美國科學(xué)家近日表示,，對(duì)研究對(duì)象腦部掃描顯示能干的人和懶人的大腦在3個(gè)具體的區(qū)域會(huì)有所不同。
為了獎(jiǎng)賞而愿意努力工作的人們?cè)谄淠X部的叫做紋狀體(striatum)和皮層(ventromedial prefrontal cortex)的部位存在更多的對(duì)神經(jīng)發(fā)出信號(hào)的化學(xué)物質(zhì)多巴胺(dopamine),。這兩個(gè)區(qū)域都在與報(bào)酬獎(jiǎng)勵(lì)關(guān)聯(lián)的感覺和動(dòng)機(jī)導(dǎo)致個(gè)體行為發(fā)生變化方面,，發(fā)揮著重要作用。
然而在為了報(bào)酬而努力工作方面稍顯被動(dòng)的“懶人們”腦部,，其“前腦島”(anterior insula)區(qū)域存在更高含量的多巴胺,。而這一部位與情緒和危機(jī)感有關(guān)。
多巴胺是一種用來幫助細(xì)胞傳送脈沖的神經(jīng)傳導(dǎo)化學(xué)物質(zhì),。聯(lián)合執(zhí)導(dǎo)這一研究的美國范德堡大學(xué)(Vanderbilt University)心理學(xué)家邁克爾▪特雷德韋(Michael Treadway)說：“過去,，人們?cè)诶鲜笊砩系难芯拷Y(jié)果表明，多巴胺對(duì)于獎(jiǎng)勵(lì)動(dòng)機(jī)具有關(guān)鍵性作用,。但是這項(xiàng)研究提供給了我們關(guān)于多巴胺是如何決定獎(jiǎng)勵(lì)尋求者之間存在的個(gè)體差異的新信息,。”
以上研究結(jié)果發(fā)表在最新一期的《神經(jīng)科學(xué)雜志》上。（生物谷Bioon.com）
doi: 10.1523/JNEUROSCI.6459-11.2012
Dopaminergic Mechanisms of Individual Differences in Human Effort-Based Decision-Making
Michael T. Treadway1,*,Joshua W. Buckholtz1,2,*,Ronald L. Cowan3,4,6,Neil D. Woodward3,4,Rui Li5, M. Sib Ansari5,Ronald M. Baldwin5,Ashley N. wartzman1, Robert M. Kessler5, and David H. Zald1,3
Preferences for different combinations of costs and benefits are a key source of variability in economic decision-making. However, the neurochemical basis of individual differences in these preferences is poorly understood. Studies in both animals and humans have demonstrated that direct manipulation of the neurotransmitter dopamine (DA) significantly impacts cost/benefit decision-making, but less is known about how naturally occurring variation in DA systems may relate to individual differences in economic behavior. In the present study, 25 healthy volunteers completed a dual-scan PET imaging protocol with [18F]fallypride and d-amphetamine to measure DA responsivity and separately completed the effort expenditure for rewards task, a behavioral measure of cost/benefit decision-making in humans. We found that individual differences in DA function in the left striatum and ventromedial prefrontal cortex were correlated with a willingness to expend greater effort for larger rewards, particularly when probability of reward receipt was low. Additionally, variability in DA responses in the bilateral insula was negatively correlated with willingness to expend effort for rewards, consistent with evidence implicating this region in the processing of response costs. These findings highlight the role of DA signaling in striatal, prefrontal, and insular regions as key neurochemical mechanisms underlying individual differences in cost/benefit decision-making.
