VII. WumanKinder: An Emergent Earthomo Transition in Individuality
2. Systems Neuroscience: Multiplex Networks and Critical Function
Carruthers, Peter. The Architecture of the Mind. Oxford: Clarendon Press, 2006. The University of Maryland philosopher makes a strong case for a massively modular brain, with certain evolutionary roots, whose remnants are with us today. In this regard, a broadly conceived evolutionary psychology is endorsed. But this academic endeavor in so many books and journals seems to labor within an assumed mechanical paradigm tacitly devoid of any extant identity or purpose. That minds are modular because they spring from and exemplify a universal tendency of self-organizing systems from genes to galaxies to form modules is not appreciated.
Cepelewicz, Jordana. To Make Sense of the Present, Brains May Predict the Future. Quanta. Online July, 2018. A science writer widely surveys the rising neuroscience school which goes by a broad “prediction coding hypothesis” umbrella. In so doing it is a popular entry to the contributions of its main founder and articulator, the British neuroscientist Karl Friston (search), along with many colleagues. The view then entails a “Bayesian brain” of better probabilistic inferences, and personal “enactive” aspects as they may flow from working memory to goal-directed behaviors. Advocates and doubters are given voice, but the general approach seems to be gaining much interest and avail. See also a Special Issue on Predictive Brains and Embodied, Enactive Cognition in Synthese (195/6, 2018) for much more. We note herein some papers by Michael Kirchhoff, Micah Allen and Karl Friston.
A controversial theory suggests that perception, motor control, memory and other brain functions all depend on comparisons between ongoing actual experiences and the brain’s modeled expectations.
Chang, Le and Doris Tsao. The Code for Facial Identity in the Primate Brain. Cell. 169/6, 2017. A main technical paper from Tsao’s CalTech lab about her collegial breakthrough decipherment of how pixelated neuronal architectures and mosaic areas are dynamically able to recognize whole faces. See also a commentary How Do We Recognize a Face? by Rodrigo Quiroga in this issue.
Primates recognize complex objects such as faces with remarkable speed and reliability. Here, we reveal the brain’s code for facial identity. Experiments in macaques demonstrate an extraordinarily simple transformation between faces and responses of cells in face patches. By formatting faces as points in a high-dimensional linear space, we discovered that each face cell’s firing rate is proportional to the projection of an incoming face stimulus onto a single axis in this space, allowing a face cell ensemble to encode the location of any face in the space. Using this code, we could precisely decode faces from neural population responses and predict neural firing rates to faces. Our work suggests that other objects could be encoded by analogous metric coordinate systems. (Abstract excerpt)
Changeux, Jean-Pierre. Climbing Brain Levels of Organisation from Genes to Consciousness. Trends in Cognitive Sciences. 21/3, 2017. The College de France, Institute Pasteur, Paris senior neuroscientist, now 80 years young, continues to advance the expansive understandings of life’s long Darwinian evolution as it lately becomes known as a neural cognitive development. In regard, a dynamic nesting of brain levels of organization is cast from genomes to gene-brain networks to synaptic epigenesis and long-range cerebral connectivities. Human aware sociality is then seen to be facilitated by and arise from this emergent scale.
The College de France, Institute Pasteur, Paris senior neuroscientist, now 80 years young, continues to advance the expansive understandings of life’s long Darwinian evolution as it lately becomes known as a neural cognitive development. In regard, a dynamic nesting of brain levels of organization is cast from genomes to gene-brain networks to synaptic epigenesis and long-range cerebral connectivities. Human aware sociality is then seen to be facilitated by and arise from this emergent scale.
Charvet, Christine, et al. Variation in Human Brains may Facilitate Evolutionary Change Toward a Limited Range of Phenotypes. Brain, Behavior and Evolution. 81/2, 2013. With coauthors Richard Darlington and Barbara Finlay, Cornell University neuropsychologists first cite recent studies that rejoin evolution and development, aka evo-devo, as a “conservation of programs specifying the initial body plan and fundamental physiological control processes in vertebrates and invertebrates” that serves to restrict somatic forms. They then proceed to show that similar constraints apply to “the domain of basic architecture in neural computation.”
