P 151. The right (but not the left) lateral occipital complex is causally implicated in visual mirror symmetry detection: An fMRI-guided TMS study

2013 ◽  
Vol 124 (10) ◽  
pp. e135-e136
Author(s):  
S. Bona ◽  
A. Herbert ◽  
C. Toneatto ◽  
J. Silvanto ◽  
Z. Cattaneo
Keyword(s):  
Mirror Symmetry ◽  
Symmetry Detection ◽  
Lateral Occipital Complex ◽  
The Right

The causal role of the lateral occipital complex in visual mirror symmetry detection and grouping: An fMRI-guided TMS study

Cortex ◽  
2014 ◽  
Vol 51 ◽  
pp. 46-55 ◽  
Author(s):  
Silvia Bona ◽  
Andrew Herbert ◽  
Carlo Toneatto ◽  
Juha Silvanto ◽  
Zaira Cattaneo
Keyword(s):  
Mirror Symmetry ◽  
Causal Role ◽  
Symmetry Detection ◽  
Lateral Occipital Complex

scholarly journals Mirror symmetry of higher order aberrations between right and left eyes

2014 ◽  
Vol 73 (1) ◽  
Author(s):  
M. Oberholzer ◽  
W.D.H. Gillan ◽  
A. Rubin
Keyword(s):  
Wave Front ◽  
South African ◽  
Visual Function ◽  
Mirror Symmetry ◽  
Correlation Coefficients ◽  
Higher Order ◽  
Pearson Product Moment Correlation ◽  
Scatter Plots ◽  
The Right ◽  
High Order Aberrations

Introduction: There is evidence that certain measures of visual function show some type of relationship between right and left eyes in the same individual.  Similarly, particular ocular maladies may be related, or be symmetric, in the right and left eyes of the same person. There is also evidence to suggest that certain relationships do not exist between eyes in an individual. For example, diseases such as glaucoma are often asymmetric in their progression in the two eyes of an afflicted individual. Inter-ocular mirror symmetry between right and left eyes, when considering ocular wave-front aberrations (WAs), has been shown to exist by some authors. This study investigates whether mirror symmetry of high order aberrations (HOAs) exists between the right and left eyes in a cohort of South African subjects. Method: Third to 5th order Zernike coefficients (HOAs) were measured on both eyes of 66 subjects (132 eyes) using a Zywave aberrometer. A total of 15 Zernike coefficients for each eye were obtained. Mirror symmetry was investigated using correlation coefficients between the various measurements obtained from each eye. Results: Pearson product-moment correlation coefficients provide evidence that the majority of the 15 Zernike coefficients suggest the presence of mirror symmetry between right and left eyes of the 66 subjects. Examples of individual scatter plots comparing right and left eyes are presented.  Conclusion: The results of this study suggest that mirror symmetry exists in the HOAs obtained from the 132 eyes measured and thus care should be exercised when combining eyes of individuals for analysis. (S Afr Optom 2013 73(1) 39-44)

scholarly journals Gap junction structures. IV. Asymmetric features revealed by low-irradiation microscopy.

1983 ◽  
Vol 96 (1) ◽  
pp. 204-216 ◽  
Author(s):  
T S Baker ◽  
D L Caspar ◽  
C J Hollingshead ◽  
D A Goodenough
Keyword(s):  
Mirror Symmetry ◽  
Uranyl Acetate ◽  
Threefold Axis ◽  
Lattice Vector ◽  
Electron Dose ◽  
Projected Image ◽  
The Right ◽  
Junction Structure ◽  
Two Sides ◽  
Low Irradiation

