Plasticity and the Human Brain: Insights from Functional Imaging

1996 ◽  
Vol 2 (6) ◽  
pp. 353-362 ◽  
Author(s):  
Richard S.J. Frackowiak
Keyword(s):  
Human Brain ◽  
Functional Imaging ◽  
Large Scale ◽  
Imaging Techniques ◽  
Functional Reorganization ◽  
Neuronal Populations ◽  
Normal Behavior ◽  
Definition Of ◽  
The Brain

This article begins with a definition of cerebral plasticity in human brain that rests on the concept of a long-term alteration in patterns of task- or behavior-related activity in distributed brain systems. The theme is then developed to show how such a concept and the mechanisms it implies can be investigated and mapped using modern noninvasive functional imaging techniques. The human experimental literature is critically presented in relation to normal behavior, especially in relation to the acquisition of motor skills and learning. A discussion of the functional reorganization that follows brain injury and that is associated with spontaneous recovery from motor and perceptual deficits is then presented from the perspective of understanding the brain mechanisms at the level of large-scale neuronal populations.

Bistability of somatic pattern memories: stochastic outcomes in bioelectric circuits underlying regeneration

2021 ◽  
Vol 376 (1821) ◽  
pp. 20190765 ◽  
Author(s):  
Giovanni Pezzulo ◽  
Joshua LaPalme ◽  
Fallon Durant ◽  
Michael Levin
Keyword(s):  
Large Scale ◽  
Computational Models ◽  
State Of The Art ◽  
Memory Representation ◽  
Theme Issue ◽  
Evolutionary Innovation ◽  
New Interpretation ◽  
The Brain

Nervous systems’ computational abilities are an evolutionary innovation, specializing and speed-optimizing ancient biophysical dynamics. Bioelectric signalling originated in cells' communication with the outside world and with each other, enabling cooperation towards adaptive construction and repair of multicellular bodies. Here, we review the emerging field of developmental bioelectricity, which links the field of basal cognition to state-of-the-art questions in regenerative medicine, synthetic bioengineering and even artificial intelligence. One of the predictions of this view is that regeneration and regulative development can restore correct large-scale anatomies from diverse starting states because, like the brain, they exploit bioelectric encoding of distributed goal states—in this case, pattern memories. We propose a new interpretation of recent stochastic regenerative phenotypes in planaria, by appealing to computational models of memory representation and processing in the brain. Moreover, we discuss novel findings showing that bioelectric changes induced in planaria can be stored in tissue for over a week, thus revealing that somatic bioelectric circuits in vivo can implement a long-term, re-writable memory medium. A consideration of the mechanisms, evolution and functionality of basal cognition makes novel predictions and provides an integrative perspective on the evolution, physiology and biomedicine of information processing in vivo . This article is part of the theme issue ‘Basal cognition: multicellularity, neurons and the cognitive lens’.

scholarly journals Amplification and Suppression of Distinct Brain-wide Activity Patterns by Catecholamines

2018 ◽  
Author(s):  
RL van den Brink ◽  
S Nieuwenhuis ◽  
TH Donner
Keyword(s):  
Spatial Distribution ◽  
Human Brain ◽  
Spatial Patterns ◽  
Large Scale ◽  
Network Dynamics ◽  
Brain Network ◽  
Heterogeneous Distribution ◽  
Neurotransmitter Systems ◽  
The Brain ◽  
Catecholamine Levels

