Handedness and circadian motor asymmetries in humans: preliminary findings.
Previous research studies indicate that a motor activity in the first half of nocturnal sleep is lateralized to the non-dominant hand. It was suggested that such phenomenon may be due to a more pronounced homeostatic deactivation of the dominant hemisphere (referring to the hypothesis of the use-dependent recovery function of sleep). If this were the case we should expect a reversed pattern of motor activity asymmetries between right- and left-handed subjects. We tested this hypothesis in an ecological study assessing the circadian motor activity in seventeen right- and seventeen left-handed subjects. All subjects wore actigraphs on both the left and right wrists for at least twelve consecutive days. In line with previous studies, right-handed subjects showed higher motor activity in the left vs. the right hand in late evening. We did not however find a reverse pattern of results in left-handed participants. On the whole the results do not seem to support the use-dependent recovery hypothesis, and are suggestive of a different circadian phase relationship between the two hemispheres regardless of handedness.
Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40127 Bologna, Italy. vincenzo.natale@unibo.it
Vincenzo
V
Natale
Hanna
H
Lehnkering
Renate
R
Siegmund
D056044:Actigraphy; D054022:Cerebrum / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006706:Homeostasis; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D055815:Young Adult