McGinty Vincent B, Grace Anthony A
Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Cereb Cortex. 2008 Aug;18(8):1961-72. doi: 10.1093/cercor/bhm223. Epub 2007 Dec 7.
Medial prefrontal cortex (mPFC) neurons respond to Pavlovian conditioned stimuli, and these responses depend on input from the basolateral amygdala (BLA). In this study, we examined the mPFC efferent circuits mediating conditioned responding by testing whether specific subsets of mPFC projection neurons receive BLA input and respond to conditioned stimuli. In urethane-anesthetized rats, we identified mPFC neurons that projected to the nucleus accumbens (NAcc) or to the contralateral mPFC (cmPFC) using antidromic activation. Stimulation of the BLA and Pavlovian conditioned odors selectively activated a subpopulation of ventral mPFC neurons that projected to NAcc, but elicited virtually no activation in mPFC neurons that projected to cmPFC. BLA stimulation typically evoked inhibitory responses among nonactivated neurons projecting to either site. These results suggest that the ventral mPFC-to-NAcc pathway may support behavioral responses to conditioned cues. Furthermore, because projections from the BLA (which also encode affective information) and the mPFC converge within the NAcc, the BLA may recruit the mPFC to drive specific sets of NAcc neurons, and thereby exert control over prefrontal cortical-striato-thalamocortical information flow.
内侧前额叶皮质（mPFC）神经元对巴甫洛夫条件刺激有反应，且这些反应依赖于来自基底外侧杏仁核（BLA）的输入。在本研究中，我们通过测试mPFC投射神经元的特定子集是否接受BLA输入并对条件刺激做出反应，来研究介导条件反应的mPFC传出回路。在乌拉坦麻醉的大鼠中，我们利用逆向激活鉴定出投射到伏隔核（NAcc）或对侧mPFC（cmPFC）的mPFC神经元。刺激BLA和巴甫洛夫条件气味选择性地激活了投射到NAcc的腹侧mPFC神经元亚群，但在投射到cmPFC的mPFC神经元中几乎没有引起激活。BLA刺激通常在投射到任一部位的未激活神经元中诱发抑制性反应。这些结果表明，腹侧mPFC到NAcc的通路可能支持对条件线索的行为反应。此外，由于来自BLA（也编码情感信息）和mPFC的投射在NAcc内汇聚，BLA可能招募mPFC来驱动特定组的NAcc神经元，从而对前额叶皮质-纹状体-丘脑-皮质信息流施加控制。
