Flexible utilization of spatial- and motor-based codes for the storage of visuo-spatial information

Abstract

Working memory provides flexible storage of information in service of upcoming behavioral goals. Some models propose specific fixed loci and mechanisms for the storage of visual information in working memory, such as sustained spiking in parietal and prefrontal cortex during working memory maintenance. An alternative view is that information can be remembered in a flexible format that best suits current behavioral goals. For example, remembered visual information might be stored in sensory areas for easier comparison to future sensory inputs, or might be re-coded into a more abstract action-oriented format and stored in motor areas. Here, we tested this hypothesis using a visuo-spatial working memory task where the required behavioral response was either known or unknown during the memory delay period. Using functional magnetic resonance imaging (fMRI) and multivariate decoding, we found that there was less information about remembered spatial position in early visual and parietal regions when the required response was known versus unknown. Furthermore, a representation of the planned motor action emerged in primary somatosensory, primary motor, and premotor cortex during the same task condition where spatial information was reduced in early visual cortex. These results suggest that the neural networks supporting working memory can be strategically reconfigured depending on specific behavioral requirements during a canonical visual working memory paradigm.

Temporally dissociable mechanisms of spatial, feature, and motor selection during working memory-guided behavior

“…This is particularly important in the case of working memory (WM), a short-duration, capacity-limited system that forms a temporal bridge between fleeting sensory phenomena and possible actions (1)(2). Recent studies in humans, nonhuman primates, and rodents suggest a tight coupling between brain networks and circuits that control access to the contents of WM and those that control access to possible actions (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Complementary studies suggest that the human brain stores representations of sensory stimuli and prospective action plans in WM (15)(16)(17)(18) and can select task-relevant mnemonic and action representations in parallel to support rapid and efficient memory-guided behaviors (15).…”

“…Memory systems are useful only insofar as they can be used to inform current and future actions. Although several recent studies have examined circuit-, network-, and brain-level interactions between WM and motor planning during overt action (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18), few studies have examined the mechanisms responsible for prospective memoryguided actions. We leverage the high temporal precision of human EEG recordings to demonstrate that when planning a memory guided behavior the brain transitions from a visuomotor code to a motor-only code that persists until actions are executed (i.e., concurrent selection of visual and motor representations stored in memory followed by sustained selection of only motor representations; Fig 2C and Fig 3).…”

“…This is particularly important in the case of working memory (WM), a durationand capacity-limited system that forms a temporal bridge between fleeting sensory phenomena and possible actions (1). Recent theoretical conceptualizations of WM have begun to emphasize the action-oriented nature of this system (e.g., 2-5), and recent empirical findings suggest that behavioral (6)(7), circuit-level (8)(9)(10), and systems-level (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) mechanisms of WM storage and action planning are tightly interwoven.…”

Preparing for the unknown: How working memory provides a link between perception and anticipated action

“…In line with these findings, Henderson, Rademaker and Serences (2021) proposed that information stored in working memory can be represented in a rather flexible format, based on the requirements of the task at hand. For example, when it is required to compare the representation of a visual stimulus to a memory probe, the stored mental representation might be based on a “retrospective” visual code.…”

Changes in behavioral priority influence the accessibility but not the quality of working memory content

“…WM can be conceptualized as a temporal bridge between fleeting sensory phenomena and possible actions. Recent theoretical conceptualizations of WM have begun to emphasize the action-oriented nature of this system (e.g., Olivers & Roelfsema, 2020; Heuer et al, 2020; van Ede & Nobre, 2022), and recent empirical findings suggest that behavioral (Ohl & Rolfs, 2020), circuit-level (Pho et al, 2018; Tang et al, 2020; Panichello & Buschman, 2021), and systems-level (Chatham et al, 2014; van Ede et al, 2019; Boettcher et al, 2021; Galero-Salas et al, 2021; Rac-Lubashevsky & Frank, 2021; Henderson et al, 2022) mechanisms of WM storage and action planning are tightly interwoven. In dynamic contexts where the future can take on several possibilities, the (potential) behavioral relevance of information stored in WM is often unknown.…”