcome of a really long period of artificial selection. One characteristic of domestication is the alterations in brain size and brain composition. The influence of domestication on brain morphology has been reviewed in the past, but mostly with a focus on mammals. Studies on avian species have seldom been taken into account. In this review, we would like to give an overview about the changes and variations in (brain) morphology and behavior in the domestic chicken, taking into consideration the constraints of evolutionary theory and the sense or nonsense of excessive artificial selection.

scholarly journals Human-specific ARHGAP11B induces hallmarks of neocortical expansion in developing ferret neocortex

2018 ◽  
Author(s):  
Nereo Kalebic ◽  
Carlotta Gilardi ◽  
Mareike Albert ◽  
Takashi Namba ◽  
Katherine R. Long ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Progenitor Cell ◽  
Radial Glia ◽  
Specific Gene ◽  
Cell Type ◽  
Embryonic Mouse ◽  
Neuron Density ◽  
Developing Neocortex ◽  
Radial Dimension ◽  
Human Specific

AbstractThe evolutionary increase in size and complexity of the primate neocortex is thought to underlie the higher cognitive abilities of humans. ARHGAP11B is a human-specific gene that, based on its expression pattern in fetal human neocortex and progenitor effects in embryonic mouse neocortex, has been proposed to have a key function in the evolutionary expansion of the neocortex. Here, we study the effects of ARHGAP11B expression in the developing neocortex of the gyrencephalic ferret. In contrast to its effects in mouse, ARHGAP11B markedly increases proliferative basal radial glia, a progenitor cell type thought to be instrumental for neocortical expansion, and results in extension of the neurogenic period and an increase in upper-layer neurons. As a consequence, the postnatal ferret neocortex exhibits an increased neuron density in the upper cortical layers and expands in the radial dimension. Thus, human-specific ARHGAP11B can elicit hallmarks of neocortical expansion in developing ferret neocortex.

scholarly journals A human-specific modifier of cortical circuit connectivity and function improves behavioral performance

2019 ◽  
Author(s):  
Ewoud R.E. Schmidt ◽  
Hanzhi T. Zhao ◽  
Jung M. Park ◽  
Jacob B. Dahan ◽  
Chris C. Rodgers ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Brain Evolution ◽  
Specific Gene ◽  
Behavioral Performance ◽  
Cortical Connectivity ◽  
Cortical Circuit ◽  
And Function ◽  
Circuit Function ◽  
And Behavior ◽  
Human Specific

SUMMARYThe remarkable cognitive abilities characterizing humans are thought to emerge from our unique features of cortical circuit architecture, including increased feedforward and feedback connectivity. However, our understanding of the evolutionary origin and nature of these changes in circuit connectivity, and how they impact cortical circuit function and behavior is currently lacking. Here, we demonstrate that expression of the human-specific gene duplication SRGAP2C leads to a specific increase in feedforward and feedback cortico-cortical connectivity. Moreover, humanized SRGAP2C mice display improved cortical sensory coding, and an enhanced ability to learn a cortex-dependent sensory discrimination task. Our results identify a novel substrate for human brain evolution whereby the emergence of SRGAP2C led to increased feedforward and feedback cortico-cortical connectivity, improved cortical sensory processing and enhanced behavioral performance.

scholarly journals Evolution of brain elaboration

2015 ◽  
Vol 370 (1684) ◽  
pp. 20150054 ◽  
Author(s):  
Sarah M. Farris
Keyword(s):  
Cognitive Abilities ◽  
Brain Size ◽  
Sensory Modality ◽  
Limited Range ◽  
Developmental Gene Expression ◽  
Social Grouping ◽  
Architectural Features ◽  
Deep Homology ◽  
The Common ◽  
The Brain

Large, complex brains have evolved independently in several lineages of protostomes and deuterostomes. Sensory centres in the brain increase in size and complexity in proportion to the importance of a particular sensory modality, yet often share circuit architecture because of constraints in processing sensory inputs. The selective pressures driving enlargement of higher, integrative brain centres has been more difficult to determine, and may differ across taxa. The capacity for flexible, innovative behaviours, including learning and memory and other cognitive abilities, is commonly observed in animals with large higher brain centres. Other factors, such as social grouping and interaction, appear to be important in a more limited range of taxa, while the importance of spatial learning may be a common feature in insects with large higher brain centres. Despite differences in the exact behaviours under selection, evolutionary increases in brain size tend to derive from common modifications in development and generate common architectural features, even when comparing widely divergent groups such as vertebrates and insects. These similarities may in part be influenced by the deep homology of the brains of all Bilateria, in which shared patterns of developmental gene expression give rise to positionally, and perhaps functionally, homologous domains. Other shared modifications of development appear to be the result of homoplasy, such as the repeated, independent expansion of neuroblast numbers through changes in genes regulating cell division. The common features of large brains in so many groups of animals suggest that given their common ancestry, a limited set of mechanisms exist for increasing structural and functional diversity, resulting in many instances of homoplasy in bilaterian nervous systems.

