The Parent Infant Centre

it can be too late
but never too early

Welcome to ourNews, where we keep up-to-date with research and other news related to infant mental health. These articles can be of interest to both parents and professionals.
We are keen to know your views and so please do comment on our articles.
Is there a topic that you would like us to write about? Just send us a message via 'Contact us'.

ourAdvice, our other blog, has brief posts with advice for parents.

ourNews

Brain connectivity, preschool poverty and school-age depression

Geoff Ferguson - February 16th 2016

A recent study has linked early childhood poverty with reduced connectivity between the hippocampus and amygdala and other key brain regions. It is suggested that these differences provide one way in which the experience of early poverty is associated with later social and psychological difficulties.

sad child

For some years we have known of the correlation between early childhood poverty and a range of later difficulties for the child. A 2013 paper by Luby et al 1 lists these difficulties as including 'poorer cognitive outcomes and school performance, and...[a] higher risk for antisocial behaviours and mental disorders'. More recently researchers have begun to investigate the possibility that these early experiences bring about changes to various brain structures and that these may contribute to the child's later problematic development.

For example, the previously quoted study by Luby et al, looked at links between poverty and the volumes of the hippocampus and the amygdala, and the volumes of the brain's white matter and cortical gray matter. If changes to the volumes of these brain structures, especially the hippocampus, can then be linked with later mood disorders, then these changes could provide one possible pathway by which earlier poverty leads on to later psychological difficulties. The evidence for such links has been mixed. In the case of hippocampal volume, there has been conflicting evidence when depressed and non-depressed individuals have been compared. However, a recent meta-analysis2 claims to have established that individuals with a recurrent major depressive disorder do tend to have a smaller hippocampus.

Technological advances have enabled more recent research to look at how these brain structures function, rather than just to measure their volume. A recent study reported in the American Journal of Psychiatry throws new light on how changes to the function of brain structures may mediate between early poverty and later mood disorders. This study by Barch et al3 looked at the relationship between poverty experienced in early childhood and changes to the connectivity of the hippocampus and the amygdala. Both of these brain structures are important for learning and for memory, and both are part of systems associated with the regulation of emotions. Both are also susceptible to the impact of stress. Several studies have described how changes to these structures are associated with various mood disorders. See this recent study regarding changes to the amygdala4 and the previously mentioned meta-analysis regarding the hippocampus2.

The 2015 study by Barch et al followed 105 preschool children, aged 3-5, through to ages 7-12. Each child's level of poverty as a preschooler was calculated on an income-to-needs basis, which relates the family's income to its size. Some years later, when the children reached ages 7-12, the researchers used functional magnetic resonance imaging (fMRI) to analyse the connectivity of the hippocampus and the amygdala with other key brain regions.  

The study found that a greater level of poverty amongst the children at a preschool age was associated, when the child was older, with reduced levels of connectivity between the amygdala and hippocampus, and other brain regions including 'the superior frontal cortex, lingual gyrus, posterior cingulate, and putamen' (Barch et al). Moreover, both early poverty and the reduced connectivity of these structures were predictive of higher rates of clinical depression in the older child. The researchers considered that this reduced connectivity meant that the older children were less able to regulate their emotions and levels of stress, a situation that contributed to their later psychological difficulties.

The study by Barch et al suggests that reduced connectivity between these brain regions may be one mediating link between the child's early experience of poverty and later psychological difficulties. The ways in which poverty might lead to this reduced connectivity could involve environmental factors such as poorer nutrition and higher levels of stress – as noted before, the hippocampus and the amygdala are particularly susceptible to the impact of stress.5 

The authors cast some doubt on the ability of positive experiences to reverse this reduced connectivity. However, they are not without hope...

"Many things can be done to foster brain development and positive emotional development. Poverty doesn't put a child on a predetermined trajectory, but it behooves us to remember that adverse experiences early in life are influencing the development and function of the brain. And if we hope to intervene, we need to do it early so that we can help shift children onto the best possible developmental trajectories."6

This report provides further evidence of the importance of early interventions where families are experiencing difficulties. These neurological studies also provide added weight to the insights of psychodynamic theory, for they show how profoundly our early experiences come to shape our later selves. 

1 Luby et al The Effects of Poverty on Childhood Brain Development. JAMA Pediatr. 2013;167(12):1135-1142.

2 Conflicting results have been obtained when looking at differences in hippocampal volume between depressed and non-depressed individuals. However, a recent meta-analysis claims to have established that individuals with a recurrent major depressive disorder tend to have a smaller hippocampus. See Schaal et al. Subcortical brain alterations in major depressive disorder: findings from the ENIGMA Major Depressive Disorder working group. Molecular Psychiatry advance online publication 30 June 2015. Other differences have also been noted. See, for example, Posener et al. High-Dimensional Mapping of the Hippocampus in Depression. Am J Psychiatry 2003; 160:83–89

3 Barch et al. Effect of Hippocampal and Amygdala Connectivity on the Relationship Between Preschool Poverty and School-Age Depression. American Journal of Psychiatry. http://dx.doi.org/10.1176/appi.ajp.2015.15081014

4 See,for example, Aberrant amygdala functional connectivity at rest in pediatric anxiety disorders. Hamm et al. Biology of Mood & Anxiety Disorders 2014 4:15

5 See for example this 2003 paper by Teicher, et al (https://goo.gl/WPG6WS).

6 From a press release via http://www.eurekalert.org/pub_releases/2016-01/wuso-plt011516.php


Comments
Post has no comments.
Post a Comment




Captcha Image

Trackback Link
http://www.infantmentalhealth.com/BlogRetrieve.aspx?BlogID=10293&PostID=619265&A=Trackback
Trackbacks
Post has no trackbacks.

Welcome to ourNews, where we keep up-to-date with research and other news related to infant mental health. These articles can be of interest to both parents and professionals.
We are keen to know your views and so please do comment on our articles.
Is there a topic that you would like us to write about? Just send us a message via 'Contact us'.

ourAdvice, our other blog, has brief posts with advice for parents.

Recent Posts


Tags


Archive

4