Sex Differences in Adolescent Brain Development & Depression Risk

[BillTre]

Here is a study on the sexual differences in development of certain parts of the brain of human adolescents who may become depressed.
I am not an expert on this stuff, so comments would be interesting to me.

https://www.science.org/doi/full/10...edium=email&utm_content=alert&utm_source=sfmc

Sexual differences in human brain development could be relevant to sex differences in the incidence of depression during adolescence. We tested for sex differences in parameters of normative brain network development using fMRI data on N = 298 healthy adolescents, aged 14 to 26 years, each scanned one to three times. Sexually divergent development of functional connectivity was located in the default mode network, limbic cortex, and subcortical nuclei. Females had a more “disruptive” pattern of development, where weak functional connectivity at age 14 became stronger during adolescence. This fMRI-derived map of sexually divergent brain network development was robustly colocated with: i prior loci of reward-related brain activation ii a map of functional dysconnectivity in major depressive disorder (MDD), and iii an adult brain gene transcriptional pattern enriched for genes on the X chromosome, neurodevelopmental genes, and risk genes for MDD. We found normative sexual divergence in adolescent development of a cortico-subcortical brain functional network that is relevant to depression.

So differences in brain development in boys vs. girls appears to be related to brain development at a time in life when depression could more likely arise in females.
This connects phenomena in neurobiology, behavior (pretty much neurobiology anyway at a conceptual level), and psychology and mental health (which involves functions in the internally experienced world of mental phenomena).

Although this is showing a sexual difference (particular details of brain development and the likelihood of developing depression), there are males in pretty much all of the statistical categories. Its only a difference in frequency.
So, don't go all sexist on it.

Nevertheless, there are sexual differences.
Its biological underpinnings and how it plays out remain complex.

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By the way, I have no idea if this article is open access (I have a subscription, so I can always get it), but in my opinion, it should be (this is one of my "things").
For several reasons:

• its most likely paid for my the government and ultimately everyone's taxes
• it has general interest in the wider public
• it always good PR to make people (tax payers) happy by giving them something for free.
• Any charge for making the article open access would be small compared to the cost of the project, or the number of authors, or the number of people who might be interested in it.

It is isn't, complaints should be made to the authors, their funders, and your congress-person(s).

 

[berkeman]

By the way, I have no idea if this article is open access (I have a subscription, so I can always get it), but in my opinion, it should be (this is one of my "things").

I'm able to click right into it. Reading it now; thanks Bill.

 

[berkeman]

Sorry, are there fMRI studies showing brain function differences in MDD?

This fMRI-derived map of sexually divergent brain network development was robustly colocated with i prior loci of reward-related brain activation ii a map of functional dysconnectivity in major depressive disorder (MDD)

 

[BillTre]

Sorry, are there fMRI studies showing brain function differences in MDD?

I think that's what fig. 3 is about:

 

[Laroxe]

I have to admit that I am less than impressed with a great deal of fMRI and genetic studies in mental health. The claims of various research studies are all over the place, and there are various other issues that can't be ignored.

The first is in the overall reliability of fMRI in psychological studies and what the data collected actually means. fMRI relies on very impressive technology, unlike MRI it attempts to measure brain activity, usually when it is engaged in various tasks. Scans in the normal population are hugely variable so single scans tell us very little and the main differences seen in repeated scans are usually context dependent. This means that 1-3 scans won't tell you much about anything. The next problem is the scans represent the activity seen in an area of the brain (a voxel) these will typically include a large number of neurones, many of which will not be related to the primary questions. Neurones when firing may be involved in activating or inhibiting their target neurones, we don't know which, and the speed of neural activity cannot be matched by the machine. Even more problematic is the fact the neurone function cannot be measured itself, so what is measured is the amount of oxygen used metabolically in that region of tissue. This is a proxy measure, with a time delay, of an average level of activity over a length of time. The machine's sensitivity makes these signals prone to error, and the massive amount of data generated requires extensive filtering by computers. There are lots of other issues but I did wonder if the differences claimed were greater than individual differences, this has been a significant issue in other gender studies.

Of course adolescence is a time of significant change and girls generally start many transitions earlier than boys, these changes occur across the body, not just in the brain. In fact the majority of studies on mood during this period focus on the massive changes in social issues, depression rating scales tend to identify specific issues rather than just mood.

We then drift into the swamp that is the genetics of mental illness, but I'll let you read a few bits, these appear to represent the current consensus on these issues.

https://www.cambridge.org/core/jour...n-depression/0770B51752F17A5A081F9878B0952608

https://www.ndcn.ox.ac.uk/divisions/fmrib/what-is-fmri/how-is-fmri-used

https://pubmed.ncbi.nlm.nih.gov/33333475/