Researchers used mice in controlled studies to explore this further.
In one study, female mice were prevented from nurturing their pups for up to 3 hours per day during the first 2 weeks of life. Later in life, their offspring exhibited behaviours similar to what we would see of depression in humans, worsening as they aged.
Some of the males did not express the behaviours themselves, but epigenetically transmitted the behavioural changes to their female offspring. The key gene involved was CRF2, which regulates anxiety.
It is commonly known that human infants who’ve been separated from their mothers can experience similar challenges as a result.
During a study in 2014 with rats at the University of Lethbridge in Canada, researchers examined the effects of stress on pregnant mothers and delivering preterm babies, who also bore daughters that had shortened pregnancies. Granddaughters of stressed grandmothers had shorter pregnancies than mothers who had not been stressed.
Stress can be transmitted through at least 3 generations.
The Brain Research Institute of the University of Zurich in 2014 subjected male mice to repeated and prolonged intense stress by separating them from their mothers. The mice displayed depression-like symptoms; their pups that followed in the next 2 generations also displayed the same symptoms of trauma despite never being exposed to it first-hand.
The microRNA was present in their sperm, blood, and hippocampi (the hippocampus is the region of the brain responsible for stress responses). This research demonstrates that trauma can also be passed on through the father to their offspring via their sperm.
Isabelle Monsuit, a professor in neuro-epigenetics, conducted an experiment with mice, separating them from their mothers, causing stress. They then placed the mice in water.
Those that were NOT traumatised, swam to escape.
Those that WERE traumatised, did not try to escape, and drowned.
In a study in 2016, researchers found that trauma symptoms could be reversed after they lived positive, low stress lives. Not only did they display different behaviours, BUT their DNA methylation expression was ALSO altered, thus not passing on to their offspring.
Another experiment that demonstrates how trauma can be shared through generations, was conducted by Emory University School of Medicine in 2013. Mice were trained to fear a scent similar to cherry blossom, known as acetophenone. Each time they were exposed to the scent, they would receive an electric shock. Over time they had a greater amount of smell receptors to that particular scent, meaning they could smell it at a lower concentration. Researchers could also identify changes in the mice’s sperm.
The next 2 generations, when exposed to the same scent, became nervous, jumpy, and avoided it, having never experienced it before. Their brains and sperm also had the same cellular response as the original mice.
Brian Dias, one of the researchers, suggested that there is something in the sperm that is informing that information to be inherited.
This demonstrates that they not only had the same sensitivity to the scent but also the same response to it, which becomes fascinating to humans, meaning that ancestors unknowingly have informed us of a particular environment that was negative for them.
Researcher’s term this “Transgenerational Epigenetic Inheritance” the notion that behaviours can pass from one generation to another: recurring patterns of illness, depression, anxiety, relationship struggles, financial problems and so on.
“Fractured parts of us need to be integrated”
Every time we experience trauma, we disconnect, and the trauma lies within our somatic memory, whether the trauma is ours or inherited. This creates holes in our core, we can’t self-regulate, and we REACT to experiences, instead of RESPONDING.
Experiences that don’t feel safe or are uncomfortable will cause an unconscious tightening, a lack of oxygen to that area holding the trauma, causing pain and disease.
For example, someone who cannot stand to hear a crying baby – the generations before them, babies were left to cry it out, this can trigger uncomfortable memories for them that they are unconsciously aware of.