Luber Bruce, Jangraw David C, Appelbaum Greg, Harrison Austin, Hilbig Susan, Beynel Lysianne, Jones Tristan, Sajda Paul, Lisanby Sarah H
Department of Psychiatry and Behavioral Science, Duke University School of Medicine, Durham, NC, United States.
Department of Biomedical Engineering, Columbia University, New York, NY, United States.
Front Hum Neurosci. 2020 Jan 24;14:4. doi: 10.3389/fnhum.2020.00004. eCollection 2020.
Previous research has suggested that the lateral occipital cortex (LOC) is involved with visual decision making, and specifically with the accumulation of information leading to a decision. In humans, this research has been primarily based on imaging and electroencephalography (EEG), and as such only correlational. One line of such research has led to a model of three spatially distributed brain networks that activate in temporal sequence to enable visual decision-making. The model predicted that disturbing neural processing in the LOC at a specific latency would slow object decision-making, increasing reaction time (RT) in a difficult discrimination task. We utilized transcranial magnetic stimulation (TMS) to test this prediction, perturbing LOC beginning at 400 ms post-stimulus onset, a time in the model corresponding to LOC activation at a particular difficulty level, with the expectation of increased RT. Thirteen healthy adults participated in two TMS sessions in which left and right LOC were stimulated separately utilizing neuronavigation and robotic coil guidance. Participants performed a two-alternative forced-choice task selecting whether a car or face was present on each trial amidst visual noise pre-tested to approximate a 75% accuracy level. In an effort to disrupt processing, pairs of TMS pulses separated by 50 ms were presented at one of five stimulus onset asynchronies (SOAs): -200, 200, 400, 450, or 500 ms. Behavioral performance differed systematically across SOAs for RT and accuracy measures. As predicted, TMS at 400 ms resulted in a significant slowing of RT. TMS delivered at -200 ms resulted in faster RT, indicating early stimulation may result in priming and performance enhancement. Use of TMS thus causally demonstrated the involvement of LOC in this task, and more broadly with perceptual decision-making; additionally, it demonstrated the role of TMS in testing well-developed neural models of perceptual processing.
先前的研究表明，枕外侧皮层（LOC）参与视觉决策，特别是参与导致决策的信息积累过程。在人类中，这项研究主要基于成像和脑电图（EEG），因此只是相关性的。这类研究中的一条线索导致了一个由三个空间分布的脑网络组成的模型，这些网络按时间顺序激活以实现视觉决策。该模型预测，在特定潜伏期干扰LOC中的神经处理会减慢物体决策速度，在困难的辨别任务中增加反应时间（RT）。我们利用经颅磁刺激（TMS）来测试这一预测，从刺激开始后400毫秒开始干扰LOC，这个时间在模型中对应于特定难度水平下的LOC激活，预期会增加反应时间。13名健康成年人参加了两次TMS实验，在实验中利用神经导航和机器人线圈引导分别刺激左右LOC。参与者执行一项二选一的强制选择任务，在视觉噪声中判断每次试验中是否有汽车或面部出现，视觉噪声经过预测试以接近75%的准确率水平。为了干扰处理过程，在五个刺激起始异步（SOA）之一：-200、200、400、450或500毫秒，呈现间隔50毫秒的成对TMS脉冲。在反应时间和准确率测量方面，行为表现因SOA不同而有系统地差异。如预测的那样，400毫秒时的TMS导致反应时间显著减慢。-200毫秒时施加的TMS导致反应时间加快，表明早期刺激可能导致启动和表现增强。因此，TMS的使用因果性地证明了LOC参与这项任务，更广泛地说，参与了感知决策；此外，它还证明了TMS在测试完善的感知处理神经模型中的作用。
