Cerebral Polymorphisms for Lateralisation: Modelling the Genetic and Phenotypic Architectures of Multiple Functional Modules

Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, visuo-spatial functioning, while typically left, left right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers participants are finding module combinations, which here termed cerebral polymorphisms—qualitatively different lateral organisations cognitive functions. Polymorphisms more frequent in left-handers than right-handers, but it is far from the case right-handers all organisation described introductory textbooks. In computational terms, this paper extends original, monogenic McManus DC (dextral-chance) model handedness language dominance to multiple modules, a polygenic compatible molecular genetics handedness, biology visceral asymmetries primary ciliary dyskinesia. Distributions polymorphisms calculated families twins, consequences implications explored explaining aphasia due damage, as well possible talents deficits arising inter- intra-hemispheric modular connections. The set broader context testing psychological theories, issues laterality measurement, mutation-selection balance, evolution brain asymmetries.