Constant learning is part of our lives. If we are unable to store and retrieve experience, we will hardly be able to cope with the demands of everyday life. An important issue in the understanding of memory weakness is: Where do learning processes take place in the brain and how do brain cells communicate with each other?
Aided by so-called functional magnetic resonance tomography (fMRT), scientists from the Geronto-Psychiatric Department of the University of Heidelberg's Psychiatric Hospital working under the leadership of Professor Dr. Johannes Schröder and in collaboration with the German Cancer Research Centre (privatdozent Dr. Marco Essig) have succeeded for the first time in tracing the brain activities that set in after four weeks of learning. The brain accustoms itself to the training process. Initially increased activity in the nerve cells levels out as intellectual performance is stepped up. The results of the study will be published in the American Journal of Psychiatry on 2 April 2004.
Functional magnetic resonance tomography opens up a window on the brain
The scientists' dream of being able to observe the human brain in action finally came true in the 1990s. So-called functional magnetic resonance tomography (fMRT) makes it possible to measure and visualise processes in the brain without the administration of radio-active substances. The oxygen content of the blood is measured in different regions of the brain and the oxygen consumption in activated regions is visualised. One of the things fMRT can do is to identify which regions of the brain are responsible for certain movements, perceptions or thought processes.
Nine healthy young right-handed male university graduates took part in the Heidelberg study. The brain training they underwent took the form of three problems of increasing difficulty set them twice a day. They were asked to identify and memorise figures in an experimental field. The processes going on in the brain were measured by fMRT in three stages: before study commencement, after two weeks and at the end of the four weeks of training.
The brain accustoms itself to repeated memory training
The learning process activates two main areas of the brain, the gyrus frontalis inferior in the frontal lobe and the right intraparietal sulcus in the temporal lobe. After two weeks of training the memory function improved noticeably, an effect that was still present at the end of the four-week training stint. Intellectual effort initially caused increased brain activity in the frontal and temporal lobes, but after four weeks it returned to its original level.
"As the learning success was consolidated, the activation of these brain areas receded again," explains Professor Schröder. The performance of the probands had improved and it remained stable after the reduction of activation. "The initial learning effort was followed by consolidation and an economisation of brain power."
A better understanding of functional losses following brain damage
This analysis is significant for the treatment of patients with brain damage. Functional deficits may be compensated for by other areas of the brain. "So we need to know which areas of the brain are active in different learning processes," says Professor Schröder, "and what those processes actually involve." The hope is that the fMRT method can be used to gain insight into diseases like Alzheimer or Parkinson and turn those insights to account for early diagnosis and to speed up treatment for patients.
"It may be that the activation patterns we have detected play a role in other areas of the brain and in specific tasks," says Professor Schröder. There are also plans to determine whether learning processes are dependent on age and what influence gender and education have on learning.
Prof. Dr. Johannes Schröder
Department of Geronto-Psychiatry
University of Heidelberg Psychiatric Hospital
phone: 06221/565468 (Frau Woelk, secretary)
Albrecht Hempel, Frederik L. Geisel, Nohazarahit M. Garcia Caraballo, Michael Amann, Heiko Meyer, Torsten Wüstenberg, Marco Essig, and Johannes Schröder: Plasticity of Cortical Activation Related to Working Memory During Training. Am J Psychiatry 2004 161: 745-747.
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