scholarly journals Neural mechanisms underlying the precision of visual working memory

2018 ◽  
Author(s):  
Yijie Zhao ◽  
Shuguang Kuai ◽  
Theodore P. Zanto ◽  
Yixuan Ku

AbstractThe neural mechanisms associated with the limited capacity of working memory has long been studied, but it is still unclear how the brain maintains the fidelity of representations in working memory. Here, an orientation recall task for estimating the precision of visual working memory was performed both inside and outside an fMRI scanner. Results showed that the trial-by-trial recall error (in radians) was correlated with delay period activity in the lateral occipital complex (LOC) during working memory maintenance, regardless of the memory load. Moreover, delay activity in LOC also correlated with the individual participant’s precision of working memory from a separate behavioral experiment held two weeks prior. Furthermore, a region within the prefrontal cortex, the inferior frontal junction (IFJ), exhibited greater functional connectivity with LOC when the working memory load increased. Together, our findings provide unique evidence that the LOC supports visual working memory precision, while communication between the IFJ and LOC varys with visual working memory load.

2012 ◽  
Vol 25 (0) ◽  
pp. 58
Author(s):  
Katrina Quinn ◽  
Francia Acosta-Saltos ◽  
Jan W. de Fockert ◽  
Charles Spence ◽  
Andrew J. Bremner

Information about where our hands are arises from different sensory modalities; chiefly proprioception and vision. These inputs differ in variability from situation to situation (or task to task). According to the idea of ‘optimal integration’, the information provided by different sources is combined in proportion to their relative reliabilities, thus maximizing the reliability of the combined estimate. It is uncertain whether optimal multisensory integration of multisensory contributions to limb position requires executive resources. If so, then it should be possible to observe effects of secondary task performance and/or working memory load (WML) on the relative weighting of the senses under conditions of crossmodal sensory conflict. Alternatively, an integrated signal may be affected by upstream influences of WML or a secondary task on the reliabilities of the individual sensory inputs. We examine these possibilities in two experiments which examine effects of WML on reaching tasks in which bisensory visual-proprioceptive (Exp. 1), and unisensory proprioceptive (Exp. 2) cues to hand position are provided. WML increased visual capture under conditions of visual-proprioceptive conflict, regardless of the direction of visual-proprioceptive conflict, and the degree of load imposed. This indicates that task-switching (rather than WML load) leads to an increased reliance on visual information regardless of its task-specific reliability (Exp. 1). This could not be explained due to an increase in the variability of proprioception under secondary working memory task conditions (Exp. 2). We conclude that executive resources are involved in the relative weighting of visual and proprioceptive cues to hand position.


2019 ◽  
Vol 82 (3) ◽  
pp. 1290-1303
Author(s):  
Jason Rajsic ◽  
Matthew D. Hilchey ◽  
Geoffrey F. Woodman ◽  
Jay Pratt

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