Longitudinal circadian rhythms in reaction time (RT) to light and other signals were documented in two studies,
to test the hypothesis that the prominent rhythm τ varies between the DH and the NDH when performing tasks of different complexity. These studies were carried in close cooperation between workers71 at Tel Aviv University and a group investigators72 at the Fondation Adolphe de Rothschild Inhibitors,research,lifescience,medical in Paris. The French study72 assessed performance of easy single reaction time (SRT) tests involving a series of 32 yellow light signals following simple and nonvarying instructions; it also assessed the performance of a complex and difficult task, a choice reaction time (CRT) test, involving a series of 96 yellow, red, or green signals Inhibitors,research,lifescience,medical following different instructions from test to test, including which hand to use. The Israeli study71 explored DH and NDH RTs of men with an aviation background who were expert in the use of the pilot evaluation system, a flight simulator designed as a modern cockpit
with “hands on throttle and stick” instrumentation to test performance under 7 scenarios of varying levels of complexity, from easy to very difficult. Despite differences Inhibitors,research,lifescience,medical in methods, subjects, and data gathering, the two studies yielded similar results. When the task is easy (ie, SRT), the prominent period RT rhythm has τ=24 h for both DH and NDH. When the task is complex and tricky (ie, CRT), the DH maintains a prominent τ=24 h in performance, while the NDH shows a prominent rhythm with τ 24 h, eg, τ=8 h, 6 Inhibitors,research,lifescience,medical h, or 12 h. These findings suggest that: Biological clocks are present in right and left hemispheres of the human cortices. Functional differences in prominent performance rhythm are task-load-related, and the NDH side is more sensitive than the DH. The aim of another study73 was to assess the influence of age and gender on the difference in τ for RT of the DH and NDH, in comparison to the grip strength rhythm. Healthy subjects of both genders were involved (9 adolescents [10 to 16 years old] and
15 adults [18 to 67 years old]). They were Inhibitors,research,lifescience,medical active between 8 am ±1 h and 11 pm ±1 h; wrist actigraphs were used to assess the activity/rest rhythm, as well as sleep logs. Data were gathered longitudinally at home AV-951 and work four to seven times daily for 11 to 20 days. In almost all cases, a 24-h sleep/wake rhythm was detected. For the SRT in adults, a prominentτ=24 h was documented for both DH and NDH, whereas for the CRT a prominent τ=24 h was detected for DH, but τ<24 h for the NDH. This phenomenon was not genderrelated, but was age-related since it was seldom observed in adolescent subjects. Hand-side differences in grip strength rhythms in the same individuals were detected: τ was ultradian rather than circadian in adolescent subjects, while τ frequently differed from that of the rhythm in CRT in mature subjects.