Variations of hemispheric functional segregation in the laterality spectrum: Comment on “Phenotypes in hemispheric functional segregation? Perspectives and challenges” by Guy Vingerhoets

doi:10.1016/j.plrev.2019.08.006

Physics of Life Reviews

Volume 30, October 2019, Pages 27-29

https://doi.org/10.1016/j.plrev.2019.08.006 Get rights and content

Highlights

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A clear scientific definition of typical (language) lateralisation does not exist.
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Laterality is double coded by stable traits and temporary/situational states.
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The relationship between laterality and cognitive performance is not clear-cut.

Section snippets

What is a/typical language lateralisation?

The term atypical (language) lateralisation implies that there is a clear scientific definition of what typical (language) lateralisation is and what is not, which is usually defined by strong laterality biases at the population level. Vingerhoets [1] proposed that instead of categorising (or dichotomising) individuals based on hemisphere dominance, it might be more useful to consider the raw distribution of lateralisation indices. Vingerhoets [1] introduced the term “laterality spectrum”,

Is language lateralisation a trait?

The majority of individuals are right-handed and left lateralised for specific language functions and similar laterality biases at the population level exist for non-human species [5]. Due to the fact that functional asymmetries are a ubiquitous phenomenon that can be quite stable over time, Vingerhoets [1] emphasised that functional lateralisation is a fundamental principle of brain organisation “molded by evolution and genetically blueprinted”. However, researchers have tried to fit genetic

Is functional lateralisation evolutionarily adaptive?

Vingerhoets [1], as have many before him [5], argues that functional lateralisation must be beneficial and evolutionarily adaptive, given that it is such a ubiquitous phenomenon across species. However, surprisingly few studies have directly investigated the relationship between functional lateralisation and performance. Vingerhoets [1] concluded that “degree, not direction of lateralisation, predicts performance and that absence of clear functional lateralisation results in reduced task

Declaration of Competing Interest

None.

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There are more references available in the full text version of this article.

Cited by (5)

Sex/Gender differences in the human brain
2021, Encyclopedia of Behavioral Neuroscience: Second Edition
Recent years have seen a substantial increase in the amount of research concerning sex/gender differences in the human brain. In this chapter, we review and synthesize some key research findings concerning sex/gender differences in brain structure, brain function, and structural/functional connectivity. In light of the findings, we concluded that although sex/gender differences in the brain exist at multiple levels, results in some areas are inconsistent, partly because the large inter- and intra-individual variability within each sex/gender has not been sufficiently considered. Consequently, neuroscience research should routinely include both men and women. Moreover, concepts referring to “male brain”, “female brain” or “sexual dimorphism” are outdate and incorrect, and therefore should be avoided in the neuroscientific literature. Finally, neuroscientists with a focus on sex/gender difference should adopt a psychobiosocial approach whenever possible, because structural and functional differences in the brains of men and women will never be fully understood, if psychological, biological and environmental/social factors are not routinely taken into account in combination.
Antipsychotic effects of sex hormones and atypical hemispheric asymmetries
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Citation Excerpt :
A small number of studies investigating the use of estrogen as an adjunct to antidepressant therapy specifically for peri-menopausal women and reported positive results (e.g., Kulkarni et al., 2018; for a review see Worsley et al., 2012). It has been argued that FCAs are double-coded by stable characteristics (traits) and temporary situational aspects (states) (e.g., Hausmann, 2019). Sex hormones are assumed to contribute to the establishment of FCAs during early development (via organising effects) and also dynamically change FCAs in certain constraints throughout life, for example in younger women during different cycle phases (Hausmann, 2017), and in postmenopausal women in response to hormone therapy (Bayer & Hausmann, 2011).
Functional cerebral asymmetries (FCAs) are a fundamental principle of brain organisation. While specific patterns of asymmetry are characteristic of healthy human brains, atypical or reduced FCAs have been reported for several psychotic disorders, including schizophrenia and mood disorders. However, it is unclear whether atypical FCAs reflect a predisposition to psychotic disorders or a compensatory neural strategy for the progressive structural and functional changes in the brain associated with psychosis. A separate stream of research has demonstrated the antipsychotic effects of sex hormones in clinical populations. Moreover, modern neuroscience has shown that sex hormones, particularly estrogen and progesterone, can affect FCAs due to their organising effects (e.g., during prenatal development), and also by their activating effects throughout life (e.g., in younger women during the menstrual cycle or in post-menopausal women as a consequence of hormone therapy). By combining these research streams, this narrative literature review explores the relationship between the neuromodulatory properties of estrogen, FCAs and psychotic and psychotic-like symptoms. This research is not only of theoretical interest for the understanding of FCAs and psychotic symptoms, but might also be of clinical relevance for the development of stratified treatment approaches for women and men suffering from psychosis and mood disorders.
Toward a multidimensional description of individual variation in hemispheric functional segregation: Reply to comments on “Phenotypes in hemispheric functional segregation? Perspectives and challenges”
2019, Physics of Life Reviews
Sex/Gender Differences in Brain Lateralisation and Connectivity
2023, Current Topics in Behavioral Neurosciences
Sex/Gender Differences in the Human Brain
2021, Encyclopedia of Behavioral Neuroscience: Volumes 1-3, Second edition

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CommentVariations of hemispheric functional segregation in the laterality spectrum: Comment on “Phenotypes in hemispheric functional segregation? Perspectives and challenges” by Guy Vingerhoets

Highlights

Section snippets

What is a/typical language lateralisation?

Is language lateralisation a trait?

Is functional lateralisation evolutionarily adaptive?

Declaration of Competing Interest

First page preview

Phys Life Rev

Brain Cogn

Brain Cogn

Brain Cogn

Cortex

Brain Cogn

Neuropsychologia

Brain Cogn

Comment
Variations of hemispheric functional segregation in the laterality spectrum: Comment on “Phenotypes in hemispheric functional segregation? Perspectives and challenges” by Guy Vingerhoets