User:Bpfeife1/sandbox: Difference between revisions
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A '''zeitgeber''' (German for "time giver" or "synchronizer") is any external cue |
A '''zeitgeber''' (German for "time giver" or "synchronizer") is any external cue in the environment that sets or synchronizes an organism's biological rhythms with the body's circadian clock.<ref name="ehlers1988">Ehlers, C.L., Frank, E. & Kupfer, D.J. (1988). Social zeitgebers and biological rhythms. ''Arch Gen Psychiatry, 45'', 948-952.</ref> (different/other source?) |
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==History== |
==History== |
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The term "zeitgeber" was first used by [http://en.wikipedia.org/wiki/Jürgen_Aschoff Jürgen Aschoff], who was one of the founders of the field of [http://en.wikipedia.org/wiki/Chronobiology chronobiology]. His work demonstrated the existence of endogenous |
The term "zeitgeber" was first used by [http://en.wikipedia.org/wiki/Jürgen_Aschoff Jürgen Aschoff], who was one of the founders of the field of [http://en.wikipedia.org/wiki/Chronobiology chronobiology]. His work demonstrated the existence of [http://en.wikipedia.org/wiki/Endogeny endogenous] (internal) biological clocks, which synchronize biological rhythms. In addition, he found that certain [http://en.wikipedia.org/wiki/Exogenous exogenous] (external) cues, which he called zeitgebers, also influence the timing of these internal clocks. '''This section makes it seem like you are discounting the importance of zeitgebers before you even really describe them''' |
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==Examples of zeitgebers== |
==Examples of zeitgebers== |
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===Zeitgebers and mood disorders=== |
===Zeitgebers and mood disorders=== |
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Recent studies have also found a connection between the disruption of social rhythms and the triggering of [http://en.wikipedia.org/wiki/Mania manic episodes] in [http://en.wikipedia.org/wiki/Bipolar_disorder bipolar disorder].<ref>Malkoff-Schwartz, S., Frank, E., Anderson, B. P, Hlastala, S. A., Luther, J. F., Sherril, J. T., et al. (2000). Social rhythm disruption and stressful life events in the onset of bipolar and unipolar episodes. ''Psychological Medicine, 30'', 1005−1016.</ref> |
Recent studies have also found a connection between the disruption of social rhythms and the triggering of [http://en.wikipedia.org/wiki/Mania manic episodes] in [http://en.wikipedia.org/wiki/Bipolar_disorder bipolar disorder].<ref>Malkoff-Schwartz, S., Frank, E., Anderson, B. P, Hlastala, S. A., Luther, J. F., Sherril, J. T., et al. (2000). Social rhythm disruption and stressful life events in the onset of bipolar and unipolar episodes. ''Psychological Medicine, 30'', 1005−1016.</ref> However, differentiating between zeitgeber disturbances that lead to depression and those that lead to manic episodes has proven difficult. |
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===Seasonal Affective Disorder=== |
===Seasonal Affective Disorder=== |
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Revision as of 19:25, 6 March 2013
A zeitgeber (German for "time giver" or "synchronizer") is any external cue in the environment that sets or synchronizes an organism's biological rhythms with the body's circadian clock.[1] (different/other source?)
History
The term "zeitgeber" was first used by Jürgen Aschoff, who was one of the founders of the field of chronobiology. His work demonstrated the existence of endogenous (internal) biological clocks, which synchronize biological rhythms. In addition, he found that certain exogenous (external) cues, which he called zeitgebers, also influence the timing of these internal clocks. This section makes it seem like you are discounting the importance of zeitgebers before you even really describe them
Examples of zeitgebers
- Light
- Temperature
- Social interactions
- Pharmacological manipulation
- Exercise
- Eating/drinking patterns
How do zeitgebers work?
