A Swiss study shows that conditioning can also be done without a brain

Even animals without brains can be conditioned. This is confirmed by a new study from the University of Freiburg in the journal “Pnas”. To do this, a research team taught a mindless sea anemone to modify its behavior based on past experiences.

The sea anemone Nematostella vectensis therefore has a simple form of memory, the University of Freiburg writes in a statement on Tuesday.

The researchers did experiments on the animals with stimuli consisting of light and electric current. Some sea anemones were exposed to light and current at the same time, while others had their pulses staggered so that no correlation could be established between the two stimuli.

And indeed, the animals responded to the training. Over time, the anemones in which the two pulses were used simultaneously contracted their bodies from the mere use of the light pulse. They had learned that the appearance of light is accompanied by an electrical stimulus – classical conditioning.

It is not clear from the research how exactly the animals can be conditioned without brains. “Very little is known about how learning is organized in animals with apparently simple neural networks. We assume that certain synapses are also strengthened in them,” said study leader Simon Sprecher in a statement from the university.

According to Sprecher, the findings also raise the question of how and when learning arose during evolution. “The first ancestors of all animals with brains lived about 560 million years ago. Those with a nerve network already existed 100 to 150 million years earlier,” Sprecher said. Perhaps animals that can learn have been around longer than previously thought.

(sda)