Symmetry

Research

11 pages, 2453 KiB

Open AccessArticle

Unified Visual Working Memory without the Anterior Corpus Callosum

by Yair Pinto, Edward H.F. de Haan, Maria-Chiara Villa, Sabrina Siliquini, Gabriele Polonara, Claudia Passamonti, Simona Lattanzi, Nicoletta Foschi and Mara Fabri

Symmetry 2020, 12(12), 2106; https://doi.org/10.3390/sym12122106 - 18 Dec 2020

Cited by 2 | Viewed by 2954

Abstract

One of the most fundamental, and most studied, human cognitive functions is working memory. Yet, it is currently unknown how working memory is unified. In other words, why does a healthy human brain have one integrated capacity of working memory, rather than one [...] Read more.

One of the most fundamental, and most studied, human cognitive functions is working memory. Yet, it is currently unknown how working memory is unified. In other words, why does a healthy human brain have one integrated capacity of working memory, rather than one capacity per visual hemifield, for instance. Thus, healthy subjects can memorize roughly as many items, regardless of whether all items are presented in one hemifield, rather than throughout two visual hemifields. In this current research, we investigated two patients in whom either most, or the entire, corpus callosum has been cut to alleviate otherwise untreatable epilepsy. Crucially, in both patients the anterior parts connecting the frontal and most of the parietal cortices, are entirely removed. This is essential, since it is often posited that working memory resides in these areas of the cortex. We found that despite the lack of direct connections between the frontal cortices in these patients, working memory capacity is similar regardless of whether stimuli are all presented in one visual hemifield or across two visual hemifields. This indicates that in the absence of the anterior parts of the corpus callosum working memory remains unified. Moreover, it is important to note that memory performance was not similar across visual fields. In fact, capacity was higher when items appeared in the left visual hemifield than when they appeared in the right visual hemifield. Visual information in the left hemifield is processed by the right hemisphere and vice versa. Therefore, this indicates that visual working memory is not symmetric, with the right hemisphere having a superior visual working memory. Nonetheless, a (subcortical) bottleneck apparently causes visual working memory to be integrated, such that capacity does not increase when items are presented in two, rather than one, visual hemifield. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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19 pages, 3757 KiB

Open AccessArticle

Asymmetrical Pseudo-Extinction Phenomenon in the Illusory Line Motion

by Vidheya G. Del Vicario, Rossana Actis-Grosso, Nadia Bolognini and Roberta Daini

Symmetry 2020, 12(8), 1322; https://doi.org/10.3390/sym12081322 - 7 Aug 2020

Viewed by 2412

Abstract

Illusory Line Motion (i.e., a static line, presented after a lateral cue, is perceived as movement in the opposite direction to the cue) has been used to study a phenomenon of perceptual asymmetry. We have demonstrated the presence of an illusion of leftward [...] Read more.

Illusory Line Motion (i.e., a static line, presented after a lateral cue, is perceived as movement in the opposite direction to the cue) has been used to study a phenomenon of perceptual asymmetry. We have demonstrated the presence of an illusion of leftward movement, even in the presence of bilateral symmetrical cues. We have classified this phenomenon as one of pseudo-extinction. The paradigm of the four experiments performed was always the same: a white line, briefly presented alone or preceded by one or two lateral cues (150 ms), was judged by a group of young participants to be moving either to one side or the other. The asymmetrical effect in the bilateral cue condition was observed with horizontal lines (Experiment 1 and 4), and not with vertical or oblique (Experiment 2 and 3). These results suggest that the effect is linked to the asymmetry of the horizontal spatial planum and the mechanisms of spatial attention. Experiment 4 verified whether the Illusory Line Motion involves the collicular pathway by using blue stimuli for the cues, which activate less the Superior Colliculus (SC), with negative results. We interpreted the asymmetrical pseudo-extinction phenomenon in terms of a right-space exogenous attention advantage. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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15 pages, 1454 KiB

