Poor living conditions in childhood inhibits the activity of genes responsible for neurotransmitter antidepressant. Now no one argues with the fact that our emotions, our mood, our thoughts, all the mental state is largely dependent on brain neurochemistry. Under the neurochemistry understand in the first place neurotransmitters – special molecules through which neurons communicate to each other the electrochemical signal.
A number of neurotransmitters, their distribution along nerve networks, their utilization, etc. greatly affect our mood and our ability to think. And if, for example, you have fallen into a depression, then the reason may not necessarily be any real trouble or unsolvable existential contradictions that you suddenly find in your own being, and the lack of neurotransmitter in the nervous circuits that serve the feelings of happiness and pleasure.
What may be the lack of neurotransmitter? Obviously, from the fact that genes encoding the enzymes required for its synthesis, have a bad run, have become inactive. The genes themselves can be bad because of mutations, which they were – then it makes sense to speak of congenital mental anomalies. But external conditions affect the activity of genes, inhibiting some and stimulating others.
One of the most effective ways to change the genetic activity is DNA methylation. If a DNA fragment is covered with methyl groups (with special metiliruetsa enzymes), then it appears as if sealed – it can’t get access to proteins involved in transcription, i.e. the synthesis of RNA, and no RNA and no protein. In other words, the gene is switched off, the protein they encoded from the cage disappears. Methylation refers to the so-called epigenetic ways of regulation of gene activity, and retained by epigenetic modifications to the genes for a very long time, almost a lifetime (and sometimes somehow go even in the next generation).
Epigenetic regulation, repeat, very sensitive to external stimuli. Suppose there is an external stimulus – for example, stress due to which the methyl group sealed a gene responsible for a neurotransmitter, for example serotonin, which are necessary for a good mood and protect against depression. Long-term epigenetic link between external stress and of serotonin as shown in his article in Molecular Psychiatry Ahmad Hariri (Ahmad Hariri and his colleagues from Duke University. The researchers decided to focus on the SLC6A4 gene, the encoder receptor for serotonin – Pro SLC6A4 is known that failure in it associated with the development of depression (probably due to the fact that nerve cells do not feel neurotransmitter), and many antidepressants created in order to compensate for poor performance of this receptor.
But most importantly here is what a stress was considered by the authors. They compared the status of the SLC6A4 gene have nearly two hundred children 11-15 years. In addition, neuroscientists using MRI scans assessed how children’s brains react to stress – for example, if they show someone scary (angry, threatening) face: those who are especially sensitive to external troubles, it is possible to see a heightened activity of the amygdala, or the amygdala, which serves as one of the main emotional centres.
The point is that some of the children growing up in poverty and some in plenty. All of them watched for quite a long time, for three years, regularly checking the serotonin gene SLC6A4 on the methyl status, and the brain – the stress response. It turned out that throughout the three years SLC6A4 those who grew up in poverty, was more covered with the sealing epigenetic marks, and the stronger their brain reacted to psychological stress. The lack of serotonin due to the low activity of SLC6A4 and sensitivity to stress can easily lead to depression.
It must be reiterated that we are not talking about genetic predisposition. The person may be a normal gene inherited from his parents, but the conditions of life were such that gene just will not turn on or turns on but is working at half capacity. The second thing that should be clarified in connection with the above work is that the stress here refers to rather weak, i.e. it is an injury, not a sudden loss, but not too strong external pressure, which, however, lasts a long time. As for the stress that accompanies poverty, here everything is clear: even if the family is low, as they say, socioeconomic status everything is in order with domestic relations, still can not escape from poor nutrition, from living in a cheap area with a poor environment, etc.
Of course, it is not necessary to interpret the results so that childhood and youth spent in poverty, will clearly lead to depression. First, the study involved still not a very large sample – a total of 183 child. Secondly, it may well be that epigenetic marks, gene archiving of a serotonin receptor, for all his durability still eventually disappear (it would be extremely interesting to trace the fate of these methyl groups throughout a person’s life, especially if his life circumstances changed over time). Finally, here it is not quite clear causality: does poverty directly provokes bad epigenetics, or the relationship is much more complex and ambiguous.
But in fact, more data suggests that the causal relationship here is quite clear. Neuroscientists and psychologists a lot of attention paid to the question of poverty and mental development. Generally speaking, anyone in their right mind must recognize that bad living conditions are not conducive to health, either physical or mental (prominent stories about the poor should not be taken into account – because they all remember that these stories stand out).
Poor nutrition and the struggle for survival affect the body both for mother and child, and the brain feels the effect is one of the first. A year ago in the article about how poverty harms the brain, we gave examples of some of the research on this topic. For example, there is evidence that the number of white and gray matter in children 6-12 years old can learn, in what conditions the child lived in early childhood: both the poor turns out to be less, which is primarily noticeable in areas of the brain responsible for learning and resistance to stress. Accordingly, the mental development of such children is delayed for a year or two. By the way, if a child grows up in poverty, but without stress, the development of the brain occurs more or less normally.
In another work, published in last year’s article in Nature Neuroscience, says that the development of the cortex of the hemispheres correlates with socioeconomic characteristics of the family. So, it was better than parental education, the more time and effort they spent on it, the more the child was the total area of the bark, and especially those areas that are responsible for the reading, language, and organization behavior. The difference between children and young people whose parents went to University, and those whose parents were without a College degree, was the fact that the first area of the cortex was 3% more.
Material wealth also contributed to the development of the brain, but here the pattern was more complicated. Differences between children from very poor families and children from slightly less poor families were great, but then the growth of the cortex decreased, and with a certain level of income the difference in the economic situation at its height is almost not affected. According to the authors, these differences affected the results of at least one of the cognitive tests, the most sensitive and here was the memory and the ability to organize their own behavior. As for the ethno-genetic factors, then there’s no correlation could be found – belonging to a particular race had no impact on the relationship between brain development and socio-economic position.
The General conclusion, which can be done here, looks like this: from the neurobiological point of view, poverty is not a lifelong stigma, inherited from ancestors, with whom nothing can be done and which we can only hope for some kind of a successful mutation. But while poverty can ruin the life not only in terms of material well-being, but also literally changing the brain and therefore the psyche. In other words, to obtain a healthy society, need to care not about that, that was not rich, and about how to not be poor.
Poverty harms brain?
