Nature 457, 147 (8 January 2009) | doi:10.1038/457147a; Published online 7 January 2009

Replacement of animals in research will never be possible

See associated Correspondence: Crum, Nature 457, 657 (February 2009)

Roberto Caminiti1

  1. Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy


Your Editorial 'Call to action' (Nature 456, 281–282;2008), concerning the draft of the new European directive on the use of animals in scientific research, correctly points out the risk of severely limiting the use of non-human primates in invasive studies of brain function. Performing such experiments requires humane treatment of animals and painless experimental procedures. This 'refinement' of procedure is the first of the 3Rs, the philosophy underlying the European Union (EU) directive. During the past 20 years, technical improvements have significantly reduced both the time and the number of animals used in a project, while increasing the data yield. Thus, the second of the 3Rs, 'reduction', is already firmly established.

What needs to be clearly appreciated is that 'replacement' (the third R) of this type of research will never be possible. The current draft of the EU directive, in confining the use of non-human primates as far as possible to projects aimed at understanding life-threatening diseases, takes a direction that is both incorrect and illusory, towards a future ban that it considers desirable. As stated in your Editorial, this is a real threat. We must combat it with strength and without compromise. A ban could be justified only if and when all brain function is understood, and if no further challenge is posed to neuroscience by the evolution of modern societies and their pathologies. Obviously, neither of these conditions will ever be realized.

From my privileged observatory as chair of the Programme of European Neuroscience Schools (, I can testify to the increasing interest among the younger generation in the integrative study of brain function. At the same time, I stress the dramatic negative consequences that a severe limitation or ban on the use of non-human primates will have on education, in a discipline that currently places Europe at the forefront of modern research in neuroscience.

Behavioural studies have the power to shed light on some of the most common neurological syndromes that affect our societies. They have already provided encouraging first answers about Parkinson's disease and the principles underlying neural prosthetics and brain–machine interface devices, among other examples. The enforced abandonment of research on great apes has phased out experimental studies on, for example, brain evolution, malaria, hepatitis C and respiratory syncytial virus infection. Prohibiting studies on primates will confine Europe to the periphery of the neuroscience and biomedical arena, with negative consequences for the quality of life of future generations.

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