Micrographs of mouse liver gap junctions, isolated with detergents, and negatively stained with uranyl acetate, have been recorded by low-irradiation methods. Our Fourier-averaged micrographs of the hexagonal junction lattice show skewed, hexameric connexons with less stain at the threefold axis than at the six indentations between the lobes of the connexon image. These substructural features, not clearly observed previously, are acutely sensitive to irradiation. After an electron dose less than that normally used in microscopy, the image is converted to the familiar doughnut shape, with a darkly stained center and a smooth hexagonal outline, oriented with mirror symmetry in the lattice. Differences in appearance among 25 reconstructed images from our low-irradiation micrographs illustrate variation in staining of the connexon channel and the space between connexons. Consistently observed stain concentration at six symmetrically related sites approximately 34 A from the connexon center, 8 degrees to the right or left of the (1, 1) lattice vector may reveal an intrinsic asymmetric feature of the junction structure. The unexpected skewing of the six-lobed connexon image suggests that the pair of hexagonal membrane arrays that form the junction may not be structurally identical. Because the projected image of the connexon pair itself appears mirror symmetric, each pair may consist of two identical connexon hexamers related by local (noncrystallographic) twofold axes in the junctional plane at the middle of the gap. All connexons may be chemically identical, but their packing in the hexagonal arrays on the two sides of the junction appears to be nonequivalent.

Cross-modal Processing in the Occipito-temporal Cortex: A TMS Study of the Müller-Lyer Illusion

2011 ◽  
Vol 23 (8) ◽  
pp. 1987-1997 ◽  
Author(s):  
Flavia Mancini ◽  
Nadia Bolognini ◽  
Emanuela Bricolo ◽  
Giuseppe Vallar
Keyword(s):  
Temporal Cortex ◽  
Visual Modality ◽  
Lateral Occipital Complex ◽  
Lyer Illusion ◽  
Superior Parietal Cortex ◽  
Left And Right ◽  
Neural Underpinnings ◽  
The Right ◽  
Underlying Processes

The Müller-Lyer illusion occurs both in vision and in touch, and transfers cross-modally from vision to haptics [Mancini, F., Bricolo, E., & Vallar, G. Multisensory integration in the Müller-Lyer illusion: From vision to haptics. Quarterly Journal of Experimental Psychology, 63, 818–830, 2010]. Recent evidence suggests that the neural underpinnings of the Müller-Lyer illusion in the visual modality involve the bilateral lateral occipital complex (LOC) and right superior parietal cortex (SPC). Conversely, the neural correlates of the haptic and cross-modal illusions have never been investigated previously. Here we used repetitive TMS (rTMS) to address the causal role of the regions activated by the visual illusion in the generation of the visual, haptic, and cross-modal visuo-haptic illusory effects, investigating putative modality-specific versus cross-modal underlying processes. rTMS was administered to the right and the left hemisphere, over occipito-temporal cortex or SPC. rTMS over left and right occipito-temporal cortex impaired both unisensory (visual, haptic) and cross-modal processing of the illusion in a similar fashion. Conversely, rTMS interference over left and right SPC did not affect the illusion in any modality. These results demonstrate the causal involvement of bilateral occipito-temporal cortex in the representation of the visual, haptic, and cross-modal Müller-Lyer illusion, in favor of the hypothesis of shared underlying processes. This indicates that occipito-temporal cortex plays a cross-modal role in perception both of illusory and nonillusory shapes.

Representation of Action in Occipito-temporal Cortex

2011 ◽  
Vol 23 (7) ◽  
pp. 1765-1780 ◽  
Author(s):  
Alison J. Wiggett ◽  
Paul E. Downing
Keyword(s):  
Cognitive Neuroscience ◽  
Social Cognitive ◽  
Temporal Cortex ◽  
Adaptation Effect ◽  
Whole Body ◽  
Lateral Occipital Complex ◽  
Specific Adaptation ◽  
Face Area ◽  
The Right ◽  
Adaptation Effects

