Could a human brain be miniaturized?

Office for Technology Assessment at the German Bundestag

TA project

brain research

Subject area: Bio and medical technologies
Analysis approach: TA project
Thematic initiative: Committee on Education, Research and Technology Assessment
Status: completed
Running time: 2005 to 2007

Brain research and neurosciences are generally considered to be a research field with enormous application potential. This concerns, for example, new perspectives for the treatment of neurodegenerative diseases, but also the possibility of expanding human capabilities and manipulating human behavior. Since the beginning of the 1990s, advances in understanding human brain functions have also led to an intense debate between the natural sciences and the humanities about human consciousness and free will.

Subject and aim of the investigation

The aim of the study on the subject of brain research, carried out on behalf of the Committee for Education, Research and Technology Assessment, was, on the one hand, to ascertain the status and prospects of research, and, on the other hand, to assess the most comprehensive possible assessment of the findings from the explanation of the functioning of the human brain and the coupling of such findings possible applications resulting from other fields of scientific research and technological development, as well as the social consequences that may be associated with them.

In view of the variety of possible applications to be examined, it was decided to develop an overview of the state of basic neuroscientific research and selected questions and fields of application with particular social relevance. The focal points of the investigation were defined:

  • Overview of the state of research and development nationally and internationally
  • Investigation of the objectives of the most important funding programs for brain research as well as research activities in various disciplines
  • Processing of the internal scientific discussion about the goals, perspectives and consequences of brain research (possible fields of application, importance of basic research, social relevance)
  • Status of the discussion about the convergence of technologies and the resulting challenges and perspectives for research and development
  • Status of the discussion between the natural sciences and the humanities about the cultural significance of findings from the neurosciences (consciousness and free will)

The research carried out by the Fraunhofer Institute for Systems and Innovation Research as part of the TAB project on international funding programs and priorities in neuroscientific research was completed in spring 2006 and published separately as TAB Background Paper No. 15. The final report on the overall project was presented in April 2007. (TAB work report No. 117).


The modern neurosciences make use of practically all scientific work and method areas and therefore do not represent a single discipline, but rather form a multidisciplinary field of research. Thanks to contributions and advances in knowledge in various areas, including classical neurology, genetic research, information science, and the use of new methods (such as high-resolution imaging processes), the data on the functioning of the nervous system and with them the understanding of the biological basis of cognitive performance are enormous grown. The advances in basic neuroscientific research have long been reflected in differentiated ways in the treatment of not only neurological but also psychiatric diseases, including pharmacological and psychotherapeutic applications. In addition, the neurosciences also initiate the development of technological applications in computer science. They contribute both to the optimization of information processing systems and to the development of human-machine interfaces that can be used to support people who are affected by functional losses, such as those of the sensory organs.

State of basic research

Usually, the various approaches and research subjects in neuroscience are roughly assigned to three levels of description: a subcellular and cellular level, a middle level of neural network associations and the level of functional systems, which focuses on the overall function of the brain. The progress made in recent years particularly affects the subcellular and cellular levels as well as the (superordinate) level of the functional systems. At the level of the functional systems (in particular by means of imaging processes) it has been possible to significantly refine the mapping of the brain, i.e. to assign various mental functions to specific brain regions. So there is no doubt that there are functional specializations in the brain; On the other hand, it has become clear in the course of research that complex cognitive functions are usually distributed over numerous, different brain regions, so that we can only speak of specializations, but not of an exclusive function. On the cellular and subcellular level, the structure, the electrophysiological mode of action and the cooperation of neurons could be elucidated. Molecular genetics has made it possible to molecularly characterize certain groups of neurons and assign them to certain services. Likewise, significant progress has been made in the localization and clarification of the importance of neurotransmitters as messenger and carrier substances between nerve cells, which also opens up new therapeutic options for mental illnesses.

The previous limits for the understanding of the biological basis of mental performance and processes and thus the essential challenges for research lie on the so-called middle level of the neuron groups. Here, the stimuli passed through the sensory organs into the brain are translated into information and meaningful mental content (emotions, terms, thoughts). The cooperation of the neural networks forms the level on which consciousness is ultimately constituted. Despite the advances in the characterization of different groups of neurons or an improved description of their interaction (e.g. in certain perceptual processes), an actual understanding of how neurons realize consciousness is still a long way off. In addition to understanding the cooperation between neurons in neural networks, brain plasticity, i.e. the change in brain structures over time (as is characteristic of learning processes, for example), and the inter-individual variance in the structure of the brain form the central questions of current brain research.

Mind and brain

Far-reaching epistemological and philosophical theses by leading neuroscientists on the possibilities of a scientific explanation of mental processes have attracted public attention in recent years. According to these theses, the findings of modern neuroscience would lead to an upheaval in human self-understanding, i.e. our ideas of subjectivity and personal identity, of self-confidence, will and action control.

