The Occipital Cortex in the Blind

Studying the brains of blind individuals provides a unique opportunity to investigate how the brain changes and adapts in response to afferent (input) and efferent (output) demands. We discuss evidence suggesting that regions of the brain normally associated with the processing of visual information undergo remarkable dynamic change in response to blindness. These neuroplastic changes implicate not only processing carried out by the remaining senses but also higher cognitive functions such as language and memory. A strong emphasis is placed on evidence obtained from advanced neuroimaging techniques that allow researchers to identify areas of human brain activity, as well as from lesion approaches (both reversible and irreversible) to address the functional relevance and role of these activated areas. A possible mechanism and conceptual framework for these physiological and behavioral changes is proposed.

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Recruitment of occipital cortex by arithmetic processing follows computational bias in early blind

10.1101/319343 ◽

2018 ◽

Cited By ~ 1

Author(s):

Virginie Crollen ◽

Latifa Lazzouni ◽

Antoine Bellemare ◽

Mohamed Rezk ◽

Franco Lepore ◽

...

Keyword(s):

Brain Activity ◽

Occipital Cortex ◽

Spatial Processing ◽

Functional Flexibility ◽

Multiplication Task ◽

The Right ◽

High Level ◽

Blind Individuals ◽

The Brain

AbstractArithmetic reasoning activates the occipital cortex of early blind people (EB). This activation of visual areas may reflect functional flexibility or the intrinsic computational role of specific occipital regions. We contrasted these competing hypotheses by characterizing the brain activity of EB and sighted participants while performing subtraction, multiplication and a control verbal task. In both groups, subtraction selectively activated a bilateral dorsal network commonly activated during spatial processing. Multiplication triggered more activity in temporal regions thought to participate in memory retrieval. No between-group difference was observed for the multiplication task whereas subtraction induced enhanced activity in the right dorsal occipital cortex of the blind individuals only. As this area overlaps and exhibits increased functional connectivity with regions showing selective tuning to auditory spatial processing, our results suggest that the recruitment of occipital regions during high-level cognition in the blind actually relates to the intrinsic computational role of the reorganized regions.

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Consciousness, decision making, and volition: freedom beyond chance and necessity

Theory in Biosciences ◽

10.1007/s12064-021-00346-6 ◽

2021 ◽

Author(s):

Hans Liljenström

Keyword(s):

Decision Making ◽

Free Will ◽

Brain Activity ◽

Brain Structures ◽

Complex Process ◽

Neural Information ◽

Neural Information Processing ◽

Stochastic Population Model ◽

The Brain

AbstractWhat is the role of consciousness in volition and decision-making? Are our actions fully determined by brain activity preceding our decisions to act, or can consciousness instead affect the brain activity leading to action? This has been much debated in philosophy, but also in science since the famous experiments by Libet in the 1980s, where the current most common interpretation is that conscious free will is an illusion. It seems that the brain knows, up to several seconds in advance what “you” decide to do. These studies have, however, been criticized, and alternative interpretations of the experiments can be given, some of which are discussed in this paper. In an attempt to elucidate the processes involved in decision-making (DM), as an essential part of volition, we have developed a computational model of relevant brain structures and their neurodynamics. While DM is a complex process, we have particularly focused on the amygdala and orbitofrontal cortex (OFC) for its emotional, and the lateral prefrontal cortex (LPFC) for its cognitive aspects. In this paper, we present a stochastic population model representing the neural information processing of DM. Simulation results seem to confirm the notion that if decisions have to be made fast, emotional processes and aspects dominate, while rational processes are more time consuming and may result in a delayed decision. Finally, some limitations of current science and computational modeling will be discussed, hinting at a future development of science, where consciousness and free will may add to chance and necessity as explanation for what happens in the world.

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Changes in thalamocortical connectivity as a potential mechanism of cross-modal plasticity in congenitally blind individuals

10.1101/449009 ◽

2018 ◽

Author(s):

Theo Marins ◽

Maite Russo ◽

Erika Rodrigues ◽

jorge Moll ◽

Daniel Felix ◽

...

