scholarly journals Visuopathy of prematurity: is retinopathy just the tip of the iceberg?

2021 ◽  
Author(s):  
Sigrid Hegna Ingvaldsen ◽  
Tora Sund Morken ◽  
Dordi Austeng ◽  
Olaf Dammann
Keyword(s):  
Visual Processing ◽  
Structural Changes ◽  
Developmental Trajectories ◽  
Visual Pathway ◽  
Visual Stream ◽  
Visual Deficits ◽  
Cortical Areas ◽  
Cellular Architecture ◽  
Increased Risk ◽  
Dorsal Visual Stream

AbstractResearch on retinopathy of prematurity (ROP) focuses mainly on the abnormal vascularization patterns that are directly visible for ophthalmologists. However, recent findings indicate that children born prematurely also exhibit changes in the retinal cellular architecture and along the dorsal visual stream, such as structural changes between and within cortical areas. Moreover, perinatal sustained systemic inflammation (SSI) is associated with an increased risk for ROP and the visual deficits that follow. In this paper, we propose that ROP might just be the tip of an iceberg we call visuopathy of prematurity (VOP). The VOP paradigm comprises abnormal vascularization of the retina, alterations in retinal cellular architecture, choroidal degeneration, and abnormalities in the visual pathway, including cortical areas. Furthermore, VOP itself might influence the developmental trajectories of cerebral structures and functions deemed responsible for visual processing, thereby explaining visual deficits among children born preterm.

Grasping Execution and Grasping Observation Activity of Single Neurons in the Macaque Anterior Intraparietal Area

2014 ◽  
Vol 26 (10) ◽  
pp. 2342-2355 ◽  
Author(s):  
Pierpaolo Pani ◽  
Tom Theys ◽  
Maria C. Romero ◽  
Peter Janssen
Keyword(s):  
Visual Field ◽  
Premotor Cortex ◽  
Visually Guided ◽  
Simple Shape ◽  
Visual Stream ◽  
Cortical Areas ◽  
Person Perspective ◽  
First Person Perspective ◽  
Dorsal Visual Stream ◽  
Passive Fixation

Primates use vision to guide their actions in everyday life. Visually guided object grasping is known to rely on a network of cortical areas located in the parietal and premotor cortex. We recorded in the anterior intraparietal area (AIP), an area in the dorsal visual stream that is critical for object grasping and densely connected with the premotor cortex, while monkeys were grasping objects under visual guidance and during passive fixation of videos of grasping actions from the first-person perspective. All AIP neurons in this study responded during grasping execution in the light, that is, became more active after the hand had started to move toward the object and during grasping in the dark. More than half of these AIP neurons responded during the observation of a video of the same grasping actions on a display. Furthermore, these AIP neurons responded as strongly during passive fixation of movements of a hand on a scrambled background and to a lesser extent to a shape appearing within the visual field near the object. Therefore, AIP neurons responding during grasping execution also respond during passive observation of grasping actions and most of them even during passive observation of movements of a simple shape in the visual field.

scholarly journals Effects of visual attention modulation on dynamic effective connectivity and visual fixation during own-face viewing in body dysmorphic disorder

2021 ◽  
Author(s):  
Wan-wa Wong ◽  
D. Rangaprakash ◽  
Joel P. Diaz-Fong ◽  
Natalie M. Rotstein ◽  
Gerhard S. Hellemann ◽  
...  
Keyword(s):  
Visual Attention ◽  
Visual Processing ◽  
Fixation Duration ◽  
Body Dysmorphic Disorder ◽  
Effective Connectivity ◽  
Visual Fixation ◽  
Imaging Data ◽  
Visual Scanning ◽  
Visual Stream ◽  
Dorsal Visual Stream

AbstractBackgroundIn individuals with body dysmorphic disorder (BDD), selective attention biases and aberrant visual scanning patterns may cause imbalances in global vs. detailed visual processing, contributing to perceptual distortions for appearance. The mechanistic effects of modifying visual attention on brain function in BDD, which may be critical to developing perceptual-based treatments, have not been explored. This study tested the effects of visual-attention modulation on dorsal and ventral visual stream activation and connectivity, and eye behaviors.MethodsWe acquired functional magnetic resonance imaging data in 37 unmedicated adults with BDD and 30 controls. Participants viewed their faces under two conditions: a) unconstrained (naturalistically), and b) holding their gaze on the center of the image (visual-attention modulation), monitored with an eye-tracking camera. We analyzed activation and dynamic effective connectivity in dorsal and ventral visual streams and visual fixation duration.ResultsVisual-attention modulation resulted in longer fixation duration and reduced activation in dorsal and ventral visual streams in both groups compared with naturalistic viewing. Longer fixation duration was associated with greater effective connectivity from V1 to early dorsal visual stream during the second naturalistic viewing, across groups. During naturalistic viewing, there was greater V1 to early dorsal visual stream connectivity after, compared with before, visual-attention modulation.ConclusionsWhen viewing one’s face, longer visual fixation may confer greater communication in dorsal visual system, facilitating global/holistic visual processing. The finding that reduction in visual scanning while viewing one’s face results in persistent effects during unconstrained viewing has implications for perceptual retraining treatment design for BDD.

