Previous studies indicated that, in specific conditions, pointing movements during encoding facilitate the recognition of spatial arrays in a working memory task. Another set of studies examined the representation of another person's actions and suggested that they are encoded in the same way as one's own actions. A different line of research have examined that imagining performing an action, and actually performing it, activates the same areas in the brain. Hence, given these findings, the present study is aimed at investigating the question of how self- performed movements, observed movements or imagined movements are represented and how they interact with visuo-spatial working memory. Lateralized Readiness Potentials (LRPs) and NoGo P3 are expected to give insights about the movement preparation, inhibition and monitoring in both a joint task setting and an individual setting. Participants will perform a task that requires the maintenance of two consecutive arrays of three or four items, one encoded only by visual observation, the other by visual observation accompanied by pointing movements (performed either by the participant or by the experimenter or imagined). We predict that movement- observation and imagination should result into facilitated array recognition, and that this effect should be similar to that produced by self-performed pointing movements. LRPs are expected to appear in each action condition (observation, imagination and execution) and NoGo P3 component is expected to appear for the NoGo trials the joint setting condition when it's not the participant's turn to point. We propose that this performance benefit reflects either motor simulation or richness of encoding.
The present study will provide the first evidence of performed, observed or imagined movements influencing the performance in a visuospatial working memory (VSWM) task in a joint setting. As a human neither we are alone nor we perform our activities in isolation. We interact with others, observe them, sometimes imitate them, or imagine ourselves or others doing a task, on a daily basis. For example, observing a bartender preparing a cup of coffee, your friend waving at you and you imitate them by waving back or imagining yourself doing the most important task of the day or mentally rehearsing your upcoming dance performance etc. Such mental processes are a subsequent part of our daily life. Hence it becomes an interesting question to investigate the influences of such processes on memory. To date, several researchers had compared the performance in a jointly performed task to that obtained when the same task was performed alone. Such studies are focused on ¿co-action¿, and therefore require two or more people to achieve a common goal during the task. Such scenarios can be seen very common in day to day life activities, such as lifting a table by two people, holding a cup of coffee from the bartender etc.; they require the participation of at least two people who need to comprehend each other¿s intentions in order to achieve the desired goal. These activities can be easily understood by co-acting individuals engaged in sport activities, or musical duets. Researchers are investigating the processes of action planning, coordination, control and co-execution of joint task in such scenarios (Sebanz et al. 2003; 2006; 2011; Obhi & Sebanz, 2011).
Present study will answer the open questions about the interaction of performed movements, observed movements or imagined movements, with visuospatial working memory. The topic has not been studied widely in spite of having a close relationship with daily life activities such as instructing directions to someone, learning the dance moves in time and space and observing the finger movements in musical instruments learning. Imagery plays a well-known role in rehearsal in a number of activities such as dance performances, sport activities etc. For example, while learning the ballet moves, some dancers rely on the observation of spatial configurations while some rely on imagery (Karen Bradley, 2006). Imagery has demonstrated positive effects in maintaining psychological states such as decreasing anxiety, enhancing self- confidence, self- efficacy and concentration (Garza & Feltz, 1998; Post & Wrisberg, 2012). Present study can also help stimulating research for the improvement of VSWM performance in patients with movement disorders such as Parkinson's disease (PD). A selective deficit in spatial working memory in mild to moderate PD takes place due to greater disruption of visuospatial processing circuits (Possin et al., 2008), where richness of encoding of the information via observation or imagination can be of great help. It can also be helpful moving forward in the direction of VSWM improvement in population with attention deficiency such as attention- deficit/ hyperactivity disorder (ADHD). Present study might also provide helpful tools for children with learning disabilities and dysthymic disorder.
Present study will uncover new directions for studies based on 'movement observation' and 'mental- imagery', which to date remains an open question of how the complex interaction between movement and VSWM happens. Our study is an effort to shade a light about how the observation of others' actions influences VSWM in a joint environment; in future, the present results might be useful to better understand disorders of spatial orientations and navigations and might inspire new rehabilitation techniques.