Forward modeling allows feedback control for fast reaching movements

“1), which is then combined with the relevant visual exteroceptive information enabling a fast online visual feedback pathway (2).”

“…to reach to a target, may be integrated with target location information in order to provide on-line corrective feedback during a reaching movement (Bard et al., 1999; Desmurget et al., 1999; Desmurget & Grafton, 2000; Van Sonderen, Gielen, & Denier, 1989; Wolpert, Ghahramani, & Jordan, 1995).”

“The latter appears to be too long to directly influence hand trajectory during fast movements (Desmurget and Grafton, 2000).”

“Actual feedback when it becomes available can also be used for corrections as well as to update the forward models (for full descriptions of these models, see Desmurget and Grafton 2000; Wolpert et al. 1995; Wolpert and Kawato, 1998).”

“motor commands, musculature, environment and sensory feedback (Desmurget and Grafton 2000; Flanagan and Wing 1993; Shadmehr and Mussa-Ivaldi 1994).”

“Humans leverage internal models of the world for motor control [53, 30, 14, 34, 49], goal-directed decision making [7], and representing the mental states of other agents [39].”

“information to an internal feedback loop effectively avoids the delays associated with reliance on peripheral feedback (Wolpert, Ghahramani & Jordan, 1995; Desmurget & Grafton, 2000 ).”

“The cerebellum may serve as a monitor of motor errors (Marr 1969; Kitazawa et al. 1998; Doya 2000; Desmurget and Grafton 2000; Seidler et al. 2004), and through this process it is involved in the online tuning of movements.”

“The assumption that anticipations of behavioral effects are involved in the online feedback control of movements corresponds well to the recent literature on feed forward mechanisms in behavioral control (e.g. [ 11 ]). 60 Joachim Hoffmann”

“Nevertheless, it has been suggested that the cerebellum might be involved in feedforward computations of muscle dynamics (e.g., Desmurget and Grafton 2000; Kawato et al. 2003; Miall et al. 1993), and it cannot be ruled out that such mechanisms might be able to calculate CE reference lengths…”

“For rapid hitting and coincidence anticipation tasks, the preprogrammed account is more plausible and is compatible with the dominant view that aimed movements involve an initial preprogrammed component (e.g., Desmurget & Grafton, 2000; Elliott et al., 2001).”

“In motor control, there may be a considerable time delay before feedback comes available to the IMC; this delay may be upwards of several hundred milliseconds (Sabes, 2000; Desmurget and Grafton, 2000; Kawato, 1999; Wolpert and Gharharmini, 2000).”

“In other words, optimal preparationmay rely on an implicit forwardmodel predicting the future motor consequences of preparatory activity—not motor commands, as in classical theories (Wolpert et al., 1995; Desmurget and Grafton, 2000; Scott, 2012)—and feeding back these predictions for online correction of the cortical…”

“A large body of evidence suggests that the neural substrates underpinning real-time low-level error evaluation include posterior parietal cortex (PPC) and the cerebellum (Blakemore et al., 2001; Desmurget et al., 1999, 2001; Desmurget and Grafton, 2000; Gréa et al., 2002; Miall et al., 2001).”

“Finally, Wolpert and Ghahramani (2000), Wolpert, Ghahramani, and Jordan (1995) and Miall, Weir, Wolpert , and Stein (1993) (cf. Desmurget & Grafton, 2000) have argued for ''forward models'' of motor control, on the basis of principles of engineering.”

“There is evidence that such prediction also plays a role in the human motor control system (Desmurget & Grafton, 2000).”

“Limb reaching, an intensively studied form of biological movement, uses visual feedback to guide spatial trajectories online (Desmurget and Grafton, 2000; Saunders and Knill, 2003).”

“Internal forward models can predict the next state of a system from its current state and motor command (Bernstein 1967; Wolpert et al. 1995; Desmurget and Grafton 2000).”

“…that the estimate of limb state is derived not just based on sensory feedback , but is also crucially dependent on the prediction of the sensory consequences of movement commands (Danion & Sarlegna, 2007; Desmurget & Grafton, 2000; Shadmehr, Smith, & Krakauer, 2010; Wolpert & Flanagan, 2001).”

“, visual) feedback signal associated with the ongoing movement in order to adjust the movement in mid-flight (feedback control) [9,10,13].”

“Evidence for internal models in the brain has grown increasingly stronger (e.g., see Desmurget and Grafton 2000; Kawato 1999 for recent reviews).”

“This study indicates that the motor system can modify unseen erroneous trajectories using central feedback loops comparing the goal and an efferent copy (i.e. a forward internal model of the upper limb response), or using a feedforward correction mode.”

“Motor systems are engineered as anticipation devices (c.f., e.g., Desmurget and Grafton, 2000; Wolpert and Flanagan, 2001; Jordan and Wolpert, 1999 ).”

