Absence of hemispheric dominance for mental rotation ability: a transcranial Doppler study.
Mean blood flow velocity (MFV) of the middle cerebral arteries was monitored in 19 healthy, adult, right-handed subjects during the resting phase and the execution of a series of neuropsychological tests: two right/left discrimination tasks, two mental rotation paradigms (the Ratcliff's test and a cube comparison test) and a phonemic fluency task, which was utilised as an internal control. In the group as a whole, the Ratcliff's test was associated with a significant bilateral increase in MFV versus both the resting state (right: p < .000001, left: p < .000001) and right/left discrimination tasks (task 1: right: p = .003, left: p = .005; task 2: right: p = .001, left: p = .001). The cube comparison in turn produced a significant increase in MFV versus both the baseline conditions (right: p < .000001, left: p < .000001) and the Ratcliff's test (right: p = .01, left: p = .002). As expected, the fluency task was associated with a significant asymmetric increase in cerebral perfusion (left > right: p = .0001). Increasing task difficulty (right/left discrimination < Ratcliffs test < cube comparison) was paralleled by a roughly proportional rise in MFV values (right: r = .424, p < .01; left: r = .331, p = .01). In conclusion, we were able to demonstrate that (1) in addition to the amount of MFV variation due to right/left discrimination (when required), mental rotation per se causes a bihemispheric activation irrespective of the experimental paradigm; (2) the MFV variation is proportional to the difficulty of the tasks.
Dipartimento di Scienze Neurologiche e della Visione, Università di Genova, Italy. cserrati@neurologia.unige.it
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Serrati
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Finocchi
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Calautti
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Bruzzone
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Colucci
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Gandolfo
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Del Sette
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PB
Lantieri
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Favale
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004453:Echoencephalography / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D013028:Space Perception / Q000502:physiology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*