Lateralised visual attention is unrelated to language lateralisation, and not influenced by task difficulty – A functional transcranial Doppler study

• Published in: Neuropsychologia Vol. 50; no. 5; pp. 810 - 815
• Main Authors: Rosch, Richard E., Bishop, Dorothy V.M., Badcock, Nicholas A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2012; Elsevier; Pergamon Press
• Subjects: Adult; Anatomical correlates of behavior; Attention; Attention - physiology; Behavioral psychophysiology; Biological and medical sciences; Brain; Brain Mapping; Cerebral Cortex - diagnostic imaging; Cerebral Dominance; Cerebral laterality; Cerebrovascular Circulation; Cognitive ability; Difficulty; Dominance, Cerebral - physiology; Evolution; Female; Functional transcranial Doppler ultrasound (fTCD); Fundamental and applied biological sciences. Psychology; Handedness; Hemispheric laterality; Humans; Landmark task; Language; Language Processing; Lateralization; Male; Miscellaneous; Neurolinguistics; Neuropsychological Tests; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Ultrasonography, Doppler, Transcranial; Ultrasound; Verbal fluency; Visual perception; Visual Perception - physiology; Visuospatial attention; Vocabulary; Word generation task; Young Adult; Verbal fluency; Visuospatial attention; Word generation task; Difficulty; Cerebral laterality; Landmark task; Functional transcranial Doppler ultrasound (fTCD); Doppler ultrasound study; Word; Spatial attention; Central nervous system; Cognition; Space perception; Verbal production; Encephalon; Task difficulty; Language; Laterality; Sonography; Human; fTCD; Hemispheric specialization; Experimental study; Vision; Functional transcranial Doppler ultrasound; Visual attention
• ISSN: 0028-3932; 1873-3514; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2012.01.015

[Display omitted] ► fTCD gives a reliable index of cerebral lateralisation for visuospatial attention. ► Task difficulty has no effect on the laterality index in the visuospatial paradigm. ► Visuospatial and language lateralisation are not correlated within subjects. ► The results challenge single-factor theories of hemispheric specialisation. Historically, most theoretical accounts of hemispheric specialisation have proposed a single underlying factor that leads to left hemisphere language and right hemisphere visuospatial processing in the majority of people. More recently empirical evidence has started to challenge this view, suggesting lateralisation of language and visuospatial attention are independent. However, so far studies did not control for a possible confound, task difficulty. For this study, 20 healthy right-handed volunteers underwent functional laterality assessment using functional transcranial Doppler ultrasound (fTCD). We assessed laterality using both a word generation task and a novel variation of the visuospatial landmark task that can be adjusted along two dimensions of difficulty (temporal and spatial). The visuospatial laterality measures were highly intercorrelated and unaffected by task difficulty. Furthermore, there was no correlation between visuospatial and verbal lateralisation within individuals – neither qualitatively (in direction of lateralisation), nor quantitatively (in laterality index size). These results substantiate a growing body of evidence suggesting multiple independent biases leading to the hemispheric lateralisation of different cognitive domains, thus further questioning previously accepted models of laterality development and evolution.