“Area V6Amight thus act as a state estimator (Kawato 1999; Desmurget and Grafton 2000; Shadmehr and Krakauer 2008; Grafton 2010; Shadmehr et al. 2010), comparing the desired position of moving limb and the desired configuration of preshaping hand (estimated through forward models of the movement to…”

“C & # = = , , , , ,=7 , , + ,”

“A strong candidate for this area is the posterior parietal cortex—a brain region thought to be involved in integrating sensory signals with feedforward information from internal models (Desmurget et al., 1999; Desmurget and Grafton, 2000; Shadmehr and Krakauer, 2008) and shown to be involved in fast online corrections…”

“The use of corrections does not imply that the hand comes to rest between movements because corrections could be generated on the basis of sensory information while the hand is moving at high speeds (e.g., Desmurget & Grafton, 2000).”

“Indeed, it is the updating of the target location at the end of the main saccadic response that allows implementation of the required movement correction (Prablanc et al., 1986; Prablanc and Martin, 1992; Desmurget and Grafton, 2000).”

“Thus, posterior parietal cortex is not only important for online control of visual feedback (Desmurget and Grafton, 2000), but also somatosensory feedback.”

“Indeed, in many tasks, both feedback and feedforward processes are in effect, and so visual motor control involves multiple processes and time scales beyond that of just reflecting the minimal movement time that is uninfluenced by vision ( Desmurget & Grafton, 2000; Newell, Slobounov, Slobounova, & Molenaar, 1997).”

“…the fact that the initial hand position becomes less relevant as the hand approaches the target, or might reflect the change from movement planning to feedback control of movement in these areas (Desmurget et al., 1999; Desmurget and Grafton, 2000; Mulliken et al., 2008; Archambault et al., 2009).”

“In natural reaching behavior, feed-forward computations of the desired movement are combined with feedback control during the motor execution stage (Desmurget & Grafton, 2000).”

“The error signal can, in turn, modulate the motor command [27].”

“Sensory-motor delays vary across modality but may be in the order of 100–300 ms [9–12].”

“Modern theories of motor control incorporate forward models that combine sensory information and motor commands to predict future sensory states [1, 2].”

“might use a nonsensory feedback mechanism based on motor outflow (Desmurget and Grafton 2000), as well as sensory information, such as retinal error (Blouin et al.”

“We suggest that imagined movements are mediated by a “forward model” that not only specifies the timing and force of muscle contractions but also anticipates the sensory consequences of that action (Blakemore et al., 1999; Desmurget and Grafton, 2000).”

“In line with computational studies of predictive internal model control [21,22], computational mechanisms for quick reaching adjustment have been explained by the internal feedback control using a predictive forward model [23].”

“According to the hierarchical error processing hypothesis, target errors are mediated within PPC and/or the cerebellum (Desmurget et al. 1999, 2001; Desmurget and Grafton 2000; Gréa et al. 2002; Miall et al. 2001; Pisella et al. 2000) and outcome errors are evaluated by a medial-frontal…”

“The v-d stream links to the inferior parietal lobe, a flexible dynamic area that serves goal-dependent updating and execution of action [65] and mediates high-level visual control of movement [66].”

“…problem, which can sometimes be solved with automatic synchronization mechanisms but, in most nonroutine cases, requires an accurate prediction of the actions of others, their timing, and the details of their execution (Desmurget and Grafton 2000; Pezzulo 2008, 2011; Wolpert and Flanagan 2001).”

“Many empirical and simulative studies (Desmurget and Grafton 2000; Miall and Wolpert 1996; Pezzulo and Calvi 2006a) report the adaptive advantage of exploiting anticipatory representations instead of just relying on the sensorimotor flow.”

“In fast movements, the reference is not compared to actually available, but to anticipated, feedback during movement execution—thus implying a feedforward of movement consequences (Desmurget and Grafton 2000).”

“Importantly, such perceptual binding is compatible with a recent theoretical framework of motor control, which involves a predictive model called the forward model [9–11].”

“Late differential activity in BA17 might be due to activation of sensory feedback loops (Desmurget and Grafton, 2000; Lamme and Roelfsema, 2000).”

“The high processing speed of the system that allows for closed-loop control even during quick movements (Desmurget and Grafton 2000) has led to its characterization as an "auto-pilot" system that automatically guides the hand towards a visual target without intervention of consciousness.”

“1994), relegating the relatively slow visual feedback control mechanisms to the last phases of reaching movements which require higher degrees of accuracy (Desmurget and Grafton 2000).”

“…to the adaptive control of movement through sensorimotor adaptation, there is mounting evidence that the cerebellum is also involved in many other perceptual (Ivry, 1996; Petacchi et al., 2005) and cognitive behaviors (Fiez et al., 1992; Desmond and Fiez, 1998; Thach, 1998; Strick et al., 2009).”

