VI. Earth Life Emergence: Development of Body, Brain, Selves and Societies
1. The Evolution of Brain Anatomy and Cognizance
While a general increase in bodily complexity and dexterity from trilobites to humans is admitted, what is in tandem process (and there really is something going on) is an essential ramification of cerebral capacities. By attributes of bilateral asymmetry, semi-specialized modules, which array in concerted and mosaic modes, crowned by a frontal lobe neocortex, brains evolve by much expanding the size of these components in place from the earliest neural stirrings. This steady course of life’s encephalization adds a further component to trace a central evolutionary axis and vector.
Aboitiz, Francisco and Juan Montiel. Morphological Evolution of the Vertebrate Forebrain: From Mechanical to Cellular Processes. Evolution & Development. 21/6, 2019. While relative brain anatomies vary with the animal classes, Chilean neuroscientists (search) add another report of the presence of consistent, homologous features. Thus, one may speak of a genetically based neurogenesis as life proceeds to evolve and develop from its earliest rudiments to our socially inquisitive selves.
Although the cerebral hemispheres are among the defining characters of vertebrates, each class is characterized by a different anatomical organization of this structure, which has become problematic for comparative neurobiology. In this article, we discuss some mechanisms involved in the generation of morphological divergence, based on spatial constraints for neurogenesis, mechanical forces generated by increasing neuronal numbers during development, and cellular strategies used by each group to overcome these limitations. We expect this view to help unify the diverging vertebrate brain morphologies into general, simple mechanisms that can establish homologies across groups. (Abstract)
Towards a Computational Comparative Neuroprimatology: Framing the Language-Ready Brain.
Physics of Life Reviews.
We cite this 50 page essay by the veteran USC neuroscientist for its integrative content and to review novel findings about dual ventral and dorsal streams of recognition and response. For Arbib, to gloss an extensive text, these two modes attend to object, item, word identity and their resultant spatial frames. As a sampling of papers next conveys, in their ongoing study researchers evaluate and nuance these relative features. Our interest is another occasion of an archetypal complementarity via discrete, elemental aspects, along with a holistic context. Its ubiquitous prevalence gives further credence to an universal edifying code. See also by Dorsal and Ventral Streams in the Evolution of the Language-Ready Brain by Arbib in the Journal of Neurolinguistics (43B/227, 2017).
We make the case for developing a Computational Comparative Neuroprimatology to inform the analysis of the function and evolution of the human brain. First, we update the mirror system hypothesis on the evolution of the language-ready brain by (i) modeling action and action recognition and opportunistic scheduling of macaque brains to hypothesize the nature of the last common ancestor of macaque and human (LCA-m); and then (ii) introduce dynamic brain modeling to show how apes could acquire gesture through ontogenetic ritualization, hypothesizing the nature of evolution from LCA-m to the last common ancestor of chimpanzee and human (LCA-c). We then (iii) hypothesize the role of imitation, pantomime, protosign and protospeech in biological and cultural evolution from LCA-c to Homo sapiens with a language-ready brain.
Argembeau, Arnaud and Eric Salmon. The Neural Basis of Semantic and Episodic Forms of Self-Knowledge. Lopez-Larrea, Carlos, ed. Sensing in Nature. Dordrecht: Springer, 2012. University of Liege, Belgium, researchers use Functional Neuroimaging to study, how human, and universe, it would seem, are engaged in achieving mental representations and realizations of themselves.
Throughout evolution, hominids have developed greater capacity to think about themselves in abstract and symbolic ways. This process has reached its apex in humans with the construction of a concept of self as a distinct entity with a personal history. This chapter provides a review of recent functional neuroimaging studies that have investigated the neural correlates of such “higher-level” aspects of the human self, focusing in particular on processes that allow individuals to consciously represent and reflect on their own personal attributes (semantic forms of self-knowledge) and experiences (episodic forms of self-knowledge). (Abstract)
Balanoff, Amy, et al. Evolutionary Origins of the Avian Brain. Nature. 501/93, 2013. As the extended abstract conveys, American Museum of Natural History, and University of Texas, Austin, neural paleontologists reconstruct a persistent course of enhanced evolutionarily encephalization from dinosaur reptiles to fledgling birds by way of transitional, intermediate forms.
