A Tale of Two Mothers

In 1967 two scientists, Sigi Levine and Victor Denenberg, made what seemed like minor observations. They noted that rat pups, when briefly handled during the first 7 days of their lives, demonstrated less ‘stress’ when they were fully mature.

The scientists noted that the non-handled animal reacted with a larger stress response – as measured by behavior and corticosterone levels. In other words, rat pups that were taken briefly from their home cage, gently stroked with a soft paintbrush, and then returned to their home cage, were emotionally different than pups that were not taken from the cage, not handled, not gently stroked with a soft paintbrush during their first seven days of life. And further that these handled pups, when mature, made more ‘discriminating’ decisions as to what warranted a full stress response and what did not. They had more control over fear. Something had changed. And whatever that something was lasted for the rest of the animals’ lives.

These seemingly ‘minor’ observations marked the beginning of experimental epigenetics. In other words, these minor observations were major.

A research team in Montreal headed by Michael Meaney, continued the investigations of Levine and Denenberg. They noted that when the pup was reunited with the dam, it was not the pup but the dam whose behavior changed.

“Formal observations showed that when the dam is reunited with the pups, she immediately approaches the pups, to restore maternal care followed by a sustained increase in several forms of maternal behaviors. These behaviors include increased licking and grooming (LG) and crouching over the pups in an active form of nursing known as arched-back nursing (ABN)" (Kaffman and Meaney 2007).

Meaney and his group selectively bred rat dams that naturally displayed the maternal characteristics of either low licking and grooming/low arched back nursing or high licking and grooming/high arched back nursing dams. The pups raised by high LG/ABN dams were emotionally different as adults than pups raised by low LG/ABN dams. The high LG/ABN pups when adult, showed less fear. They had more control over their response to stress.

But what caused this difference? Was it the pups' inheritance - their genes - or was it the environment - the behavior of the dam?

The pups were cross fostered. Pups that had been birthed to low LG/ABN dams were switched to the nests of high LG/ABN dams. Pups birthed to high LG/ABN dams were given to low LG/ABN dams.

When mature, the pups showed the characteristics of their rearing and not the characteristics of their inheritance. It was not the result of their inheritance (nature) that led to greater stress tolerance. It was the effect of the behavior of the dams (nurture).

The work of Meaney and colleagues demonstrated a specific effect of maternal licking and grooming/arched back nursing on the genome of the pup - in this case on the expression of the gene that codes for the glucocorticoid receptor, a critical component of the stress response. These findings were huge. They were the first biologic demonstration of the ‘causal mechanisms’ of environmental effects on the genome. They were the first biologic demonstration of epigenetics – of how the environment effects the expression of the gene.

My Mother's Illness

My mother suffered from bipolar depression. Throughout the pregnancy and for the first three months of my life, she was severely depressed. She had little interest in the world, little interest in me. She was the equivalent of a stressed, low licking, low grooming, low arched backed nursing dam.

And then twelve months after her illness began – that is to say, three months after I was born – my mother was hospitalized and received 16 rounds of electroconvulsive, or ‘shock’, therapy.

After the treatments, her depression ‘went away’. It was as if she had converted from a low licking and grooming/low arched back nursing dam, to a high licking and grooming/high arched back nursing dam.

It was as if I were being raised by a different dam.

It was as if I had two mothers.

“I watched, not sure I could trust my eyes,” our neighbor Katie Galst said. It was Katie Galst and my Aunt Fran who took care of me while my mother was ill. “Your mother came into the room, took you in her arms, and then just unbuttoned her shirt right then and there,” Katie Galst said remembering the day.

Stress Essential Reads

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“Ruthie, what are you doing?’ I said thinking maybe all that shock had gone to her head. ‘Ruthie?’ And she just dropped her shirt to the floor - ‘Ruthie?’ - I said, and then your mother just turned her back to me, and said, ‘Undo it.’”

“‘Undo it?’”

‘’‘I’d undo it myself but as you can see both of my hands - ’”

“So I undid her bra. And your mother just let it fall off her shoulder as she held you to her breast. And you took it. Like it was full. Like it was flowing,” Katie Galst said leaning back in her Lazy Boy chair. “We all knew she was dry, but you sucked like that didn’t matter.” Katie said closing he eyes. “Get me some water.”

There is reason to believe that the ‘quality’ of care that a dam gives to her pup is measured by the frequency of touch - the quantity not the quality being the measure of care. It’s the dam’s way of telling her pups about the world she foresees. The dam’s way of telling what kind of world her pups should expect when they grow. It’s the best information the pup will get.

The low licking and grooming, low arched back nursing dam is telling her pups a story about a world where they will find little food and many cats. She is telling them a story that puts their stress response system on alert.

It is as if she is telling her pups not to expect. Not to trust. It is as if she is saying that if you learn anything from my lack of touch, learn not to care. Learn not to bond. Not to love. Not to breed. Or if you must, do it quickly, then leave.

And one other thing, my breasts are dry. You will encounter a world without milk, without honey. And there will be cats. Many cats.

“All cellular processes derive from a constant dialogue between the genome and environmental signals” (Meaney, 2010).

Two Mothers

And then three months after delivering me to the world, another dam, another mother came back.

My second mother was different from my first. She touched, she smiled, she hugged. She was more like a high licking, high grooming, high arched back nursing dam. And she brought a different view of the world. Her frequency of touch told a different story about the world.

Three months after my birth, my second mother arrived.

I had two mothers. One mother was low licking and grooming. The other was high.

The stories told by each of my mothers, prepared me for worlds each as different as were they.

They each told stories narrated by hormones, neurotransmitters, epigenetic factors, and genes. Stories about the world that lay ahead, as each one saw coming.

Two stories as told by two mothers - through behavior and touch. Different signals from the dam led to different pathways in the pup.

I had ‘two’ mothers. Each with different signals. Different brushes. Different stories.

I had two mothers.

Different touch.