Childhood adversity wires the brain

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Chapter 10 endnote 14, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:

Cumulative imbalance in the body budget ​— ​say, from growing up in adversity, where you don’t feel safe or are deprived of basic necessities like nutritious food, quiet time to sleep, and so on ​— ​also changes the structure of your interoceptive network, rewiring your brain and reducing its ability to accurately regulate your body budget.

The human brain has an extended period of development after birth, through childhood into early adulthood, so that it wires itself to its surroundings. Early threat and deprivation wires the brain to predict and prepare for negative events that might no longer materialize, causing increased challenges in body-budget regulation (i.e., increased reactivity), imbalances in the autonomic, immune, and endocrine systems, accelerated aging, and illness.[1][2] This is sometimes called "biological embedding." Prolonged body-budgeting imbalances (sometimes called "allostatic load") lead to structural changes in key regions of the interoceptive system that regulate the body's budget (i.e., in viscerormotor regions), including:

  • the hippocampus (e.g., reduced volume, because the dendrites of neurons shrink and lose their spines, meaning they are less equipped to receive information from other neurons and therefore the brain is less equipped to learn)[3]
  • the medial prefrontal cortex (e.g., loss of gray matter volume)[4]
  • the anterior cingulate cortex (which is equivalent to the medial prefrontal cortex in rats; e.g., smaller gray matter volume and shortening of dendrites of neurons in Layers 2 and 3)[3][4][5]
  • the lateral orbitofrontal cortex (conflicting results; e.g., one study shows reduced gray matter volume but another shows expansion of dendritic tree in Layers 2 and 3)[3][4]
  • the anterior insula (e.g., reduced gray matter volume)[4]
  • the amygdala (e.g., dendrite growth, meaning they are more equipped to process prediction error and increase arousal)[3][5]

The overall picture, then, is a brain that is wired not to learn from prediction error well (i.e., poorer memory and impoverished conceptual system), and therefore not to predict as well, meaning the world is inherently less predictable (and more disruptive to the body's budget). If you combine this with the absence of others who can help regulate the child's body budget to begin with, and you have the recipe for making a brain that is prone to distress and wired for illness.

For other evidence, see [6][7][8][9][10][11][12][13][14][15].


Notes on the Notes

  1. ↑ Sheridan, Margaret A., and Katie A. McLaughlin. 2014. "Dimensions of early experience and neural development: deprivation and threat." Trends in Cognitive Sciences 18 (11): 580-585.
  2. ↑ Danese, A., and Bruce McEwen. 2012. "Adverse childhood experiences, allostasis, allostatic load, and age-related disease." Physiology and Behavior, 106: 29-39.
  3. ↑ 3.0 3.1 3.2 3.3 McEwen, Bruce S., Carla Nasca, and Jason D. Gray. 2015. "Stress effects on neuronal structure: Hippocampus, amygdala and prefrontal cortex." Neuropsychopharmacology Reviews, 41: 3-23.
  4. ↑ 4.0 4.1 4.2 4.3 Ansell, Emily B., Kenneth Rando, Keri Tuit, Joseph Guarnaccia, and Rajita Sinha. 2012 Cumulative adversity and smaller gray matter volume in medial prefrontal, anterior cingulate, and insula regions. Biol. Psychiatry 72, 57–64.
  5. ↑ 5.0 5.1 Callaghan, Bridget L., Regina M. Sullivan, Brittany Howell, and Nim Tottenham. 2014. "The International Society for Developmental Psychobiology Sackler Symposium: Early adversity and the maturation of emotion circuits — A cross-species analysis." Developmental Psychobiology 56 (8): 1635-1650.
  6. ↑ Hart, Heledd, and Katya Rubia. 2012. "Neuroimaging of child abuse: a critical review." Frontiers in Human Neuroscience 6 (52): 1-24. 
  7. ↑ Hanson, Jamie L., Annchen R. Knodt, Bartholomew D. Brigidi, and Ahmad R. Hariri. 2015. "Lower structural integrity of the uncinate fasciculus is associated with a history of child maltreatment and future psychological vulnerability to stress." Development and Psychopathology 27 (4pt2): 1611-1619.
  8. ↑ Hair, Nicole L., Jamie L. Hanson, Barbara L. Wolfe, and Seth D. Pollak. 2015. "Association of child poverty, brain development, and academic achievement." JAMA Pediatrics 169 (9): 822-829.
  9. ↑ Hanson, Jamie L., Brendon M. Nacewicz, Matthew J. Sutterer, Amelia A. Cayo, Stacey M. Schaefer, Karen D. Rudolph, Elizabeth A. Shirtcliff, Seth D. Pollak, and Richard J. Davidson. 2015. "Behavior problems after early life stress: Contributions of the hippocampus and amygdala." Biological Psychiatry 77 (4): 314-23.
  10. ↑ Caldwell, Jessica ZK, Jeffrey M. Armstrong, Jamie L. Hanson, Matthew J. Sutterer, Diane E. Stodola, Michael Koenigs, Ned H. Kalin, Marilyn J. Essex, and Richard J. Davidson. 2015. "Preschool externalizing behavior predicts gender-specific variation in adolescent amygdala, hippocampus, and prefrontal cortical volumes." PLoS ONE 10 (2): e0117453.
  11. ↑ Gorka, Adam X., Jamie L. Hanson, Spenser R. Radtke, and Ahmad R. Hariri. 2014. "Reduced hippocampal and medial prefrontal gray matter mediate the association between reported childhood maltreatment and trait anxiety in adulthood and predict sensitivity to future life stress." Biology of Mood & Anxiety Disorders, 4 (1): 12. 
  12. ↑ Hanson, Jamie L., Nicole Hair, Dinggang G. Shen, Feng Shi, John H. Gilmore, Barbara L. Wolfe, and Seth D. Pollak. 2013. "Family poverty affects the rate of human infant brain growth." PLoS ONE 8 (12): e80954.
  13. ↑ Hanson, Jamie L., Nagesh Adluru, Moo K. Chung, Andrew L. Alexander, Richard J. Davidson, and Seth D. Pollak. 2013. "Early neglect is associated with alterations in white matter integrity and cognitive functioning." Child Development 84 (5): 1566-78. 
  14. ↑ McGowan, Patrick O. and others. 2009. "Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse." Nature Neuroscience, 12(3): 342-348.
  15. ↑ Reviewed in Goldstein, Andrea N., and Matthew P. Walker. 2014. "The role of sleep in emotional brain function." Annual Review of Clinical Psychology 10: 679-708.
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