Symmetry

Research

15 pages, 522 KiB

Open AccessArticle

Vertical Symmetry Is Special to Infants; Vertical Symmetry in Upright Human Faces More So

by Marc H. Bornstein, Clay Mash, Martha E. Arterberry and Gianluca Esposito

Symmetry 2023, 15(9), 1767; https://doi.org/10.3390/sym15091767 - 15 Sep 2023

Cited by 2 | Viewed by 1547

Symmetry has long been viewed as a feature of objects that facilitates ease of perception. Three experiments investigated 4- to 5-month-old infants’ detection and processing of vertical symmetry, oblique symmetry, and asymmetry in novel patterns and faces. In Experiment 1, infants showed the [...] Read more.

Symmetry has long been viewed as a feature of objects that facilitates ease of perception. Three experiments investigated 4- to 5-month-old infants’ detection and processing of vertical symmetry, oblique symmetry, and asymmetry in novel patterns and faces. In Experiment 1, infants showed the fewest shifts in visual fixations to vertical symmetry in patterns and faces, supporting the view that vertical symmetry is processed more efficiently than oblique symmetry or asymmetry. In Experiment 2, stimulus presentation disallowed more than a single visual fixation, and infants looked longer at a face that is vertically symmetrical compared to obliquely symmetrical or asymmetrical, and they looked equally to patterns regardless of symmetry. In Experiment 3, where pattern exposures were prolonged and inverted faces viewed, infants discriminated vertical symmetry in patterns but lost the advantage with vertical symmetry in faces. Thus, symmetry in patterns requires more processing time from infants, and inverting the face costs infants the normal perceptual advantage of symmetry, even though components of the face remain symmetrical. These findings suggest that infants are prepared to exploit symmetry in their everyday perceptual worlds. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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16 pages, 3495 KiB

Open AccessArticle

P1 Component Discloses Gender-Related Hemispheric Asymmetries during IAPS Processing

by Zaira Romeo and Chiara Spironelli

Symmetry 2023, 15(3), 610; https://doi.org/10.3390/sym15030610 - 28 Feb 2023

Cited by 3 | Viewed by 2538

Abstract

Background: Although some studies showed distinct electrophysiological correlates of emotions in men and women about 300 ms after the stimulus onset, little is known about the automatic visual phases of emotional processing. Investigating both early and late event-related potential (ERP) components (e.g., [...] Read more.

Background: Although some studies showed distinct electrophysiological correlates of emotions in men and women about 300 ms after the stimulus onset, little is known about the automatic visual phases of emotional processing. Investigating both early and late event-related potential (ERP) components (e.g., the P1, P300) could allow us to clarify the effect of gender on the temporal dynamics underlying emotional processing. Methods: Twenty men and twenty women similar in age, education and empathy traits passively viewed emotional and neutral IAPS pictures during EEG recording, providing their subjective evaluations about valence and arousal. ERP and source analyses were implemented to examine gender effects on emotional processing. Results: The P1 analysis revealed gender-related asymmetries, consisting of the greater amplitude of right vs. left parietal sites for women, and bilateral activation for men, almost for each emotional category. These findings were also supported by source analyses. Conversely, during the fear stimulus processing, women showed an involvement of the left cuneus, and men of the right homologous. No group differences appeared in the P300 component analysis. Conclusions: Our findings support the hypothesis that men and women adopt different strategies when processing visual emotional information, and suggest that gender is a crucial variable in emotional research. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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23 pages, 424 KiB

Open AccessFeature PaperArticle

Taking Sides: Asymmetries in the Evolution of Human Brain Development in Better Understanding Autism Spectrum Disorder

by Gerry Leisman, Robert Melillo, Ty Melillo, Calixto Machado, Yanin Machado-Ferrer, Mauricio Chinchilla and Eli Carmeli

Symmetry 2022, 14(12), 2689; https://doi.org/10.3390/sym14122689 - 19 Dec 2022

Cited by 4 | Viewed by 6785

Abstract

Confirmation from structural, functional, and behavioral studies agree and suggest a configuration of atypical lateralization in individuals with autistic spectrum disorders (ASD). It is suggested that patterns of cortical and behavioral atypicality are evident in individuals with ASDs with atypical lateralization being common [...] Read more.