Open AccessArticle

Mental Rotation Ability: Right or Left Hemisphere Competence? What We Can Learn from Callosotomized and Psychotic Patients

by Chiara Pierpaoli, Luigi Ferrante, Nicoletta Foschi, Simona Lattanzi, Riccardo Sansonetti, Gabriele Polonara, Massimo Mari, Bernardo Nardi and Mara Fabri

Symmetry 2020, 12(7), 1137; https://doi.org/10.3390/sym12071137 - 7 Jul 2020

Cited by 4 | Viewed by 2975

Abstract

Mental rotation is an abstract operation whereby a person imagines rotating an object or a body part to place it in a different position. The ability to perform mental rotation was attributed to right hemisphere for objects, to the left for one’s own [...] Read more.

Mental rotation is an abstract operation whereby a person imagines rotating an object or a body part to place it in a different position. The ability to perform mental rotation was attributed to right hemisphere for objects, to the left for one’s own body images. Mental rotation seems to be basic for imitation in anatomical mode. Previous studies showed that control subjects, callosotomized and psychotic patients chose the mirror-mode when imitating without instructions; when asked to use the same or opposite limb as the model, controls chose the anatomical mode, callosotomized patients mainly used mirror mode, psychotic patients were in between. The preference of callosotomized subjects is likely due to defective mental rotation, because of the lack of the corpus callosum (CC), thus suggesting an asymmetry in the hemispheric competence for mental rotation. Present research investigated the mental rotation ability in control subjects, callosotomized and psychotic patients. All subjects were shown pictures of a model, in first or third person perspective, with a cup in her right or left hand. They had to indicate which model’s hand held the cup, by answering with a verbal or motor modality in separate experimental sessions. In both sessions, control subjects produced 99% of correct responses, callosotomy patients 62%, and psychotic patients 91%. The difference was statistically significant, suggesting a role of the CC in the integration of the two hemispheres’ asymmetric functions in mental rotation. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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12 pages, 673 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Keep a Left Profile, Baby! The Left-Cradling Bias Is Associated with a Preference for Left-Facing Profiles of Human Babies

by Gianluca Malatesta, Daniele Marzoli and Luca Tommasi

Symmetry 2020, 12(6), 911; https://doi.org/10.3390/sym12060911 - 1 Jun 2020

Cited by 17 | Viewed by 7015

Abstract

The left-cradling bias (LCB) refers to the (typically female) preference to hold an infant on the left side of one’s own body. Among the three main accounts proposed for such a phenomenon, namely the “handedness”, “heartbeat” and “hemispheric asymmetry” hypotheses, the latter has [...] Read more.

The left-cradling bias (LCB) refers to the (typically female) preference to hold an infant on the left side of one’s own body. Among the three main accounts proposed for such a phenomenon, namely the “handedness”, “heartbeat” and “hemispheric asymmetry” hypotheses, the latter has met with the greatest empirical success. Accordingly, the LCB would facilitate the communication of socio-emotional information through the right hemisphere of both the cradled and the cradling individual, and should emerge mainly in face-to-face interactions. In this regard, it should be noticed that when the infant’s body is oriented toward the cradler, the left or right side of their face is relatively more visible to left- and right-cradlers, respectively. Therefore, we hypothesized that the LCB might also be associated with a preference for left-facing profiles (i.e., those showing the left, and more expressive, hemiface/cheek) of human babies. In order to test our hypothesis, we assessed the cradling-side preferences of female participants, as well as their preference for the left- or right-facing profile of a human infant depicted in a drawing. Left-cradlers exhibited a significantly larger preference for the left-facing version of the drawing compared with right-cradlers, a finding further corroborating the right-hemisphere hypothesis. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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13 pages, 1267 KiB

Open AccessFeature PaperArticle

Spatializing Emotions Besides Magnitudes: Is There a Left-to-Right Valence or Intensity Mapping?

by Giulia Prete

Symmetry 2020, 12(5), 775; https://doi.org/10.3390/sym12050775 - 7 May 2020

Cited by 7 | Viewed by 3010

Abstract

The Spatial–Numerical Association of Response Codes (SNARC), namely the automatic association between smaller numbers and left space and between larger numbers and right space, is often attributed to a Mental Number Line (MNL), in which magnitudes would be placed left-to-right. Previous studies have [...] Read more.

