Rapid prediction of biomechanical costs during action decisions

Abstract

When given a choice between actions that yield the same reward, we tend to prefer the one that requires the least effort. Recent studies have shown that humans are remarkably accurate at evaluating the effort of potential reaching actions and can predict the subtle energetic demand caused by the nonisotropic biomechanical properties of the arm. In the present study, we investigated the time course over which such information is computed and comes to influence decisions. Two independent approaches were used. First, subjects performed a reach decision task in which the time interval for deciding between two candidate reaching actions was varied from 200 to 800 ms. Second, we measured motor-evoked potential (MEPs) to single-pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to probe the evolving decision at different times after stimulus presentation. Both studies yielded a consistent conclusion: that a prediction of the effort associated with candidate movements is computed very quickly and influences decisions within 200 ms after presentation of the candidate actions. Furthermore, whereas the MEPs measured 150 ms after stimulus presentation were well correlated with the choices that subjects ultimately made, later in the trial the MEP amplitudes were primarily related to the muscular requirements of the chosen movement. This suggests that corticospinal excitability (CSE) initially reflects a competition between candidate actions and later changes to reflect the processes of preparing to implement the winning action choice.

Effort, success, and nonuse determine arm choice

“…In a simple-choice reaching task, similar to ours, transcranial magnetic stimulation (TMS) over the left parietal cortex reduced the probability of choosing the right arm by biasing the competitive process between the two arms (Oliveira et al 2010). A recent study using TMS suggests that the primary motor cortex is involved in the computation or prediction of the biomechanical costs in choosing to move to one of two targets (Cos et al 2014). Such involvement of the motor system in the computation of biomechanical effort makes sense, given that effort computation or prediction requires access to movement-related kinematic and dynamic variables.…”

Effect of Aging on Motor Inhibition during Action Preparation under Sensory Conflict

“…Note that MEPs PREP were purposely elicited relatively far from movement onset, at a time when inhibitory influences are strongest during action preparation (see “Materials and Method” Section). This time epoch occurs before corticospinal excitability of the selected effector begins to ramp up due to excitatory processes (Cos et al, 2014; Duque et al, 2014; Klein et al, 2016). …”

Dissociating the influence of response selection and task anticipation on corticospinal suppression during response preparation

“…Computational and neurobiological approaches view decision making as a continuous process in which evidence simultaneously accumulates for different options, with selection occurring when the activity associated with a particular action reaches a threshold (Cisek, 2006; Cos, Duque, & Cisek, 2014; Domenech & Dreher, 2010; Kim & Basso, 2010; Klein-Flugge & Bestmann, 2012; Klein, Olivier, & Duque, 2012; Link & Heath, 1975; Mazurek, Roitman, Ditterich, & Shadlen, 2003; Tosoni, Galati, Romani, & Corbetta, 2008). Many variants of decision-making models assume that inhibitory mechanisms contribute to this accumulation process (Coles, Gratton, Bashore, Eriksen, & Donchin, 1985; Usher & McClelland, 2004) but see Brown and Heathcote (2008)).…”