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flower clock

Die BlumenUhr

Linnaeus' flower clock (1751)


Andrew Marvell, in his poem "The Garden" (1678): How well the skilful gardener drew of flow'rs and herbs this dial new; where from above the milder sun does through a fragrant zodiac run; and, as it works, th' industrious bee computes its time as well as we. How could such sweet and wholesome hours be reckoned but with herbs and flow'rs!




Chronobiology or biological timing refers to "the process by which organisms time physiolgy and behavior, so that everything takes place in a rhythmic fashion" Amita Sehgal 


Life on earth evolved under conditions ruled by cycles, and consequently, rhythmicity became an integral component of all forms of life on earth. In fact, every organism, unicellular or multicellular, plant or animal is composed of molecular clocks or "Biological Clocks".


I am a Chronobiologist by training, fascinated by biological clocks and the rhythms they so elegantly generate, drive and maintain. Endogenous clocks regulate all aspects of physiology and behavior and thus, represent a vital component of life. The evolution of time keeping systems is directly linked to the survival of any organism and represents an adaptation that defines the essence of "PLASTICITY". Unfortunately, the advancement of technology and modern life style force us to fight our clock on a daily basis! Is it not astonishing how we as human create our diseases and contribute to our own destruction? 


My mission in this life and hence, the focus of my research is dedicated to the understanding of the interactions and mode of communication between the circadian system and physiological processes that eventually determine behaviour. WHY? The illumination of such interconnections is essential to target specifically and hence efficiently, diseases that originate from our self-destructive behavior directed towards our inner clocks primarily and consequently all downstream coupled physiology.  



disrupted clock

They who dream by day are cognizant of many things which escape those who dream only by night.

Edgar Allan Poe


Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.



cover page of Science  16 Nov 2007: Vol. 318, Issue 5853, pp. 1144-1146

I have always been intrigueed and fascinated by the importance of the biological time-keeping system in regulating processes as complex and important as learning and memory. We often refer to memories as a defining factor for who we are, similar to a passport or fingerprint "we are our memories". The efficiency by which we aqcuire new information (learning) and form memories is dependent on temporal factors imposed on those anatomical structures involved in memory processing by our inner time-keeping system. This phenomenon has deep fundamental evolutionary roots since the circadian modulation of learning and memory is conserved across species as we and others have demonstrated. My research focuses on identifying the biological clocks and pacemakers that regulate hippocampus-dependent learning and memory processes and deciphering the means of communication between the clock and the limbic system (an anatomical structure related to information and emotion processing and storrage). Thus, the memories that shape our behavior are restricted to information we efficiently aquire, which is dependent on the time-of-day when the processing of the information takes place. 

Melatonin Suppresses Nighttime Memory Formation in Zebrafish

Oliver Rawashdeh, Nancy Hernandez de Borsetti, Gregg Roman*, Gregory M. Cahill

Department of Biology and Biochemistry, University of Houston, 369 Science and Research II, Houston, TX 77204–5001, USA.



Fighting the Clock "MAN made DISEASE"


Naturally, our clocks are in synchrony with the environment we live in, however, this has changed for the worse with the progress of technology and our ever rapidly accelerating modern lifestyle which, nothing less than, forces us to fight our clock on a daily basis. We argue that the complexity and sophistication of modern life style suggests that humans evolved to become resistant to the influences by daily cycles. Basically, we can control the darkness of the night by simply operating an electric switch. Women that take birth control pills enforce a self-made ‘convenient’ and controlled monthly cycle over their natural menstrual rhythm. Our climate-controlled infrastructures protect us from the extremes and unpredictability of seasonal weather. Such interventions only make us believe that we are architects rather than slaves of our cycling environment. In fact the consequences of such actions on our health are enormous considering that the circadian system with its autonomous and slave oscillators is an integral component of almost every cell in our bodies. Hence, factors that target our clocks will influence and interfere with the proper functioning of cells, tissues, organs, systems and eventually reflect on behavior.




Instead of ignoring or fighting daily cycles in physiology we should use them to our advantage. Exercise is most likely beneficial when your heart and lungs are strongest, and your metabolic rate is highest. Taking medicines at specific times of the body’s circadian cycle naturally enhances their effectiveness and efficiency. Resting when we experience an energy plunge rather than meeting it with stimulants like coffee can naturally boost productivity and mental state. Remaining awake when we should be sleeping and resting when we should be awake it is not surprising that we have developed the symptoms indicative of a system out of sync. Apathy and lethargy are the most typical signs, but digestive problems, headaches, depression, poor memory and lack of coordination are common.




Humans are under the mercy of rapidly changing technological advancements and an ever accelerating socio-economic life-style. Unfortunately, our bodies are not designed to function in a manner that would allow us to meet these demands, simply because evolution is lagging behind! Since we are less likely to change the directionality of modern-life style and its demands, we ought to invest in the science that aims to develop strategies that to adapt to rapid environmental changes without sacrificing physiological integrity. Understanding the fundamentals of how the circadian system interacts to modulate physiology, particularly memory processing, is the first step towards this greater initiative.


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