Phase response curves to light and to melatonin Essay

Phase response curves to spark and to melatonin - Essay ExampleIn homo light PRC (Figure 1), the y-axis of the PRC shows the direction and relative magnitude of the phase shift in hours bring forth by light exposure (solid line). Circadian Time Zero (CT0) corresponds to 1100 am and CT22-CT18 is the duration for twenty-four hours while activity. The black bar, which indicates the time period between 1200 midnight 800am, along x-axis represents the duration for sleeping. buttonlike light treatment causes the phase-delay of circadian phase, which is represented by the area from CT10 to CT18. During this period, bright light treatment causes by and by onset of sleeping/ wakening motorbike. As time progresses from CT10, stronger essence on phase-delay is discover. At CT18, this phase-delay effect is changed dramatically to phase- move on effect. The peak phase-advancing effect coincides with sunrise. From CT18 to CT3, bright light treatment induces phase-advancing effect, causi ng earlier onset of sleeping / awakening cycle. This effect gradually decreases from CT19 to CT3. As noted in the graph, little or no effect is observed when bright light treatment is applied from CT14 to CT20, in which this time period corresponds to 200pm to 800pm. The intensity level of the light used in bright light treatment can have direct effect on the magnitude of the phase advancement or delay. ... After this time consign, this effect decreases to the lowest point to CT12. It should be noted that during this time period, bright light treatment has no phase-shifting effect on circadian rhythm. From CT18 to CT0, melatonin administration induces a phase-delay effect on circadian rhythm, however, this effect is relatively small when compared with the phase advancing effect induced by bright light treatment. From 2 hours before the onset of sleeping (CT12) before until time of sunrise (CT18), administration of melatonin does not exert any effect on circadian rhythm. This time duration coincides with phase delaying effect of bright light treatment. b. Using this knowledge of the phase response curves to light and to melatonin, design a protocol to alleviate the effects of jet lag when travelling from London capital of Singapore (8 time zones eastward) The flights for travelling from London to Singapore are available both in the morning and at night. The local anesthetic time in Singapore is ahead of London by 8 hours (8 time zones eastward). assume there are two flights travelling from London to Singapore, one flight has the depart time at 1100 am (London local time) and arrive in Singapore at 700 am (Singapore local time, one day ahead) the other flight departs at 2200 pm (London local time) and arrives at 1800 pm (Singapore local time, one day ahead). The total duration of the flight is approximately 13 hours. The circadian rhythm may be entrained by advance or delay the sleep/awake cycle and both intake of melatonin at about 4 hours before to its nat ural peak in the circadian cycle or bright light treatment may induce an advance response (3). The spare-time activity protocol is devised from