scholarly journals Congenital visual deprivation modulates the perception of own, but not others’ body size

2021 ◽  
Author(s):  
Elena Nava ◽  
Luigi Tamè ◽  
Serena Giurgola ◽  
Nadia Bolognini
Keyword(s):  
Visual Experience ◽  
Visual Deprivation ◽  
The Body ◽  
Sensory Inputs ◽  
Body Model ◽  
Congenital Limb ◽  
Ideal Body ◽  
Blind Individuals ◽  
The Brain ◽  
Limb Aplasia

Abstract Neuropsychological reports of phantom sensations in congenital limb aplasia have often been taken as evidence of the existence of an innate, ‘hard-wired’, representation of the body in the brain that does not need to be constructed from, or updated by, online afferent sensory inputs, including vision. However, when asked to draw the contour of their own body and of an ideal body (i.e. body with perfect proportions), congenitally, but not late blind individuals, exhibited a magnified representation of their own body, specifically of their hands, in comparison to sighted controls. This over-representation did not extend to their ideal body model. These findings show that the representation of the own body metric is shaped by early visual experience, and that seeing one’s own and other bodies early in development contributes to the construction of a unified internal model, in which ‘own’ and ‘other’ merge.

scholarly journals Visual experience shapes the neural networks remapping touch into external space

2017 ◽  
Author(s):  
Virginie Crollen ◽  
Latifa Lazzouni ◽  
Mohamed Rezk ◽  
Antoine Bellemare ◽  
Franco Lepore ◽  
...  
Keyword(s):  
Visual Experience ◽  
Temporal Order Judgment ◽  
Interaction Analysis ◽  
Brain Network ◽  
Visual Deprivation ◽  
The Body ◽  
External Space ◽  
Touch Perception ◽  
Congenitally Blind ◽  
The Brain

AbstractLocalizing touch relies on the activation of skin-based and externally defined spatial frames of references. Psychophysical studies have demonstrated that early visual deprivation prevents the automatic remapping of touch into external space. We used fMRI to characterize how visual experience impacts on the brain circuits dedicated to the spatial processing of touch. Sighted and congenitally blind humans (male and female) performed a tactile temporal order judgment (TOJ) task, either with the hands uncrossed or crossed over the body midline. Behavioral data confirmed that crossing the hands has a detrimental effect on TOJ judgments in sighted but not in blind. Crucially, the crossed hand posture elicited more activity in a fronto-parietal network in the sighted group only. Psychophysiological interaction analysis revealed that the congenitally blind showed enhanced functional connectivity between parietal and frontal regions in the crossed versus uncrossed hand postures. Our results demonstrate that visual experience scaffolds the neural implementation of touch perception.Significance statementAlthough we seamlessly localize tactile events in our daily life, it is not a trivial operation because the hands move constantly within the peripersonal space. To process touch correctly, the brain has therefore to take the current position of the limbs into account and remap them to their location in the external world. In sighted, parietal and premotor areas support this process. However, while visual experience has been suggested to support the implementation of the automatic external remapping of touch, no studies so far have investigated how early visual deprivation alters the brain network supporting touch localization. Examining this question is therefore crucial to conclusively determine the intrinsic role vision plays in scaffolding the neural implementation of touch perception.

scholarly journals Multisystemic Increment of Cortical Thickness in Congenital Blind Children

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Alberto Inuggi ◽  
Anna Pichiecchio ◽  
Benedetta Ciacchini ◽  
Sabrina Signorini ◽  
Federica Morelli ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Visual Experience ◽  
Low Vision ◽  
Physiological Mechanism ◽  
Visual Deprivation ◽  
Cortical Surface ◽  
Blind Children ◽  
Neural Growth ◽  
The Brain ◽  
Ct Studies

