Left or right? Rapid visuomotor coding of hand laterality during motor decisions.

To interact successfully with a dynamic world, our brain must quickly process incoming visual information regarding objects in our immediate environment, and integrate it with the current position of our hands. In particular, previous research shows that visual information about hand position contributes both to the planning and correction of movements (van Beers et al., 2002, Reichenbach et al., 2014, Sober and Sabes, 2005). However, visual information provided in these studies is typically underspecified – limb position is represented using a point-light, cursor, or virtual image. The fact that vision of the hand in these paradigms is typically degraded may contribute to sensory uncertainty, with consequences for visuomotor integration (Körding & Wolpert, 2004). This is particularly relevant as the sensorimotor system responds to relatively more detailed visual features of the hand. For example, firing rates of neurons in area 5 of the macaque brain are affected by visual information of static hand identity; Tonic neuronal activity was modulated only when hand laterality was congruent with hand position from an egocentric perspective (Graziano, Cooke, & Taylor, 2000; see also Fadiga et al., 2013). Here, we investigate the contribution of visual information about hand laterality during online response selection