Confirmation from structural, functional, and behavioral studies agree and suggest a configuration of atypical lateralization in individuals with autistic spectrum disorders (ASD). It is suggested that patterns of cortical and behavioral atypicality are evident in individuals with ASDs with atypical lateralization being common in individuals with ASDs. The paper endeavors to better understand the relationship between alterations in typical cortical asymmetries and functional lateralization in ASD in evolutionary terms. We have proposed that both early genetic and/or environmental influences can alter the developmental process of cortical lateralization. There invariably is a “chicken or egg” issue that arises whether atypical cortical anatomy associated with abnormal function, or alternatively whether functional atypicality generates abnormal structure. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

13 pages, 981 KiB

Open AccessArticle

EEG Frontal Asymmetry in Dysthymia, Major Depressive Disorder and Euthymic Bipolar Disorder

by Chiara Spironelli, Francesca Fusina, Marco Bortolomasi and Alessandro Angrilli

Symmetry 2021, 13(12), 2414; https://doi.org/10.3390/sym13122414 - 13 Dec 2021

Cited by 6 | Viewed by 4127

Abstract

In the last few decades, the incidence of mood disorders skyrocketed worldwide and has brought an increasing human and economic burden. Depending on the main symptoms and their evolution across time, they can be classified in several clinical subgroups. A few psychobiological indices [...] Read more.

In the last few decades, the incidence of mood disorders skyrocketed worldwide and has brought an increasing human and economic burden. Depending on the main symptoms and their evolution across time, they can be classified in several clinical subgroups. A few psychobiological indices have been extensively investigated as promising markers of mood disorders. Among these, frontal asymmetry measured at rest with quantitative EEG has represented the main available marker in recent years. Only a few studies so far attempted to distinguish the features and differences among diagnostic types of mood disorders by using this index. The present study measured frontal EEG asymmetry during a 5-min resting state in three samples of patients with bipolar disorder in a Euthymic phase (EBD, n = 17), major depressive disorder (MDD, n = 25) and persistent depressive disorder (PDD, n = 21), once termed dysthymia. We aimed to test the hypothesis that MDD and PDD lack the typical leftward asymmetry exhibited by normal as well as EBD patients, and that PDD shows greater clinical and neurophysiological impairments than MDD. Clinical scales revealed no symptoms in EBD, and significant larger anxiety and depression scores in PDD than in MDD patients. Relative beta (i.e., beta/alpha ratio) EEG asymmetry was measured from lateral frontal sites and results revealed the typical greater left than right frontal beta activity in EBD, as well as a lack of asymmetry in both MDD and PDD. The last two groups also had lower bilateral frontal beta activity in comparison with the EBD group. Results concerning group differences were interpreted by taking into account both the clinical and the neurophysiological domains. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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16 pages, 3919 KiB

Open AccessArticle

The Influence of Mental Imagery Expertise of Pen and Paper Players versus Computer Gamers upon Performance and Electrocortical Correlates in a Difficult Mental Rotation Task

by Johannes Rodrigues, Dorna Marzban and Johannes Hewig

Symmetry 2021, 13(12), 2337; https://doi.org/10.3390/sym13122337 - 6 Dec 2021

Viewed by 2644

Abstract

We investigated the influence of mental imagery expertise in 15 pen and paper role-players as an expert group compared to the gender-matched control group of computer role-players in the difficult Vandenberg and Kuse mental rotation task. In this task, the participants have to [...] Read more.

We investigated the influence of mental imagery expertise in 15 pen and paper role-players as an expert group compared to the gender-matched control group of computer role-players in the difficult Vandenberg and Kuse mental rotation task. In this task, the participants have to decide which two of four rotated figures match the target figure. The dependent measures were performance speed and accuracy. In our exploratory investigation, we further examined midline frontal theta band activation, parietal alpha band activation, and parietal alpha band asymmetry in EEG as indicator for the chosen rotation strategy. Additionally, we explored the gender influence on performance and EEG activation, although a very small female sample section was given. The expected gender difference concerning performance accuracy was negated by expertise in pen and paper role-playing women, while the gender-specific difference in performance speed was preserved. Moreover, gender differences concerning electro-cortical measures revealed differences in rotation strategy, with women using top-down strategies compared to men, who were using top-down strategies and active inhibition of associative cortical areas. These strategy uses were further moderated by expertise, with higher expertise leading to more pronounced activation patters, especially during successful performance. However, due to the very limited sample size, the findings of this explorative study have to be interpreted cautiously. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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14 pages, 1584 KiB

Open AccessArticle

Paradoxical Enhancement of Spatial Learning Induced by Right Hippocampal Lesion in Rats

by Yukitoshi Sakaguchi and Yoshio Sakurai

Symmetry 2021, 13(11), 2138; https://doi.org/10.3390/sym13112138 - 10 Nov 2021

Cited by 1 | Viewed by 2257

Abstract

The left–right hemispheric differences in some brain functions are well known in humans. Among them, savant syndrome has unique features, such as exceptional abilities in vision, memory, computation, and music, despite brain abnormalities. In cases of acquired savant and transient savant, brain damage [...] Read more.