scholarly journals Your head is there to move you around: Goal-driven models of the primate dorsal pathway

2021 ◽  
Author(s):  
Patrick J Mineault ◽  
Shahab Bakhtiari ◽  
Blake A Richards ◽  
Christopher C Pack
Keyword(s):  
Moving Objects ◽  
Explanatory Power ◽  
Dorsal Stream ◽  
Visual Pathway ◽  
Mammalian Brain ◽  
Visual Stream ◽  
Dorsal Pathway ◽  
Simulated Environment ◽  
Self Motion ◽  
Dorsal Visual Stream

Neurons in the dorsal visual pathway of the mammalian brain are selective for motion stimuli, with the complexity of stimulus representations increasing along the hierarchy. This progression is similar to that of the ventral visual pathway, which is well characterized by artificial neural networks (ANNs) optimized for object recognition. In contrast, there are no image-computable models of the dorsal stream with comparable explanatory power. We hypothesized that the properties of dorsal stream neurons could be explained by a simple learning objective: the need for an organism to orient itself during self-motion. To test this hypothesis, we trained a 3D ResNet in a self-supervised manner to predict an agent's self-motion parameters from visual stimuli in a simulated environment. We found that the responses in this network accounted well for the selectivity of neurons in a large database of single-neuron recordings from the dorsal visual stream of non-human primates. In contrast, ANNs trained for action recognition or with a contrastive objective could not explain responses in the dorsal stream, despite also being trained on naturalistic videos with moving objects. These results demonstrate that an ecologically relevant, self-supervised cost function can account for dorsal stream properties in the primate brain.

scholarly journals Responses of Ventral Posterior Thalamus Neurons to Three-Dimensional Vestibular and Optic Flow Stimulation

2010 ◽  
Vol 103 (2) ◽  
pp. 817-826 ◽  
Author(s):  
Hui Meng ◽  
Dora E. Angelaki
Keyword(s):  
Optic Flow ◽  
Visual Motion ◽  
Three Dimensional ◽  
Cerebellar Nuclei ◽  
Visual Stream ◽  
Posterior Thalamus ◽  
Cortical Areas ◽  
3D Space ◽  
Flow Stimulation ◽  
Dorsal Visual Stream

Multisensory neurons tuned to both vestibular and visual motion (optic flow) signals are found in several cortical areas in the dorsal visual stream. Here we examine whether such convergence occurs subcortically in the macaque thalamus. We searched the ventral posterior nuclei, including the anterior pulvinar, as well as the ventro-lateral and ventral posterior lateral nuclei, areas that receive vestibular signals from brain stem and deep cerebellar nuclei. Approximately a quarter of cells responded to three-dimensional (3D) translational and/or rotational motion. More than half of the responsive cells were convergent, thus responded during both rotation and translation. The preferred axes of translation/rotation were distributed throughout 3D space. The majority of the neurons were excited, but some were inhibited, during rotation/translation in darkness. Only a couple of neurons were multisensory being tuned to both vestibular and optic flow stimuli. We conclude that multisensory vestibular/optic flow neurons, which are commonly found in cortical visual and visuomotor areas, are rare in the ventral posterior thalamus.

scholarly journals Direction Selectivity of Neurons in the Macaque Lateral Intraparietal Area

2009 ◽  
Vol 101 (1) ◽  
pp. 289-305 ◽  
Author(s):  
Alessandra Fanini ◽  
John A. Assad
Keyword(s):  
Saccadic Eye Movements ◽  
Spatial Location ◽  
Direction Selectivity ◽  
Average Strength ◽  
Visual Stream ◽  
Lateral Intraparietal Area ◽  
Cortical Areas ◽  
Saccade Task ◽  
Direction Tuning ◽  
Dorsal Visual Stream