Keyword(s):

Visual Cortex ◽

Cortical Thickness ◽

Visual Information ◽

Brain Plasticity ◽

Temporal Cortex ◽

Occipital Cortex ◽

Brain Structures ◽

Congenitally Blind ◽

Blind Individuals ◽

Neuroimaging Techniques

ABSTRACTEvidence of cross-modal plasticity in blind individuals has been reported over the past decades showing that non-visual information is carried and processed by classical “visual” brain structures. This feature of the blind brain makes it a pivotal model to explore the limits and mechanisms of brain plasticity. However, despite recent efforts, the structural underpinnings that could explain cross-modal plasticity in congenitally blind individuals remain unclear. Using advanced neuroimaging techniques, we mapped the thalamocortical connectivity and assessed cortical thickness and integrity of white matter of congenitally blind individuals and sighted controls to test the hypothesis that aberrant thalamocortical pattern of connectivity can pave the way for cross-modal plasticity. We described a direct occipital takeover by the temporal projections from the thalamus, which would carry non-visual information (e.g. auditory) to the visual cortex in congenitally blinds. In addition, the amount of thalamo-occipital connectivity correlated with the cortical thickness of primary visual cortex (V1), supporting a probably common (or related) reorganization phenomena. Our results suggest that aberrant thalamocortical connectivity as one possible mechanism of cross-modal plasticity in blinds, with potential impact on cortical thickness of V1.SIGNIFICANT STATEMENTCongenitally blind individuals often develop greater abilities on spared sensory modalities, such as increased acuity in auditory discrimination and voice recognition, when compared to sighted controls. These functional gains have been shown to rely on ‘visual’ cortical areas of the blind brain, characterizing the phenomenon of cross-modal plasticity. However, its anatomical underpinnings in humans have been unsuccessfully pursued for decades. Recent advances of non-invasive neuroimaging techniques allowed us to test the hypothesis of abnormal thalamocortical connectivity in congenitally blinds. Our results showed an expansion of the thalamic connections to the temporal cortex over those that project to the occipital cortex, which may explain, the cross-talk between the visual and auditory systems in congenitally blind individuals.

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Is Artistic Composition in Abstract Art Detected Automatically?

10.1093/oso/9780197513620.003.0021 ◽

2021 ◽

pp. 102-106

Author(s):

Claudia Menzel ◽

Gyula Kovács ◽

Gregor U. Hayn-Leichsenring ◽

Christoph Redies

Keyword(s):

Human Brain ◽

Significant Role ◽

Mismatch Negativity ◽

Brain Activity ◽

Perceptual Processing ◽

Abstract Art ◽

Electrical Brain Activity ◽

Image Set ◽

The Brain

Most artists who create abstract paintings place the pictorial elements not at random, but arrange them intentionally in a specific artistic composition. This arrangement results in a pattern of image properties that differs from image versions in which the same pictorial elements are randomly shuffled. In the article under discussion, the original abstract paintings of the author’s image set were rated as more ordered and harmonious but less interesting than their shuffled counterparts. The authors tested whether the human brain distinguishes between these original and shuffled images by recording electrical brain activity in a particular paradigm that evokes a so-called visual mismatch negativity. The results revealed that the brain detects the differences between the two types of images fast and automatically. These findings are in line with models that postulate a significant role of early (low-level) perceptual processing of formal image properties in aesthetic evaluations.

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The Role of Adrenoceptors in the Retina

Cells ◽

10.3390/cells9122594 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2594

Author(s):

Yue Ruan ◽

Tobias Böhmer ◽

Subao Jiang ◽

Adrian Gericke

Keyword(s):

Visual Information ◽

Vision Loss ◽

Retinal Diseases ◽

System A ◽

The Central Nervous System ◽

The Individual ◽

And Function ◽

The Brain

The retina is a part of the central nervous system, a thin multilayer with neuronal lamination, responsible for detecting, preprocessing, and sending visual information to the brain. Many retinal diseases are characterized by hemodynamic perturbations and neurodegeneration leading to vision loss and reduced quality of life. Since catecholamines and respective bindings sites have been characterized in the retina, we systematically reviewed the literature with regard to retinal expression, distribution and function of alpha1 (α1)-, alpha2 (α2)-, and beta (β)-adrenoceptors (ARs). Moreover, we discuss the role of the individual adrenoceptors as targets for the treatment of retinal diseases.