The passage through the discussion between neurosciences, philosophy and cultural studies undertaken in this report shows, however, that such theses on the determination of mental processes by neuronal events in the brain and on the illusory character of free will have so far not been sufficiently supported empirically. Both neuroscientists and representatives of the humanities and cultural sciences are faced with the problem of translating the mental into the neural or from the neural into the mental. The reproach of some protagonists of the neurosciences against the humanities is that their concepts of the relationship between mind and brain ultimately amounted - contrary to their own intentions - to the scientifically untenable assumption of the existence of an independent spiritual substance alongside the material, because they could not explain how mental processes are realized on the basis of neural activity. The reproach of an "explanatory gap" hits the neurosciences themselves, as long as they cannot solve the problem of creating meaning using some kind of "neural code". The meaning of consciousness is constituted socially and objectified through language and writing or other symbol systems. How this is realized at the neural level is not yet understood.

The question of the possible social consequences of the findings or theses of the neurosciences on the relationship between mind and brain can be answered - following a position common in philosophical discussion - with a (preliminary) “So what?” Until the neural-based laws of mental states and Processes are deciphered to such an extent that feeling, thinking, behavior and decisions can be predicted on the basis of observed processes in the brain. With regard to the often mentioned possible consequences of advances in neuroscience for criminal law, this would mean that the state of the brain that existed immediately before a criminal act would have to be reconstructable and the decision to act could be recognized as being clearly determined by this state of the brain. Since research seems to be far from this, there is currently no reason for a fundamental revision of our everyday conception of guilt and responsibility, free will and the criminal law concept of guilt.

Knowledge and learning

The interest of both the general public and educational research in the methods and findings of brain research is based on the hope that these can contribute to better learning. Obviously, the results of neurophysiological research so far in the context of learning are extremely rarely clearly interpretable. Today it is better understood which information processing mechanisms one has to adopt in order to explain the occurrence of (different) learning successes, why people learn different things differently in certain phases of their life or how, for example, certain learning processes are physically or chemically realized in the brain and how learning processes are reflected in the brain architecture. But which activities exactly take place in the brain before there is a corresponding learning success is one of the still unanswered questions. If neural prerequisites are missing, proven learning environments are ineffective. When learning opportunities are not available, people with efficient brains remain incompetent. Most of the causes of learning difficulties lie between these two extremes and can be explained by the learning history. A look at the neurophysiology of the brain alone does not help here.

Against this background, this report discusses what brain research and educational research can expect from each other, what implications result from neurophysiological studies of the human brain for cognitive science, learning psychology and pedagogical theories in the context of learning and teaching / learning research. It is also shown that findings from brain research can describe the framework conditions under which successful learning can take place, but that the contributions of the neurosciences have so far been too vague to be able to give concrete instructions for the design of school and extracurricular learning opportunities. Nevertheless, brain research was able to confirm many of the results of many years of teaching and learning research: With a number of cognitive science results, psychological insights and educational practices, we now know better why they work or why they don't.

Neuroelectric interfaces and neuroprosthetics

There are currently three disease clusters that have already been treated with neuroelectric interfaces. The first cluster includes diseases and injuries in the area of ​​the sensory systems. The neuroelectric interfaces used are auditory and visual implants as well as implants to restore the sense of balance. The second cluster relates to diseases and injuries to the motor system. These include movement disorders, the cause of which lies in the area of ​​involuntary motor skills, such as Parkinson's disease or dystonia, but also disorders of voluntary motor skills with paraplegia and stroke as the main causes. The systems used enable the patient to express movement in his environment. The systems used so far include so-called brain-machine interfaces and deep brain stimulation. A third cluster of disorders relates to the "milieu intérieur" of the human body. This includes chronic pain, obsessive-compulsive disorder, depression and epilepsy. The interfaces used (including vagus nerve, deep brain, motor cortex and spinal cord stimulation) have no direct interactions with the environment. The development status of the various systems is very different and ranges from broad clinical use - e.g. with cochlear implants to restore hearing in over 100,000 cases worldwide or spinal cord stimulation to treat painful conditions in more than 50,000 patients - to research into the fundamentals of Laboratory or on individual subjects (e.g. with retina implants).

Recently, the development of neuroelectric interfaces has accelerated rapidly, and the range of new areas of application is growing noticeably. This trend is fed by advances in information and communication technology, the miniaturization of mechanical and electronic systems, and the latest findings on how the brain works. Neuroprosthetics is a field in which visions of possible technological developments in the future play a role that should not be underestimated, and which also attract a great deal of public attention. Although it is sometimes difficult to reliably assess the reality content of such visions, they are nevertheless of great importance, especially for the public perception of the research field. For the development of new neuroprosthetic applications, international military research is of particular importance, for which considerable funding is available.