The left–right hemispheric differences in some brain functions are well known in humans. Among them, savant syndrome has unique features, such as exceptional abilities in vision, memory, computation, and music, despite brain abnormalities. In cases of acquired savant and transient savant, brain damage or inhibition is often seen in the left hemisphere, suggesting a link between left hemispheric dysfunction and these talents. On the other hand, some functional left–right differences have been reported in rodent brains, and therefore, unilateral damage in rodents may also result in savant-like enhancements. In the present study, we examined the effects of hippocampal damage on spatial learning in rats with left, right, or bilateral hippocampal lesion. The results showed that learning performance was impaired in the bilateral lesion group, and there was no significant difference in the left lesion group, while performance was enhanced in the right lesion group. These results suggest that damage to the right hippocampus in rats may lead to savant-like enhancement in learning and memory. The construction of the savant model through these results will contribute to the neuroscientific elucidation of the paradoxical phenomenon observed in savants, that some abilities are enhanced despite their brain dysfunction. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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9 pages, 4288 KiB

Open AccessEditor’s ChoiceArticle

Individual Laterality in Ghost Crabs (Ocypode saratan) Influences Burrowing Behavior

by Reuven Yosef, Michal Daraby, Alexei Semionovikh and Jakub Z. Kosicki

Symmetry 2021, 13(8), 1512; https://doi.org/10.3390/sym13081512 - 17 Aug 2021

Cited by 7 | Viewed by 3317

Abstract

Behavioral handedness is known to enhance an individual’s handling capabilities. However, the ecological advantages in brachyuran crustaceans remain unclear, despite the Ocypode species having been studied extensively. Thus, in this study, we analyzed the laterality of the endemic Red Sea ghost crab on [...] Read more.

Behavioral handedness is known to enhance an individual’s handling capabilities. However, the ecological advantages in brachyuran crustaceans remain unclear, despite the Ocypode species having been studied extensively. Thus, in this study, we analyzed the laterality of the endemic Red Sea ghost crab on one beach in Eilat, Israel. We successfully documented the laterality of the large cheliped in 125 crabs; in 60 (48.0%), the right cheliped was larger, and in 64 (51.2%), the left. We also observed temporal segregation between the right- and left-clawed crabs. The right-handed crabs start activity just after sunrise, while left-handed crabs appear ca. 40 min after it. Similarly, temporal segregations were also observed in the evening. The right-clawed crab activity peaked ca. 20 min before sunset, while the left-clawed crabs were active uniformly. Additionally, burrow entrances corresponded to the larger cheliped of the resident individual and is probably a self-defense-related behavior. We conclude that cheliped laterality in O. saratan populations should be considered as a bimodal trait, where left- and right-handedness is not under natural selection pressure. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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19 pages, 2951 KiB

Open AccessArticle

Hemifield-Specific Rotational Biases during the Observation of Ambiguous Human Silhouettes

by Chiara Lucafò, Daniele Marzoli, Caterina Padulo, Stefano Troiano, Lucia Pelosi Zazzerini, Gianluca Malatesta, Ilaria Amodeo and Luca Tommasi

Symmetry 2021, 13(8), 1349; https://doi.org/10.3390/sym13081349 - 26 Jul 2021

Cited by 2 | Viewed by 1962

Abstract

Both static and dynamic ambiguous stimuli representing human bodies that perform unimanual or unipedal movements are usually interpreted as right-limbed rather than left-limbed, suggesting that human observers attend to the right side of others more than the left one. Moreover, such a bias [...] Read more.

Both static and dynamic ambiguous stimuli representing human bodies that perform unimanual or unipedal movements are usually interpreted as right-limbed rather than left-limbed, suggesting that human observers attend to the right side of others more than the left one. Moreover, such a bias is stronger when static human silhouettes are presented in the RVF (right visual field) than in the LVF (left visual field), which might represent a particular instance of embodiment. On the other hand, hemispheric-specific rotational biases, combined with the well-known bias to perceive forward-facing figures, could represent a confounding factor when accounting for such findings. Therefore, we investigated whether the lateralized presentation of an ambiguous rotating human body would affect its perceived handedness/footedness (implying a role of motor representations), its perceived spinning direction (implying a role of visual representations), or both. To this aim, we required participants to indicate the perceived spinning direction (which also unveils the perceived handedness/footedness) of ambiguous stimuli depicting humans with an arm or a leg outstretched. Results indicated that the lateralized presentation of the stimuli affected both their perceived limb laterality (a larger number of figures being interpreted as right-limbed in the RVF than in the LVF) and their perceived spinning direction (a larger number of figures being interpreted as spinning clockwise in the LVF than in the RVF). However, the hemifield of presentation showed a larger effect size on the perceived spinning direction than on the perceived limb laterality. Therefore, as we already proposed, the implicit representation of others’ handedness seems to be affected more by visual than by motor processes during the perception of ambiguous human silhouettes. Full article

(This article belongs to the Special Issue Symmetry and Biology Section: Feature Papers in Neuroscience and Behavior)

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