Abstract It has been shown that the total or partial lack of visual experience is associated with a plastic reorganization at the brain level, more prominent in congenital blind. Cortical thickness (CT) studies, to date involving only adult subjects, showed that only congenital blind have a thicker cortex than age-matched sighted population while late blind do not. This was explained as a deviation from the physiological mechanism of initial neural growth followed by a pruning mechanism that, in congenital blind children, might be reduced by their visual deprivation, thus determining a thicker cortex. Since those studies involved only adults, it is unknown when these changes may appear and whether they are related to impairment degree. To address this question, we compared the CT among 28 children, from 2 to 12 years, with congenital visual impairments of different degree and an age-matched sighted population. Vertex-wise analysis showed that blind children, but not low vision one, had a thicker cortical surface in few clusters located in occipital, superior parietal, anterior-cingular, orbito-frontal, and mesial precentral regions. Our data suggest that the effect of visual impairment on determining thicker cortex is an early phenomenon, is multisystemic, and occurs only when blindness is almost complete.

scholarly journals Untangling Sequences: Behavior vs. External Causes

2017 ◽  
Author(s):  
Subutai Ahmad ◽  
Jeff Hawkins
Keyword(s):  
Sensory Input ◽  
Neural Mechanism ◽  
The Body ◽  
External Factors ◽  
Sensory Inputs ◽  
External Causes ◽  
Cortical Regions ◽  
Temporal Sequences ◽  
The Brain ◽  
Brain Change

ABSTRACTThere are two fundamental reasons why sensory inputs to the brain change over time. Sensory inputs can change due to external factors or they can change due to our own behavior. Interpreting behavior-generated changes requires knowledge of how the body is moving, whereas interpreting externally-generated changes relies solely on the temporal sequence of input patterns. The sensory signals entering the neocortex change due to a mixture of both behavior and external factors. The neocortex must disentangle them but the mechanisms are unknown. In this paper, we show that a single neural mechanism can learn and recognize both types of sequences. In the model, cells are driven by feedforward sensory input and are modulated by contextual input. If the contextual input includes information derived from efference motor copies, the cells learn sensorimotor sequences. If the contextual input consists of nearby cellular activity, the cells learn temporal sequences. Through simulation we show that a network containing both types of contextual input automatically separates and learns both types of input patterns. We review experimental data that suggests the upper layers of cortical regions contain the anatomical structure required to support this mechanism.

scholarly journals A transgressão do corpo nu na fotografia

2012 ◽  
Vol 19 (1.2) ◽  
Author(s):  
André Melo Mendes
Keyword(s):  
The Body ◽  
Body Model ◽  
Critical Attention ◽  
Ideal Body

Nowadays the imposition of an ideal body model, linked to the pattern of classical art, has intensified and called critical attention for its impact on society. This article presents the works of Joel-Peter Witkin and Jan Saudek, photographers who challenge a model of beauty that does not accept the decay of the body and deny the nearness of death. Through their work, they contribute to weaken the hegemony of this apollonian discourse and promote the visibility of other body models.

scholarly journals The size-weight illusion is unimpaired in individuals with a history of congenital visual deprivation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rashi Pant ◽  
Maria J. S. Guerreiro ◽  
Pia Ley ◽  
Davide Bottari ◽  
Idris Shareef ◽  
...  
Keyword(s):  
Visual Experience ◽  
Multisensory Processing ◽  
Visual Deprivation ◽  
Congenital Cataracts ◽  
Congenitally Blind ◽  
History Of ◽  
Set Up ◽  
Weight Illusion ◽  
Blind Individuals ◽  
Similar Task

AbstractVisual deprivation in childhood can lead to lifelong impairments in multisensory processing. Here, the Size-Weight Illusion (SWI) was used to test whether visuo-haptic integration recovers after early visual deprivation. Normally sighted individuals perceive larger objects to be lighter than smaller objects of the same weight. In Experiment 1, individuals treated for dense bilateral congenital cataracts (who had no patterned visual experience at birth), individuals treated for developmental cataracts (who had patterned visual experience at birth, but were visually impaired), congenitally blind individuals and normally sighted individuals had to rate the weight of manually explored cubes that differed in size (Small, Medium, Large) across two possible weights (350 g, 700 g). In Experiment 2, individuals treated for dense bilateral congenital cataracts were compared to sighted individuals in a similar task using a string set-up, which removed haptic size cues. In both experiments, indistinguishable SWI effects were observed across all groups. These results provide evidence that early aberrant vision does not interfere with the development of the SWI, and suggest a recovery of the integration of size and weight cues provided by the visual and haptic modality.

