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.

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.

scholarly journals Genetic influences on brain representations of natural audiovisual experiences

2021 ◽  
Author(s):  
Satoshi Nishida ◽  
Shunsuke Toyoda ◽  
Chika Honda ◽  
Mikio Watanabe ◽  
Miina Ollikainen ◽  
...  
Keyword(s):  
Genetic Factors ◽  
Brain Regions ◽  
Genetic Influence ◽  
Control Individual ◽  
Brain Response ◽  
Subcortical Structures ◽  
Movie Clip ◽  
Pattern Similarity ◽  
Sensory Cortices ◽  
The Brain

Abstract Natural sensory inputs in everyday situations induce unique experiences that vary between individuals, even when inputs are identical. This experiential uniqueness stems from the representations of sensory signals in each brain. We investigated whether genetic factors control individual differences in sensory representations in the brain by studying the brain representations of natural audiovisual signals in twin-pairs. We measured the brain response to natural movies in twins using functional magnetic resonance imaging and quantified the genetic influence on the multivoxel-pattern similarity of movie clip representations between each twin. The whole-brain analysis revealed a genetic influence on the multivoxel-pattern similarity in widespread brain regions, which included the occipitotemporal sensory cortices as well as the frontoparietal association cortices and subcortical structures. Our findings suggest that genetic factors exhibit an effect on natural audiovisual signaling by controlling audiovisual representations in the brain.

scholarly journals Oxytocinergic Feedback Circuitries: An Anatomical Basis for Neuromodulation of Social Behaviors

2021 ◽  
Vol 15 ◽  
Author(s):  
Arthur Lefevre ◽  
Diego Benusiglio ◽  
Yan Tang ◽  
Quirin Krabichler ◽  
Alexandre Charlet ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Brain Regions ◽  
Neuron Activity ◽  
Behavioral Context ◽  
Subcortical Structures ◽  
Social Brain ◽  
Social Stimuli ◽  
Anatomical Basis ◽  
Sensory Cortices ◽  
The Brain

Oxytocin (OT) is a neuropeptide produced by hypothalamic neurons and is known to modulate social behavior among other functions. Several experiments have shown that OT modulates neuronal activity in many brain areas, including sensory cortices. OT neurons thus project axons to various cortical and subcortical structures and activate neuronal subpopulations to increase the signal-to-noise ratio, and in turn, increases the saliency of social stimuli. Less is known about the origin of inputs to OT neurons, but recent studies show that cells projecting to OT neurons are often located in regions where the OT receptor (OTR) is expressed. Thus, we propose the existence of reciprocal connectivity between OT neurons and extrahypothalamic OTR neurons to tune OT neuron activity depending on the behavioral context. Furthermore, the latest studies have shown that OTR-expressing neurons located in social brain regions also project to other social brain regions containing OTR-expressing neurons. We hypothesize that OTR-expressing neurons across the brain constitute a common network coordinated by OT.

scholarly journals Signal propagation via cortical hierarchies

2020 ◽  
Author(s):  
Bertha Vázquez-Rodríguez ◽  
Zhen-Qi Liu ◽  
Patric Hagmann ◽  
Bratislav Mišić
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 labelled 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 re-routed. Altogether, the present work highlights how the cortical hierarchy shapes signal exchange and imparts behaviourally-relevant communication patterns in brain networks.

scholarly journals The topology of higher-order complexes associated with brain hubs in human connectomes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Miroslav Andjelković ◽  
Bosiljka Tadić ◽  
Roderick Melnik
Keyword(s):  
Complex Dynamics ◽  
Simplicial Complexes ◽  
Brain Regions ◽  
Higher Order ◽  
Core Networks ◽  
Right Cerebral Hemisphere ◽  
Left And Right ◽  
Order Complexes ◽  
The Brain

