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Zeitgeber
A zeitgeber ( , ) is any external or environmental cue that entrains or synchronizes an organism's biological rhythms, usually naturally occurring and serving to entrain to the Earth's 24-hour light/dark and 12-month cycles. History The term ' () was first used by Jürgen Aschoff, 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 zeitgeber, influence the timing of these internal clocks. Photic and nonphotic zeitgebers * Light (light is the most potent regulator of circadian rhythms). * Atmospheric conditions * Medication * Temperature * Social interactions * Exercise * Eating/drinking patterns Circadian rhythms Any biological process in the body that repeats itself over a period of approximately 24 hours and maintains this rhythm in the absence of external stimuli is considered a circ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the environment (is Entrainment (chronobiology), entrained by the environment). Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life. The term ''circadian'' comes from the Latin ', meaning "around", and ', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jetlag
Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones (east–west or west–east). For example, someone travelling from New York to London, i.e. from west to east, feels as if the time were five hours ''earlier'' than local time, and someone travelling from London to New York, i.e. from east to west, feels as if the time were five hours ''later'' than local time. The phase shift when travelling from east to west is referred to as ''phase-delay'' of the circadian cycle, whereas going west to east is ''phase-advance'' of the cycle. Most travellers find that it is harder to adjust time zones when travelling east. Jet lag is caused by a misalignment between the internal circadian clock and the external environment, and it has been classified within the category of a circadian rhythm sleep-wake disorder, reflecting its basis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interpersonal And Social Rhythm Therapy
Interpersonal and social rhythm therapy (IPSRT) is an intervention for people with bipolar disorder (BD). Its primary focus is stabilizing the circadian rhythm disruptions that are common among people with bipolar disorder (BD). IPSRT draws upon principles from interpersonal psychotherapy, an evidence-based treatment for depression and emphasizes the importance of daily routine (rhythm). IPSRT was developed by Ellen Frank, PhD at the University of Pittsburgh who published a book on her theories: ''Treating Bipolar Disorder, a Clinician's Guide to Interpersonal and Social Rhythm Therapy''. Her research on IPSRT has shown that, in combination with medication, solving interpersonal problems and maintaining regular daily rhythms of sleeping, waking, eating, and exercise can increase quality of life, reduce mood symptoms, and help prevent relapse in people with BD. __TOC__ Social Zeitgeber Hypothesis ''Zeitgebers'' (“time givers”) are environmental cues that synchronize biologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jürgen Aschoff
Jürgen Walther Ludwig Aschoff (January 25, 1913 – October 12, 1998) was a German physician, biologist and behavioral physiologist. Together with Erwin Bünning and Colin Pittendrigh, he is considered to be a co-founder of the field of chronobiology. Aschoff's work in the field of chronobiology introduced ideas of light interactions in the circadian rhythms of nocturnal and diurnal species as summarized by Aschoff's Rules. Life Aschoff was born in Freiburg Im Breisgau, the fifth child of pathologist Ludwig Aschoff (known for discovering the Aschoff-Tawara or atrioventricular node) and his wife Clara. He grew up in the liberal but morally strict world of Prussian academia. After the Abitur at a humanistic high school, he – according to his own statement "lacking a specific interest" – studied medicine at the University of Bonn, where he joined the Burschenschaft (fraternity) Alemannia Bonn. Aschoff's scientific career began in 1938, when he moved to the University of Göttin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entrainment (chronobiology)
In the study of chronobiology, entrainment refers to the synchronization of a biological clock to an environmental cycle. An example is the interaction between circadian rhythms and environmental cues, such as light and temperature. Entrainment helps organisms adapt their bodily processes according to the timing of a changing environment. For example, entrainment is manifested during travel between time zones, hence why humans experience jet lag. Biological rhythms are endogenous; they persist even in the absence of environmental cues as they are driven by an internal mechanism, most notably the circadian clock. Of the several possible cues (known as '' zeitgebers,'' German for 'time-givers') that can contribute to entrainment of the circadian clock, light has the greatest impact. Units of circadian time (CT) are used to describe entrainment to refer to the relationship between the rhythm and the light signal/pulse. Modes of entrainment There are two general modes of entrainm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Therapy
