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Evolution of cerebral asymmetry
1School of Psychology, University of Auckland, Auckland, New Zealand.
Progress in Brain Research
|November 10, 2019
Summary
Brain imaging reveals hemispheric asymmetry is complex and multidimensional, not a simple left-right duality. Individual differences in brain asymmetry are adaptive and widespread across species.
Area of Science:
- Neuroscience
- Evolutionary Biology
- Genetics
Background:
- The human brain is popularly viewed as a left-right duality, with individuals categorized as
- left-brained
- or
- right-brained
- .
- Hemispheric asymmetry, including handedness, is a key feature of brain organization.
- This asymmetry is often considered uniquely human.
Purpose of the Study:
- To explore the multidimensional nature of hemispheric asymmetry.
- To investigate the evolutionary origins and genetic basis of brain asymmetries.
- To examine the prevalence and adaptive significance of asymmetry in humans and other species.
Main Methods:
- Analysis of recent brain imaging data.
- Comparative studies across species.
- Genetic analyses considering complex gene interactions.
Main Results:
- Hemispheric asymmetry is multidimensional, involving independent lateralized circuits.
- Asymmetries likely evolved through the specialization of ancestral systems.
- Variation in asymmetry is genetically complex and not controlled by a single gene.
- Cerebral and behavioral asymmetries are widespread in the animal kingdom.
- Individual differences in asymmetry are adaptive, facilitating societal function.
Conclusions:
- The traditional left-right brain duality is an oversimplification.
- Hemispheric asymmetry is an ancient, widespread, and genetically complex trait.
- Individual variations in brain asymmetry are evolutionarily advantageous and crucial for social complexity.
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