2012 / Authors: Špela Petrič andMaja Smrekar / Collaborators: Miha Tomšič (programming and hardware), Andrej Strehovec (design) / Acknowledgments: Marko Živin, Gregor Majdič, Irena Furlan, Joško Račnik / The project is supported by the Ministry of Culture of the Republic of Slovenia and the Municipality of Ljubljana Department for Culture / The project is part of the KiiCS - Knowledge Incubation in Innovation and Creation for Science programme, supported by a grant from European Comission, 7th Framework Programme
Produced by Kapelica Gallery
Circadian rhythms (from Latin “circa dies” = approximately one day) are present in almost all living organisms and are a product of evolutional development as an adjustment to Earth’s revolution around its axis. They are driven by internal molecular clocks that are synchronised with the environment by external factors, most significantly, by sunlight. The digitalisation of communication environment, lack of daylight and the subsequently fast change of the spatial perception are altering the sensibility of human organism. The phenomenon of fast paced living joined within the surveillance of daily activities, influences integration of human bodies in the key systems of production, which is an imperative dynamics of the survival of capitalism. By acting within these social structures, humans generate novel ecological niches and modify the selective pressures, which are slowly followed by our biological adjustments. The paradigm of molecular biopolitics in this project paraphrases the process of social mutation of an individual into a biomedical self through the ontology of life in co-dependence of health dynamics and productivity. The current dis-synchronicity between evolutionary new – high productivity oriented forms of action and circadian rhythms (which are our evolutionary adaptation to day and night) is a contributing factor to the increase in modern diseases, such as depression, diabetes, cancer and cardiovascular diseases. The bioart project Circadian Drift is an interactive installation, which reflects the human’s circadian rhythm thus paraphrasing the lack of synchronicity between the natural and sovereign body in the dynamics of modern society. A rat, a species that has similar mechanisms of managing circadian rhythms as humans, is, through sensors, telematically exposed to identical lighting conditions as the human volunteer. After several days, the rhythms of both species synchronize and the rat, which is not conditioned by our human culture, serves as the bioindicator of our natural rhythm of activity.
Biological rhythms are an important evolutionary development as they help organisms adapt to periodically changing environmental conditions. We can divide them into two groups: internal and external. External rhythms are a direct result of environmtental activities while internal rhythms follow our internal biological clock. Internal rhythms can be maintained even after we remove all external stimulation. The biological rhythms of an organism or cells can have a frequency ranging from years to miliseconds. The rhythms that oscillate every 24 hours are called circadian rhythms. Ther most commonly known circadian rhythms in humans are the sleep/wake rhythm and the body temperature rhythm, but so far more than 100 biological processes have been shown to follow circadian periodicity. The rhythms of human activity and sleep/wake cycle generally coincide with biological clocks. If desynchronization occurs, the readiness to work or sleep are affected the most. The latter may occur during night shifts, going rapidly through multiple time zones (travelling by plane) or, as it is the case with older people, it may be a consequence of hormonal imbalance. PROPERTIES OF CIRCADIAN RHYTHMS: Circadian rhythms are innate to the human body and as such, genetically predetermined. The rhythm is run by an inner clock with a pacemaker in the suprachiasmatic nucleus. Alongside this pacemaker mammals also have peripheral oscillators in other organs (the heart, liver, kidney, intestines, stomach, muscles), but the suprachiasmic nucleus is superior to the others. Even though the circadian rhythm is internal, the biological clock is subject to the influence of daily changes in lighting conditions. The changes of physiological variables can be used in tracking different phases of circadian rhythms. It has been established that a strong light at the beginning of the biological night causes a delay of the system regulating circadian rhythms, while on a contrary a bright light in a late stage of the biological night causes the system to rush ahead.
Water and food are available to the rats at all times, but the lighting conditions vary according to the intensity of the light source to which the human volunteer is exposed. The light sensor (photodiode) worn on the volunteer’s arm sends the light intensity readings to a smartphone via Arduino microcontroller and Bluetooth. The smartphone with a specifically constructed software then sends these values to the internet and to the computer in the gallery every ten minutes. The software calculates the mean values every 2 hours in a 24-hour period (12 values) and then assigns them in one of 10 logaritmic classes of light intensity and compares them to the threshold value. The threshold value is set according to the data acquired in the literature as the minimal light intensity necessary for the “day” signal to be transmitted through special photoreceptors in the eyes to the suprachiasmatic nucleus (in the hipotalamus), which is the main synchronizer of various body tissue’s clocks (liver, glands, other parts of the brain…). The lighting of the living unit is then synchronized via the microcontroller with the light intensity that our volunteer is exposed to; the analogue illumination of the sensor is thus translated to efective night (“night”) and efective day (“day”), key parameters for our inner biological clock. The “day” in the labyrinth is created by intense LEDs and “night” is mimicked by the low-frequency red light which does not effect the activity of the rat’s suprachiasmatic nucleus, allowing us to observe their behaviour. After several days of coordinated exposure, the circadian rhythms of rats and the human are synchronized. As rats are nocturnal animals their activity cycle is shifted for 12 hours in respect to human activity. The impact of ligting conditions, which humans are exposed to in contemporary society is observed by rat activity and ultrasound vocalizations. The rats’ activity is measured by three beams of infrared light which are disturbed by the movement of the rats. Two ultrasound microphones are also installed. The first one records sound at 22kHz and the second one at 50 kHz. The sounds that the rats make expresses their comfort (45 – 55 kHz) or distress (22 kHz). By recording the sound in these frequency ranges we can estimate the well-being of the animals and at the same time create an unique sound environment.