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The neurobiology of risk: the ventral striatum

The ventral striatum is a relatively small area tucked deep inside the brain near the basal ganglia. Until recently, not much was known about it. But it’s recently been linked to reward, decisions, and risk, and as a result is getting much more press than it used to. It’s important in what we perceive as rewarding (such as status and keeping up with the Joneses) and how rewarding it is. It’s been linked to pathological gambling, and it matters when you’re thinking about what to do next with your portfolio.

The ventral striatum consists of two portions, the nucleus accumbens and the olfactory tubercle. Its most important neurotransmitter–to our current knowledge–is dopamine. Dopamine is associated with pleasure and with motor functions. (Dopamine-increasing drugs are used to treat Parkinson’s disease.) The ventral striatum is closely linked with the limbic system, which involves emotion and motivation: it receives input from it and sends output to it, mainly inhibitory. It’s thought that the ventral striatum helps to suppress certain mechanisms in the limbic system, thereby selecting the appropriate ones and silencing others.

When you consider all that, it’s a natural nominee for the reward center of the brain, and that seems to be its function. There have been several studies recently that look at different kinds of reward, and they all light up the ventral striatum. As described in the Society for Neuroscience, anticipating financial gain increases dopamine in the ventral striatum, which increases pleasure. Thinking about loss, on the other hand, decreases dopamine. It turns out that most people are more sensitive to decreases of dopamine than increases, which is where risk aversion comes from. The ventral striatum tells your limbic system that the behavior you’re considering is risky or that the loss you’ve just suffered is a bad thing, and the limbic system tells your conscious mind that it feels bad about what just happened, which affects your decision-making.

The ventral striatum is a tiny structure with big effects on our behavior. Most of decision-making, including financial decision-making, includes processing risk, which includes weighing rewards and losses. The ventral striatum is instrumental in modulating those behaviors and processes.

Gardening is good for the mind, body, and pocketbook

My garden is just getting into full swing. The lettuce and spinach are just about ready to pick; the onions and leeks are slender versions of their mature selves; the carrots and dill are putting out their delicate foliage. I’ve got squash and melon plants waiting for slightly warmer weather, but when that warmer weather hits, my yard will be full of good things to eat.

Why post this in Money and Minds? Because gardening is good for your mind, body, and pocketbook.

Digging in the dirt has actually been found to be beneficial for mood. A Neuroscience article last year described the finding that bacteria in the soil may have the same effect as antidepressants. Antidepressants work by increasing the amount of serotonin, a neurotransmitter, in the brain, which then goes on to affect various brain structures. Current neurotransmitters either reduce the brain’s ability to inactive serotonin (MAOs) or slow its ability to remove it from synapses where it does its work (SSRIs). These bacteria, on the other hand, cause neurons to release more serotonin. The result: if you’ve got your hands in the dirt, you may be happier.

Anyone who’s done gardening–any yardwork at all, in fact–knows it can be a workout. Researchers have found that any daily physical activity, including housework, gardening, and sports, is correlated with lower risk of psychological distress. The minimum level of activity that showed a benefit was 20 minutes per week, but the more activity, the better the mood. And being more active helps keep your body fit, which improves your self-image and, ultimately, benefits your bank account through fewer doctor’s visits and medications.

And the benefit of vegetable gardening to the pocketbook should be evident to anyone who’s buying food these days. When you’re saving money by shopping for produce in your backyard instead of your local grocery, rising prices of gas and bread aren’t quite so painful. A packet of lettuce seed, for example, will cost you around $1.50, but contains enough seeds to keep you in salad for as many years as the seeds will last (around 5 years if you store them cool and dry). A single tomato plant, also around $3, will typically yield around ten pounds of tomatoes. And the taste is far superior to anything you can get at the grocery store.

Gardening gives you exercise, fresh vegetables, and a good mood, both from the serotonin and from the feeling of empowerment. Anyone with access to sunshine, water, and seeds can do it. You might have a few startup costs, but the price of a couple of bags of soil and a spade will be more than offset by the cheap, delicious, nutritious vegetables you can grow. If you’ve never gardened before, a book from the library or a search of the Internet will help you. Here are a few sites to start with:

It’s not too late to start a garden. We’ve just come upon the last frost date for many regions, which is when you want to wait to plant most vegetables. So consider digging in a bit of earth, growing some cheap food, and reaping the benefits.