Abstract Higher-order connectivity in complex systems described by simplexes of different orders provides a geometry for simplex-based dynamical variables and interactions. Simplicial complexes that constitute a functional geometry of the human connectome can be crucial for the brain complex dynamics. In this context, the best-connected brain areas, designated as hub nodes, play a central role in supporting integrated brain function. Here, we study the structure of simplicial complexes attached to eight global hubs in the female and male connectomes and identify the core networks among the affected brain regions. These eight hubs (Putamen, Caudate, Hippocampus and Thalamus-Proper in the left and right cerebral hemisphere) are the highest-ranking according to their topological dimension, defined as the number of simplexes of all orders in which the node participates. Furthermore, we analyse the weight-dependent heterogeneity of simplexes. We demonstrate changes in the structure of identified core networks and topological entropy when the threshold weight is gradually increased. These results highlight the role of higher-order interactions in human brain networks and provide additional evidence for (dis)similarity between the female and male connectomes.

Remote memory for public figures in Alzheimer's disease: Relationships to regional cortical and limbic brain volumes

2001 ◽  
Vol 7 (3) ◽  
pp. 384-390 ◽  
Author(s):  
ROSEMARY FAMA ◽  
PAULA K. SHEAR ◽  
LAURA MARSH ◽  
JEROME A. YESAVAGE ◽  
JARED R. TINKLENBERG ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Regions ◽  
Remote Memory ◽  
Brain Volumes ◽  
Presidential Candidates ◽  
Cortical Areas ◽  
Prefrontal Cortical ◽  
Public Figures ◽  
The Brain

This study examined the relationships between regional cortical and hippocampal brain volumes and components of remote memory (recall, recognition, sequencing, and photo naming of presidential candidates) in 13 individuals with Alzheimer's disease (AD). Recognition and sequencing of remote memory for public figures were associated with regional cortical volumes. Specifically, lower recognition and sequencing scores were associated with smaller parietal–occipital cortical volumes; poorer sequencing was also associated with smaller prefrontal cortical volumes. By contrast, poorer anterograde but not remote memory scores were correlated with smaller hippocampal volumes. Within the constraints of the brain regions measured, these findings highlight the importance of the posterior cortical areas for selective remote memory processes and provide support for the dissociation between cortically mediated remote memory and hippocampally mediated anterograde memory. (JINS, 2001, 7, 384–390.)

scholarly journals Mass spectrometry imaging identifies abnormally elevated brain l-DOPA levels and extrastriatal monoaminergic dysregulation in l-DOPA–induced dyskinesia

2021 ◽  
Vol 7 (2) ◽  
pp. eabe5948
Author(s):  
Elva Fridjonsdottir ◽  
Reza Shariatgorji ◽  
Anna Nilsson ◽  
Theodosia Vallianatou ◽  
Luke R. Odell ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Side Effects ◽  
Mass Spectrometry Imaging ◽  
Brain Regions ◽  
Stria Terminalis ◽  
Brain Areas ◽  
Bed Nucleus ◽  
Neuronal Signaling ◽  
Cortical Areas ◽  
The Brain

l-DOPA treatment for Parkinson’s disease frequently leads to dyskinesias, the pathophysiology of which is poorly understood. We used MALDI-MSI to map the distribution of l-DOPA and monoaminergic pathways in brains of dyskinetic and nondyskinetic primates. We report elevated levels of l-DOPA, and its metabolite 3-O-methyldopa, in all measured brain regions of dyskinetic animals and increases in dopamine and metabolites in all regions analyzed except the striatum. In dyskinesia, dopamine levels correlated well with l-DOPA levels in extrastriatal regions, such as hippocampus, amygdala, bed nucleus of the stria terminalis, and cortical areas, but not in the striatum. Our results demonstrate that l-DOPA–induced dyskinesia is linked to a dysregulation of l-DOPA metabolism throughout the brain. The inability of extrastriatal brain areas to regulate the formation of dopamine during l-DOPA treatment introduces the potential of dopamine or even l-DOPA itself to modulate neuronal signaling widely across the brain, resulting in unwanted side effects.

scholarly journals Hierarchical Organization of Corticothalamic Projections to the Pulvinar

