Illustrating the Cost of Neglect

- Image from the Society for Neuroscience

These are two pictures of rat's brains. The rat whose brain we see on the left was raised in a lab with its mother and littermates. The rat on the right was part of a group that, in the words of Brain Briefings,

... [was] removed from their moms and placed in an incubator as a group for a few hours a day for several days.

So what are the brown spots you ask? Dead neurons. Killed by what? The study continues:

.. lack of touch triggers an inappropriate activation of the stress system. Scientists found that merely stroking the infant rodents with a tiny brush could prevent many of the effects of the long separation.

This is quite an image.

I wonder if those scientists used a special brush to pet the rat pups or rigged their own. What is it about that touch, any touch really, that keeps those neurons alive? Is there a sweet spot for physical contact? Can you stroke a rat pup too much and stress it out? How does the stress of isolation differ from other kinds of stress?

- Tip of the Hat to Brain Briefings.