State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research, Beijing Normal University , Beijing , People's Republic of China.
Department of Psychiatry, University of Wisconsin-Madison , Madison, Wisconsin.
J Neurophysiol. 2019 Apr 1;121(4):1222-1231. doi: 10.1152/jn.00062.2019. Epub 2019 Mar 11.
Stimulus location is not always informative during visual short-term memory (VSTM) for nonspatial features. Nevertheless, there is considerable evidence for the automatic encoding and retention of location information, regardless of its task relevance. To explore the functional and neural bases of the representation of spatial context in VSTM for nonspatial information, functional magnetic resonance imaging was performed while subjects performed delayed recall for the orientation of individual stimuli. Stimulus location varied across trials, and although this information was irrelevant for task performance, multivariate pattern analysis decoding of stimulus location sustained across trials, and also the decoding strength, predicted the precision of the recall of orientation. The influence of spatial context on the representation of orientation was operationalized by comparing the orientation reconstructions with multivariate inverted encoding models (IEM) trained in location context-dependent vs. -independent data. Although orientation reconstructions were robust for both location-dependent and location-independent IEMs, they were markedly stronger for the former. Furthermore, the functional relevance of location context was demonstrated by the fact that only the location-dependent neural representations of stimulus orientation predicted recall precision. NEW & NOTEWORTHY Neural representation strength of stimulus location predicts the precision of visual short-term memory (VSTM) recall of nonspatial stimulus, even when this information is task irrelevant. Neural representations of nonspatial stimuli that incorporate location context are stronger than those that do not, and only the former representations are strongly linked to behavior. The contributions to nonspatial VSTM performance of the representation of location context are at least partly distinct from those of the representation of stimulus content.
刺激位置在视觉短期记忆（VSTM）中对于非空间特征并不总是有信息的。尽管如此，仍然有大量证据表明位置信息会自动编码和保留，而不管其任务相关性如何。为了探索在非空间信息的 VSTM 中空间上下文表示的功能和神经基础，当被试对单个刺激的方向进行延迟回忆时，进行了功能磁共振成像。刺激位置在试验中变化，尽管该信息与任务表现无关，但跨试验的刺激位置的多元模式分析解码仍然持续，并且解码强度也预测了方向回忆的准确性。通过比较在位置相关和位置无关数据中训练的多元倒置编码模型（IEM）的方向重建来实现空间上下文对方向表示的影响。尽管对于位置相关和位置无关的 IEM，方向重建都是稳健的，但对于前者更为明显。此外，位置上下文的功能相关性是通过以下事实证明的：只有刺激方向的位置相关神经表示可以预测回忆的准确性。新的和值得注意的是，刺激位置的神经表示强度可以预测非空间刺激的 VSTM 回忆的准确性，即使该信息与任务无关。包含位置上下文的非空间刺激的神经表示比不包含位置上下文的神经表示要强，而且只有前者的表示与行为有很强的联系。位置上下文表示对非空间 VSTM 性能的贡献至少部分不同于刺激内容表示的贡献。
