Brain complexity: baby brains under study (Introduction)

by David Turell , Wednesday, July 11, 2018, 02:19 (2109 days ago) @ dhw

Changes in baby mice brains related to the Mother's care:

https://www.scientificamerican.com/article/early-life-experience-its-in-your-dna/?utm_s...

"The genome is the molecular signature of identity. The sequence of DNA contained in our genomes distinguishes each of us as unique individuals, and changes in that sequence are relatively rare. Genomic changes typically arise from rare errors during cell replication, or from exposure to carcinogens or radiation. Here, experience has an equally powerful capacity to change the genome, but only in cells of the brain. The care that a newborn receives in early life can have profound effects on psychological and intellectual growth. Attentive nurturing, feeding and grooming can reduce stress and anxiety and enhance psychological wellbeing. On the other hand, indifference can lead to increased anxiety and impaired psychological adjustment. This study reveals that one way the quality of early care could cause lifelong changes in behavior is by changing the brain’s genetic nature.

"In this study researchers identified natural differences in the quality and abundance of maternal care provided by mice based upon measures of time they spent grooming and nursing their pups. They identified groups of animals that provided either high or low maternal care. They then examined brains of their pups for differences in markers of genomic change.

"Many of the differences in the genomes of nerve cells are due to the presence of mobile genetic elements called retrotransposons. These are stretches of DNA that can be copied and, as the name suggests transposed or incorporated into other areas of the genome. This study measured the accumulation of these mobile genetic elements in the brain as a consequence of maternal care. Mobile genetic elements accumulated in specific regions of the brains of mouse pups if the pups had poor maternal care. If a pup was born to a mother animal that provided low maternal care, but raised by a mother animal that provided high maternal care that accumulation of mobile genetic elements was eliminated. This supported the idea that the accumulation of genetic elements was due to the care provided by the mothers rather than some inherited difference. Most of the excess was found in the hippocampus, a region of the brain involved in memory, but not in other regions of the brain, nor in a completely different organ like the heart, suggesting a very specific impact on brain mosaicism.

"The authors also report that the changes in levels of mobile genetic elements might in turn be mediated by a modification to the genomic DNA known as methylation. Methylation is not itself a change in the DNA sequence, but it can alter when and how DNA sequences are read and utilized by the cell. Pups raised with poor maternal care had decreased methylation of key regulatory sequences in the mobile genetic elements which in turn led to increased numbers of these elements and increases in their activity."

Comment: The mouse starts with a personality as a blank slate and everything that happens will impinge upon how the mouse turns out in personality structure. It shows the plasticity of the brain.