Biological rhythms, including cycles related to sleep and wakefulness, mood, and cognitive performance, are synchronized with the body's internal circadian clock.[2] The best way to observe the workings of this clock is to experimentally deprive individuals of external cues like light and social interaction and allow the body to experience a "free-running" environment - that is, one in which there are no zeitgebers to influence the body's rhythms.[2] Under these circumstances, the circadian clock alone modulates the body's biological rhythms. [2] Normally however, external cues like light-dark cycles and social interactions also exert an influence on the body's rhythms. These zeitgebers can alert individuals to changes in the likelihood of possible rewards or threats in the environment. For example, humans are more likely to find food and shelter in the daytime and less likely to detect predators in the nighttime, meaning wakefulness tends to be most fruitful during the day and sleep is the safest activity for the nighttime.[3] Therefore, changes in light and darkness influence the body to rise during the day and become fatigued at night.
Social zeitgebers
There are many different kinds of zeitgebers, which can have differential effects on the body depending on varying circumstances. For example, the work of Jürgen Aschoff showed that individuals can compensate for the absence of some zeitgebers like natural light by attending to social zeitgebers instead; specifically, individuals placed in total darkness for four days did not differ In what way did they not differ? What functions did they look at? in functioning from individuals placed in an artificial light-dark environment when both groups were given the same strict time schedule.[4] Meal times and interactions with other people can exert influences on biological rhythms that are similar to those of light. just a little confused by this last sentence
Zeitgebers in psychology
The 24-hour circadian clock also influences cognitive performance.[2] Is there a way you can include how it influences cognitive performance? As a result, disturbances in this clock, like working a night shift or experiencing jetlag, can negatively impact memory and emotions as well as sleep and alertness.[2] Therefore, the disturbance of biological rhythms by zeitgebers is theorized to increase risk for some forms of psychopathology.
Some researchers have suggested that the disturbances in biological rhythms present in depressed individuals may actually be the result of previous disruptions in social interactions, which serve as cues for those rhythms.[1] For example, newly married or cohabiting couples often need to adjust to each other's sleeping rhythms when beginning to share the same bed for the first time. This adjustment can be difficult and may lead to disruptions in sleep quality and quantity, and possibly increase risk for depression as a result.
Zeitgebers and mood disorders
Recent studies have also found a connection between the disruption of social rhythms and the triggering of manic episodes in bipolar disorder.[5] However, differentiating between zeitgeber disturbances that lead to depression and those that lead to manic episodes has proven difficult.
Seasonal Affective Disorder
Seasonal affective disorder is hypothesized to occur as a result of deficiencies in zeitgebers (such as light) that stimulate the reward activation system, resulting in a depressed mood. (citation?) Because circadian clocks synchronize human sleep-wake cycles to coincide with periods of the day during which reward potential is highest - that is, during the daytime[3] - and recent studies have determined that daily rhythms in reward activation in humans are modulated by circadian clocks as well,[3] external influences on those rhythms may influence an individual's mood.
References
- ^ a b Ehlers, C.L., Frank, E. & Kupfer, D.J. (1988). Social zeitgebers and biological rhythms. Arch Gen Psychiatry, 45, 948-952.
- ^ a b c d e Kyriacou, C.P. & Hastings, M.H. (2010). Circadian clocks: Genes, sleep, and cognition. Trends in Cognitive Science, 14, 259-267
- ^ a b c Murray, G., Nicholas, C.L., Kleiman, J., Dwyer, R., Carrington, M.J., Allen, N.B., & Trinder, J. (2009). Nature’s Clocks and Human Mood: The Circadian System Modulates Reward Motivation. Emotion, 9, 5, 705–716.
- ^ Aschoff, J. et al. (January 1971). "Circadian Rhythms in Continuous Darkness: Entrainment by Social Cues". Science 171 (3967): 213–215.
- ^ Malkoff-Schwartz, S., Frank, E., Anderson, B. P, Hlastala, S. A., Luther, J. F., Sherril, J. T., et al. (2000). Social rhythm disruption and stressful life events in the onset of bipolar and unipolar episodes. Psychological Medicine, 30, 1005−1016.