ABSTRACTThe widely projecting catecholaminergic (norepinephrine and dopamine) neurotransmitter systems profoundly shape the state of neuronal networks in the forebrain. Current models posit that the effects of catecholaminergic modulation on network dynamics are homogenous across the brain. However, the brain is equipped with a variety of catecholamine receptors with distinct functional effects and heterogeneous density across brain regions. Consequently, catecholaminergic effects on brain-wide network dynamics might be more spatially specific than assumed. We tested this idea through the analysis of functional magnetic resonance imaging (fMRI) measurements performed in humans (19 females, 5 males) at ‘rest’ under pharmacological (atomoxetine-induced) elevation of catecholamine levels. We used a linear decomposition technique to identify spatial patterns of correlated fMRI signal fluctuations that were either increased or decreased by atomoxetine. This yielded two distinct spatial patterns, each expressing reliable and specific drug effects. The spatial structure of both fluctuation patterns resembled the spatial distribution of the expression of catecholamine receptor genes: α1 norepinephrine receptors (for the fluctuation pattern: placebo > atomoxetine), ‘D2-like’ dopamine receptors (pattern: atomoxetine > placebo), and β norepinephrine receptors (for both patterns, with correlations of opposite sign). We conclude that catecholaminergic effects on the forebrain are spatially more structured than traditionally assumed and at least in part explained by the heterogeneous distribution of various catecholamine receptors. Our findings link catecholaminergic effects on large-scale brain networks to low-level characteristics of the underlying neurotransmitter systems. They also provide key constraints for the development of realistic models of neuromodulatory effects on large-scale brain network dynamics.SIGNIFICANCE STATEMENTThe catecholamines norepinephrine and dopamine are an important class of modulatory neurotransmitters. Because of the widespread and diffuse release of these neuromodulators, it has commonly been assumed that their effects on neural interactions are homogenous across the brain. Here, we present results from the human brain that challenge this view. We pharmacologically increased catecholamine levels and imaged the effects on the spontaneous covariations between brain-wide fMRI signals at ‘rest’. We identified two distinct spatial patterns of covariations: one that was amplified and another that was suppressed by catecholamines. Each pattern was associated with the heterogeneous spatial distribution of the expression of distinct catecholamine receptor genes. Our results provide novel insights into the catecholaminergic modulation of large-scale human brain dynamics.

The Power of Poetry

2021 ◽  
pp. 182-187
Author(s):  
Eugen Wassiliwizky ◽  
Winfried Menninghaus
Keyword(s):  
Human Brain ◽  
Experimental Psychology ◽  
Large Scale ◽  
Multidisciplinary Approach ◽  
Scientific Investigation ◽  
Poetic Language ◽  
Social And Emotional ◽  
Parent Child Interactions ◽  
The Brain ◽  
Parent Child

From prehistory onward, poetic language has been widely used in the context of great personal, social, and emotional significance, reaching from large scale events, such as religious ceremonies, political occasions (including inaugurations of American presidents), and artistic contexts to more private gatherings, such as birthday parties, declarations of love, and parent–child interactions. Poetic language is capable of reaching deeply into the phylogenetically ancient structures of the human brain and providing profound aesthetic pleasures to its recipients. Yet a thorough scientific investigation of the workings of poetic language in the brain is only at its very beginnings. In the article under discussion, the authors review a study that focused on the emotional power of poetic language. In this project, they strived to integrate and interrelate perspectives from experimental psychology, neuroscience, rhetoric/poetics, psychophysiology, and philosophy. They argue that such a multidisciplinary approach is key to unraveling the mysteries of human aesthetic processing.

scholarly journals Brain network dynamics are hierarchically organized in time

2017 ◽  
Vol 114 (48) ◽  
pp. 12827-12832 ◽  
Author(s):  
Diego Vidaurre ◽  
Stephen M. Smith ◽  
Mark W. Woolrich
Keyword(s):  
Large Scale ◽  
Temporal Dynamics ◽  
Brain Network ◽  
Specific Measure ◽  
Brain Areas ◽  
Neuronal Populations ◽  
Subject Specific ◽  
Large Scale Networks ◽  
Network Patterns ◽  
The Brain

The brain recruits neuronal populations in a temporally coordinated manner in task and at rest. However, the extent to which large-scale networks exhibit their own organized temporal dynamics is unclear. We use an approach designed to find repeating network patterns in whole-brain resting fMRI data, where networks are defined as graphs of interacting brain areas. We find that the transitions between networks are nonrandom, with certain networks more likely to occur after others. Further, this nonrandom sequencing is itself hierarchically organized, revealing two distinct sets of networks, or metastates, that the brain has a tendency to cycle within. One metastate is associated with sensory and motor regions, and the other involves areas related to higher order cognition. Moreover, we find that the proportion of time that a subject spends in each brain network and metastate is a consistent subject-specific measure, is heritable, and shows a significant relationship with cognitive traits.

Is the human brain only responsive?

