Article

Encoding and representation of simultaneous and sequential arrays in visuospatial working memory.

Colorado State University, Fort Collins, CO, USA.
Quarterly journal of experimental psychology (2006) (Impact Factor: 1.82). 03/2010; 63(5):856-62. DOI: 10.1080/17470211003690680
Source: PubMed

ABSTRACT The effect of presentation type on organization in visuospatial working memory (VSWM) was examined. Stimuli were presented sequentially or simultaneously at study, and participants made same/different judgements at test. The test array varied in four different spatial configuration conditions: one featuring no changes from study, one in which two items switched, one in which the same array repeated but in a different location, and one in which a completely novel test stimulus appeared. Results indicated the use of a global configuration for both simultaneous and sequential presentations and showed increased impairment of item-level knowledge with sequential presentations. Overall, these results support the use of a global configuration organization as a fundamental aspect of VSWM processing.

0 Bookmarks
 · 
108 Views
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The relationship between working memory (WM) and attention is a highly interdependent one, with evidence that attention determines the state in which items in WM are retained. Through focusing of attention, an item might be held in a more prioritized state, commonly termed as the focus of attention (FOA). The remaining items, although still retrievable, are considered to be in a different representational state. One means to bring an item into the FOA is to use retrospective cues ("retro-cues") which direct attention to one of the objects retained in WM. Alternatively, an item can enter a privileged state once attention is directed towards it through bottom-up influences (e.g., recency effect) or by performing an action on one of the retained items ("incidental" cueing). In all these cases, the item in the FOA is recalled with better accuracy compared to the other items in WM. Far less is known about the nature of the other items in WM and whether they can be flexibly manipulated in and out of the FOA. We present data from three types of experiments as well as transcranial magnetic stimulation (TMS) to early visual cortex to manipulate the item inside FOA. Taken together, our results suggest that the context in which items are retained in WM matters. When an item remains behaviorally relevant, despite not being inside the FOA, re-focusing attention upon it can increase its recall precision. This suggests that a non-FOA item can be held in a state in which it can be later retrieved. However, if an item is rendered behaviorally unimportant because it is very unlikely to be probed, it cannot be brought back into the FOA, nor recalled with high precision. Under such conditions, some information appears to be irretrievably lost from WM. These findings, obtained from several different methods, demonstrate quite considerable flexibility with which items in WM can be represented depending upon context. They have important consequences for emerging state-dependent models of WM.
    Frontiers in Human Neuroscience 01/2014; 8:853. · 2.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In everyday life, the brain is bombarded with a multitude of concurrent and competing stimuli. Only some of these enter consciousness and memory. Attention selects relevant signals for in-depth processing depending on current goals, but also on the intrinsic properties of stimuli. We combined behavior, computational modeling, and functional imaging to investigate mechanisms supporting access to memory based on intrinsic sensory properties. During fMRI scanning, human subjects were presented with pictures of naturalistic scenes that entailed high levels of competition between possible target objects. Following a retention interval of 8 s, participants judged the location (same/different) of a target object extracted from the initial scene. We found that memory performance at retrieval increased with increasing object salience at encoding, indicating a "prior entry" for salient information. fMRI analyses revealed encoding-related activation in the posterior parietal cortex, selectively for salient objects that were later remembered. Moreover, parietal cortex showed increased functional coupling with the medial-temporal lobe, for remembered objects only. These findings reveal a parietotemporal circuit that integrates available sensory cues (based on attention-grabbing saliency signals) and current memory requirements (storing objects' locations) to encode object-related spatial information in working memory.
    Journal of Neuroscience 02/2013; 33(9):4110-7. · 6.91 Impact Factor

Full-text (2 Sources)

Download
69 Downloads
Available from
May 20, 2014