People have typically viewed the benefits that accrue with social status primarily from the perspective of external rewards. A new paper in the February 1st issue of Biological Psychiatry, published by Elsevier suggests that there are internal rewards as well.


Dr. Martinez and colleagues found that increased social status and
increased social support correlated with the density of dopamine D2/D3
receptors in the striatum, a region of the brain that plays a central
role in reward and motivation, where dopamine plays a critical role in
both of these behavioral processes.


The researchers looked at social status and social support in normal healthy volunteers who were scanned using positron emission
tomography (PET), a technology that allowed them to image dopamine type
2 receptors in the brain.

This data suggests that people who achieve greater social status are more likely to be able to experience life as
rewarding and stimulating because they have more targets for dopamine
to act upon within the striatum.


Dr. Martinez explains their findings: "We showed that low levels of dopamine receptors were associated with low social status and
that high levels of dopamine receptors were associated with higher
social status. The same type of association was seen with the
volunteer's reports of social support they experience from their
friends, family, or significant other."


Dr. John Krystal, Editor of Biological Psychiatry
commented, "These data shed interesting light into the drive to achieve
social status, a basic social process. It would make sense that people
who had higher levels of D2 receptors, i.e., were more highly motivated
and engaged by social situations, would be high achievers and would
have higher levels of social support."


These data also may have implications for understanding the vulnerability to alcohol and substance abuse, as the work of Dr. Nora
Volkow, the Director of the National Institute on Drug Abuse, and
colleagues suggests that low levels of D2/D3 receptors may contribute
to the risk for alcoholism among individuals who have family members
who abuse alcohol. The current data suggest that vulnerable individuals
with low D2/D3 receptors may be vulnerable to lower social status and
social supports, and these social factors have previously been
suggested as contributors to the risk for alcohol and substance use.


These findings are particularly exciting because they put human neurobiology into a social context, and we humans are
fundamentally social creatures. It is in these social contexts that the
biological effects on behavior obtain their real meaning.

Martinez et al. "Dopamine Type 2/3 Receptor Availability in the Striatum and Social Status in Human Volunteers." Biological Psychiatry, 2010; 67 (3): 275 DOI: 10.1016/j.biopsych.2009.07.037

Even with the best of available treatments, over a third of patients with depression may not achieve a satisfactory antidepressant response. Deep brain stimulation (DBS), a form of targeted electrical stimulation in the brain via implanted electrodes, is now undergoing careful testing to determine whether it could play a role in the treatment of patients who have not sufficiently improved during more traditional forms of treatment.


A major challenge of this work is determining the best region of the brain to stimulate. Some researchers stimulate the subgenual prefrontal cortex, a brain region implicated in depressed mood states, while others stimulate a region called the "anterior limb of the internal capsule", a nerve pathway that passes through the basal ganglia, a lower brain region.


Physicians publishing a new report in Biological Psychiatry now describe findings related to the stimulation of the nucleus accumbens, a brain region the size of a hazelnut associated with reward and motivation that is implicated in processing pleasurable stimuli, sometimes referred to as the "pleasure center" of the brain.


The inability to experience pleasure is a key symptom of depression and previous studies have shown that functioning of the nucleus accumbens is impaired in depressed individuals.


Bewernick and colleagues administered DBS treatment in ten patients with severe long-term depression who had not responded to multiple other antidepressant treatments, including psychotherapy, drug treatments and electroconvulsive treatment.


After one year of DBS, all patients showed some improvement, and half of them experienced significant improvement in their symptoms of depression, astonishing considering they had not responded to any prior antidepressant treatment. In addition, the patients showed reduced ratings of anxiety and had only minor side effects.


Importantly, none of their overall brain functioning was impaired by the DBS treatment.


"The nucleus accumbens is a brain region that animals will seek to stimulate even if they do not appear depressed and this is one reason that it is sometimes referred to as a reward center" said Dr. John Krystal, Editor of Biological Psychiatry.

"It is interesting to note that the patients in this study did not simply feel stimulated or euphoric; instead, there appeared to be reductions in depressed mood that paralleled an increase in the capacity for pleasure" he said.


"This finding will stimulate further study on the role of the nucleus accumbens in depression and its treatment."


The authors caution that because they studied only a small number of people, further research is necessary before DBS could be considered a clinically useful treatment for treatment-resistant depression.


There are also important ethical considerations, since DBS treatment first requires potentially risky brain surgery. However, these preliminary findings are promising that DBS may provide relief to individuals with severe treatment-resistant depression.