Abad-Hernando, S. 1 , Calvo-Merino, B. 1 , Galvez-Pol, A. 2, 1 & Forster, B. . 1
1 Cognitive Neuroscience Research Unit (CNRU), City, University of London
2 Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London
How do we represent observed actions in working memory? Could we differentiate between perceptual or functional roles of embodiment? Recent studies already suggest we hold information in working memory (WM) differently when it contains body information. It has been shown that visual encoding of body stimuli engages electrophysiological activity not only in visual cortices, but also in body-related areas. It was found that persistent activity increased in somatosensory cortex (SCx) only when maintaining body images in WM, whereas visual/posterior regions' activity increased significantly when maintaining non-body images (Galvez-Pol et al, 2018). The aim of this study is to clarify whether this activity is triggered by body stimuli per se, or modulated by the degree in which we embody that stimuli. For this purpose, participants performed a visual WM task (Vogel and Machizawa 2004) in which items to-be-remembered were coloured hand images (depicting 6 different hand positions and in 6 different colours). Each memory array consisted of 1 or 2 hands in each hemifield. In 50% of the trials, we elicited simultaneously VEPs and SEPs by applying task-irrelevant single tactile taps simultaneously delivered to both hands. This allowed us to do a later subtraction in order to isolate and examine the state of the somatosensory cortex (SCx) free of visually evoked activity, exposing its underlying processing during memory encoding and maintenance. We test if SCx areas involved in holding body information in memory are sensitive to the degree of embodiment elicited by different tasks while using the same body stimuli. This study will help us to dissociate the perceptual-functional roles on how working memory encodes body-related information.