Brain scans reveal critical periods for vulnerability

Navigating mental health challenges across the lifecourse (part two)

👋 Hi, this Shane O'Mara, writer of the BrainPizza Newsletter. I take a fresh look at life through an informed, empirical, neuroscience and psychology lens. I do regular in-depth treatments of topics such as our very human metabolism, George Orwell, AI hype, brain implants, memory, hunger, NIMBYism, thinking, how to write books, and much, much more, as well as occasional listicles, readings, book reviews, and commentaries. You can browse the archives here; if you’d like to get these regular in-depth emails in your inbox, you can subscribe here.¹

Last time

We discussed a series of recent papers showing that there is a silent epidemic of early death in people suffering mental disorders, and what might be done about it. Here, I want to underline that discussion with some recent findings regarding critical periods in development and how they relate to timing of particular types of mental disorders. A key idea is that there are particular critical or sensitive periods where particular conditions are more likely to develop, and that interventions prior to these critical periods might prevent mental health problems from developing in the first place.

Takeaways

• Critical periods or sensitive periods for development have long been understood as very important for brain development and brain health

• Early-life experiences profoundly shape brain development, influencing cognitive health across the lifespan.

• Recent large-scale brain scanning is very suggestive of ‘critical periods’ in brain development that may be best for targeting interventions

• Supportive interventions during critical periods are crucial for optimal brain function and for reducing the risk of cognitive decline.

• The intimate relationships between brain imaging milestones, brain development, and mental health calls for a paradigm shift in care.

• Understanding developmental trajectories can enhance mental health interventions beyond symptom management, promoting resilience throughout the lifecourse.

Brain Scans

Brain scans are great for all sorts of reasons - they give you lovely pictures of the brain at work; they can tell you if there is damage in a particular brain region (maybe), and they can (maybe) help with diagnoses of differing diseases of the brain.

Over the past 25 years, advances in brain imaging has transformed our understanding of the human brain, and in particular we are now starting to get a grip on the relationship between brain development, brain health, brain ageing, and the emergence of mental health disorders, as well as other diseases of the brain such as Alzheimer’s disease.

brain health

New brain mapping tools

An interactive online resource, www.brainchart.io, uses the largest and most diverse MRI brain imaging dataset available spanning prenatal to postnatal years: the published report says ‘MRI data were aggregated from over 100 primary studies comprising 123,984 scans that collectively spanned the age range from mid-gestation to 100 postnatal years’. This is an amazing achievement: a comprehensive analysis looking at individual differences against age-related trends and developmental milestones. There is an associated paper (preprint; final version, open access), and I want to draw a few points from the analyses presented in this paper.

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Relevant BrainPizza posts (subscribe):

• Brainstorming the Future

• Bad is stronger than good

• Dark thoughts, and how to avoid them

• Only disconnect: The pain of 'just thinking'

• How fear and pain rewire the brain, and what might be done about it

• In praise of 'mindlessness' - escaping self

• What we feel

• Therapeutic Conversations

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Critical periods for vulnerability

The figure below shows typical paths that brains follow as they grow, pointing out important stages in a person's life. There’s a lot going on the following image, and possibly the lower panel is of the greatest interest for present purposes (discussion below).