Gözenman F, Tanoue RT, Metoyer T, Berryhill ME (2014). Invalid retrocues can eliminate the retrocue benefit: Evidence for a hybridized account...

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Gözenman F, Tanoue RT, Metoyer T, Berryhill ME (2014). Invalid retrocues can eliminate the retrocue benefit: Evidence for a hybridized account. Journal of Experimental Psychology: Human Perception and Performance, 40(5):1748-54.
[ DOI: 10.1037/a0037474. PMCID: PMC4172509. ]

Abstract

The contents of visual working memory (VWM) are capacity limited and require frequent updating. The retrospective cueing (retro-cueing) paradigm clarifies how directing internal attention among VWM items boosts VWM performance. In this paradigm a cue appears prior to retrieval, but after encoding and maintenance. The retro-cue effect (RCE) refers to superior VWM after valid versus neutral retro-cues. Here we investigated the effect of the invalid retro-cues’ inclusion on VWM performance. We conducted 2 pairs of experiments, changing both probe type (recognition and recall) as well as presence and absence of invalid retro-cue trials. Furthermore, to fully characterize these effects over time, we used extended post-retro-cue delay durations. In the first set of experiments, probing VWM using recognition indicated that the RCE remained consistent in magnitude with or without invalid retro-cue trials. In the second set of experiments, VWM was probed with recall. Here, the RCE was eliminated when invalid retro-cues were included. This finer-grained measure of VWM fidelity showed that all items were subject to decay over time. We conclude that the invalid retro-cues impaired the protection of validly cues items, but they remain accessible, suggesting greater concordance with a prioritization account.

Janczyk M, Berryhill ME (2014). Orienting attention in visual working memory requires central capacity: Decreased retrocue effects under dualtask conditions. Attention, Perception and Psychophysics...

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Janczyk M, Berryhill ME (2014). Orienting attention in visual working memory requires central capacity: Decreased retrocue effects under dualtask conditions. Attention, Perception and Psychophysics, 76, 715-724.
[ DOI 10.3758/s134140130615x. PMCID: PMC4080723. ]

Abstract

The retro-cue effect (RCE) describes superior working memory performance for validly cued stimulus locations long after encoding has ended. Importantly, this happens with delays beyond the range of iconic memory. In general, the RCE is a stable phenomenon that emerges under varied stimulus configurations and timing parameters. We investigated its susceptibility to dual-task interference to determine the attentional requirements at the time point of cue onset and encoding. In Experiment 1, we compared single- with dualtask conditions. In Experiment 2, we borrowed from the psychological refractory period paradigm and compared conditions with high and low (dual-) task overlap. The secondary task was always binary tone discrimination requiring a manual response. Across both experiments, an RCE was found, but it was diminished in magnitude in the critical dual-task conditions. A previous study did not find evidence that sustained attention is required in the interval between cue offset and test. Our results apparently contradict these findings and point to a critical time period around cue onset and briefly thereafter during which attention is required.

Peterson DJ, Gurariy G, Dimotsantos GG, Arciniega H, Berryhill ME, Caplovitz GP (2014). The steady-state visual evoked potential reveals neural correlates of the items...

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Peterson DJ, Gurariy G, Dimotsantos GG, Arciniega H, Berryhill ME, Caplovitz GP (2014). The steadystate visual evoked potential reveals neural correlates of the items encoded into visual working memory. Neuropsychologia, 63, 145-153.
[ DOI: 10.1016/j.neuropsychologia.2014.08.020. PMCID: PMC4194158. ]

 

Abstract

Visual working memory (VWM) capacity limitations are estimated to be 4 items. Yet, it remains unclear why certain items from a given memory array may be successfully retrieved from VWM and others are lost. Existing measures of the neural correlates of VWM cannot address this question because they measure the aggregate processing of the entire stimulus array rather than neural signatures of individual items. Moreover, this cumulative processing is usually measured during the delay period, thereby reflecting the allocation of neural resources during VWM maintenance. Here, we use the steadystate visual evoked potential (SSVEP) to identify the neural correlates of individual stimuli at VWM encoding and test two distinct hypotheses: the focused-resource hypothesis and the diffuse-resource hypothesis, for how the allocation of neural resources during VWM encoding may contribute to VWM capacity limitations. First, we found that SSVEP amplitudes were larger for stimuli that were later remembered than for items that were subsequently forgotten. Second, this pattern generalized so that the SSVEP amplitudes were also larger for the unprobed stimuli in correct compared to incorrect trials. These data are consistent with the diffuse-resource view in which attentional resources are broadly allocated across the whole stimulus array. These results illustrate the important role encoding mechanisms play in limiting the capacity of VWM.

Salazar RF, Dotson NM, Bressler SL, Gray CM (2012). Content specific fronto-parietal synchronization during visual working memory. Science, 338:1097-1100.

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Abstract

Lateral prefrontal and posterior parietal cortical areas exhibit task-dependent activation during working memory tasks in humans and monkeys. Neurons in these regions become synchronized during attention-demanding tasks, but the contribution of these interactions to working memory is largely unknown. Using simultaneous recordings of neural activity from multiple areas in both regions, we find widespread, task-dependent, and content-specific synchronization of activity across the fronto-parietal network during visual working memory. The patterns of synchronization are prevalent among stimulus-selective neurons and are governed by influences arising in parietal cortex. These results indicate that short-term memories are represented by large-scale patterns of synchronized activity across the fronto-parietal network.