The lateral intraparietal area (LIP) of the macaque is believed to play a role in the allocation of attention and the plan to make saccadic eye movements. Many studies have shown that LIP neurons generally encode the static spatial location demarked by the receptive field (RF). LIP neurons might also provide information about the features of visual stimuli within the RF. For example, LIP receives input from cortical areas in the dorsal visual pathway that contain many direction-selective neurons. Here we examine direction selectivity of LIP neurons. Animals were only required to fixate while motion stimuli appeared in the RF. To avoid spatial confounds, the motion stimuli were patches of randomly arrayed dots that moved with 100% coherence in eight different directions. We found that the majority (61%) of LIP neurons were direction selective. The direction tuning was fairly broad, with a median direction-tuning bandwidth of 136°. The average strength of direction selectivity was weaker in LIP than that of other areas of the dorsal visual stream but that difference may be because of the fact that LIP neurons showed a tonic offset in firing whenever a visual stimulus was in the RF, independent of direction. Direction-selective neurons do not seem to constitute a functionally distinct subdivision within LIP, because those neurons had robust, sustained delay-period activity during a memory delayed saccade task. The direction selectivity could also not be explained by asymmetries in the spatial RF, in the hypothetical case that the animals attended to slightly different locations depending on the direction of motion in the RF. Our results show that direction selectivity is a distinct attribute of LIP neurons in addition to spatial encoding.

Decoding conjunctions of direction-of-motion and binocular disparity from human visual cortex

2012 ◽  
Vol 107 (9) ◽  
pp. 2335-2341 ◽  
Author(s):  
Kiley J. Seymour ◽  
Colin W. G. Clifford
Keyword(s):  
Visual Processing ◽  
Binocular Disparity ◽  
Dorsal Stream ◽  
Visual Stream ◽  
Activation Patterns ◽  
Independent Information ◽  
Uncrossed Disparity ◽  
Multivariate Pattern ◽  
Joint Encoding ◽  
Dorsal Visual Stream

Motion and binocular disparity are two features in our environment that share a common correspondence problem. Decades of psychophysical research dedicated to understanding stereopsis suggest that these features interact early in human visual processing to disambiguate depth. Single-unit recordings in the monkey also provide evidence for the joint encoding of motion and disparity across much of the dorsal visual stream. Here, we used functional MRI and multivariate pattern analysis to examine where in the human brain conjunctions of motion and disparity are encoded. Subjects sequentially viewed two stimuli that could be distinguished only by their conjunctions of motion and disparity. Specifically, each stimulus contained the same feature information (leftward and rightward motion and crossed and uncrossed disparity) but differed exclusively in the way these features were paired. Our results revealed that a linear classifier could accurately decode which stimulus a subject was viewing based on voxel activation patterns throughout the dorsal visual areas and as early as V2. This decoding success was conditional on some voxels being individually sensitive to the unique conjunctions comprising each stimulus, thus a classifier could not rely on independent information about motion and binocular disparity to distinguish these conjunctions. This study expands on evidence that disparity and motion interact at many levels of human visual processing, particularly within the dorsal stream. It also lends support to the idea that stereopsis is subserved by early mechanisms also tuned to direction of motion.

EVALUATION OF LEFT VENTRICULAR MASS IN THE PREHYPERTENSIVES BY ELECTROCARDIOGRAPHY AND ECHOCARDIOGRAPHY

2011 ◽  
pp. 119-125
Author(s):  
Thi Thuy Hang Nguyen
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Left Ventricular Mass ◽  
Ventricular Hypertrophy ◽  
Structural Changes ◽  
Left Ventricular ◽  
Control Group ◽  
Concentric Left Ventricular Hypertrophy ◽  
Increased Risk ◽  
Lv Mass ◽  
Left Ventricular Morphology

Objective: Prehypertensive individuals are at increased risk for developing hypertension and their complication. Many studies show that 2/3 prehypertensive individuals develop hypertension after 4 years. ECG and echocardiography are the routine tests used to assess LV mass. The objective of the research to determine the percentage of change in left ventricular morphology in the ECG, echocardiography, which explore the characteristics of left ventricular structural changes by echocardiography in pre-hypertensive subjects. Materials and method: We studied a total of 50 prehypertensive, 30 males (60%) and 20 females (40%), mean age 48.20±8.47years. 50 normotensive volunteers as control participants. These subjects were examined for ECG and echocardiography. Results: In prehypertensive group, with 18% of left ventricular hypertrophy on electrocardiogram, 12% of left ventricular hypertrophy on echocardiography; in the control group, we did not find any subjects with left ventricular hypertrophy. In the group with left ventricular hypertrophy, mostly eccentric left ventricular hypertrophy (83.33%), concentric left ventricular hypertrophy is 16.67%. Restructuring of left ventricular concentric for 15.9% of subjects without left ventricular hypertrophy on echocardiography. Conclusion: There have been changed in left ventricular morphology even in prehypertensive

scholarly journals Ultrasonographic Evaluation of the Shoulders and Its Associations with Shoulder Pain, Age, and Swim Training in Masters Swimmers