Features that were once considered exclusive to modern birds, such as feathers and a furcula (wishbone), are now known to have first appeared in non-avian dinosaurs. However, relatively little is known of the early evolutionary history of the hyperinflated brain that distinguishes birds from other living reptiles and provides the important neurological capablities required by flight. Here we use high-resolution computed tomography to estimate and compare cranial volumes of extant birds, the early avialan Archaeopteryx lithographica, and a number of non-avian maniraptoran dinosaurs that are phylogenetically close to the origins of both Avialae and avian flight. Previous work established that avian cerebral expansion began early in theropod history and that the cranial cavity of Archaeopteryx was volumetrically intermediate between these early forms and modern birds3, 4. Our new data indicate that the relative size of the cranial cavity of Archaeopteryx is reflective of a more generalized maniraptoran (bird-like dinosaurs) volumetric signature and in several instances is actually smaller than that of other non-avian dinosaurs. Thus, bird-like encephalization indices evolved multiple times, supporting the conclusion that if Archaeopteryx had the neurological capabilities required of flight, so did at least some other non-avian maniraptorans. This is congruent with recent findings that avialans were not unique among maniraptorans in their ability to fly in some form. (Abstract)
Baluska, Frantisek, et al. The ‘Root-Brain’ Hypothesis of Charles and Francis Darwin: Revival after More than 125 Years. Plant Signaling & Behavior. 4/12, 2009. In the last years of his life, c. 1862-1880, Charles, assisted by his son Francis, became engrossed with studies of the sensory attributes of flora. This not well known late phase, often guided by his Romantic views, led to writings such as The Power of Movement of Plants which speculates that plants actually possess and avail cerebral-like faculties. This present paper by Universities of Bonn, Frienze, and Bristol botanists, then reports upon new research that indeed confirms their active presence. With a companion article, Baluska, et al “Swarm Intelligence in Plant Roots” in Trends in Ecology and Evolution (25/12, 2010), a true, equivalent cognition is verified to abide amongst vegetations, which aids their flourishing survival.
Outlook: Complex Social Life of Plant Roots: Recent advances in chemical ecology reveal the astonishing communicative complexity of higher plants as exemplified by the battery of volatile substances which they produce and sense in order to share with other organisms information about their physiological state. The next surprise is that plants recognize self from nonself; and roots even secrete signaling exudates which mediate kin recognition. Finally, plants are also capable of a type of plantspecific cognition, suggesting that communicative and identity recognition systems are used, as they are in animal and human societies, to improve the fitness of plants and so further their evolution. Moreover, both animals and plants are non-automatic, decision- based organisms. Should Charles and Francis Darwin have witnessed these unprecedented discoveries, they would surely have been pleased by them. (1125)
Barsalou, Lawrence. Continuity of the Conceptual System Across Species. Trends in Cognitive Sciences. 9/7, 2005. An Emory University psychologist reports new evidence for the pervasive evolutionary emergence of a single cerebral development, maturation, and learning experience from prokaryote to people. Which, if we might allow, reveals a once and future central trunk and vector that stones, molecules and bones seriously misses.
In a recent neuroimaging study of macaque monkeys, Gil-da-Costa and colleagues reported that a distributed circuit of modality-specific properties represents macaques' conceptual knowledge of social situations. The circuit identified shows striking similarities to analogous circuits in humans that represent conceptual knowledge. This parallel suggests that a common architecture underlies the conceptual systems of different species, although with additional systems extending human conceptual abilities significantly. (309)
Barton, R. A. Binocularity and Brain Evolution in Primates. . Proceedings of the National Academy of Sciences. 101/10113, 2004. The increased focal convergence of binocular vision was a significant factor in the evolutionary expansion of visual brain structures and the overall size of the brain.