1995 ◽  
Vol 18 (2) ◽  
pp. 365-366
Author(s):  
Rumyana Kristeva-Feige ◽  
Bernd Feige
Keyword(s):  
Human Brain ◽  
Spontaneous Activity ◽  
Cognitive Functions ◽  
Evoked Potential ◽  
Imaging Techniques ◽  
Brain Activity ◽  
External Events ◽  
Potential Methods ◽  
The Brain

AbstractPosner & Raichle's (1994) book is a fascinating and readable account of the studies the authors have conducted on the localization of cognitive functions in the brain mainly using PET and EEC evoked potential methods. Our criticism concerns the underrepresentation of some imaging techniques (magnetoencephalography) and some forms of brain activity (spontaneous activity). Furthermore, the book leaves the reader with the impression that the brain only responds to external events.

scholarly journals “Neurocovid”: An Analysis of the Impact of Covid-19 on the Older Adults. Evolving Psychological and Neuropsychological Understanding

2021 ◽  
Author(s):  
Sara Palermo
Keyword(s):  
Older Adults ◽  
Nervous System ◽  
Adverse Effects ◽  
Human Brain ◽  
The Elderly ◽  
Cognitive Frailty ◽  
Daily Routines ◽  
The Impact ◽  
The Brain

When SARS-CoV-2 began to spread, older adults experienced disproportionately greater adverse effects from the pandemic, including exacerbation of pre-existing physical and cognitive frailty conditions. More severe complications, higher mortality, and concerns about disruptions to their daily routines and access to care. Knowledge about the impact of COVID-19 on the brain is rapidly accumulating and this is reflected in the increasing use of the term “neurocovid”. Co-involvement of the central and peripheral nervous system had already been observed in SARS patients, but COVID-19 seems to invade it with greater affinity than other coronaviruses. This chapter provides an overview of the expanding understanding of the multiple ways in which COVID-19 affects the human brain, discuss the likelihood of long-term sequelae of neurocovid, and their implications for cognitive functions and behaviors in the elderly.

scholarly journals Post-Stroke Cognitive Impairment: Pathophysiological Insights into Brain Disconnectome from Advanced Neuroimaging Analysis Techniques

2021 ◽  
Vol 23 (3) ◽  
pp. 297-311
Author(s):  
Jae-Sung Lim ◽  
Jae-Joong Lee ◽  
Choong-Wan Woo
Keyword(s):  
Cognitive Impairment ◽  
Large Scale ◽  
Imaging Techniques ◽  
Brain Network ◽  
Clinical Neurology ◽  
Post Stroke ◽  
Large Scale Networks ◽  
High Level ◽  
New Treatments ◽  
The Brain

The neurological symptoms of stroke have traditionally provided the foundation for functional mapping of the brain. However, there are many unresolved aspects in our understanding of cerebral activity, especially regarding high-level cognitive functions. This review provides a comprehensive look at the pathophysiology of post-stroke cognitive impairment in light of recent findings from advanced imaging techniques. Combining network neuroscience and clinical neurology, our research focuses on how changes in brain networks correlate with post-stroke cognitive prognosis. More specifically, we first discuss the general consequences of stroke lesions due to damage of canonical resting-state large-scale networks or changes in the composition of the entire brain. We also review emerging methods, such as lesion-network mapping and gradient analysis, used to study the aforementioned events caused by stroke lesions. Lastly, we examine other patient vulnerabilities, such as superimposed amyloid pathology and blood-brain barrier leakage, which potentially lead to different outcomes for the brain network compositions even in the presence of similar stroke lesions. This knowledge will allow a better understanding of the pathophysiology of post-stroke cognitive impairment and provide a theoretical basis for the development of new treatments, such as neuromodulation.

scholarly journals Global enhancement of cortical excitability following coactivation of large neuronal populations

2020 ◽  
Vol 117 (33) ◽  
pp. 20254-20264 ◽  
Author(s):  
Deng Zhang ◽  
Xingjian Yan ◽  
Liang She ◽  
Yunqing Wen ◽  
Mu-ming Poo
Keyword(s):  
Cortical Neurons ◽  
Neuronal Excitability ◽  
Cortical Excitability ◽  
Large Population ◽  
Neuronal Firing ◽  
Enhancement Effect ◽  
Neuronal Populations ◽  
Mouse Cortex ◽  
The Brain

