scholarly journals Spatial navigation by congenitally blind individuals

2015 ◽  
Vol 7 (1) ◽  
pp. 37-58 ◽  
Author(s):  
Victor R. Schinazi ◽  
Tyler Thrash ◽  
Daniel-Robert Chebat
Keyword(s):  
Spatial Navigation ◽  
Congenitally Blind ◽  
Blind Individuals

scholarly journals Occipital Cortex of Blind Individuals Is Functionally Coupled with Executive Control Areas of Frontal Cortex

2015 ◽  
Vol 27 (8) ◽  
pp. 1633-1647 ◽  
Author(s):  
Ben Deen ◽  
Rebecca Saxe ◽  
Marina Bedny
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Sentence Comprehension ◽  
Memory Load ◽  
Memory Task ◽  
Occipital Cortex ◽  
Memory Systems ◽  
Functional Responses ◽  
Congenitally Blind ◽  
Blind Individuals

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.

scholarly journals Shared understanding of color among congenitally blind and sighted adults

2020 ◽  
Author(s):  
Judy Sein Kim ◽  
Brianna Aheimer ◽  
Veronica Montane Manrara ◽  
Marina Bedny
Keyword(s):  
Visual Experience ◽  
Natural Kinds ◽  
Shared Understanding ◽  
Linguistic Communication ◽  
Causal Explanations ◽  
Stop Sign ◽  
Congenitally Blind ◽  
Novel Objects ◽  
Blind Individuals

Empiricist philosophers such as Locke famously argued that people born blind could only acquire shallow, fragmented facts about color. Contrary to this intuition, we report that blind and sighted people share an in-depth understanding of color, despite disagreeing about arbitrary color facts. Relative to the sighted, blind individuals are less likely to generate ‘yellow’ for banana and ‘red’ for stop-sign. However, blind and sighted adults are equally likely to infer that two bananas (natural kinds) and two stop-signs (artifacts with functional colors) are more likely to have the same color than two cars (artifacts with non-functional colors), make similar inferences about novel objects’ colors, and provide similar causal explanations. We argue that people develop inferentially-rich and intuitive “theories” of color regardless of visual experience. Linguistic communication is more effective at aligning people’s theories than their knowledge of verbal facts.

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

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.

scholarly journals Mental Imagery Follows Similar Cortical Reorganization as Perception: Intra-Modal and Cross-Modal Plasticity in Congenitally Blind

2018 ◽  
Vol 29 (7) ◽  
pp. 2859-2875 ◽  
Author(s):  
A W de Borst ◽  
B de Gelder
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Cortical Plasticity ◽  
Tactile Perception ◽  
Cortical Reorganization ◽  
Area V4 ◽  
Congenitally Blind ◽  
Early Visual Cortex ◽  
Blind Individuals ◽  
Discriminative Patterns

Abstract Cortical plasticity in congenitally blind individuals leads to cross-modal activation of the visual cortex and may lead to superior perceptual processing in the intact sensory domains. Although mental imagery is often defined as a quasi-perceptual experience, it is unknown whether it follows similar cortical reorganization as perception in blind individuals. In this study, we show that auditory versus tactile perception evokes similar intra-modal discriminative patterns in congenitally blind compared with sighted participants. These results indicate that cortical plasticity following visual deprivation does not influence broad intra-modal organization of auditory and tactile perception as measured by our task. Furthermore, not only the blind, but also the sighted participants showed cross-modal discriminative patterns for perception modality in the visual cortex. During mental imagery, both groups showed similar decoding accuracies for imagery modality in the intra-modal primary sensory cortices. However, no cross-modal discriminative information for imagery modality was found in early visual cortex of blind participants, in contrast to the sighted participants. We did find evidence of cross-modal activation of higher visual areas in blind participants, including the representation of specific-imagined auditory features in visual area V4.

Parenting Styles and the Depressive Syndrome in Congenitally Blind Individuals

1980 ◽  
Vol 74 (9) ◽  
pp. 333-337 ◽  
Author(s):  
Robert Lambert ◽  
Malcolm West
Keyword(s):  
Parenting Styles ◽  
Depressive Syndrome ◽  
Sense Of Competence ◽  
Ego Ideal ◽  
Blind Children ◽  
Congenitally Blind ◽  
Blind Individuals

This article discusses the effect on congenitally blind children of three types of parents: those who are over-protective, those who push the child toward independence too soon, and those who are “good enough.” The authors focus on how the three styles of parenting affect the blind child's ability to give and receive and develop a sense of competence. These effects are discussed in the context of the ego ideal. The authors also examine the depressive core that is often the result of the blind child's inability to live up to the dictates of the ego ideal. Finally, they suggest a fourth style of parenting that would prepare blind children better for the problems they will encounter in the sighted world.

scholarly journals Enhanced Odorant Localization Abilities in Congenitally Blind but not in Late-Blind Individuals

2020 ◽  
Author(s):  
Simona Manescu ◽  
Christine Chouinard-Leclaire ◽  
Olivier Collignon ◽  
Franco Lepore ◽  
Johannes Frasnelli
Keyword(s):  
Vision Loss ◽  
Spatial Perception ◽  
Blind People ◽  
Localization Task ◽  
Congenital Blindness ◽  
Spatial Sense ◽  
Chemosensory Perception ◽  
Congenitally Blind ◽  
Blind Individuals ◽  
Odorant Detection

