New Working Memory Paradigm for Neuroimaging Testing of Visual and Verbal Modality under Different Attentional Involvement

Working memory (WM) is a cognitive function essential for short-term maintenance of information in a highly accessible state to support goal-directed behavior. The classical behavioral model of WM includes a visuospatial sketchpad, a phonological loop and the central executive. Neuroimaging studies selectively targeted the activity associated with maintenance and processing of modality specific information. However, an experimental design is still missing that would enable the assessment of all components of WM drawing a holistic neuroimaging model. In this study, we propose a modified paradigm based on the classical retro-cue task, which allows disentangling the activity of all WM components, and in particular of the central executive. This paradigm consists of five conditions: passive perception, simple verbal storage, simple visual storage, alphabetical reordering (complex verbal) and mental rotation (complex visual). Testing on a cohort of 35 healthy adults, we obtained a similar workload for simple storage conditions with a low engagement of the central executive. A different workload was verified between the simple and complex conditions in both verbal and visual modalities. This experimental design provides the framework to assess the neural activity associated with the central executive components in different modalities and to address the question of a unitary or modality-specific central executive nature. Therefore, the paradigm is suitable for utilization in neuroimaging to potentially advance our comprehension of the WM organization.