Correlated activation of cortical neurons often occurs in the brain and repetitive correlated neuronal firing could cause long-term modifications of synaptic efficacy and intrinsic excitability. We found that repetitive optogenetic activation of neuronal populations in the mouse cortex caused enhancement of optogenetically evoked firing of local coactivated neurons as well as distant cortical neurons in both ipsilateral and contralateral hemispheres. This global enhancement of evoked responses required coactivation of a sufficiently large population of neurons either within one cortical area or distributed in several areas. Enhancement of neuronal firing was saturable after repeated episodes of coactivation, diminished by inhibition ofN-methyl-d-aspartic acid receptors, and accompanied by elevated excitatory postsynaptic potentials, all consistent with activity-induced synaptic potentiation. Chemogenetic inhibition of neuronal activity of the thalamus decreased the enhancement effect, suggesting thalamic involvement. Thus, correlated excitation of large neuronal populations leads to global enhancement of neuronal excitability.

scholarly journals Hemispheric Asymmetry of Human Brain Anatomical Network Revealed by Diffusion Tensor Tractography

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ni Shu ◽  
Yaou Liu ◽  
Yunyun Duan ◽  
Kuncheng Li
Keyword(s):  
Human Brain ◽  
Large Scale ◽  
Diffusion Tensor ◽  
Functional Integration ◽  
Brain Regions ◽  
Hemispheric Asymmetries ◽  
Characteristic Path Length ◽  
Topological Measures ◽  
Structural Connections ◽  
The Brain

The topological architecture of the cerebral anatomical network reflects the structural organization of the human brain. Recently, topological measures based on graph theory have provided new approaches for quantifying large-scale anatomical networks. However, few studies have investigated the hemispheric asymmetries of the human brain from the perspective of the network model, and little is known about the asymmetries of the connection patterns of brain regions, which may reflect the functional integration and interaction between different regions. Here, we utilized diffusion tensor imaging to construct binary anatomical networks for 72 right-handed healthy adult subjects. We established the existence of structural connections between any pair of the 90 cortical and subcortical regions using deterministic tractography. To investigate the hemispheric asymmetries of the brain, statistical analyses were performed to reveal the brain regions with significant differences between bilateral topological properties, such as degree of connectivity, characteristic path length, and betweenness centrality. Furthermore, local structural connections were also investigated to examine the local asymmetries of some specific white matter tracts. From the perspective of both the global and local connection patterns, we identified the brain regions with hemispheric asymmetries. Combined with the previous studies, we suggested that the topological asymmetries in the anatomical network may reflect the functional lateralization of the human brain.

scholarly journals Dissociated Expression of Mitochondrial and Cytosolic Creatine Kinases in the Human Brain: A New Perspective on the Role of Creatine in Brain Energy Metabolism

2013 ◽  
Vol 33 (8) ◽  
pp. 1295-1306 ◽  
Author(s):  
Matthew TJ Lowe ◽  
Eric H Kim ◽  
Richard LM Faull ◽  
David L Christie ◽  
Henry J Waldvogel
Keyword(s):  
Energy Metabolism ◽  
Human Brain ◽  
High Energy ◽  
Cellular Energy ◽  
Neuronal Populations ◽  
Neurologic Function ◽  
New Perspective ◽  
The Brain ◽  
Brain Energy

The phosphocreatine/creatine kinase (PCr/CK) system in the brain is defined by the expression of two CK isozymes: the cytosolic brain-type CK (BCK) and the ubiquitous mitochondrial CK (uMtCK). The system plays an important role in supporting cellular energy metabolism by buffering adenosine triphosphate (ATP) consumption and improving the flux of high-energy phosphoryls around the cell. This system is well defined in muscle tissue, but there have been few detailed studies of this system in the brain, especially in humans. Creatine is known to be important for neurologic function, and its loss from the brain during development can lead to mental retardation. This study provides the first detailed immunohistochemical study of the expression pattern of BCK and uMtCK in the human brain. A strikingly dissociated pattern of expression was found: uMtCK was found to be ubiquitously and exclusively expressed in neuronal populations, whereas BCK was dominantly expressed in astrocytes, with a low and selective expression in neurons. This pattern indicates that the two CK isozymes are not widely coexpressed in the human brain, but rather are selectively expressed depending on the cell type. These results suggest that the brain cells may use only certain properties of the PCr/CK system depending on their energetic requirements.

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