The Spatial–Numerical Association of Response Codes (SNARC), namely the automatic association between smaller numbers and left space and between larger numbers and right space, is often attributed to a Mental Number Line (MNL), in which magnitudes would be placed left-to-right. Previous studies have suggested that the MNL could be extended to emotional processing. In this study, participants were asked to carry out a parity judgment task (categorizing one to five digits as even or odd) and an emotional judgment task, in which emotional smilies were presented with four emotional expressions (very sad, sad, happy, very happy). Half of the sample was asked to categorize the emotional valence (positive or negative valence), the other half was asked to categorize the emotional intensity (lower or higher intensity). The results of the parity judgment task confirmed the expected SNARC effect. In the emotional judgment task, the performance of both subgroups was better for happy than for sad expressions. Importantly, a better performance was found only in the valence task for lower intensity stimuli categorized with the left hand and for higher intensity stimuli categorized with the right hand, but only for happy smilies. The present results show that neither emotional valence nor emotional intensity alone are spatialized left-to-right, suggesting that magnitudes and emotions are processed independently from one another, and that the mental representation of emotions could be more complex than the bi-dimentional left-to-right spatialization found for numbers. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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14 pages, 1668 KiB

Open AccessArticle

Is There Visual Lateralisation of the Sun Compass in Homing Pigeons?

by Charlotte Griffiths, Richard Holland and Anna Gagliardo

Symmetry 2020, 12(5), 740; https://doi.org/10.3390/sym12050740 - 5 May 2020

Cited by 6 | Viewed by 3784

Abstract

Functional lateralisation in the avian visual system can be easily studied by testing monocularly occluded birds. The sun compass is a critical source of navigational information in birds, but studies of visual asymmetry have focussed on cues in a laboratory rather than a [...] Read more.

Functional lateralisation in the avian visual system can be easily studied by testing monocularly occluded birds. The sun compass is a critical source of navigational information in birds, but studies of visual asymmetry have focussed on cues in a laboratory rather than a natural setting. We investigate functional lateralisation of sun compass use in the visual system of homing pigeons trained to locate food in an outdoor octagonal arena, with a coloured beacon in each sector and a view of the sun. The arena was rotated to introduce a cue conflict, and the experimental groups, a binocular treatment and two monocular treatments, were tested for their directional choice. We found no significant difference in test orientation between the treatments, with all groups showing evidence of both sun compass and beacon use, suggesting no complete functional lateralisation of sun compass use within the visual system. However, reduced directional consistency of binocular vs. monocular birds may reveal a conflict between the two hemispheres in a cue conflict condition. Birds using the right hemisphere were more likely to choose the intermediate sector between the training sector and the shifted training beacon, suggesting a possible asymmetry in favour of the left eye/right hemisphere (LE/RH) when integrating different cues. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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Review

Jump to: Research, Other

20 pages, 2956 KiB

Open AccessEditor’s ChoiceReview

Functional Lateralization of the Mirror Neuron System in Monkey and Humans

by Antonino Errante and Leonardo Fogassi

Symmetry 2021, 13(1), 77; https://doi.org/10.3390/sym13010077 - 5 Jan 2021

Cited by 7 | Viewed by 5317

Abstract

To date, both in monkeys and humans, very few studies have addressed the issue of the lateralization of the cortical parietal and premotor areas involved in the organization of voluntary movements and in-action understanding. In this review, we will first analyze studies in [...] Read more.

