Thursday, April 19, 2007


PLoS Biology has two essays about recent brain research, which I thought might be of interest to people.

The Genetics of Brain Wiring: From Molecule to Mind

What makes some people neurotic or schizophrenic or right-handed or fearless? Are these behavioural differences caused by literal differences in how individuals' brains are wired? If so, what causes those differences? This age-old question of nature versus nurture can be recast in more realistic terms based on our modern understanding of genetics, development, and neuroscience. The challenge in this area is to understand how genotype is mapped to phenotype, not just in terms of the average effects of single genes across populations but also in terms of their combined effects in shaping the phenotypes of individuals.

There is compelling evidence that many psychiatric disorders have their origins in disturbed neurodevelopment, resulting in altered connectivity [1,2]. Similarly, many behavioural or cognitive traits are both heritable, at least moderately [3], and correlated with functional connectivity differences in various circuits [2]. The study of the genetics of behavioural or psychiatric traits may thus be directly informed by an understanding of the genetic architecture of the developmental processes underlying brain wiring. This essay presents a systems-level overview of these processes, highlighting several important properties that can have large effects on how genotype is mapped to phenotype: epistasis (meaning non-additive gene–gene interactions in this context), compensation, and stochastic developmental variation.

I don't like the "nature vs. nurture", since it seems more likely that it's "nature and nurture" in most cases. Yet obviously mental disorders are more nature than nurture in most cases. So, to understand mental disorders, it's important to understand how the brain works, and how it gets developed. The synopsis explains what work has been done in that field, and what results have been found.

To be honest, it's not the easiest PLoS Biology essay I've come across.

The other essay is dealing with a similar subject.

Law, Responsibility, and the Brain

Archaeological discoveries of traumatic injuries in primitive hominid skulls strongly hint that our species has a long history of violence [1]. Despite repeated attempts throughout history, including efforts to eliminate violence through the imposition of criminal sanctions, we have yet to dispel our violent nature. Consequently, criminal violence remains a common feature of most societies. As policy-makers seek deeper understandings of criminally violent and anti-social behaviour, many contemporary neuroscientists assume that the essential ingredients of the human condition, including free will, empathy, and morality, are the calculable consequences of an immense assembly of neurons firing. Intuitively, this view opposes Cartesian dualism (i.e., the brain and mind are separate, but interacting, entities) and assumes that violence and antisocial behaviour emanate from a mechanistically determined brain

From this standpoint, the exciting discoveries of neuroscience resonate far beyond mere philosophical banter and may have important implications for the way government institutions, including education and legal systems, operate. For example, to the extent that legal systems attempt both to move behaviour in socially desirable directions and also to adjudicate transgressions fairly, the legal system's effectiveness can be improved by deepening our understandings about why people behave as they do and both how and why people respond to various changes in legal incentives. Specifically, neuroscience may have important implications for both how we understand the multiple influences on violent behaviour and how the legal system may better engage with violent criminals.

The essay is basicly about how our deepening understanding of how the brain works might effect our legal processes, though science cannot stand alone in our process to understand how criminals act and think.

They have some concluding remarks

The goals of science and of law are different. However, important legal questions such as moral blameworthiness, culpability, responsibility, and the likelihood of recidivism depend to some degree on improved understandings of human behaviour. Therefore, biological advances in understanding human brain architecture and function may overlap in important ways with legal inquiries. New studies of the criminal brain are likely to shape moral views on responsibility and free will, with possible impacts on how legal systems punish and treat criminals [60].

A growing body of research gives us good reason to believe that some kinds of brain dysfunction can affect the probability of different kinds of criminal behaviours. However, despite our growing knowledge of the brain abnormalities associated with anti-social and psychopathic behaviour, there are as yet no concrete biological markers—genetic or physiological—that can predict such behaviours. Violent and anti-social behaviours undoubtedly arise from a symphony of factors. Optimal understanding will require cooperation among many disciplines such as economics, sociology, psychology, evolutionary biology, cellular physiology, and neuroscience

I think it cannot be emphasised enough that we cannot predict criminal behaviours through science - and it is always debatable if we should try to do so, from a standpoint of free will (a concept that the article also addresses) and presumption of innocence.

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