scholarly journals Human-specific ARHGAP11B induces hallmarks of neocortical expansion in developing ferret neocortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Nereo Kalebic ◽  
Carlotta Gilardi ◽  
Mareike Albert ◽  
Takashi Namba ◽  
Katherine R Long ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Progenitor Cell ◽  
Radial Glia ◽  
Specific Gene ◽  
Cell Type ◽  
Cortical Layers ◽  
Embryonic Mouse ◽  
Neuron Density ◽  
Developing Neocortex ◽  
Human Specific

The evolutionary increase in size and complexity of the primate neocortex is thought to underlie the higher cognitive abilities of humans. ARHGAP11B is a human-specific gene that, based on its expression pattern in fetal human neocortex and progenitor effects in embryonic mouse neocortex, has been proposed to have a key function in the evolutionary expansion of the neocortex. Here, we study the effects of ARHGAP11B expression in the developing neocortex of the gyrencephalic ferret. In contrast to its effects in mouse, ARHGAP11B markedly increases proliferative basal radial glia, a progenitor cell type thought to be instrumental for neocortical expansion, and results in extension of the neurogenic period and an increase in upper-layer neurons. Consequently, the postnatal ferret neocortex exhibits increased neuron density in the upper cortical layers and expands in both the radial and tangential dimensions. Thus, human-specific ARHGAP11B can elicit hallmarks of neocortical expansion in the developing ferret neocortex.

Glucuronyl 3-sulfate occurs exclusively on distal unmyelinated terminals of selected sensory neurons in the peripheral nervous system

1995 ◽  
Vol 53 ◽  
pp. 958-959
Author(s):  
S.S. Spicer ◽  
B.A. Schulte
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Peripheral Nervous System ◽  
Sensory Neurons ◽  
Sensory Nerves ◽  
Tissue Antigens ◽  
The Central Nervous System ◽  
The Brain ◽  
Leu 7

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.

Neurotransmitter systems of female mouse brain during growth of malignant melanoma modeled on the background of chronic pain

2018 ◽  
pp. 49-55
Author(s):  
О.И. Кит ◽  
И.М. Котиева ◽  
Е.М. Франциянц ◽  
И.В. Каплиева ◽  
Л.К. Трепитаки ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Cerebral Cortex ◽  
Malignant Melanoma ◽  
Sciatic Nerve ◽  
Female Mouse ◽  
Combined Effects ◽  
Malignant Growth ◽  
Course Of Disease ◽  
The Brain ◽  
Melanoma Growth

Известно, что биогенные амины (БА) участвуют в злокачественном росте, их уровень изменяется в ЦНС при болевом воздействии, однако исследований о сочетанном влиянии хронической боли (ХБ) и онкопатологии на динамику БА в головном мозге не проводилось. Цель: изучить особенности баланса БА в коре головного мозга в динамике роста меланомы, воспроизведенной на фоне ХБ. Материалы и методы. Работа выполнена на 64 мышах-самках, весом 21-22 г. Животным основной группы меланому В16/F10 перевивали под кожу спины через 2 недели после перевязки седалищных нервов. Группой сравнения служили мыши с меланомой без боли. Уровни БА: адреналина, норадреналина, дофамина (ДА), серотонина (5-НТ), гистамина, а также 5-ОИУК определяли методом иммуноферментного анализа. Результаты. У мышей с ХБ уменьшается содержание большинства БА, однако уровень ДА не изменяется. Метаболизм 5-НТ происходит с участием МАО. Развитие меланомы сопровождается увеличением содержания ДА и 5-НТ, тогда как МАО - ингибируется. Направленность сдвигов БА при развитии меланомы на фоне ХБ оказалась практически такой же, как и без неё. В то же время ХБ ограничивает накопление 5-НТ в коре мозга при меланоме, что сопровождается более агрессивным её течением. Выводы. ХБ ограничивает включение стресс-лимитирующих механизмов в головном мозге при развитии меланомы у мышей, что приводит к более агрессивному течению злокачественного процесса. Biogenic amines (BA) are known to be involved in malignant growth, and their CNS levels change in pain; however, there are no studies of combined effects of chronic pain (CP) and cancer on BA dynamics in the brain. Aim: To study features of BA balance in the cerebral cortex during melanoma growth associated with CP. Material and methods. The study included 64 female mice weighing 21-22 g. In the main groups, B16/F10 melanoma was transplanted under the skin of the back two weeks following sciatic nerve ligation. Mice with melanoma without pain were used as the control. Concentrations of BA: adrenaline, noradrenaline, dopamine (DA), serotonin (5-HT), histamine and 5-HIAA were measured with ELISA. Results. Concentrations of BAs decreased in mice with CP although DA levels did not change. 5-HT metabolism involved MAO. The development of melanoma was accompanied by increases in DA and 5-HT whereas MAO was inhibited. The direction of BA changes during the development of melanoma was the same with and without CP. At the same time, CP with melanoma limited accumulation of 5-HT in the cerebral cortex, which resulted in even more aggressive course of cancer. Conclusion. CP restricted the activation of cerebral stress-limiting mechanisms during the development of melanoma in mice, which resulted in a more aggressive course of disease.

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