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Slacker or go-getter? Everyone knows that people vary substantially in how hard they arewilling to work, but the origin of these individual differences inthe brain remains a mystery. Now the veil has been pushed back by a new brain imaging study thathas found an individual's willingness to work hard to earn money isstrongly influenced by the chemistry in three specific areas of thebrain. In addition to shedding new light on how the brain works,the research could have important implications for the treatment ofattention-deficit disorder, depression , schizophrenia and other forms of mental illness characterized by decreasedmotivation. The study was published May 2 in the Journal of Neuroscience and was performed by a team of Vanderbilt scientists includingpost-doctoral student Michael Treadway and Professor of PsychologyDavid Zald. Using a brain mapping technique called positron emission tomography(PETscan), the researchers found that "go-getters" who are willingto work hard for rewards had higher release of the neurotransmitterdopamine in areas of the brain known to play an important role inreward and motivation, the striatum and ventromedial prefrontalcortex. On the other hand, "slackers" who are less willing to workhard for a reward had high dopamine levels in another brain areathat plays a role in emotion and risk perception, the anteriorinsula. "Past studies in rats have shown that dopamine is crucial forreward motivation," said Treadway, "but this study provides newinformation about how dopamine determines individual differences inthe behavior of human reward-seekers." The role of dopamine in the anterior insula came as a completesurprise to the researchers. The finding was unexpected because itsuggests that more dopamine in the insula is associated with areduced desire to work, even when it means earning less money. Thefact that dopamine can have opposing effects in different parts ofthe brain complicates the picture regarding the use of psychotropicmedications that affect dopamine levels for the treatment ofattention-deficit disorder, depression and schizophrenia because itcalls into question the general assumption that these dopaminergicdrugs have the same effect throughout the brain. The study was conducted with 25 healthy volunteers (52 percentfemale) ranging in age from 18 to 29. To determine theirwillingness to work for a monetary reward, the participants wereasked to perform a button-pushing task. First, they were asked toselect either an easy or a hard button-pushing task. Easy tasksearned $1 while the reward for hard tasks ranged up to $4. Oncethey made their selection, they were told they had a high, mediumor low probability of getting the reward. Individual tasks lastedfor about 30 seconds and participants were asked to perform themrepeatedly for about 20 minutes. "At this point, we don't have any data proving that this 20-minutesnippet of behavior corresponds to an individual's long-termachievement," said Zald, "but if it does measure a trait variablesuch as an individual's willingness to expend effort to obtainlong-term goals, it will be extremely valuable." The research is part of a larger project designed to search forobjective measures for depression and other psychological disorderswhere motivation is reduced. "Right now our diagnoses for thesedisorders is often fuzzy and based on subjective self-report ofsymptoms," said Zald. "Imagine how valuable it would be if we hadan objective test that could tell whether a patient was sufferingfrom a deficit or abnormality in an underlying neural system. Withobjective measures we could treat the underlying conditions insteadof the symptoms." Further research is needed to examine whether similar individualdifferences in dopamine levels help explain the altered motivationseen in forms of mental illness such as depression and addiction . Additional research is under way to examine how medicationsspecifically impact these motivational systems. Additional References Citations. The e-commerce company in China offers quality products such as Bluetooth Keyboard for Blackberry Playbook , China Stylus Touch Screen Pen, and more. For more , please visit Portable Bluetooth Keyboards today!
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