Skip to main content
< Back to news
From left to right: IRB researchers Valentina Maria Zinna, Salvador Aznar Benitah, Patrick Welz and Inés Marín Guillén (Photo: IRB Barcelona).

The body responds to variations in light between the day and night independently of the brain

Scientists at the Institute for Research in Biomedicine (IRB Barcelona) at PCB have revealed that although each tissue receives information from the central clock in order to coordinate its functions, each one also has the capacity to respond independently to variations in light and to detect changes in light intensity between the day and night. Published in two papers in the journal Cell, the studies confirm that this autonomy allows tissues to maintain minimal functions even when another tissue in our body is failing.


During the day, we experience a series of physical, mental and behavioural changes know as circadian rhythms. These changes are governed by a central clock, located in the hypothalamus, which lies in the centre of the brain. This clock is responsible for synchronizing our tissues to ensure that their functions are coordinated and that they work with the same clock.

Until now, there was no suitable animal model in which to test whether the clock regulating all our organs and tissues is coordinated by the brain or, as has been observed, whether these organs and tissue are capable of responding directly to the cyclic environmental changes that occur every day. Now, this research, 

The studies, published in two papers in the journal Cell (DOI: 10.1016/j.cell.2019.05.009) (DOI: 10.1016/j.cell.2019.04.025, by researchers from Stem Cells and Cancer Laboratory headed by Salvador Aznar Benitah at IRB Barcelona, in collaboration with Paolo Sassone-Corsi’s team at the University of California, Irvine (US), confirm that this autonomy allows tissues to maintain minimal functions even when another tissue in our body is failing. 

As already mentioned, although each tissue is autonomous, this does not imply the absence of communication with the rest of the body. “We confirmed that the central clock communicates from the brain with the rest of the body, providing useful information to ensure its correct function, informing, for example, the gastrointestinal tract, liver and pancreas that it is time to eat and allowing them to prepare for digestion. But when this communication fails, each organ is able to know what time it is and thus to perform their basic functions,”explains ICREA researcher Salvador Aznar Benitah.

These studies are likely to be particularly relevant during aging and in diseases in which high tissue interdependence would lead to a general deterioration of the organism,” says Aznar Benitah. “Our results have important implications for health,” he adds. 

Our current lifestyle exposes us to light when we should be in darkness. Given that each organ is able to respond independently to light, body functions that should occur during the day take place at night. This daily phase difference or social jet-lag might be responsible for premature aging and the development of certain pathologies. 

► For further infomation: IRB Barcelona website [+]