Light therapy, also called phototherapy or bright light therapy is the exposure to direct sunlight or artificial light at controlled wavelengths in order to treat a variety of medical disorders, including seasonal affective disorder (SAD), circadian rhythm sleep-wake disorders, cancers, neonatal jaundice, and skin wound infections. Treating skin conditions such as neurodermatitis, psoriasis, acne vulgaris, and eczema with ultraviolet light is called ultraviolet light therapy. Medical uses Nutrient deficiency Vitamin D deficiency Exposure to UV-B light at wavelengths of 290-300 nanometers enables the body to produce vitamin D3 to treat vitamin D3 deficiency. Skin conditions Light therapy treatments for the skin usually involve exposure to ultraviolet light. The exposures can be to a small area of the skin or over the whole body surface, as in a tanning bed. The most common treatment is with narrowband UVB, which has a wavelength of approximately 311–313 nan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Response Curve
A phase response curve (PRC) illustrates the transient change (phase response) in the cycle period of an oscillation induced by a perturbation as a function of the phase at which it is received. PRCs are used in various fields; examples of biological oscillations are the heartbeat, circadian rhythms, and the regular, repetitive firing observed in some neurons in the absence of noise. In circadian rhythms In humans and animals, there is a regulatory system that governs the phase relationship of an organism's internal circadian clock to a regular periodicity in the external environment (usually governed by the solar day). In most organisms, a stable phase relationship is desired, though in some cases the desired phase will vary by season, especially among mammals with seasonal mating habits. In circadian rhythm research, a PRC illustrates the relationship between a chronobiotic's time of administration (relative to the internal circadian clock) and the magnitude of the treatment' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infradian Rhythm
In chronobiology, an infradian rhythm is a rhythm with a period longer than the period of a circadian rhythm, i.e., one cycle is longer than 24 hours. Some examples of infradian rhythms in mammals include menstruation, breeding, migration, hibernation, molting and fur or hair growth, and tidal or seasonal rhythms. In contrast, ultradian rhythms have periods shorter (<24 hours) than the period of a circadian rhythm. Several infradian rhythms are known to be caused by hormone or neurotransmitter stimulation or by environmental factors such as the lunar cycles. For example, seasonal depression, an example of an infradian rhythm occurring once a year, can be caused by the systematic lowering of light levels during the winter. The can be classified as infradian, or as circannual, which means occurring on a yea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seasonal Affective Disorder
Seasonal affective disorder (SAD) is a mood disorder subset in which people who typically have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year. It is commonly, but not always, associated with the reductions or increases in total daily sunlight hours that occur during the winter or summer. Common symptoms include sleeping too much, having little to no energy, and overeating. The condition in the summer can include heightened anxiety.Seasonal affective disorder (SAD): Symptoms MayoClinic.com (September 22, 2011). Retrieved on March 24, 2013. However, there are significant differences in the duration, severity, and symptoms of each individual's experience of SAD. For instance, in a fifth of patients, the disor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipolar Disorder
Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in some cases months. If the elevated mood is severe or associated with psychosis, it is called ''mania''; if it is less severe and does not significantly affect functioning, it is called ''hypomania''. During mania, an individual behaves or feels abnormally energetic, happy, or irritable, and they often make impulsive decisions with little regard for the consequences. There is usually, but not always, a Sleep deprivation, reduced need for sleep during manic phases. During periods of depression, the individual may experience crying, have a negative outlook on life, and demonstrate poor eye contact with others. The risk of suicide is high. Over a period of 20 years, 6% of those with bipolar disorder died by suicide, with about one-third Suicide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depression (mood)
Depression is a mental state of low Mood (psychology), mood and aversion to activity. It affects about 3.5% of the global population, or about 280 million people worldwide, as of 2020. Depression affects a person's thoughts, behavior, feelings, and subjective well-being, sense of well-being. The pleasure or joy that a person gets from certain experiences is reduced, and the afflicted person often experiences a loss of motivation or interest in those activities. People with depression may experience sadness, feelings of dejection or hopelessness, difficulty in thinking and concentration, or a significant change in appetite or time spent sleeping; Suicidal ideation, suicidal thoughts can also be experienced. Depression can have multiple, sometimes overlapping, origins. Depression can be a symptom of some mood disorders, some of which are also commonly called ''depression'', such as major depressive disorder, bipolar disorder and dysthymia. Additionally, depression can be a norm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
