The Brain as a Hierarchical Organization

2008 ◽  
Vol 98 (4) ◽  
pp. 1312-1346 ◽  
Author(s):  
Isabelle Brocas ◽  
Juan D Carrillo
Keyword(s):  
Life Cycle ◽  
Asymmetric Information ◽  
System Organization ◽  
Dual System ◽  
Hierarchical Organization ◽  
Incentive Salience ◽  
Temporal Horizon ◽  
The Brain ◽  
Decreasing Impatience

Based on recent neuroscience evidence, we model the brain as a dual-system organization subject to three conflicts: asymmetric information, temporal horizon, and incentive salience. Under the first and second conflicts, we show that the uninformed system imposes a positive link between consumption and labor at every period. Furthermore, decreasing impatience endogenously emerges as a consequence of these two conflicts. Under the first and third conflicts, it becomes optimal to set a consumption cap. Finally, we discuss the behavioral implications of these rules for choice bracketing and expense tracking, and for consumption over the life cycle. (JEL D11, D74, D82, D87, D91)

scholarly journals Computerized physical and cognitive training improves the functional architecture of the brain in adults with Down syndrome: A network science EEG study

2020 ◽  
pp. 1-21
Author(s):  
Alexandra Anagnostopoulou ◽  
Charis Styliadis ◽  
Panagiotis Kartsidis ◽  
Evangelia Romanopoulou ◽  
Vasiliki Zilidou ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Functional Connectivity ◽  
Cognitive Training ◽  
Resting State ◽  
Network Architecture ◽  
Right Hemisphere ◽  
Random Network ◽  
Brain Activity ◽  
Hierarchical Organization ◽  
The Brain

Understanding the neuroplastic capacity of people with Down syndrome (PwDS) can potentially reveal the causal relationship between aberrant brain organization and phenotypic characteristics. We used resting-state EEG recordings to identify how a neuroplasticity-triggering training protocol relates to changes in the functional connectivity of the brain’s intrinsic cortical networks. Brain activity of 12 PwDS before and after a 10-week protocol of combined physical and cognitive training was statistically compared to quantify changes in directed functional connectivity in conjunction with psychosomatometric assessments. PwDS showed increased connectivity within the left hemisphere and from left-to-right hemisphere, as well as increased physical and cognitive performance. Our findings reveal a strong adaptive neuroplastic reorganization as a result of the training that leads to a less-random network with a more pronounced hierarchical organization. Our results go beyond previous findings by indicating a transition to a healthier, more efficient, and flexible network architecture, with improved integration and segregation abilities in the brain of PwDS. Resting-state electrophysiological brain activity is used here for the first time to display meaningful relationships to underlying Down syndrome processes and outcomes of importance in a translational inquiry. This trial is registered with ClinicalTrials.gov Identifier NCT04390321.

scholarly journals Signal propagation via cortical hierarchies

2020 ◽  
Vol 4 (4) ◽  
pp. 1072-1090 ◽  
Author(s):  
Bertha Vézquez-Rodríguez ◽  
Zhen-Qi Liu ◽  
Patric Hagmann ◽  
Bratislav Misic
Keyword(s):  
Shortest Paths ◽  
Signal Propagation ◽  
Brain Regions ◽  
Hierarchical Organization ◽  
Attention Networks ◽  
Diffusion Spectrum Imaging ◽  
Cortical Hierarchy ◽  
Spectrum Imaging ◽  
Structural Networks ◽  
The Brain

The wiring of the brain is organized around a putative unimodal-transmodal hierarchy. Here we investigate how this intrinsic hierarchical organization of the brain shapes the transmission of information among regions. The hierarchical positioning of individual regions was quantified by applying diffusion map embedding to resting-state functional MRI networks. Structural networks were reconstructed from diffusion spectrum imaging and topological shortest paths among all brain regions were computed. Sequences of nodes encountered along a path were then labeled by their hierarchical position, tracing out path motifs. We find that the cortical hierarchy guides communication in the network. Specifically, nodes are more likely to forward signals to nodes closer in the hierarchy and cover a range of unimodal and transmodal regions, potentially enriching or diversifying signals en route. We also find evidence of systematic detours, particularly in attention networks, where communication is rerouted. Altogether, the present work highlights how the cortical hierarchy shapes signal exchange and imparts behaviorally relevant communication patterns in brain networks.

The Many Sides of Hemispheric Asymmetry: A Selective Review and Outlook

2017 ◽  
Vol 23 (9-10) ◽  
pp. 710-718 ◽  
Author(s):  
Michael C. Corballis ◽  
Isabelle S. Häberling
Keyword(s):  
Human Brain ◽  
Social Life ◽  
Hemispheric Asymmetry ◽  
Brain Asymmetry ◽  
Dual System ◽  
Animal Kingdom ◽  
Internal Organs ◽  
The Many ◽  
Two Sides ◽  
The Brain

AbstractHemispheric asymmetry is commonly viewed as a dual system, unique to humans, with the two sides of the human brain in complementary roles. To the contrary, modern research shows that cerebral and behavioral asymmetries are widespread in the animal kingdom, and that the concept of duality is an oversimplification. The brain has many networks serving different functions; these are differentially lateralized, and involve many genes. Unlike the asymmetries of the internal organs, brain asymmetry is variable, with a significant minority of the population showing reversed asymmetries or the absence of asymmetry. This variability may underlie the divisions of labor and the specializations that sustain social life. (JINS, 2017, 23, 710–718)

scholarly journals Individual differences in the neuropsychopathology of addiction

