Eye gaze metrics reflect a shared motor representation for action observation and movement imagery

Abstract

Action observation (AO) and movement imagery (MI) have been reported to share similar neural networks. This study investigated the congruency between AO and MI using the eye gaze metrics, dwell time and fixation number. A simple reach-grasp-place arm movement was observed and, in a second condition, imagined where the movement was presented from the first person perspective (1PP) and the third person perspective (3PP).Dwell time and number of fixations were calculated for whole scene and regions of interest (ROIs). For whole scene, no significant differences were found in the number of fixations for condition (AO, MI) or perspective. Dwell time, however, was significantly longer in AO than MI. For ROIs, the number of fixations was significantly greater in 1PP than 3PP. The data provide support for congruence between motor simulation states but also indicate some functional differences.

Congruency of gaze metrics in action, imagery and action observation

“…Their data suggested that nystagmic activity in the horizontal plane could be elicited during movement imagery providing evidence that eye movements could be used as an objective measure of online cognitive processes. More recent research has confirmed the significant role of eye movements in movement imagery with further evidence for functional congruence of eye movements between the covert and overt states (Heremans et al, 2008, 2011; McCormick et al, 2012, 2013). These studies are discussed later in this paper.…”

“…This indirect, objective experimental approach has been used successfully to compare behaviors between the observation and imagery by a number of research groups (Flanagan and Johansson, 2003; Heremans et al, 2009; McCormick et al, 2012). Collectively, the findings suggest there are similarities but also some discrete differences between the gaze metrics.…”

“…Specifically, the observer typically fixates the agent (generally the agent's head) and then the target (Webb et al, 2010; Letesson and Edwards, 2012; McCormick et al, 2012). It could be that the agent's gaze (and hand trajectory) provides early cues about the anticipated target or goal of the action and/or the sequence is a consequence of specialized neural networks involved in action perception.…”

“…To test this idea, McCormick et al (2012) used a reach-grasp-place task to examine the gaze congruency between these two conditions and also manipulated visual perspective (first and third person). In the action observation condition participants were instructed to observe the action with the intention to imitate it at a later time.…”

The influence of early aging on eye movements during motor simulation

“…Thus both the physical and mental performance of action are governed by the speed-accuracy relationship known as Fitts’ Law (Fitts 1954). Researchers frequently exploit this phenomenon and use MT as a manipulation check to ensure task compliance in the covert tasks (Gabbard et al 2011; Heremans et al 2001; McCormick et al 2012). The temporal correspondence between AE and MI is not suggested to develop until late adolescence, with proficiency achieved once the neural systems supporting internal modelling have matured (Caeyenberghs et al 2009).…”