Structure and Function of Natural Neural Networks

Prof. Dr. Dr. h.c. Valentin Braitenberg

The research in this department was based on the combination of neuroanatomy and neurophysiology with brain theory, with the aim to understand mechanisms of brain functions. Main fields of research were the visual system of the fly, cerebellum and the physiology of movement, and structure and function of the cerebral cortex. Some topics on the cerebral cortex were: quantitative-anatomical studies on connectivity, orientation specificity in the visual cortex of primates, as well as a neurological theory of language.

In memoriam Valentin Braitenberg (1926-2011)

Valentino Braitenberg, former director at the Max Planck Institute for Biological Cybernetics, died in Tübingen on 9th September 2011 at the age of 85. His life's work and his remarkable personality are inextricably linked and will have a long-lasting impact.

I would like to begin by quoting his very own description of the science to which he dedicated his research on neuroanatomy:

“When a new science emerges every couple of centuries, those who are privileged enough to witness it from its very beginnings to its full development during the span of their own lifetime can indeed count themselves lucky. My colleagues and I, who became fully fledged after World War II, had precisely this privilege. The science to which I refer still has no proper name, but its existence can be testified to by the matter-of-fact way in which physicists, biologists and logicians discuss issues that do not fall into any of the categories of physics, biology or logic. Some call this new discipline 'informatics', others 'information science'; it may sometimes be narrowed down to 'neuroinformatics' or 'technical informatics'. […] The term cybernetics, which does not meet with universal approval, has, nonetheless, a good chance of asserting itself in the long term. This is not least due to the fact that the term was coined by its most brilliant founder, the mathematician Norbert Wiener. His solid philosophical and philological background is reflected in the fitting name that he gave to this science. The designation 'cognitive science', which is currently popular, might well one day apply to everything that we still refer to as informatics and cybernetics. But then again, the plain (and rather sloppy) term 'computer science' might come up trumps at the end of the day, as a tribute, if you like, to the fact that the whole thing did not get off the ground until large electronic data processors were invented.
However, one thing is for sure; this new field that has emerged between the humanities and natural sciences, while not professing to belong to either discipline, actually succeeds in querying the boundaries of both. Although no-one can be universally knowledgeable, there is no longer a wall to prevent us from taking a peek to see what is on the other side […]“.
Braitenberg (1999) in Göttinger Sudelblätter (Wörter, Wörter, Wörter, by S.Sabin, Z. Ghase and V. Braitenberg)

Scientific Career

Valentino Braitenberg was born in Bolzano, Italy, in 1926. His scientific career began with the study of medicine in Innsbruck, Austria, and his qualification as a consultant for neurology and psychiatry in Rome. Research stays between 1952 and 1957 took him to Oskar Vogt at the Institute for Brain Research in Neustadt, Germany, to Karl Kleist in Frankfurt and finally to Yale Medical School in New Haven, Connecticut, where he made the acquaintance of the protagonists of cybernetics (Wiener, McCulloch, von Foerster). In 1958, he returned to Italy. Together with E.R. Caianiello, he set up the department for cybernetics at the Institute for Theoretical Physics at the University of Naples and taught cybernetics there as a professore incaricato. Having gained his habilitation in cybernetics and information theory in 1963, Valentino Braitenberg was appointed director of the Department of Biocybernetics at the Consiglio Nazionale delle Ricerche in Naples. In 1968, Werner Reichardt founded the Max Planck Institute for Biological Cybernetics in Tübingen, Germany. Valentino Braitenberg, Karl Götz, and Kuno Kirschfeld were appointed co-directors. The research conducted there, ranging from behaviour to genetics, led to fundamental insight into the visual system of insects.

Braitenberg was also honorary professor at the Universities of Tübingen (Faculty of Physics) and Freiburg (Faculty of Biology), as well as honorary doctor at the University of Salzburg, Austria. Following his retirement in 1994, he continued to conduct research in both Tübingen and Italy. In 1998, he was invited by the University of Trento, Italy, to establish the Laboratory of Cognitive Sciences which is located in Rovereto. In 2001, he was made an honorary citizen of this town. In 2006, together with Norbert Gutweniger (Merano), he organized a public exhibition on the theme of cybernetics entitled “Il cervello e le idee: segnali e messaggi“ (The brain and ideas: signals and messages) in Rovereto,

The main focus of Braitenberg's research lay in the functional interpretation of brain structures. One of his merits is his contribution to the revival of neuroanatomical research as such, which, in the aftermath of the cyto- and myeloarchitectonic studies prevalent at the beginning of the last century and the monumental work of Ramon y Cajal (1911), had been put out of the limelight somewhat by the increasingly dominant discipline of electrophysiology. However, neuroanatomy had been mainly descriptive until then. Once the first electronic computers appeared on the scene in the 1950s, Braitenberg was aware of their potential as models for brain functions. His neuroanatomical research was carried out in a bid to identify the network structures specific to a given part of the brain. This made it possible to directly transpose neuronal structures into the specific working mechanisms of certain parts of the brain. His book „On the texture of brains“ (Springer, English edition in 1977) provides a fascinating insight into this cybernetic approach.

