The Inactivation Principle: Mathematical Solutions Minimizing the Absolute Work and Biological Implications for the Planning of Arm Movements

Berret, Bastien; Darlot, C.; Jean, Frédéric; Pozzo, Thierry; Papaxanthis, Charalambos; Gauthier, Jean-Paul

doi:10.1371/journal.pcbi.1000194

Cited by 126 publications

(181 citation statements)

References 53 publications

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“…For instance, vestibulo-ocular reflexes act to stabilize gaze in the face of head movements (Green and Angelaki, 2003), integration of gravito-inertial cues contributes to spatial navigation (Israël and Berthoz, 1989;Mittelstaedt, 1999), and maintaining an upright posture is a primary function of the vestibular organs (Cathers et al, 2005) and other graviceptor cues. Gravity may also be taken into account in the optimal control of vertical limb movements (Berret et al, 2008; Creve- coeur et al, 2010) and gravity sensing may contribute to the adaptation of limb kinematics in 0g (Papaxanthis et al, 2005;Gaveau et al, 2011). Here, we have implicated gravity sensing in a different type of function, i.e., that of predicting the motion of a visually perceived external object.…”

Section: Discussionmentioning

confidence: 66%

When Up Is Down in 0g: How Gravity Sensing Affects the Timing of Interceptive Actions

Senot¹,

Zago²,

Séac’h³

et al. 2012

J. Neurosci.

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Humans are known to regulate the timing of interceptive actions by modeling, in a simplified way, Newtonian mechanics. Specifically, when intercepting an approaching ball, humans trigger their movements a bit earlier when the target arrives from above than from below. This bias occurs regardless of the ball's true kinetics, and thus appears to reflect an a priori expectation that a downward moving object will accelerate. We postulate that gravito-inertial information is used to tune visuomotor responses to match the target's most likely acceleration. Here we used the peculiar conditions of parabolic flight-where gravity's effects change every 20 s-to test this hypothesis. We found a striking reversal in the timing of interceptive responses performed in weightlessness compared with trials performed on ground, indicating a role of gravity sensing in the tuning of this response. Parallels between these observations and the properties of otolith receptors suggest that vestibular signals themselves might plausibly provide the critical input. Thus, in addition to its acknowledged importance for postural control, gaze stabilization, and spatial navigation, we propose that detecting the direction of gravity's pull plays a role in coordinating quick reactions intended to intercept a fast-moving visual target.

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Section: Discussionmentioning

confidence: 66%

When Up Is Down in 0g: How Gravity Sensing Affects the Timing of Interceptive Actions

Senot¹,

Zago²,

Séac’h³

et al. 2012

J. Neurosci.

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“…This mixture of weighted error variance is related formally to phenomenological cost functions proposed to account for movement trajectories (cf. Todorov and Jordan 1998;Nakano et al 1999;Berret et al 2008). …”

Section: Motor Control and Prediction Errorsmentioning

confidence: 99%

“…This means that action is trying to suppress a mixture of [squared] sensory prediction error on position, velocity, acceleration, and jerk etc., where the relative contributions, encoded by µ s γ control the smoothness of the trajectory. This mixture is formally similar to cost-functions in the motor-control literature that try to account for smooth motor trajectories that are observed empirically (Todorov and Jordan 1998;Nakano et al 1999;Berret et al 2008). …”

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confidence: 99%

Action and behavior: a free-energy formulation

et al. 2010

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We have previously tried to explain perceptual inference and learning under a free-energy principle that pursues Helmholtz's agenda to understand the brain in terms of energy minimization. It is fairly easy to show that making inferences about the causes of sensory data can be cast as the minimization of a free-energy bound on the likelihood of sensory inputs, given an internal model of how they were caused. In this article, we consider what would happen if the data themselves were sampled to minimize this bound. It transpires that the ensuing active sampling or inference is mandated by ergodic arguments based on the very existence of adaptive agents. Furthermore, it accounts for many aspects of motor behavior; from retinal stabilization to goal-seeking. In particular, it suggests that motor control can be understood as fulfilling prior expectations about proprioceptiveThe free-energy principle is an attempt to explain the structure and function of the brain, starting from the fact that we exist: This fact places constraints on our interactions with the world, which have been studied for years in evolutionary biology and systems theory. However, recent advances in statistical physics and machine learning point to a simple scheme that enables biological systems to comply with these constraints. If one looks at the brain as implementing this scheme (minimizing a free-energy bound on disorder), then many aspects of its anatomy and physiology start to make sense. In this article, we show that free-energy can be reduced by selectively sampling sensory inputs. This leads to adaptive responses and provides a new view of how movement control might work in the brain. The main conclusion is that we only need to have expectations about the sensory consequences of moving in order to elicit movement. This means we that can replace the notion of desired movements with expected movements and understand action in terms of perceptual expectations.The Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, WC1N 3BG, sensations. This formulation can explain why adaptive behavior emerges in biological agents and suggests a simple alternative to optimal control theory. We illustrate these points using simulations of oculomotor control and then apply to same principles to cued and goal-directed movements. In short, the free-energy formulation may provide an alternative perspective on the motor control that places it in an intimate relationship with perception.

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“…The main cost of making spatially precise movements is that they take more time, so people make faster movements if it is less important to be precise (Fitts and Peterson 1964;Harris and Wolpert 1998;Schmidt et al 1979) or if they are more willing to risk failure (Nagengast et al 2011). Making more precise movements may also cost more energy, so people may also make more energy-efficient movements if it is less important to be precise (Alexander 1997;Berret et al 2008Berret et al , 2011.…”

Section: Introductionmentioning

confidence: 99%