A fundamental question for social cognitive neuroscience is how and where in the brain the identities and actions of others are represented. Here we present a replication and extension of a study by Kable and Chatterjee [Kable, J. W., & Chatterjee, A. Specificity of action representations in the lateral occipito-temporal cortex. Journal of Cognitive Neuroscience, 18, 1498–1517, 2006] examining the role of occipito-temporal cortex in these processes. We presented full-cue movies of actors performing whole-body actions and used fMRI to test for action- and identity-specific adaptation effects. We examined a series of functionally defined regions, including the extrastriate and fusiform body areas, the fusiform face area, the parahippocampal place area, the lateral occipital complex, the right posterior superior temporal sulcus, and motion-selective area hMT+. These regions were analyzed with both standard univariate measures as well as multivoxel pattern analyses. Additionally, we performed whole-brain tests for significant adaptation effects. We found significant action-specific adaptation in many areas, but no evidence for identity-specific adaptation. We argue that this finding could be explained by differences in the familiarity of the stimuli presented: The actions shown were familiar but the actors performing the actions were unfamiliar. However, in contrast to previous findings, we found that the action adaptation effect could not be conclusively tied to specific functionally defined regions. Instead, our results suggest that the adaptation to previously seen actions across identities is a widespread effect, evident across lateral and ventral occipito-temporal cortex.

scholarly journals Considering unique, shared, and dominant brain activation in the Visual Word Form Area and Lateral Occipital Cortex: A comparison of separate and combined word reading and picture naming

2021 ◽  
Author(s):  
Josh Neudorf ◽  
Layla Gould ◽  
Marla J. S. Mickleborough ◽  
Chelsea Ekstrand ◽  
Ron Borowsky
Keyword(s):  
Picture Naming ◽  
Word Reading ◽  
Visual Complexity ◽  
Occipital Cortex ◽  
Visual Word ◽  
Word Form ◽  
Lateral Occipital Complex ◽  
Visual Word Form Area ◽  
The Right ◽  
Lateral Occipital Cortex

Identifying printed words and pictures concurrently is ubiquitous in daily tasks, and so it is important to consider the extent to which reading words and naming pictures may share a cognitive-neurophysiological functional architecture. Two functional magnetic resonance imaging (fMRI) experiments examined whether reading along the left ventral occipitotemporal region (vOT; often referred to as a visual word form area, VWFA) has activation that is overlapping with referent pictures (i.e., both conditions significant and shared, or with one significantly more dominant) or unique (i.e., one condition significant, the other not), and whether picture naming along the right lateral occipital complex (LOC) has overlapping or unique activation relative to referent words. Experiment 1 used familiar regular and exception words (to force lexical reading) and their corresponding pictures in separate naming blocks, and showed dominant activation for pictures in the LOC, and shared activation in the VWFA for exception words and their corresponding pictures (regular words did not elicit significant VWFA activation). Experiment 2 controlled for visual complexity by superimposing the words and pictures and instructing participants to either name the word or the picture, and showed primarily shared activation in the VWFA and LOC regions for both word reading and picture naming, with some dominant activation for pictures in the LOC. Overall, these results highlight the importance of including exception words to force lexical reading when comparing to picture naming, and the significant shared activation in VWFA and LOC serves to challenge specialized models of reading or picture naming.

scholarly journals Сhiral and Racemic Fields Concept for Understanding of the Homochirality Origin, Asymmetric Catalysis, Chiral Superstructure Formation from Achiral Molecules, and B-Z DNA Conformational Transition

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 649 ◽  
Author(s):  
Valerii A. Pavlov ◽  
Yaroslav V. Shushenachev ◽  
Sergey G. Zlotin
Keyword(s):  
Symmetry Breaking ◽  
Asymmetric Catalysis ◽  
Mirror Symmetry ◽  
Conformational Transition ◽  
Left Handed ◽  
Primary Origin ◽  
Z Dna ◽  
The Right ◽  
First Time ◽  
Dna Helix

The four most important and well-studied phenomena of mirror symmetry breaking of molecules were analyzed for the first time in terms of available common features and regularities. Mirror symmetry breaking of the primary origin of biological homochirality requires the involvement of an external chiral inductor (environmental chirality). All reviewed mirror symmetry breaking phenomena were considered from that standpoint. A concept of chiral and racemic fields was highly helpful in this analysis. A chiral gravitational field in combination with a static magnetic field (Earth’s environmental conditions) may be regarded as a hypothetical long-term chiral inductor. Experimental evidences suggest a possible effect of the environmental chiral inductor as a chiral trigger on the mirror symmetry breaking effect. Also, this effect explains a conformational transition of the right-handed double DNA helix to the left-handed double DNA helix (B-Z DNA transition) as possible DNA damage.

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