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Cerebral asymmetry: motoring on.
1Research Centre for Cognitive Neuroscience, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Trends in Cognitive Sciences
|January 14, 2011
Summary
Cerebral asymmetry in humans likely originates from motor systems, not perceptual ones. This theory links right-handedness and speech dominance to early language evolution from manual gestures, possibly involving mirror neurons.
Area of Science:
- Neuroscience
- Evolutionary Biology
- Genetics
Background:
- Cerebral asymmetry, or brain lateralization, is a hallmark of human cognition.
- Existing genetic models propose a 'dextral' allele influences right-handedness and left-hemisphere language dominance.
- The evolutionary link between handedness and language lateralization is a key area of research.
Purpose of the Study:
- To propose that the phylogenetic and neurobiological underpinnings of human cerebral asymmetry are rooted in motor systems.
- To explore the evolutionary transition of language from manual gestures to vocalization.
- To investigate the role of mirror neurons as precursors to human language circuits.
Main Methods:
- Comparative neurobiology analysis.
- Review of genetic models of human laterality.
- Evolutionary developmental biology principles.
Main Results:
- The study argues for motor system origins of cerebral asymmetry over perceptual systems.
- A hypothesis is presented linking handedness and language lateralization to the evolution of language from gestures.
- Mirror neurons in monkeys, involved in action observation and execution, are proposed as potential precursors to human language circuits.
Conclusions:
- The motor system provides a more plausible evolutionary and neurobiological basis for human cerebral asymmetry.
- The transition to vocal language in Homo sapiens may have co-opted or modified pre-existing motor-related neural circuits.
- Further research into mirror neuron systems and their evolution is crucial for understanding language origins.
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