A debate is raging in human genetics these days as to why the massive genome-wide association studies (GWAS) that have been carried out for every trait and disorder imaginable over the last several years have not explained more of the underlying heritability. This is especially true for many of the so-called complex disorders that have [...]

It takes a lot of genes to wire the human brain. Billions of cells, of a myriad different types have to be specified, directed to migrate to the right position, organised in clusters or layers, and finally connected to their appropriate targets. When the genes that specify these neurodevelopmental processes are mutated, the result can [...]

Unlike in many other animals, injured nerve fibres in the mammalian central nervous system do not regenerate – at least not spontaneously. A lot of research has gone in to finding ways to coax them to do so, unfortunately with only modest success. The main problem is that there are many reasons why central nerve [...]

“Scientists discover gene for autism” (or ovarian cancer, or depression, cocaine addiction, obesity, happiness, height, schizophrenia… and whatever you’re having yourself). These are typical newspaper headlines (all from the last year) and all use the popular shorthand of “a gene for” something. In my view, this phrase is both lazy and deeply misleading and has [...]

The fact that the adult brain is very plastic is often held up as evidence against the idea that many psychological, cognitive or behavioural traits are innately determined. At first glance, there does indeed appear to be a paradox. On the one hand, behavioural genetic studies show that many human psychological traits are strongly heritable [...]

A new study suggests that a gene known to be causally linked to schizophrenia and other psychiatric disorders is involved in the formation of connections between the two hemispheres of the brain. DISC1 is probably the most famous gene in psychiatric genetics, and rightly so. It was discovered in a large Scottish pedigree, where 18 [...]

There is a common view that the human genome has two different parts – a “constant” part and a “variable” part. According to this view, the bases of DNA in the constant part are the same across all individuals. They are said to be “fixed” in the population. They are what make us all human [...]

Hearing voices is a hallmark of schizophrenia and other psychotic disorders, occurring in 60-80% of cases. These voices are typically identified as belonging to other people and may be voicing the person’s thoughts, commenting on their actions or ideas, arguing with each other or telling the person to do something. Importantly, these auditory hallucinations are [...]

A couple of recent papers have been making headlines in relation to autism, one claiming that it is caused less by genetics than previously believed and more by the environment and the other specifically claiming that antidepressant use by expectant mothers increases the risk of autism in the child. But are these conclusions really supported [...]

Deckard: She’s a replicant, isn’t she? Tyrell: I’m impressed. How many questions does it usually take to spot them? Deckard: I don’t get it, Tyrell. Tyrell: How many questions? Deckard: Twenty, thirty, cross-referenced. Tyrell: It took more than a hundred for Rachael, didn’t it? Deckard: [realizing Rachael believes she's human] She doesn’t know. Tyrell: She’s [...]

A debate has been raging over the last few years over the nature of the genetic architecture of so-called “complex” disorders. These are disorders – such as schizophrenia, epilepsy, type II diabetes and many others – which are clearly heritable across the population, but which do not show simple patterns of inheritance. A new study [...]

“We only use 10% of our brain”. I don’t know where that idea originated but it certainly took off as a popular meme – taxi drivers seem particularly taken with it. It’s rubbish of course – you use more than that just to see. But it captures an idea that we humans have untapped intellectual [...]

Review of “Braintrust. What Neuroscience Tells Us about Morality”, by Patricia S. Churchland The question of “where morals come from” has exercised philosophers, theologians and many others for millennia. It has lately, like many other questions previously addressed only through armchair rumination, become addressable empirically, through the combined approaches of modern neuroscience, genetics, psychology, anthropology [...]

There is a paradox at the heart of behavioural and psychiatric genetics. On the one hand, it is very clear that practically any psychological trait one cares to study is partly heritable – i.e., the differences in the trait between people are partly caused by differences in their genes. Similarly, psychiatric disorders are also highly [...]

Recent evidence indicates that psychiatric disorders can arise from differences, literally, in how the brain is wired during development. Psychiatric genetic approaches are finding new mutations associated with mental illness at an amazing rate, thanks to new genomic array and sequencing technologies. These mutations include so-called copy number variants (deletions or duplications of sections of [...]

I have a new post over on the Scientific American Mind Matters website. It describes new research which suggests that tune deafness and face blindness – two examples of conditions known as agnosias, both of which can be genetic – are caused not by a failure of the brain to recognise previously seen faces or [...]

If some guy spilt your beer by accident, would you punch him in the face? If he was unapologetic, you might at least consider it – you might in fact feel a pretty strong urge to do it. What stops you? Or, if you’re the type who acts on those urges, what doesn’t stop you? [...]

The circuitry of the brain is too complex to be completely specified by genetic information – at least not down to the level of each connection. There are hundreds of billions of neurons in your brain, each making an average of 1,000 connections to other cells. There are simply not enough genes in the genome [...]

A pair of papers from the lab of Fred Gage has provided new insights into the molecular and cellular processes affected in Rett syndrome. This syndrome is associated with arrested development and autistic features. It affects mainly girls, who typically show normal development until around age two, followed by a sudden and dramatic deterioration of [...]

An amazing study just published in Cell starts out with fruit flies insensitive to pain and ends up with what looks very like a synaesthetic mouse. Penninger and colleagues were interested in the mechanisms of pain sensation and have been using the fruit fly as a model to investigate the underlying biological processes. Like any [...]