Himmelheber A M, Sarter M, Bruno J P
Departments of Psychology and Neuroscience, Ohio State University, 31 Townshend Hall, 1885 Neil Avenue, Columbus, OH 43210, USA.
Brain Res Cogn Brain Res. 2000 Jun;9(3):313-25. doi: 10.1016/s0926-6410(00)00012-4.
Acetylcholine (ACh) efflux in the frontoparietal cortex was studied with in vivo microdialysis while rats performed in an operant task designed to assess sustained attention. Transferring animals from the baseline environment into the operant chambers elicited a robust increase in cortical ACh efflux that persisted throughout the 18-min pre-task period. Subsequent performance in the 36-min sustained attention task was associated with further significant increases in frontoparietal ACh efflux, while the termination of the task resulted in a delayed decline in ACh levels. Upon the 12-min presentation of a visual distracter (flashing houselight, 0.5 Hz) during task performance, animals initially developed a significant response bias to the left lever in the first 6-min distracter block, reflecting a reduction of attentional effort. Under continued conditions of increased attentional demand, performance recovered during the second 6-min distracter block. This return to attentional processing was accompanied by an increase in cortical ACh efflux, suggesting that the augmentation of attentional demand produced by the distracter elicited further increases in ACh release. The enhancement of cortical ACh efflux observed prior to task performance implies the presence of complex relationships between cortical ACh release and anticipatory and/or contextual factors related to operant performance and attentional processing. This finding, along with the further increases in cortical ACh efflux associated with task performance, extends hypotheses regarding the crucial role of cortical cholinergic transmission for attentional functions. Furthermore, the effects of the distracter stimulus provide evidence for a direct relationship between attentional effort and cortical ACh release.
在大鼠执行一项旨在评估持续注意力的操作性任务时，采用体内微透析技术研究了额顶叶皮质中的乙酰胆碱（ACh）外流情况。将动物从基线环境转移到操作性实验箱中，引发了皮质ACh外流的强劲增加，这种增加在18分钟的任务前阶段一直持续。随后在36分钟的持续注意力任务中的表现与额顶叶ACh外流的进一步显著增加相关，而任务结束导致ACh水平延迟下降。在任务执行期间，当呈现12分钟的视觉干扰物（闪烁的房屋灯，0.5赫兹）时，动物在最初的6分钟干扰物时间段内最初对左侧杠杆产生了显著的反应偏向，这反映了注意力努力的减少。在注意力需求增加的持续条件下，在第二个6分钟干扰物时间段内表现有所恢复。这种注意力处理的恢复伴随着皮质ACh外流的增加，表明干扰物引起的注意力需求增加引发了ACh释放的进一步增加。在任务执行前观察到的皮质ACh外流增强意味着皮质ACh释放与与操作性表现和注意力处理相关的预期和/或情境因素之间存在复杂关系。这一发现，连同与任务表现相关的皮质ACh外流的进一步增加，扩展了关于皮质胆碱能传递对注意力功能关键作用的假设。此外，干扰物刺激的效应为注意力努力与皮质ACh释放之间的直接关系提供了证据。