Individual variation is the foundation for evolutionary change, but little is known about the nature of normal variation between brains. Phylogenetic variation across mammalian brains is characterized by high intercorrelations in brain region volumes, distinct allometric scaling for each brain region and the relative independence of olfactory and limbic structure volumes from the rest of the brain. Previous work examining brain variation in individuals of some domesticated species showed that these three features of phylogenetic variation were mirrored in individual variation. We extend this analysis to the human brain and 10 of its subdivisions (e.g., isocortex and hippocampus) by using magnetic resonance imaging scans of 90 human brains ranging between 16 and 25 years of age. Human brain variation resembles both the individual variation seen in other species and variation observed across mammalian species, i.e., the relative differences in the slopes of each brain region compared to medulla size within humans and between mammals are concordant, and limbic structures scale with relative independence from other brain regions. This nonrandom pattern of variation suggests that developmental programs channel the variation available for selection. (Abstract)
Chialvo, Dante. The Brain Near the Edge. www.arxiv.org/pdf/q-bio.NC/0610041. A Northwestern University Medical School neuroscientist proposes that neural processes, via their scale-free, functional networks, are critically poised in metastable states between order and disorder. (2006) Google the author’s name to access his copious writings.
Chialvo, Dante, et al. The Brain: What is Critical About It? Ricciardi, Luigi, et al, eds. Collective Dynamics: Topics on Competition and Cooperation in the Biosciences. American Institute of Physics Conference Proceedings, 2008. Researchers from Northwestern University, Universidad de Buenos Aires, and Universidad de San Andrés, similar to Levina 2007 and Kelso 2009, find nature’s tendency toward self-organized criticality, as lately girded by statistical physics, to be likewise present in collaborative neural activities. See also Chialvo's update survey "Emergent Complex Neural Dynamics" in Nature Physics (6/10, 2010). What great discovery might we all be closing on, if only we could allow and imagine it?
The brain is a complex adaptive nonlinear system that can be studied along with other problems in nonlinear physics from a dynamical standpoint. With this perspective here we discuss a proposal claiming that the brain is spontaneously posed at the border of a second order phase transition. The claim is that the most fascinating properties of the brain are simply generic properties found at this dynamical state, suggesting a different angle to study how the brain works. From this viewpoint, all human behaviors, including thoughts, undirected or goal oriented actions, or simply any state of mind, are the outcome of a dynamical system - the brain - at or near a critical state.
Christianson, Nicolas, et al. Architecture and Evolution of Semantic Networks in Mathematics Texts. arXiv:1908.04911. University of Pennsylvania bioneuroengineers NC, Ann Blevins, and Danielle Bassett, with many colleagues, continue to parse the presence of node/link multiplex geometries as they become evident in every natural and social milieu. In this instance, even textual script and its educational content is found to be distinguished. In August 2019, we can report an increasing realization that such a singular, iconic physiology and anatomy is vitally present everywhere. A graphic core-periphery array is depicted with dense inner and sparse outer areas, while another figure cites the same Betti (search) mathematics used to analyze clusters of galaxies. See also The Network Architecture of the Human Brain is Modularly Encoded in the Genome by this team (Bertolero, May 2019). From school books to cerebral faculties and onto to quantome and cosmome phases, a natural genesis is graced by the one, same, ultimately bigender icon.
Knowledge is a network of interconnected concepts. Yet, how the topological structure of knowledge constrains its acquisition remains unknown, hampering the development of learning enhancement strategies. Here we study topological semantic networks reflecting mathematical concepts and their relations in college- linear algebra texts. We find that the networks exhibit strong core-periphery architecture, where a dense core of concepts presented early is complemented with a sparse periphery evenly throughout the exposition. Using tools from applied topology, we find that the expositional evolution of the semantic networks produces and fills knowledge gaps. Broadly, our study lays the groundwork for optimal design principles for textbook teaching in a classroom setting. (Abstract excerpt)
Churchill, Nathan, et al. The Suppression of Scale-Free fMRI Brain Dynamics across Three Different Sources of Effort: Aging, Task Novelty and Task Difficulty. Nature Scientific Reports. 6/30895, 2016. A ten person team of research physicians from Canada, United States, and South Korea employ advanced imaging capabilities to quantify and define how much brain anatomies are deeply distinguished by self-similarity. Once again our own neural endowment becomes a microcosm of these universally recurrent patterns and dynamics. By turns then a macrocosmic milieu could then be seen to take on a cerebral guise.