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A distinctive neural nexus in blind individuals supports Braille reading

10.1101/2021.04.12.439380 ◽

2021 ◽

Author(s):

Ruxue WANG ◽

Jiangtao GONG ◽

Chenying ZHAO ◽

Yingqing XU ◽

Bo HONG

Keyword(s):

Visual Cortex ◽

Functional Connectivity ◽

Frontal Cortex ◽

Reading Proficiency ◽

Occipital Cortex ◽

Resting State Functional Connectivity ◽

Crossmodal Plasticity ◽

Blind Individuals ◽

Language Areas

In the absence of visual input, occipital 'visual' cortex of blind people has been found to be engaged in non-visual higher cognitive tasks. Although the increased functional connectivity between 'visual' cortex and frontal cortex in the blind has been observed, the specific organization and functional role of this connectivity change remain to be elucidated. Here, we tested resting-state functional connectivity for primary 'visual' cortex (V1) and higher-tier lateral occipital cortex (LOC) in people with acquired blindness, and found an enhanced connectivity between the LOC but not V1 and typical frontal language areas - the inferior frontal cortex (IFC). In fact, the left-lateralized LOC-IFC connectivity strength predicted blind individuals' natural Braille reading proficiency. Furthermore, an increased bidirectional information flow between the left LOC and IFC was observed during a natural Braille reading task. In particular, the task-relevant modulation of the top-down communication from left IFC to LOC was significantly stronger than that of the bottom-up communication. Altogether, our study identified a distinctive neural nexus, LOC-IFC connection, and its behavioral significance in the acquired blind, revealing the neural correlates of the crossmodal plasticity in their 'visual' cortex underlying natural Braille reading.

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Complex of global functional network as the core of consciousness

10.31234/osf.io/89ugz ◽

2021 ◽

Author(s):

Keiichi Onoda

Keyword(s):

Dynamic System ◽

Brain Activity ◽

Posterior Part ◽

Neural Basis ◽

Attention Networks ◽

The Core ◽

Hierarchical Partition ◽

Brain Fmri ◽

The Brain

Finding the neural basis of consciousness is a challenging issue, and it is still inconclusive where the core of consciousness is distributed in the brain. The global neuronal workspace theory (GNWT) emphasizes the role of the frontoparietal regions, whereas the integrated information theory (IIT) argues that the posterior part of the brain is the core of consciousness. IIT has proposed “main complex” as the core of consciousness in a dynamic system, which is a set of elements that the information loss in a hierarchical partition approach is the largest among that of all its supersets and subsets. However, no experimental study has reported the core of consciousness using the main complex for actual brain activity. This study estimated the main complex of brain dynamics using a functional MRI. The whole-brain fMRI data of eight conditions (seven tasks and a rest state) were divided into multiple elements based on network atlases, and the main complex of the dynamic system was estimated for each condition. It is assumed that, if there is a set of elements in the complex that are common to all conditions, the set is likely to contain the core of consciousness. Executive control, salience, and dorsal/ventral attention networks were commonly included in the main complex across all conditions, implying that these networks are responsible for the core of consciousness. This finding is consistent with the GNWT, as these networks are across the prefrontal and parietal regions.

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Synchronization in the connectome: Metastable oscillatory modes emerge from interactions in the brain spacetime network

10.1101/2022.01.06.475196 ◽

2022 ◽

Author(s):

Joana Cabral ◽

Francesca Castaldo ◽

Jakub Vohryzek ◽

Vladimir Litvak ◽

Christian Bick ◽

...