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Reza Abbas Farishta ◽  
Denis Boire ◽  
Christian Casanova
Keyword(s):  
Higher Order ◽  
Hierarchical Organization ◽  
Hierarchical Level ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Visual Areas ◽  
Cortical Hierarchy ◽  
Area 21A ◽  
Extrastriate Areas ◽  
Corticothalamic Projections

Abstract Signals from lower cortical visual areas travel to higher-order areas for further processing through cortico-cortical projections, organized in a hierarchical manner. These signals can also be transferred between cortical areas via alternative cortical transthalamic routes involving higher-order thalamic nuclei like the pulvinar. It is unknown whether the organization of transthalamic pathways may reflect the cortical hierarchy. Two axon terminal types have been identified in corticothalamic (CT) pathways: the types I (modulators) and II (drivers) characterized by thin axons with small terminals and by thick axons and large terminals, respectively. In cats, projections from V1 to the pulvinar complex comprise mainly type II terminals, whereas those from extrastriate areas include a combination of both terminals suggesting that the nature of CT terminals varies with the hierarchical order of visual areas. To test this hypothesis, distribution of CT terminals from area 21a was charted and compared with 3 other visual areas located at different hierarchical levels. Results demonstrate that the proportion of modulatory CT inputs increases along the hierarchical level of cortical areas. This organization of transthalamic pathways reflecting cortical hierarchy provides new and fundamental insights for the establishment of more accurate models of cortical signal processing along transthalamic cortical pathways.

scholarly journals Higher-order interaction of brain microstructural and functional connectome

2021 ◽  
Author(s):  
Hao Wang ◽  
Hui-Jun Wu ◽  
Yang-Yu Liu ◽  
Linyuan Lu
Keyword(s):  
Structure Function ◽  
Higher Order ◽  
Global Network ◽  
Order Structure ◽  
Sensory Cortices ◽  
Brain Microstructure ◽  
Function Relationship ◽  
The Individual ◽  
Local Circuits ◽  
The Brain

Despite a relatively fixed anatomical structure, the human brain can support rich cognitive functions, triggering particular interest in investigating structure-function relationships. Myelin is a vital brain microstructure marker, yet the individual microstructure-function relationship is poorly understood. Here, we explore the brain microstructure-function relationships using a higher-order framework. Global (network-level) higher-order microstructure-function relationships negatively correlate with male participants' personality scores and decline with aging. Nodal (node-level) higher-order microstructure-function relationships are not aligned uniformly throughout the brain, being stronger in association cortices and lower in sensory cortices, showing gender differences. Notably, higher-order microstructure-function relationships are maintained from the whole-brain to local circuits, which uncovers a compelling and straightforward principle of brain structure-function interactions. Additionally, targeted artificial attacks can disrupt these higher-order relationships, and the main results are robust against several factors. Together, our results increase the collective knowledge of higher-order structure- function interactions that may underlie cognition, individual differences, and aging.

scholarly journals A role for descending auditory cortical projections in songbird vocal learning

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Yael Mandelblat-Cerf ◽  
Liora Las ◽  
Natalia Denisenko ◽  
Michale S Fee
Keyword(s):  
Cortical Area ◽  
Internal Representation ◽  
Vocal Learning ◽  
Brain Regions ◽  
Motor Behaviors ◽  
Cortical Areas ◽  
Cortical Projections ◽  
Ongoing Behavior ◽  
External Reward ◽  
The Brain

Many learned motor behaviors are acquired by comparing ongoing behavior with an internal representation of correct performance, rather than using an explicit external reward. For example, juvenile songbirds learn to sing by comparing their song with the memory of a tutor song. At present, the brain regions subserving song evaluation are not known. In this study, we report several findings suggesting that song evaluation involves an avian 'cortical' area previously shown to project to the dopaminergic midbrain and other downstream targets. We find that this ventral portion of the intermediate arcopallium (AIV) receives inputs from auditory cortical areas, and that lesions of AIV result in significant deficits in vocal learning. Additionally, AIV neurons exhibit fast responses to disruptive auditory feedback presented during singing, but not during nonsinging periods. Our findings suggest that auditory cortical areas may guide learning by transmitting song evaluation signals to the dopaminergic midbrain and/or other subcortical targets.

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