Skip to ContentSkip to Navigation
About usNews and EventsNews articles

Mammalian mechanism of time-place learning clarified

30 May 2008

We are all aware of the places you can better avoid in the dead of night. And we all know that the freshest, tastiest food can be bought at the open-air market early in the morning. In the animal kingdom, too, it is of the utmost importance to circumvent certain places at certain times (due to predators) and to visit others at other times (due to the availability of food). Until recently, the exact way in which mammals established this link between time and place remained a mystery. However, researchers at the University of Groningen have finally unravelled the secret. Their findings will be published in Current Biology on 3 June 2008.

The researchers began by observing how mice in the lab could be taught to connect time and place – the so-called ‘time-place learning’. Prof. Menno Gerkema, the last author of the article, explains that an attempt was made to emulate natural circumstances as much as possible. ‘Animals always have to weigh up the situation when gathering food. To them, food is never free. A mouse can always be seized by predators. We tried to incorporate that risk in our experiment.’  

Time-place learning

The researchers used a construction with three passages through which the mice could run. At the end of each passage, the mice could find food behind a platform. Depending on the time of day, however, an electric shock was applied through the platform. It soon became evident that the mice were perfectly capable of finding those places where food was freely available at certain times and of avoiding certain places where food could only be obtained at the cost of incurring an unpleasant shock. This finding was extraordinary in itself because, up to the present, no method of studying time-place learning in mammals had been constructed.  

Biological clock

But what kind of mechanism do the mice use in this time-place learning? The researchers suspected that the mice made use of their biological clock, just as birds and bees do in time-place learning. To test this hypothesis, use was made of genetically modified mice that lack certain genes (called ‘Cry1’ and ‘Cry2’) so that they had to work without a biological clock. These mice turned out to be incapable of obtaining food in the passages at the appropriate moments. With this finding, the researchers have finally been able to ascertain that mammals make use of the biological clock in time-place learning.

Humans

People also learn to connect time and place. ‘A subconscious link between time and place is established in a great number of learning processes. If, for example, you cannot recall something, it helps to revisit the spot where the idea that you want to remember originated. The forming of associations between place and time helps us structure our memory.’ Gerkema surmises that time-place learning occurs in much the same way in humans as it does in mice, because both have roughly the same biological clock system.

Alzheimer’s disease

The researchers, Menno Gerkema and Eddy van der Zee, now wish to investigate how time-place learning changes as people grow older. Gerkema: ‘In humans, you see that the ability to connect time and place declines as one grows older. Some patients with Alzheimer’s disease completely lose their notion of time at a certain moment. This is a dramatic development, in view of the fact that they do not recognize the difference between day and night. That is why round-the-clock care is necessary and the patient usually has to be hospitalized.’ Insight into time-place learning may help in postponing this moment as long as possible.  

Curriculum vitae

Menno Gerkema (1949) is a professor at the University of Groningen. He has a dual chair in Chronobiology and Behaviour and Science in Policy and Management. The time-place memory study is a co-operative project with the department of Molecular Neurobiology (Prof. Eddy van der Zee) of the University of Groningen and the Erasmus University Rotterdam. Gerkema was previously associated to the Max Planck Institut für Verhaltensphysiologie in Andechs, Germany, and the University of Yokohama in Japan. Recent chronobiological research has taken place in conjunction with the universities of Tromsø, Geneva and Western Australia.  

More information

- Prof. Dr Menno Gerkema, tel. +31 (0)50-363 2027 (work),

e-mail: m.p.gerkema@rug.nl

Last modified:30 November 2017 4.04 p.m.

More news

  • 17 April 2019

    Why lightning often strikes twice

    In contrast to popular belief, lightning often does strike twice, but the reason why a lightning channel is ‘reused’ has remained a mystery. Now, an international research team led by the University of Groningen has used the LOFAR radio telescope to...

  • 16 April 2019

    Still going strong after four decades

    On March 29th professor of Applied Physics Jeff de Hosson was offered a farewell symposium, a few months after his official retirement date near the close of 2018. ‘But 29 March was the 100th birthday of Jan Francken, my predecessor.’ Besides, De Hosson...

  • 11 April 2019

    Ben Feringa in orbit around the Sun

    Dozens of minor planets that used to orbit the Sun anonymously were named by the International Astronomical Union on 6 April 2019. The asteroid that used to be known as ‘minor planet 12655’ was named after Prof. Ben Feringa, winner of the 2016 Nobel...