Functionally segregated neural substrates for arbitrary audiovisual paired-association learning
Functionally segregated neural substrates for arbitrary audiovisual paired-association learning
复制标题
DOI：
10.1523/jneurosci.0636-05.2005
复制
发表时间：
2005-07-06
影响因子：
5.3
通讯作者：
Sadato, N
中科院分区：
文献类型：
--
作者：
Tanabe, HC;Honda, M;Sadato, N
为了阐明跨模关联学习过程中的神经基质及其动态，我们在延迟匹配样本任务的视听配对关联学习过程中进行了功能磁共振成像（MRI）。30名受试者参与了这项研究；15人完成了视听配对联想学习任务，其余的人完成了对照视听任务。每次试验包括连续呈现一对刺激。受试者被要求通过试错来识别预先定义的视听或视听配对。无论回答正确与否，每次试验都会给出反馈。在延迟期间，随着学习的进行，几个区域的MRI信号增加：与视觉或听觉区域相对应的单峰区域的跨峰活动增加，枕颞交界处和海马旁回的多峰反应增加。在视觉-视觉模内配对联想学习任务中没有观察到这种模式，这表明跨模联想可能是通过多模区结合单模感觉区域形成的。在视听任务和视-视任务中，颞上沟（STS）响应第二刺激和反馈的MRI信号在学习早期达到峰值，然后下降，表明无论刺激类型如何，STS都可能是配对联想形成的关键。与上述区域的活动变化相反，在两个任务的延迟期间，额顶叶回路都有持续的活动，这意味着形成和储存成对联想的神经基质与工作记忆回路不同。
To clarify the neural substrates and their dynamics during crossmodal association learning, weconducted functional magnetic resonance imaging (MRI) during audiovisual paired-association learning of delayed matching- to-sample tasks. Thirty subjects were involved in the study; 15 performed an audiovisual paired-association learning task, and the remainder completed a control visuo-visual task. Each trial consisted of the successive presentation of a pair of stimuli. Subjects were asked to identify predefined audiovisual or visuo-visual pairs by trial and error. Feedback for each trial was given regardless of whether the response was correct or incorrect. During the delay period, several areas showed an increase in the MRI signal as learning proceeded: crossmodal activity increased in unimodal areas corresponding to visual or auditory areas, and polymodal responses increased in the occipitotemporal junction and parahippocampal gyrus. This pattern was not observed in the visuo-visual intramodal paired-association learning task, suggesting that crossmodal associations might be formed by binding unimodal sensory areas via polymodal regions. In both the audiovisual and visuo-visual tasks, the MRI signal in the superior temporal sulcus (STS) in response to the second stimulus and feedback peaked during the early phase of learning and then decreased, indicating that the STS might be key to the creation of paired associations, regardless of stimulus type. In contrast to the activity changes in the regions discussed above, there was constant activity in the frontoparietal circuit during the delay period in both tasks, implying that the neural substrates for the formation and storage of paired associates are distinct from working memory circuits.