Electrophysiological correlates of the flexible allocation of visual working memory resources

Abstract

1Visual working memory is a brief, capacity-limited store of visual information that is involved in 2 a large number of cognitive functions. To guide one's behavior effectively, one must efficiently 3 allocate these limited memory resources across memory items. Previous research has suggested 4 that items are either stored in memory or completely blocked from memory access. However, 5 recent behavioral work proposes that memory resources can be flexibly split across items based 6 on their level of task importance. Here, we investigated the electrophysiological correlates of 7 flexible resource allocation by manipulating the distribution of resources amongst systematically 8 lateralized memory items. We examined the contralateral delay activity (CDA), a waveform 9 typically associated with the number of items held in memory. Across three experiments, we 10 found that, in addition to memory load, the CDA flexibly tracks memory resource allocation. 11This allocation occurred as early as attentional selection, as indicated by the N2pc. Additionally, 12CDA amplitude was better-described when fit with a continuous model predicted by load and 13 resources together than when fit with either alone. Our findings show that electrophysiological 14 markers of attentional selection and memory maintenance not only track memory load, but also 15 the proportion of memory resources those items receive. 16

Fear not! Anxiety biases attentional enhancement of threat without impairing working memory filtering

“…Accordingly, there is evidence that unnecessary storage does not predict VWM performance as well as the preceding attentional control-related brain activity (Emrich & Busseri, 2015). In addition, several studies have found that a strict all-or-none memory filter (wherein all targets are let into memory and all distractors are denied access) is not sufficient to describe memory performance (Dube et al, 2017;Emrich et al, 2017;Salahub et al, 2019). The ability to flexibly allocate memory resources amongst items may be related to attentional control, a likely candidate for the underlying mechanism driving the relationship between anxiety and the mis-allocation of VWM resources observed in prior studies.…”

The role of meaning in visual working memory: Real-world objects, but not simple features, benefit from deeper processing.

“…Thus, we hypothesized that although there are object benefits even in studies with simultaneous presentations of a large number of items (i.e., Brady & Störmer, 2020), such conditions may nevertheless be among the most favorable conditions for simple stimuli and least favorable for realistic meaningful stimuli. In real-world scenarios where participants use visual working memory to perform tasks (e.g., holding in mind the target of an eye movement: Hollingworth et al 2008; or the target of an action: Ballard et al 1995;Hayhoe et al 2003), they are relatively unlikely to try to equally encode many stimuli at once, and instead to focus additional resources on more task-relevant stimuli (e.g., Salahub et al 2019) and encode stimuli sequentially (e.g., Ballard et al 1995).…”

Sensory Delay Activity: More than an Electrophysiological Index of Working Memory Load

“…1 The CDA was so-named by Vogel and Machizawa (2004) because it was found contralateral to task-relevant stimuli during the delay period of a memory task. However, as pointed out by Luria et al, (2016), the CDA has also been labelled the sustained posterior contralateral negativity (SPCN; , or the contralateral search activity (CSA; Emrich et al, 2019) to reflect the fact that this component can be elicited during tasks without a working memory delay period. While it remains unclear whether all observations of contralateral activity discussed here reflect a single phenomenon, for simplicity and consistency with the literature, we will use the umbrella term CDA to refer to lateralized delay activity elicited in visual tasks, and tactile CDA (or tCDA) when referring to tactile experiments.…”