No effect of delay on the spatial representation of serial reach targets

Abstract

When reaching for remembered target locations, it has been argued that the brain primarily relies on egocentric metrics and especially target position relative to gaze when reaches are immediate, but that the visuo-motor system relies stronger on allocentric (i.e., object-centered) metrics when a reach is delayed. However, previous reports from our group have shown that reaches to single remembered targets are represented relative to gaze, even when static visual landmarks are available and reaches are delayed by up to 12 s. Based on previous findings which showed a stronger contribution of allocentric coding in serial reach planning, the present study aimed to determine whether delay influences the use of a gaze-dependent reference frame when reaching to two remembered targets in a sequence after a delay of 0, 5 or 12 s. Gaze was varied relative to the first and second target and shifted away from the target before each reach. We found that participants used egocentric and allocentric reference frames in combination with a stronger reliance on allocentric information regardless of whether reaches were executed immediately or after a delay. Our results suggest that the relative contributions of egocentric and allocentric reference frames for spatial coding and updating of sequential reach targets do not change with a memory delay between target presentation and reaching.

Contextual factors determine the use of allocentric information for reaching in a naturalistic scene

“…There is converging evidence that reach targets are represented in both egocentric (e.g., Cohen & Anderson, 2002;Lacquaniti & Caminiti, 1998;Thompson & Henriques, 2011) and allocentric reference frames (e.g., Byrne & Crawford, 2010;Diedrichsen et al, 2004;Krigolson et al, 2007;Obhi & Goodale, 2005;Schütz et al, 2013Schütz et al, , 2015. So far, little is known about the factors contributing to how allocentric information is used for reaching when multiple environmental cues are available in more complex situations, such as in naturalistic images.…”

“…First, these studies mainly investigated if allocentric information (in addition to egocentric information) contributes at all to reaching behavior but hardly examined how allocentric information is used if multiple cues are available in the environment. Second, previous studies presented rather isolated and abstract Citation: Klinghammer, M., Blohm, G., & Fiehler, K. (2015). Contextual factors determine the use of allocentric information for reaching in a naturalistic scene.…”

Facilitation of allocentric coding by virtue of object-semantics

“…However, allocentric FoR also contribute to spatial coding for action 5 , leading to improved movement precision and accuracy in online and delayed reaching 6–8 . The presence of landmarks reduces but does not fully cancel gaze-dependent reaching errors suggesting that humans integrate egocentric and allocentric FoR 9,10 , probably in a statistically optimal manner 11 .…”

The role of gaze and prior knowledge on allocentric coding of reach targets

“…Regarding egocentric reference frames, targets for reaching are predominantly coded and updated with respect to gaze, i.e., in a gaze-centered or retinal coordinate system (Crawford, Henriques, & Medendorp, 2011). There is converging evidence for a combined use of egocentric and allocentric reference frames, which has been shown to result in increased accuracy and precision of reaching movements to present and remembered targets (Byrne, Cappadocia, & Crawford, 2010;de Grave, Brenner, & Smeets, 2004;Diedrichsen, Werner, Schmidt, & Trommerhäuser, 2004;Krigolson, Clark, Heath, & Binsted, 2007;Krigolson & Heath, 2004;Obhi & Goodale, 2005;Schütz, Henriques, & Fiehler, 2013;Schütz, Henriques, & Fiehler, 2015).…”