Eagle Dawn M, Baunez Christelle, Hutcheson Daniel M, Lehmann Olivia, Shah Aarti P, Robbins Trevor W
Department of Experimental Psychology, University of Cambridge, Cambridge, UK.
Cereb Cortex. 2008 Jan;18(1):178-88. doi: 10.1093/cercor/bhm044. Epub 2007 May 20.
The stop-signal reaction-time (SSRT) task measures inhibition of a response that has already been initiated, that is, the ability to stop. Human subjects classified as "impulsive," for example, those with attention deficit and hyperactivity disorder, are slower to respond to the stop signal. Although functional and structural imaging studies in humans have implicated frontal and basal ganglia circuitry in the mediation of this form of response control, the precise roles of the cortex and basal ganglia in SSRT performance are far from understood. We describe effects of excitotoxic fiber-sparing lesions of the orbitofrontal cortex (OF), infralimbic cortex (IL), and subthalamic nucleus (STN) in rats performing a SSRT task. Lesions to the OF slowed SSRT, whereas lesions to the IL or the STN had no effect. On the go-signal trials, neither cortical lesion affected go-trial reaction time (GoRT), but STN lesions speeded such latencies. The STN lesion also significantly reduced accuracy of stopping at all stop-signal delays, indicative of a generalized stopping impairment that was independent of the SSRT itself.
停止信号反应时间（SSRT）任务用于测量对已经启动的反应的抑制能力，即停止能力。例如，被归类为“冲动型”的人类受试者，如患有注意力缺陷多动障碍的人，对停止信号的反应较慢。尽管人类的功能和结构成像研究表明额叶和基底神经节回路参与了这种反应控制形式的调节，但皮质和基底神经节在SSRT表现中的精确作用仍远未明确。我们描述了在执行SSRT任务的大鼠中，眶额叶皮质（OF）、边缘下皮质（IL）和丘脑底核（STN）的兴奋性毒性纤维保留损伤的影响。OF损伤会减慢SSRT，而IL或STN损伤则没有影响。在启动信号试验中，两种皮质损伤均未影响启动试验反应时间（GoRT），但STN损伤会加快这种潜伏期。STN损伤还显著降低了在所有停止信号延迟时的停止准确性，表明存在一种与SSRT本身无关的普遍停止障碍。