2017 ◽  
Vol 19 (3) ◽  
pp. 217-229 ◽  
Keyword(s):  
Substance Use ◽  
Individual Differences ◽  
Substance Use Disorder ◽  
Negative Reinforcement ◽  
Incentive Salience ◽  
Cognitive Profiles ◽  
Pharmacological Treatments ◽  
Brain Reward ◽  
The Brain

Drug addiction or substance-use disorder is a chronically relapsing disorder that progresses through binge/intoxication, withdrawal/negative affect and preoccupation/anticipation stages. These stages represent diverse neurobiological mechanisms that are differentially involved in the transition from recreational to compulsive drug use and from positive to negative reinforcement. The progression from recreational to compulsive substance use is associated with downregulation of the brain reward systems and upregulation of the brain stress systems. Individual differences in the neurobiological systems that underlie the processing of reward, incentive salience, habits, stress, pain, and executive function may explain (i) the vulnerability to substance-use disorder; (ii) the diversity of emotional, motivational, and cognitive profiles of individuals with substance-use disorders; and (iii) heterogeneous responses to cognitive and pharmacological treatments. Characterization of the neuropsychological mechanisms that underlie individual differences in addiction-like behaviors is the key to understanding the mechanisms of addiction and development of personalized pharmacotherapy.

Mathematical Modeling of Within-Host Dynamics of Toxoplasma Gondii

2011 ◽  
Author(s):  
Adam Sullivan ◽  
Xiaopeng Zhao ◽  
Chunlei Su
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Cellular Automata ◽  
Three Dimensional ◽  
Host Cells ◽  
Time Step ◽  
Cellular Automata Model ◽  
Entire Life ◽  
Entire Life Cycle ◽  
The Brain

Toxoplasma gondii is a protozoan capable of replicating sexually in cats and asexually in other warm-blooded animals. By using a three dimensional mesh of both the brain and spleen, it is possible to simulate using a computational model to demonstrate the entire life-cycle within an intermediate host of the parasite as it completes the life-cycle using host cells of these organs. A cellular automata model is developed to demonstrate the dynamics of the parasite, where each cell follows the same set of rules for each discrete time-step. This cellular automata model allows for data simulations to be run of the parasite within a mouse and display graphical images and animations.

Novel Cognitive Functions Arise at the Convergence of Macroscale Gradients

2021 ◽  
pp. 1-16
Author(s):  
Heejung Jung ◽  
Tor D. Wager ◽  
R. McKell Carter
Keyword(s):  
Brain Regions ◽  
Higher Order ◽  
Hierarchical Organization ◽  
Functional Modules ◽  
Cortical Areas ◽  
Future Space ◽  
Close Proximity ◽  
Sensory Cortices ◽  
Developmental Characteristics ◽  
The Brain

Abstract Functions in higher-order brain regions are the source of extensive debate. Although past trends have been to describe the brain—especially posterior cortical areas—in terms of a set of functional modules, a new emerging paradigm focuses on the integration of proximal functions. In this review, we synthesize emerging evidence that a variety of novel functions in the higher-order brain regions are due to convergence: convergence of macroscale gradients brings feature-rich representations into close proximity, presenting an opportunity for novel functions to arise. Using the TPJ as an example, we demonstrate that convergence is enabled via three properties of the brain: (1) hierarchical organization, (2) abstraction, and (3) equidistance. As gradients travel from primary sensory cortices to higher-order brain regions, information becomes abstracted and hierarchical, and eventually, gradients meet at a point maximally and equally distant from their sensory origins. This convergence, which produces multifaceted combinations, such as mentalizing another person's thought or projecting into a future space, parallels evolutionary and developmental characteristics in such regions, resulting in new cognitive and affective faculties.

On Diplostomulum tregenna, the Diplostomulum Stage of Diplostomum tregenna Nazmi Gohar, 1932 with an Experimental Demonstration of Part of the Life Cycle

1963 ◽  
Vol 37 (3) ◽  
pp. 199-206 ◽  
Author(s):  
L. F. Khalil
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
Cranial Nerves ◽  
Blood Stream ◽  
Experimental Demonstration ◽  
Fat Tissue ◽  
Cranial Cavity ◽  
Feeding Experiments ◽  
White Nile ◽  
The Brain

While working on the cranial nerves of the Nile fish Clarias lazera Cuvier and Valenciennes, my attention was drawn to the presence of a very large number of trematode larvae on the brain. Subsequently twenty-four fishes were examined, both from the White Nile and the Blue Nile in Khartoum area in the Sudan, and twenty-two fishes were found to be heavily infected, each with several hundreds of the parasite. The parasite was identified through the help of Dawes' book—The Trematoda—and after feeding experiments, as Diplostomulum tregenna the larval stage of Diplostomum tregenna Nazmi Gohar, 1932. The parasite was found above or in front of the brain in the fat tissue, in the cranial cavity. Closer examination did not reveal the presence of the parasite in the brain tissues and its cavities, nor in the eyes, two of the most common places in which the majority of similar larvae occur. In some of the heavily infected fishes haemorrhage occurred which may suggest that the parasites reached the brain through the blood stream.

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