Sensory Recruitment in Visual Short-Term Memory: A Systematic Review and Meta-Analysis of Sensory Visual Cortex Interference Using Transcranial Magnetic Stimulation

Abstract

Visual short-term memory (VSTM) links perception with higher cognitive processes by maintaining visual information that is absent from the environment. Yet, it remains unclear if sensory visual cortex is a necessary component of the brain network that underlies short-term maintenance of visual information. Previous reviews remain inconclusive and open to interpretation. Here, we aimed to systematically identify and review studies that have investigated the role of the sensory visual cortex in VSTM using transcranial magnetic stimulation (TMS), a method that allows exploration of causal relationships, and to quantitatively explore the effect of TMS interference on the sensory visual cortex during VSTM using meta-analytic methodology. Thirteen studies were identified and qualitatively reviewed. Out of those, seven studies provided sufficient statistical data for meta-analysis and yielded a total of 30 effect sizes, which were included in the meta-analyses. Two meta-analyses were conducted, one regarding the encoding phase of VSTM (19 effect sizes), and one regarding the maintenance phase of VSTM (11 effect sizes). The results from the systematic review and the two meta-analyses indicate that the sensory visual cortex is likely involved in both the encoding and maintenance phase of VSTM. In some cases, evidence did not show significant effects of TMS, however, this is suggested to be due to low memory load or low perceptual task demands. Overall, these findings support the idea that sensory visual areas are part of the brain network responsible for successfully maintaining information in short-term memory when no physical stimulus is present in the environment.