Bassett, Danielle, et al. Dynamic Reconfiguration of Human Brain Networks during Learning. Proceedings of the National Academy of Sciences. 108/7641, 2011. As the quotes explain, University of California, Santa Barbara, Oxford University, and University of North Carolina neuroscientists contend that as we think and know, our neural networks shift their topologies and weighted bias as they join in fluid modular arrangements. See also “Dynamic Network Centrality Summarizes Learning in the Human Brain” (arXiv:1207.5047) by a similar team with Bassett, Ernesto Estrada, Sue Grafton, et al. In addition, compare with “The Evolution of Interdisciplinary in Physics Research” by Raj Kumar Pan, et al (Nature Scientific Reports, August 1, 2012) herein where similar active modular networks are described, as if a learning global brain.
Human learning is a complex phenomenon requiring flexibility to adapt existing brain function and precision in selecting new neurophysiological activities to drive desired behavior. These two attributes—flexibility and selection—must operate over multiple temporal scales as performance of a skill changes from being slow and challenging to being fast and automatic. Such selective adaptability is naturally provided by modular structure, which plays a critical role in evolution, development, and optimal network function. Using functional connectivity measurements of brain activity acquired from initial training through mastery of a simple motor skill, we investigate the role of modularity in human learning by identifying dynamic changes of modular organization spanning multiple temporal scales. Our results indicate that flexibility, which we measure by the allegiance of nodes to modules, in one experimental session predicts the relative amount of learning in a future session. We also develop a general statistical framework for the identification of modular architectures in evolving systems, which is broadly applicable to disciplines where network adaptability is crucial to the understanding of system performance. (7641)
Bond, Alan. An Information-Processing Analysis of the Functional Architecture of the Primate Neocortex. Journal of Theoretical Biology. 227/1, 2004. A California Institute of Technology neuroscientist proposes that the neocortex can be understood in terms of a hierarchical arrangement of both its components from neurons to cortical regions and its cogitation involving data type and complexity, memory, motor function and so on.
Breidbach, Olaf and W. Kutsch, eds. The Nervous Systems of Invertebrates: An Evolutionary and Comparative Approach. Basel: Birkhauser, 1995. Research papers suggest a common Bauplan for invertebrate nervous systems along with parallels between early embryogenesis and evolutionary neurogenesis.
Bressler, Steven and Vinod Menon. Large-Scale Brain Networks in Cognition. Trends in Cognitive Science. 14/6, 2010. Florida Atlantic University and Stanford University neuroscientists expand at an 80th birthday conference in honor of Walter Freeman to endorse an historic advance from initially separate brain areas, then to disparate modules, and on to the ubiquitous presence of dynamic nested nets that span local and global cerebration.
Briscoe, Steven and Clifton Ragsdale. Homology, Neocortex, and the Evolution of Developmental Mechanisms. Science. 362/190, 2018. In a special Brain Development section, MPI Molecular Cell Biology, and University of Chicago researchers can now lay out the full homologous continuity of amniote neural formation. By this novel view, an expansive, mosaic and concerted ramification from earliest invertebrates to amphibians, reptiles, birds, mammals becomes apparent. Once again, life’s cerebral faculty increasingly seems to evolve as if an embryonic gestation. Lastly homo and anthropo beings emerge as a major sapiensphere transition whom are cognitively able to reconstruct how me and we came to be. A third quote from the section introduction by Pamela Hines offer further urban analogy.
The six-layered neocortex of the mammalian pallium has no clear homolog in birds or non-avian reptiles. Recent research indicates that although these extant amniotes possess a variety of divergent and nonhomologous pallial structures, they share a conserved set of neuronal cell types and circuitries. These findings suggest a principle of brain evolution: that natural selection preferentially preserves the integrity of information-processing pathways, whereas other levels of biological organization, such as the three-dimensional architectures of neuronal assemblies, are less constrained. We review the similarities of pallial neuronal cell types in amniotes, delineate candidate gene regulatory networks for their cellular identities, and propose a model for the divergence of amniote pallial structures. (Abstract)