Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di Tecnologia, Corso Bettini 31, 38068, Rovereto (TN), Italy.
Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di Tecnologia, Corso Bettini 31, 38068, Rovereto (TN), Italy; Butte College, Oroville, CA, 95965, USA.
Brain Stimul. 2023 May-Jun;16(3):715-723. doi: 10.1016/j.brs.2023.04.006. Epub 2023 Apr 14.
Attention optimizes the selection of visual information, while suppressing irrelevant visual input through cortical mechanisms that are still unclear. We set to investigate these processes using an attention task with an embedded to-be-ignored interfering visual input.
We delivered electrical stimulation to attention-related brain areas to modulate these facilitatory/inhibitory attentional mechanisms. We asked whether overtly training on a task while being covertly exposed to visual features from a visually identical but different task tested at baseline might influence post-training performance on the baseline task.
In Experiment one, at baseline subjects performed an orientation discrimination (OD) task using a pair of gratings presented at individual's psychophysical threshold. We then trained participants over three-day separate sessions on a temporal order judgment task (TOJ), using the exact same gratings but presented with different time offsets. On the last post-training session we re-tested OD. We coupled training with transcranial random noise stimulation (tRNS) over the parietal cortex, the human middle temporal area or sham, in three separate groups. In Experiment two, subjects performed the same OD task at baseline and post-training, while tRNS was delivered at rest during the same sessions and stimulation conditions as in Experiment one.
Results showed that tRNS over parietal cortex facilitated learning of the trained TOJ task. Moreover, we found a detrimental effect on the untrained OD task when subjects received parietal tRNS coupled with training (Experiment one), but a benefit on OD when subjects received stimulation while at rest (Experiment two).
These results clearly indicate that task-irrelevant information is actively suppressed during learning, and that this prioritization mechanism of selection likely resides in the parietal cortex.
注意力通过皮质机制优化视觉信息的选择，同时抑制不相关的视觉输入，但这些皮质机制尚不清楚。我们使用一项包含需忽略的干扰视觉输入的注意任务来研究这些过程。
我们对与注意力相关的脑区进行电刺激，以调节这些促进/抑制注意力的机制。我们想知道，在进行一项任务的显性训练的同时，隐性地暴露于在基线测试中视觉上相同但不同任务的视觉特征，是否会影响基线任务的训练后表现。
在实验一中，在基线时，被试使用呈现于个体感觉阈限的一对光栅进行方向辨别（OD）任务。然后，我们在三个单独的三天会议上使用相同的光栅，但呈现不同的时间偏移，对被试进行时间顺序判断任务（TOJ）的训练。在最后一次训练会议上，我们重新测试 OD。我们将训练与经颅随机噪声刺激（tRNS）相结合，分别在三个单独的组中刺激顶叶皮层、人类中颞区或假刺激。在实验二中，被试在基线和训练后进行相同的 OD 任务，而在相同的会议和刺激条件下，在休息时进行 tRNS 刺激。
结果表明，顶叶皮层的 tRNS 促进了训练 TOJ 任务的学习。此外，当被试在接受顶叶 tRNS 刺激的同时接受训练时，我们发现对未训练的 OD 任务有不利影响（实验一），但当被试在休息时接受刺激时，对 OD 任务有好处（实验二）。
这些结果清楚地表明，在学习过程中，任务不相关的信息被主动抑制，而这种选择的优先级机制可能位于顶叶皮层。