Medicina ◽  
2020 ◽  
Vol 57 (1) ◽  
pp. 29
Author(s):  
Yuta Suzuki ◽  
Noriaki Maeda ◽  
Junpei Sasadai ◽  
Kazuki Kaneda ◽  
Taizan Shirakawa ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Shoulder Pain ◽  
Structural Changes ◽  
Partial Tear ◽  
Increased Risk ◽  
High Prevalence ◽  
History Of ◽  
Long Head ◽  
Competitive Swimmers ◽  
Rotator Cuff Tendinopathy

Background and objectives: The long head of the biceps (LHB) and rotator cuff tendinopathy is the major cause of shoulder pain in competitive swimmers. The risk of tendinopathy increases with aging; however, the structural changes of LHB and rotator cuff in populations of masters swimmers have not been well examined. The purpose of this study was to investigate the prevalence of ultrasonographic abnormalities of the shoulders in masters swimmers, and the association of pain, age, and swim training with structural changes in this population. Materials and Methods: A total of 60 subjects participated in this study, with 20 masters swimmers with shoulder pain, 20 asymptomatic masters swimmers, and 20 sex- and age-matched controls. All swimmers completed a self-reported questionnaire for shoulder pain, their history of competition, and training volume. Each subject underwent ultrasonographic examination of both shoulders for pathologic findings in the LHB tendon, rotator cuff (supraspinatus (SSP) and subscapularis (SSC)) tendons, and subacromial bursa (SAB) of both shoulders and had thickness measured. Results: The prevalence of tendinosis (LHB, 48.8%; SSP, 17.5%; SSC, 15.9%), partial tear (SSP, 35.0%), and calcification (SSC, 10.0%) were higher in swimmers than in controls. LHB and SSP tendinosis were associated with shoulder pain. Older age and later start of competition were associated with an increased risk of LHB tendinosis and SSC calcification. Earlier initiation of swimming and longer history of competition were associated with an increased risk of SSP and SSC tendinosis. The thicker SSP tendon significantly increased the risk of tendinosis and partial tear. Conclusions: A high prevalence of structural changes in the rotator cuff and biceps tendons in masters swimmers reflects the effect of shoulder symptoms, aging, and swim training.

scholarly journals Social relations and self-rated health in a multi-ethnic social housing area undergoing demolition

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M F Kvorning ◽  
A Srivarathan ◽  
S Nygaard ◽  
R Lund
Keyword(s):  
Social Relations ◽  
Social Housing ◽  
Structural Changes ◽  
Ethnically Diverse ◽  
Political Agenda ◽  
Residential Areas ◽  
Self Rated Health ◽  
Housing Area ◽  
Increased Risk ◽  
Contact Frequency

Abstract Background During the coming years, selected social housing areas in Denmark will undergo large structural changes as part of a political agenda. Previous studies on the effects of such interventions are inconclusive. Residential areas are important for the development of social relations and health. The aim of this study was to explore the associations between social relations and self-rated health (SRH) and the interaction with country of origin in an ethnically diverse social housing area undergoing demolition, and compare results with the municipality. Methods Data include multilingual interviewer driven surveys with residents aged 45+ years before demolition began in 2018 (N = 209) and during the demolition in 2019 (N = 132), and a health survey on municipality level (N = 1638). Information on social relations include contact frequency with and support from family, friends and neighbors. SRH was dichotomized into high/low. Descriptive and multivariate logistic regression analyses adjusted for age, sex and Western/non-Western origin are presented. Results In cross-sectional analyses from 2018, low contact frequency and low support increased the risk of low SRH, OR = 1.44 (0.63-3.29) and OR = 1.23 (0.62-2.48), especially when also having non-Western origin compared to having high contact frequency or support and Western origin, OR = 6.27 (1.80-21.84) and OR = 4.43 (1.68-11.69), respectively. The same association was seen in 2019 and on municipality level. Low contact frequency in 2018 was associated with higher risk of developing or maintaining low SRH in 2019 compared to the group with high contact frequency in 2018 in longitudinal analyses, OR = 3.04 (0.91-10.91). Conclusions Poor social relations increased the risk of low SRH, especially when also having non-Western origin. Having poor social relations before the demolition was associated with an increased risk of developing or maintaining low SRH during the demolition in an ethnically diverse social housing area. Key messages Having low contact frequency before area demolition in a social housing area in Denmark increased the risk of developing or maintaining low self-rated health after demolition had begun. Having poor social relations and non-Western origin is associated with a strong increased risk of low self-rated health in a deprived ethnic diverse social housing area in Denmark.

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