There is growing evidence that fluctuations in brain activity may exhibit scale-free (“fractal”) dynamics. Scale-free signals follow a spectral-power curve of the form P(f ) ∝ f−β, where spectral power decreases in a power-law fashion with increasing frequency. In this study, we demonstrated that fractal scaling of BOLD (blood oxygen level dependent) fMRI signal is consistently suppressed for different sources of cognitive effort. Decreases in the Hurst exponent (H), which quantifies scale-free signal, was related to three different sources of cognitive effort/task engagement: 1) task difficulty, 2) task novelty, and 3) aging effects. These results indicate a potential global brain phenomenon that unites research from different fields and indicates that fractal scaling may be a highly sensitive metric for indexing cognitive effort/task engagement. (Abstract excerpts)
Cicchetti, Dante and Geraldine Dawson. Editorial: Multiple Levels of Analysis. Development and Psychopathology. 14/417, 2002. An introduction to a special issue to explore how systems neuroscience from genetic to behavioral levels is quantifying a self-organizing brain.
Cocchi, Luca, et al. Criticality in the Brain: A Synthesis of Neurobiology, Models and Cognition. arXiv:1707.05952. Queensland Institute for Medical Research and University of Melbourne neuroscientists including Michael Breakspear post an extensive case for this poised state as the preferred mode of cerebral activity. It opens with evidence of an innate, constant tendency for natural, self-organized complex systems to reach an optimum condition between too much order or chaos. By virtue of this basis, critical neural dynamics can then be connected to and rooted in physical phenomena. Such a balanced accord has been sensed for some years, search Dante Chialvo, this network enters a 2017 affirmation. From a traditional view, one might see a 21st century exemplar of an active, integral balance of these archetypal complements.
Cognitive function requires the coordination of neural activity across many scales, from neurons and circuits to large-scale networks. As such, it is unlikely that an explanatory framework focused upon any single scale will yield a comprehensive theory of brain activity and cognitive function. Modelling and analysis methods for neuroscience should aim to accommodate multiscale phenomena. Emerging research now suggests that multi-scale processes in the brain arise from so-called critical phenomena that occur very broadly in the natural world. Criticality arises in complex systems perched between order and disorder, and is marked by fluctuations that do not have any privileged spatial or temporal scale. We review the core nature of criticality, the evidence supporting its role in neural systems and its explanatory potential in brain health and disease. (Abstract)
Costa, Ariadne, et al. Fractal Analyses of Networks of Integrate-and-Fire Stochastic Spiking Neurons. arXiv: 1801.08087. We note because Indiana University and University of Central Florida neuroscientists including Olaf Sporns cite additional evidence for the brain’s critically-poised functional states, along with resultant (multi) fractal, self-similar geometries that they exhibit.
Although there is increasing evidence of criticality in the brain, the processes that guide neuronal networks to reach or maintain criticality remain unclear. The present research examines the role of neuronal gain plasticity in time-series of simulated neuronal networks composed of integrate-and-fire stochastic spiking neurons, and the utility of fractal methods in assessing network criticality. Fractal scaling was greatest in networks with a mid-range of neuronal plasticity, versus extremely high or low levels of plasticity. Peak fractal scaling corresponded closely to additional indices of criticality, including average branching ratio. Networks near critical states exhibited mid-range multifractal spectra width and tail length, which is consistent with literature suggesting that networks poised at quasi-critical states must be stable enough to maintain organization but unstable enough to be adaptable. (Abstract excerpts)