Here is a selection of his research results and publications:

The cerebellum as a clock in the millisecond range. Braitenberg's research on the cerebellum was a first example of the functional interpretation of a neuronal histology right down to the level of the single neuron and synapse (Braitenberg and Atwood 1958; Braitenberg and Onesto 1960; Braitenberg 1967). Later versions of this model (representation of speeds; see Braitenberg, Heck and Sultan 1997) provided convincing explanations for the role of the cerebellum in movement.

Precise connectivity in the insect eye. Braitenberg's examination of the visual system of the fly, inspired by the behavioural analyses of Werner Reichardt and Karl Götz in Tübingen, revealed a very high precision in connectivity of each individual fibre. His analysis of the network between the eye and the first visual ganglion provided the proof (Braitenberg, 1967; in parallel to Trujillo-Cenóz and Melamed, 1966) for the ‘neural superposition eye’ predicted by Kuno Kirschfeld (Kirschfeld, 1967).

The cerebral cortex as an associative memory. Braitenberg first dealt with the human cerebral cortex in connection with his clinical research in Rome. Later he focused on the mouse cortex. Thanks to his quantitative studies, he could identify basic properties of the structure of the cortex: a network comprised mainly of excitatory and modifiable connections, and primarily connected onto itself in a highly divergent and convergent manner (e.g. Braitenberg, 1978 a; Braitenberg and Schüz, 1991, 1998). The results of his studies supported the Hebbian theory (1949) that memory is stored associatively in the form of 'cell assemblies'. Braitenberg and his colleague Günther Palm augmented this theory and defined fundamental aspects of it more precisely (Braitenberg 1978 b; Palm 1982), rendering it a powerful tool for understanding the neural mechanisms of cognitive functions.

Braitenberg made further noteworthy contributions to the funtion of the visual system (circular arrangement of orientation columns in the primary visual cortex of primates; theory on the mechanism of orientation selectivity; see Braitenberg und Braitenberg 1979; Braitenberg 1984), to a neurological theory of language (Braitenberg and Pulvermüller, 1992), to the topic of logic and the brain (Braitenberg, 1986, 1991), as well as to behaviour and artificial intelligence.

Braitenberg was the author of numerous books, and was equally at ease writing in German, English and Italian. His book “Vehicles” (MIT Press, 1984), an unconventional approach to artificial intelligence, was particularly influential. It shows how mechanisms of behaviour, which appear incomprehensible to begin with, can be explained in an astonishingly simple manner.

Braitenberg's last book, 'Information – der Geist in der Natur' (Schattauer, 2011) was published only a few months before his death. This work, together with his previous book 'Das Bild der Welt im Kopf. Eine Naturgeschichte des Geistes', aims at the demystification of concepts. It is an approach to comprehend the world and it reflects his deep respect for nature and its laws. Braitenberg himself called his research ‘Looking over God's shoulder’.

With this 'love of understanding' which is a heading in one of the above-mentioned books, together with his special ability to explain things vividly, Braitenberg inspired many young people. He was a catalyst; wherever he was, vivacious conversations would ensue, frequently in his family circle, where students and colleagues were always welcome. Braitenberg was scientist through and through: neuroscience was a kind of licence for him to deal with all sorts of interesting themes that have, in some way or another, to do with the brain, right down to religion and politics. This proved to be infectious. His seminar at the faculty of physics, entitled 'Information processing in the brain' became legendary. Each semester, the seminar would deal with a new and exciting subtopic of this general theme, such as music and the brain, the brain and language, logic, as well as themes from psychiatry, neurology, psychology or automata theory.

The New Zealand brain scientist Robert Miller wrote: 'I know no others of a younger generation who can take his place', and he is right. I am deeply grateful for all that I learned from him in the many years we worked together.

Adapted from: Almut Schüz (2011) Valentin Braitenberg. Nervenheilkunde 11: 930-1

Translated by Shirley Würth

References: For References by V. Braitenberg and by K. Kirschfeld: see publication list

  • Palm G (1982) Neural Assemblies. An alternative approach to artificial intelligence. Springer, Berlin, Heidelberg
  • Trujillo-Cenóz and J. Melamed (1966): Electron microscope observations on the peripheral and intermediate retinas of dipterans. In: The functional organization of the compound eye. Ed. C.G. Bernhard, Pergamon Press, Oxford
Go to Editor View