Dipartimento di Psicologia 39, Sapienza Università di Roma, Roma, Italy; Laboratorio di Neuropsicologia, Fondazione Santa Lucia IRCCS, Roma, Italy.
Laboratorio di Neuropsicologia, Fondazione Santa Lucia IRCCS, Roma, Italy; Libera Università Maria Santissima Assunta - LUMSA, Roma, Italy.
Cortex. 2018 May;102:57-66. doi: 10.1016/j.cortex.2017.09.011. Epub 2017 Oct 3.
fMRI investigations in healthy humans have documented phasic changes in the level of activation of the right temporal-parietal junction (TPJ) during cued voluntary orienting of spatial attention. Cues that correctly predict the position of upcoming targets in the majority of trials, i.e., predictive cues, produce higher deactivation of the right TPJ as compared with non-predictive cues. Since the right TPJ is the recipient of noradrenergic (NE) innervation, it has been hypothesised that changes in the level of TPJ activity are matched with changes in the level of NE activity. Based on aforementioned fMRI findings, this might imply that orienting with predictive cues is matched with different levels of NE activity as compared with non-predictive cues. To test this hypothesis, we measured changes in pupil dilation, an indirect index of NE activity, during voluntary orienting of attention with highly predictive (80% validity) or non-predictive (50% validity) cues. In agreement with current interpretations of the tonic/phasic activity of the Locus Coeruleus-Norepinephrinic system (LC-NE), we found that the steady level of cue predictiveness that characterised both the predictive and non-predictive conditions caused, across consecutive blocks of trials, a progressive decrement in pupil dilation during the baseline-fixation period that anticipated the cue period. With predictive cues we observed increased pupil dilation as compared with non-predictive cues. In addition, the relative reduction in pupil size observed with non-predictive cues increased as a function of cue-duration. These results show that changes in the predictiveness of cues that guide voluntary orienting of spatial attention are matched with changes in pupil dilation and, putatively, with corresponding changes in LC-NE activity.
在健康人类的 fMRI 研究中，记录到在提示性自愿空间注意定向过程中，右侧颞顶联合区（TPJ）的激活水平呈阶段性变化。在大多数试验中，即预测性线索，正确预测即将到来目标位置的线索会导致右侧 TPJ 的去激活程度高于非预测性线索。由于右侧 TPJ 是去甲肾上腺素（NE）传入的受体，因此有人假设 TPJ 活动水平的变化与 NE 活动水平的变化相匹配。基于上述 fMRI 发现，这可能意味着与非预测性线索相比，使用预测性线索进行定向与不同水平的 NE 活动相匹配。为了检验这一假设，我们在使用高度预测性（80%有效性）或非预测性（50%有效性）线索进行自愿注意力定向时，测量了瞳孔扩张的变化，瞳孔扩张是 NE 活动的间接指标。与当前对蓝斑-去甲肾上腺素系统（LC-NE）的紧张/阶段性活动的解释一致，我们发现，两种预测性和非预测性条件的特征是线索预测性的稳定水平，在连续的试验块中，在预期线索期之前，在基线固定期，瞳孔扩张逐渐减少。与非预测性线索相比，我们观察到使用预测性线索时瞳孔扩张增加。此外，与非预测性线索相比，观察到的瞳孔大小相对减少随着线索持续时间的增加而增加。这些结果表明，引导自愿空间注意定向的线索的可预测性变化与瞳孔扩张变化相匹配，并且可能与相应的 LC-NE 活动变化相匹配。
