86Thousand400: The brain, depression & exercise link

When drugs don't work, exercise does. As of yet no-one has been able to find an antidepressant without side effects.

MRI scans point towards a radical notion: that chronic depression may cause structural damage in the thinking brain.

It’s known that the amygdala is central to our emotional life and it’s been shown that the hippocampus of depressed patients can be up to 15% smaller compared to that of the controls. It’s also been shown that the degree of shrinkage is directly related to the length of depression.

High levels of the stress hormone cortisol kill neurons in the hippocampus. If you put a neuron in a petri dish and flood it with cortisol, its vital connection to other cells retract. Fewer synapses develop and the dendrites wither. This causes a communication breakdown, which, in the hippocampus of a depressed brain, could partly explain why it gets locked into thinking negative thoughts - it's recycling a negative memory, perhaps because it can't branch out to form alternative connections.

We learned that new nerve cells are born every day in the hippocampus and possibly in the prefrontal cortex – however these two areas are shriveled in depressed patients.

Now we see depression as a physical alteration of the brain's emotional circuitry. Norepinephrine, dopamine, and serotonin are essential messengers that ferry information across the synapses, but without enough good connections in place, these neurotransmitters can only do so much.

As far as the brain is concerned, it's job is to transfer information and constantly re-wire itself to help us adapt and survive.

In depression, it seems that in certain areas, the brain's ability to adapt grinds to a halt. The shutdown in depression is a shutdown of learning at the cellular level. Not only is the brain locked into a negative loop of self-hate, but it also loses the flexibility to work its way out of the hole.

It's not just a matter of feeling empty, helpless, and hopeless. It affects learning, attention, energy, and motivation. Depression also affects the body, shutting down the drive to sleep, eat, have sex, and generally look after ourselves on a primitive level.

When the emotional landscape turns wintry, our neurobiology tells us to stay inside. Except that it can last much longer than a season. It's as if our entire being has said, there's nothing out there for me, so I may as well quit.

The flip side to this is to get out there and get moving and granted when things do look a little gloomy this is extremely tough, however if we can dig deep and look within ourselves we’ll realize there truly is more in us than one thinks!