title: Hand preference is selectively related to common and internal carotid arterial asymmetry.
abstract: This study documents relationships between handedness and carotid arterial asymmetries. The article is divided into two sections, considering first geometric (n = 195) and then haemodynamic (n = 228) asymmetries. In the geometric study, diameters, lengths, and angles of the common carotid arteries in left and right-handed participants were measured using computed tomography angiography scans. Resistance to blood flow was calculated according to Poiseuille's formula. In the haemodynamic study, peak systolic and end-diastolic velocity, vessel diameter, and volume flow rate of the common, internal, and external carotid arteries were measured in left and right-handed participants, using Doppler ultrasonography. The findings reveal for the first time that the extracranial arteries supplying the cerebral hemispheres are asymmetrical in a direction that increases blood flow to the hemisphere dominant for handedness. Significant handedness interactions were identified in arterial length, diameter, resistance to blood flow, velocity and flow volume rate (p < .001). Arterial resistance and volume flow rates significantly predicted hand preference and proficiency. Our findings reveal a vascular correlate of handedness, but causality cannot be determined from this study alone. These asymmetries appear to be independent of aortic arch anomalies, suggesting a top-down, possibly demand-driven, pattern of development.
authors.affiliation: a Department of Psychology , University of Cape Town , Rondebosch , South Africa.
authors.forename: Anica
authors.initials: A
authors.lastname: Jansen van Vuuren
authors.affiliation: b Melbourne School of Psychological Sciences, University of Melbourne , Parkville , VIC , Australia.|c Florey Institute of Neurosciences and Mental Health , Melbourne , Australia.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Saling
authors.affiliation: a Department of Psychology , University of Cape Town , Rondebosch , South Africa.
authors.forename: Ozyar
authors.initials: O
authors.lastname: Ameen
authors.affiliation: a Department of Psychology , University of Cape Town , Rondebosch , South Africa.
authors.forename: Nadraj
authors.initials: N
authors.lastname: Naidoo
authors.affiliation: a Department of Psychology , University of Cape Town , Rondebosch , South Africa.
authors.forename: Mark
authors.initials: M
authors.lastname: Solms
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology*; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000502:physiology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000502:physiology*; D000072226:Computed Tomography Angiography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D018608:Ultrasonography, Doppler
keywords: Handedness; arterial asymmetry; arterial geometry and haemodynamics; cerebral lateralization; common and internal carotid arteries