scholarly journals The influence of visual experience and cognitive goals on spatial representations of nociceptive stimuli

2019 ◽  
Author(s):  
Camille Vanderclausen ◽  
Louise Manfron ◽  
Anne De Volder ◽  
Valéry Legrain
Keyword(s):  
Visual Experience ◽  
Reference Frames ◽  
Temporal Order ◽  
Temporal Order Judgment ◽  
The Body ◽  
Spatial Representations ◽  
Spatial Reference ◽  
Spatial Reference Frames ◽  
The Right ◽  
The Brain

AbstractLocalizing pain is an important process as it allows detecting which part of the body is being hurt and identifying in its surrounding which stimulus is producing the damage. Nociceptive inputs should therefore be mapped according to both somatotopic (“which limb is stimulated?”) and spatiotopic representations (“where is the stimulated limb?”). Since the limbs constantly move in space, the brain has to realign the different spatial representations, for instance when the hands are crossed and the left/right hand is in the right/left part of space, in order to adequately guide actions towards the threatening object. Such ability is thought to be dependent on past sensory experience and contextual factors. This was tested by comparing performances of early blind and normally sighted participants during nociceptive temporal order judgment tasks. The instructions prioritized either anatomy (left/right hands) or the external space (left/right hemispaces). As compared to an uncrossed hands posture, sighted participants’ performances were decreased when the hands were crossed, whatever the instructions. Early blind participants’ performances were affected by crossing the hands only during spatial instruction, but not during anatomical instruction. These results indicate that nociceptive stimuli are automatically coded according to both somatotopic and spatiotopic representations, but the integration of the different spatial reference frames would depend on early visual experience and ongoing cognitive goals, illustrating the plasticity and the flexibility of the nociceptive system.

EXPERIMENTAL ASSESSMENT OF THE NANOPARTICLES TOXICITY OF NICKEL OXIDE IN TWO SIZES IN THE SUBCHRONIC EXPERIMENT

2018 ◽  
pp. 30-35
Author(s):  
M.P. Sutunkova ◽  
B.A. Katsnelson ◽  
L.I. Privalova ◽  
S.N. Solovjeva ◽  
V.B. Gurvich ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Nervous Activity ◽  
Equal Mass ◽  
The Body ◽  
Subchronic Toxicity ◽  
Physiological Mechanisms ◽  
Nickel Oxide Nanoparticles ◽  
The Relationship ◽  
The Brain ◽  
Nanoparticles Toxicity

We conducted a comparative assessment of the nickel oxide nanoparticles toxicity (NiO) of two sizes (11 and 25 nm) according to a number of indicators of the body state after repeated intraperitoneal injections of these particles suspensions. At equal mass doses, NiO nanoparticles have been found to cause various manifestations of systemic subchronic toxicity with a particularly pronounced effect on liver, kidney function, the body’s antioxidant system, lipid metabolism, white and red blood, redox metabolism, spleen damage, and some disorders of nervous activity allegedly related to the possibility of nickel penetration into the brain from the blood. The relationship between the diameter and toxicity of particles is ambiguous, which may be due to differences in toxicokinetics, which is controlled by both physiological mechanisms and direct penetration of nanoparticles through biological barriers and, finally, unequal solubility.

The musculature and nervous system of the plerocercoid larva of Dibothriorhynchus grossum (Rud.)

Parasitology ◽  
1941 ◽  
Vol 33 (4) ◽  
pp. 373-389 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Muscle Mass ◽  
Nerve Cells ◽  
The Body ◽  
Lateral Nerve ◽  
Posterior Median ◽  
The Brain ◽  
Ventral Muscle ◽  
Nerve Cords ◽  
Extrinsic Muscles

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.2. The musculature of the body and scolex is described.3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.

Visual experience and the establishment of spatial and tactile maps in the brain

2013 ◽  
Vol 26 (1-2) ◽  
pp. 98
Author(s):  
Achille Pasqualotto ◽  
Michael J. Proulx ◽  
Martin I. Sereno
Keyword(s):  
Visual Experience ◽  
Tactile Maps ◽  
The Brain
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