To date, both in monkeys and humans, very few studies have addressed the issue of the lateralization of the cortical parietal and premotor areas involved in the organization of voluntary movements and in-action understanding. In this review, we will first analyze studies in the monkey, describing the functional properties of neurons of the parieto-frontal circuits, involved in the organization of reaching-grasping actions, in terms of unilateral or bilateral control. We will concentrate, in particular, on the properties of the mirror neuron system (MNS). Then, we will consider the evidence about the mirror neuron mechanism in humans, describing studies in which action perception, as well as action execution, produces unilateral or bilateral brain activation. Finally, we will report some investigations demonstrating plastic changes of the MNS following specific unilateral brain damage, discussing how this plasticity can be related to the rehabilitation outcome Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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19 pages, 355 KiB

Open AccessFeature PaperReview

Hypnotizability-Related Asymmetries: A Review

by Vilfredo De Pascalis and Enrica Laura Santarcangelo

Symmetry 2020, 12(6), 1015; https://doi.org/10.3390/sym12061015 - 16 Jun 2020

Cited by 6 | Viewed by 2475

Abstract

Hypnotizability is a dispositional trait reflecting the individual ability to modify perception, memory and behavior according to imaginative suggestions. It is measured by validated scales that classify the general population in high (highs), medium (mediums) and low (lows) hypnotizable persons, predicts the individual [...] Read more.

Hypnotizability is a dispositional trait reflecting the individual ability to modify perception, memory and behavior according to imaginative suggestions. It is measured by validated scales that classify the general population in high (highs), medium (mediums) and low (lows) hypnotizable persons, predicts the individual proneness to respond to suggestions, and is particularly popular in the field of the cognitive control of pain and anxiety. Different hypnotizability levels, however, have been associated with specific brain morpho-functional characteristics and with peculiarities in the cognitive, sensorimotor and cardiovascular domains also in the ordinary state of consciousness and in the absence of specific suggestions. The present scoping review was undertaken to summarize the asymmetries observed in the phenomenology and physiological correlates of hypnosis and hypnotizability as possible indices of related hemispheric prevalence. It presents the findings of 137 papers published between 1974 and 2019. In summary, in the ordinary state of consciousness, behavioral, neurophysiological and neuroimaging investigations have revealed hypnotizability related asymmetries mainly consisting of pre-eminent left hemisphere information processing/activation in highs, and no asymmetries or opposite directions of them in lows. The described asymmetries are discussed in relation to the current theories of hypnotizability and hypnosis. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

12 pages, 676 KiB

Open AccessReview

Asymmetry of Motor Behavior and Sensory Perception: Which Comes First?

by Lesley J. Rogers

Symmetry 2020, 12(5), 690; https://doi.org/10.3390/sym12050690 - 29 Apr 2020

Cited by 9 | Viewed by 4332

Abstract

By examining the development of lateralization in the sensory and motor systems of the human fetus and chick embryo, this paper debates which lateralized functions develop first and what interactions may occur between the different sensory and motor systems during development. It also [...] Read more.

By examining the development of lateralization in the sensory and motor systems of the human fetus and chick embryo, this paper debates which lateralized functions develop first and what interactions may occur between the different sensory and motor systems during development. It also discusses some known influences of inputs from the environment on the development of lateralization, particularly the effects of light exposure on the development of visual and motor lateralization in chicks. The effects of light on the human fetus are related in this context. Using the chick embryo as a model to elucidate the genetic and environmental factors involved in development of lateralization, some understanding has been gained about how these lateralized functions emerge. At the same time, the value of carrying out much more research on the development of the various types of lateralization has become apparent. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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12 pages, 270 KiB

Open AccessFeature PaperReview

Bilaterally Symmetrical: To Be or Not to Be?

by Michael C. Corballis

Symmetry 2020, 12(3), 326; https://doi.org/10.3390/sym12030326 - 25 Feb 2020

Cited by 20 | Viewed by 12387

Abstract

We belong to a clade of species known as the bilateria, with a body plan that is essentially symmetrical with respect to left and right, an adaptation to the indifference of the natural world to mirror-reflection. Limbs and sense organs are in bilaterally [...] Read more.