Keyword(s):

Coupled Oscillators ◽

Brain Activity ◽

Power Spectra ◽

Brain Areas ◽

Neural Mass ◽

Spatially Distributed ◽

Weakly Stable ◽

Human Brains ◽

The Brain

A rich repertoire of oscillatory signals is detected from human brains with electro- and magnetoencephalography (EEG/MEG). However, the principles underwriting coherent oscillations and their link with neural activity remain unclear. Here, we hypothesise that the emergence of transient brain rhythms is a signature of weakly stable synchronization between spatially distributed brain areas, occurring at network-specific collective frequencies due to non-negligible conduction times. We test this hypothesis using a phenomenological network model to simulate interactions between neural mass potentials (resonating at 40Hz) in the structural connectome. Crucially, we identify a critical regime where metastable oscillatory modes emerge spontaneously in the delta (0.5-4Hz), theta (4-8Hz), alpha (8-13Hz) and beta (13-30Hz) frequency bands from weak synchronization of subsystems, closely approximating the MEG power spectra from 89 healthy individuals. Grounded in the physics of delay-coupled oscillators, these numerical analyses demonstrate the role of the spatiotemporal connectome in structuring brain activity in the frequency domain.

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Beauty is not always in the eye of the beholder: the role of vision in the emergence of mate preferences

10.31234/osf.io/nt3xj ◽

2019 ◽

Author(s):

Meike Scheller ◽

Francine Matorres ◽

Lucy Tompkins ◽

Anthony C. Little ◽

Alexandra A. de Sousa

Keyword(s):

Sex Differences ◽

Physical Attractiveness ◽

Visual Information ◽

Visual Cues ◽

Mate Preferences ◽

Personality Factors ◽

High Status ◽

Partner Characteristics ◽

Blind Individuals

Cross-cultural research has repeatedly demonstrated sex differences in the importance of different partner characteristics when choosing a mate. Men typically report higher preferences for younger, more physically attractive women, while women prefer men that are wealthier and of higher status. As the assessment of such partner characteristics often relies on visual cues, this raises the question whether visual experience is necessary for sex-specific mate preferences to develop. To shed more light onto the emergence of sex differences in mate choice, the current study assessed how preferences for attractiveness, resources, and personality factors differ between sighted and blind individuals using an online questionnaire. We further investigate the role of social factors and sensory cue selection in these sex differences. Our sample consisted of 94 sighted and blind participants with different ages of blindness-onset, 19 blind/28 sighted males, and 19 blind/28 sighted females. Results replicated well-documented findings in the sighted, with men placing more importance on physical attractiveness and women placing more importance on status and resources. However, while physical attractiveness was less important to blind men, blind women considered physical attractiveness as important as sighted women. The importance of a high status and likeable personality was not influenced by sightedness. Blind individuals considered auditory cues more important than visual cues, while sighted males showed the opposite pattern. Further, relationship status and indirect, social influences were related to preferences. Overall, our findings shed light on the availability of visual information for the emergence of sex differences in mate preference.

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The modular and integrative functional architecture of the human brain

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1510619112 ◽

2015 ◽

Vol 112 (49) ◽

pp. E6798-E6807 ◽

Cited By ~ 228

Author(s):

Maxwell A. Bertolero ◽

B. T. Thomas Yeo ◽

Mark D’Esposito

Keyword(s):

Human Brain ◽

Cognitive Functions ◽

Topic Model ◽

Brain Activity ◽

Modular Function ◽

Imaging Data ◽

Functional Architecture ◽

Brain Imaging Data ◽

The Brain

Network-based analyses of brain imaging data consistently reveal distinct modules and connector nodes with diverse global connectivity across the modules. How discrete the functions of modules are, how dependent the computational load of each module is to the other modules’ processing, and what the precise role of connector nodes is for between-module communication remains underspecified. Here, we use a network model of the brain derived from resting-state functional MRI (rs-fMRI) data and investigate the modular functional architecture of the human brain by analyzing activity at different types of nodes in the network across 9,208 experiments of 77 cognitive tasks in the BrainMap database. Using an author–topic model of cognitive functions, we find a strong spatial correspondence between the cognitive functions and the network’s modules, suggesting that each module performs a discrete cognitive function. Crucially, activity at local nodes within the modules does not increase in tasks that require more cognitive functions, demonstrating the autonomy of modules’ functions. However, connector nodes do exhibit increased activity when more cognitive functions are engaged in a task. Moreover, connector nodes are located where brain activity is associated with many different cognitive functions. Connector nodes potentially play a role in between-module communication that maintains the modular function of the brain. Together, these findings provide a network account of the brain’s modular yet integrated implementation of cognitive functions.

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