“The manipulation was less effective in recalibrating the visuomotor relationships in children with DCD, indicating a decreased capacity to establish or adjust a forward model (Desmurget & Grafton, 2000).”

“…of schizophrenia (Andreasen et al., 1992; Spence, Hirsch, Brooks, & Grasby, 1998), we suggest that the prefrontal areas play a key role in the conscious access of the internal representation of hand position stored in the superior parietal lobe (Desmurget & Grafton, 2000; Wolpert et al., 1998).”

“discussed as an area that transforms sensory input into motor commands and continuously updates the ongoing movement with respect to the aspired movement goal (Desmurget and Grafton 2000).”

“A gradual switch to forward control is seen during development together with the facility for fast online control.(26) In short, motor learning is designed to deal with uncertainty and to implement rapid corrections as learning environments throw up new challenges in real time.”

“Instead, it is thought that the brain generates estimates of the current and future states of the arm by combining a copy of the command signal produced by motor cortex with a model of the dynamics of the limb (Desmurget and Grafton, 2000; Wolpert and Miall, 1996).”

“Previous studies have suggested that the posterior parietal cortex (PPC) is involved in feedback control based on internal estimates of effectors (Desmurget and Grafton, 2000; Blakemore and Sirigu, 2003).”

“In addition to these brain areas, posterior parietal cortex (PPC) is an important structure in the online control of reaching (Desmurget & Grafton, 2000).”

“…simulative sensorimotor processing , computationally formalized in control-theoretic models (Wolpert and Miall 1996; Wolpert and Ghahramani 2000; Desmurget and Grafton 2000; Frith et al. 2000; Wolpert et al. 2003; Grush 2004; Lakoff and Gallese 2005; Shadmehr and Krakauer 2008) These models…”

“A more feasible explanation is that the reaching movement was already planned in advance of the saccade in some body-centered coordinate frame appropriate for activation of the arm muscles (Soechting et al., 1991, 1995; Flanders et al., 1992; Henriques et al., 1998; Desmurget and Grafton, 2000).”

“…the involvement of more anterior brain regions in triggering tactile suppression is plausible given the extant theory that a forward model is at work for every movement that we perform (see Desmurget & Grafton, 2000; Wolpert, Diedrichsen, & Flanagan, 2011; Wolpert & Flanagan, 2001, for reviews).”

“Online corrections might rely on a nonsensory feedback mechanism based on motor outflow (Desmurget and Grafton, 2000), as well as on sensory information (Blouin et al., 1995; Desmurget et al., 1999).”

“Optimal postural control depends on a combination of both feedforward and feedback processes.(50) The mechanics of postural control during standing are often described using an inverted pendulum model, and the goal of control is to maintain the COP, the weighted average of all pressures over the area that is contactin…”

“This internal estimate is informed by proprioceptive information, and the predictions arising from a forward model through an efference copy [22] of the executed motor commands [23–25].”

“Previous studies have shown that the parietal operculum contributes to somatosensory processing in humans (Burton et al. 1993; Disbrow et al. 2000; Ledberg et al. 1995).”

“…(forward) model that makes them able to predict the sensory consequences of their actions can overcome delays in feedback and neural processing and are typically better at perceptual processing when their input is corrupted by noise (Desmurget & Grafton, 2000; Shadmehr, Smith, & Krakauer, 2010).”

“More specifically, we contend that imagined movements are mediated by a “forward model” that not only specifi es the timing and force of muscle contractions, but also anticipates the sensory consequences of that action (Desmurget & Grafton, 2000 ).”

“…early days of AMT, the concept of forward and inverse models in the CNS, particularly in the cerebellum, is now widely endorsed both theoretically and experimentally (for review see Desmurget and Grafton (2000), Kawato (1999), Wolpert et al (1998)) but the configurations in which they are used vary.”

“Such further development has been shown experimentally to occur in motor control in the brain [4].”

“…of numerous oculomotor control models (e.g., Becker & Jü rgens, 1979; Robinson, 1968; Scudder, 1985) as well as feedforward control in error correction systems (e.g., Bernstein, Scheffers, & Coles, 1995; Desmurget & Grafton, 2000; Shadmehr & Mussa-Ivaldi, 1994; Wolpert, Ghahramani, & Jordan, 1995).”

“In fact, the imagined movements made by neurologically intact individuals must rely almost entirely on a forward model of the intended movement (Desmurget and Grafton, 2000).”

“It has been proposed that the parietal cortex creates forward models of intended movements (Andersen and Buneo, 2002; Blakemore and Sirigu, 2003; Desmurget and Grafton, 2000; Wolpert et al., 1998).”