We belong to a clade of species known as the bilateria, with a body plan that is essentially symmetrical with respect to left and right, an adaptation to the indifference of the natural world to mirror-reflection. Limbs and sense organs are in bilaterally symmetrical pairs, dictating a high degree of symmetry in the brain itself. Bilateral symmetry can be maladaptive, though, especially in the human world where it is important to distinguish between left and right sides, and between left-right mirror images, as in reading directional scripts. The brains of many animals have evolved asymmetries, often but not exclusively in functions not dependent on sensory input or immediate reaction to the environment. Brain asymmetries in humans have led to exaggerate notions of a duality between the sides of the brain. The tradeoff between symmetry and asymmetry results in individual differences in brain asymmetries and handedness, contributing to a diversity of aptitude and divisions of labor. Asymmetries may have their origin in fundamental molecular asymmetries going far back in biological evolution. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

Other

Jump to: Research, Review

25 pages, 1288 KiB

Open AccessOpinion

The Brain’s Asymmetric Frequency Tuning: Asymmetric Behavior Originates from Asymmetric Perception

by Arianna Felisatti, David Aagten-Murphy, Jochen Laubrock, Samuel Shaki and Martin H. Fischer

Symmetry 2020, 12(12), 2083; https://doi.org/10.3390/sym12122083 - 15 Dec 2020

Cited by 11 | Viewed by 4077

Abstract

To construct a coherent multi-modal percept, vertebrate brains extract low-level features (such as spatial and temporal frequencies) from incoming sensory signals. However, because frequency processing is lateralized with the right hemisphere favouring low frequencies while the left favours higher frequencies, this introduces asymmetries [...] Read more.

To construct a coherent multi-modal percept, vertebrate brains extract low-level features (such as spatial and temporal frequencies) from incoming sensory signals. However, because frequency processing is lateralized with the right hemisphere favouring low frequencies while the left favours higher frequencies, this introduces asymmetries between the hemispheres. Here, we describe how this lateralization shapes the development of several cognitive domains, ranging from visuo-spatial and numerical cognition to language, social cognition, and even aesthetic appreciation, and leads to the emergence of asymmetries in behaviour. We discuss the neuropsychological and educational implications of these emergent asymmetries and suggest future research approaches. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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6 pages, 525 KiB

Open AccessOpinion

Is the Horizontal-Vertical Illusion Mainly a By-Product of Petter’s Rule?

by Alessandra Pecunioso and Christian Agrillo

Symmetry 2020, 12(1), 6; https://doi.org/10.3390/sym12010006 - 18 Dec 2019

Cited by 2 | Viewed by 4982

Abstract

The horizontal-vertical (HV) illusion is a classical example of an asymmetrical perception of size in the vertical and horizontal axes, also known as ‘anisotropy of the perceived space’. Several authors argued that the horizontally-oriented ellipse of the binocular visual field might play an [...] Read more.

The horizontal-vertical (HV) illusion is a classical example of an asymmetrical perception of size in the vertical and horizontal axes, also known as ‘anisotropy of the perceived space’. Several authors argued that the horizontally-oriented ellipse of the binocular visual field might play an important role in the emergence of this illusion. Alternatively, a length bisection bias and size-constancy mechanisms have been advocated to account for the asymmetrical perception in the two dimensions. To investigate this phenomenon, participants are commonly required to estimate the length of two separate lines, one vertical and one horizontal, often arranged in an inverted-T pattern. Here we suggest that this type of stimulus may introduce physical and subjective biases that prevent a fine investigation. In particular, we believe that Petter’s rule, that applies to two-dimensional patterns formed by two overlapping surfaces, may play a critical role that will not support an interpretation based on the shape of the binocular visual field nor a length bisection bias. Full article

(This article belongs to the Special Issue Symmetry and Asymmetry in Brain Behavior and Perception)

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