Preceding movement effects on sequential aiming

Abstract

In this study, two experiments were devised to examine the control strategy used by individuals when performing sequential aiming movements. Of particular interest was the aiming behavior displayed when task difficulty was changed midway through a sequence of movements. In Experiment 1, target size was manipulated, as the targets were made either larger or smaller, between the 8th and 12th movement of the sequence. In Experiment 2, the amplitude between the two targets was similarly changed while the target size remained constant. Results revealed that in Experiment 1, individuals took two movements following the perturbation to target size, to re-tune their movement times in order to correspond with the new task difficulty. Conversely for Experiment 2, movement time changed immediately and in correspondence with the new target amplitude. These findings demonstrate that participants can use information from the preceding movement to prepare and guide subsequent movements--but only when target size is changed. When response amplitude changes mid-sequence, it seems individuals rely more on immediate, target-derived information. Therefore, counter to some current accounts of visual movement control, it appears that memory representations of the preceding movement can guide subsequent movements; however, this information appears selectively accessed in a context-dependent fashion.

The antisaccade task: Vector inversion contributes to a statistical summary representation of target eccentricities

“…Thus, our group proposed that the observed SSR for antisaccades evinces that top-down control renders sensorimotor transformations via the same relative visual information as perceptions. 2 Moreover, we note that our conclusion is consistent with work demonstrating that the spatial location of a target on trial N-1 or N-2 influences the endpoint location for a to-be-performed trial (Rastgardani, Lau, Barton, & Abegg, 2012; see also Abegg, Rodriguez, Lee, & Barton, 2010;Cheng, De Grosbois, Smirl, Heath, & Binsted, 2011;DeSimone, Everling, & Heath, 2015).…”

Having several options does not increase the time it takes to make a movement to an adequate end point

“…Participants may consider the instructions and the conditions they encountered within a session (and possibly previous sessions) to quickly develop a consistent movement pattern. Alternatively, they may change their behaviour after each tap on the basis of the circumstances during that tap, leading to serial dependencies across trials (Brenner and Smeets 2011 ; Cheng et al 2011 ; de Lussanet et al 2001 ; Volcic and Domini 2018 ). In both cases, one might expect participants to move faster in sessions in which there is never a choice between different kinds of targets.…”

Functional architectures and structured flows on manifolds: A dynamical framework for motor behavior.

“…Conversely, reducing task difficulty (via target width or distance manipulation) evokes an immediate lengthening of the deceleration phase followed by slower adjustments similar to those observed when increasing task difficulty. These findings were interpreted in terms of two concurrent processes at different time scales (Fernandez, Warren, & Bootsma, 2006; for similarities in a discrete Fitts's task, see Cheng, De Grosbois, Smirl, Heath, & Binsted, 2011;Heath, Hodges, Chua, & Elliott, 1998). The slow adaptation can be understood in terms of a parameterization of the functional dynamics (cf.…”