Abstract Although often considered a nondominant sense for spatial perception, chemosensory perception can be used to localize the source of an event and potentially help us navigate through our environment. Would blind people who lack the dominant spatial sense—vision—develop enhanced spatial chemosensation or suffer from the lack of visual calibration on spatial chemosensory perception? To investigate this question, we tested odorant localization abilities across nostrils in blind people compared to sighted controls and if the time of vision loss onset modulates those abilities. We observed that congenitally blind individuals (10 subjects) outperformed sighted (20 subjects) and late-blind subjects (10 subjects) in a birhinal localization task using mixed olfactory-trigeminal stimuli. This advantage in congenitally blind people was selective to olfactory localization but not observed for odorant detection or identification. We, therefore, showed that congenital blindness but not blindness acquired late in life is linked to enhanced localization of chemosensory stimuli across nostrils, most probably of the trigeminal component. In addition to previous studies highlighting enhanced localization abilities in auditory and tactile modalities, our current results extend such enhanced abilities to chemosensory localization.

scholarly journals Generic Properties of Curvature Sensing through Vision and Touch

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Birgitta Dresp-Langley
Keyword(s):  
Power Law ◽  
Sensory Modality ◽  
Generic Properties ◽  
Scale Invariant ◽  
Curvature Sensing ◽  
Mathematical Properties ◽  
Universal Power Law ◽  
Sensory Modalities ◽  
Congenitally Blind ◽  
Blind Individuals

Generic properties of curvature representations formed on the basis of vision and touch were examined as a function of mathematical properties of curved objects. Virtual representations of the curves were shown on a computer screen for visual scaling by sighted observers (experiment 1). Their physical counterparts were placed in the two hands of blindfolded and congenitally blind observers for tactile scaling. The psychophysical data show that curvature representations in congenitally blind individuals, who never had any visual experience, and in sighted observers, who rely on vision most of the time, are statistically linked to the same mathematical properties of the curves. The perceived magnitude of object curvature, sensed through either vision or touch, is related by a mathematical power law, with similar exponents for the two sensory modalities, to the aspect ratio of the curves, a scale invariant geometric property. This finding supports biologically motivated models of sensory integration suggesting a universal power law for the adaptive brain control and balance of motor responses to environmental stimuli from any sensory modality.

Working memory training in congenitally blind individuals results in an integration of occipital cortex in functional networks

2018 ◽  
Vol 348 ◽  
pp. 31-41 ◽  
Author(s):  
Helene Gudi-Mindermann ◽  
Johanna M. Rimmele ◽  
Guido Nolte ◽  
Patrick Bruns ◽  
Andreas K. Engel ◽  
...  
Keyword(s):  
Working Memory ◽  
Occipital Cortex ◽  
Working Memory Training ◽  
Memory Training ◽  
Functional Networks ◽  
Congenitally Blind ◽  
Blind Individuals

scholarly journals Effects of Visual Experience on the Human MT+ Functional Connectivity Networks: An fMRI Study of Motion Perception in Sighted and Congenitally Blind Individuals

2010 ◽  
Vol 4 ◽  
Author(s):  
Lorenzo Sani ◽  
Emiliano Ricciardi ◽  
Claudio Gentili ◽  
Nicola Vanello ◽  
James V. Haxby ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Motion Perception ◽  
Visual Experience ◽  
Fmri Study ◽  
Congenitally Blind ◽  
Blind Individuals

scholarly journals Reading Modality Modifies Reading Network: Insights from Neural basis of Braille in Proficient Blind Readers

2021 ◽  
Author(s):  
Mengyu Tian ◽  
Elizabeth J. Saccone ◽  
Judy S. Kim ◽  
Shipra Kanjlia ◽  
Marina Bedny
Keyword(s):  
Sensory Modality ◽  
Word Form ◽  
Neural Basis ◽  
Cortical Function ◽  
Congenitally Blind ◽  
Posterior Parietal ◽  
Physical Features ◽  
Blind Individuals ◽  
Parietal Cortices ◽  
Visual Reading

The neural basis of reading is highly consistent across a variety of languages and visual scripts. An unanswered question is whether the sensory modality of symbols influences the neural basis of reading. According to the modality-invariant view, reading depends on the same neural mechanisms regardless of the sensory input modality. Consistent with this idea, previous studies find that the visual word form area (VWFA) within the ventral occipitotemporal cortex (vOTC) is active when blind individuals read Braille by touch. However, connectivity-based theories of brain function suggest that the neural entry point of written symbols (touch vs. vision) may influence the neural architecture of reading. We compared the neural basis of the visual print (sighted n=15) and tactile Braille (congenitally blind n=19) in proficient readers using analogous reading and listening tasks. Written stimuli varied in word-likeness from real words to consonant strings and non-letter shape strings. Auditory stimuli consisted of words and backward speech sounds. Consistent with prior work, vOTC was active during Braille and visual reading. However, in sighted readers, visual print elicited a posterior/anterior vOTC word-form gradient: anterior vOTC preferred larger orthographic units (words), middle vOTC preferring consonant strings, and posterior vOTC responded to shapes (i.e., lower-level physical features). No such gradient was observed in blind readers of Braille. Consistent with connectivity predictions, in blind Braille readers, posterior parietal cortices (PPC) and parieto-occipital areas were recruited to a greater degree and PPC contained word-preferring patches. Lateralization of Braille in blind readers was predicted by laterality of spoken language, as well as by reading hand. These results suggested that the neural basis of reading is influenced by symbol modality and support connectivity-based views of cortical function.

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