A special feature of neuroelectric interfaces in contrast to other implants (e.g. an artificial heart) is that they can directly influence the central nervous system and thus at least potentially affect human behavior, the human psyche and personality, which raises fundamental ethical questions. The hypothetical possibilities of improving human mental abilities through neuroelectric interfaces (the so-called »neuro-enhancement«) also play a not insignificant role in this context.

Mental and neurological diseases

The medically oriented, that is, research focused on disease processes, represents the most important area in the overall field of brain research and neuroscience, both in terms of public and private investments and resources as well as in terms of the knowledge and results obtained on the function and dysfunction of the brain or Nervous system. Brain-specific diseases are usually divided into psychological (such as anxiety disorders, depression, psychoses) and neurological (such as Alzheimer's, epilepsy, migraine, Parkinson's) diseases, although it is hardly possible to draw a clear line between the two categories. Mental illnesses are those whose origins are predominantly associated with the brain, in which changes in personality are in the foreground and which - at least so far - are mainly described on the level of symptoms and not on the basis of the (physiological) mechanisms that lead to the disease to lead. Differentiation and attribution of psychological versus neurological diseases - which can also affect the peripheral nervous system - are clearly shaped by social assessments: While diseases of the nervous system are generally considered to be "normal" diseases such as diabetes or cardiovascular diseases, mentally ill people often occur specific reservations.

Neurological, especially neurodegenerative diseases are playing a growing role in an aging society, while mental illnesses seem to be on the rise worldwide. The (difficult to determine) total numbers are estimated at 25 to 30% of the population in Germany and Europe, including two thirds of the mentally ill. The European Commission sees an increasing threat to health and the economy and is working on the »development of a strategy for the promotion of mental health in the European Union«.

This report uses the clinical pictures of anxiety disorders, ADHD, depression, Parkinson's, schizophrenia and their treatment approaches to exemplify the medical and social significance of mental and neurological diseases. The extremely broad spectrum of analytical, diagnostic and therapeutic procedures for researching and treating neurological and psychological diseases can only be sketched out.The focus is on active ingredient-oriented, pharmaceutical processes, including in particular psychotropic drugs with potential non-medical everyday use (including addictive substances and stimulants). Psychotherapy methods are only addressed with a view to the often complementary, but sometimes also competing, relationship to biological-medical-based neuroscientific approaches. The scientifically important research areas of genome and proteome analysis as well as gene and cell therapy are only dealt with in a condensed manner with regard to their scientific and medical significance, because they are not very application-oriented and primarily oriented towards the fundamentals compared to pharmaceutical processes.

A (strongly) increasing use of psychotropic drugs in everyday life is documented in the USA for larger parts of the population, especially for the performance-oriented, and is increasingly observed in Europe. In many respects, the consequences for the individual and society as a whole are difficult to foresee, but they seem fundamentally far-reaching. The discussion of social tendencies and implications of new medically usable results in neurosciences therefore focuses on the increasing use of psychotropic drugs, in particular to improve performance, to manipulate oneself and others. The problem is closely related to perhaps the greatest health and socio-political challenge of the coming decades, the demographic increase in neurodegenerative diseases. Many drugs used to treat them are potentially also suitable for improving the performance of healthy people.

The present report outlines the central motives and goals of psychopharmacological interventions, such as promoting the ability to concentrate, improving communication skills, etc., as well as compensating for age-related restrictions. Overall, there are pressing questions for politics, society and technology assessment.

Further TA needs

The present study provides an overview of the state of neuroscientific research in various fields of application, outlines current and potential future scientific and technical developments as well as the consequences and problems that may be associated with them. It became clear that in a number of developments in the medical application of neurosciences, in-depth TA examinations appear sensible and important, e.g. for the development of neurodegenerative diseases in an aging society and the resulting challenges for the health system. Dealing with this problem would, however, imply an approach that goes beyond the subject of »neurosciences« and includes social and health policy issues. On the other hand, there are aspects or topics, such as the debate about the connection between mind and brain or the neuroscientific findings on knowledge and learning, which could not be discussed in detail in the present report, but whose in-depth discussion does not give rise to any politically relevant insights at the moment .

A TA project on the subject of "Pharmacological and technical neurointerventions: benefits and risks in medicine and everyday life" is particularly suitable as brain research-specific in the narrower sense. This would address the problem of the possible improvement and enhancement of human performance through the use of neuroscientific knowledge (»cognitive enhancement«), which is currently in the political discussion, and the socially and politically most important scientific and technical developments (psychotropic drugs and neuroelectric interfaces). The topic of enhancement would also relate to the current research policy-relevant debate on the convergence of nanotechnology, computer science, bio and neurosciences (“converging technologies”).