Forward modeling allows feedback control for fast reaching movements

“The task goal of producing a target force level introduced the use of visual feedback and feedforward processes so that the force signal was of a higher dimension (Desmurget and Grafton 2000).”

“The concurrent processing of proprioceptive feedback and its comparison with the predicted feedback when an action is executed, is one major sensory source for controlling the accuracy of the movement itself ( Desmurget and Grafton, 2000 ).”

“…and includes both the pre-programming of the motor command before the onset of movement, aka the feedforward control, and the adjustment of the motor command in near real time, aka the online control (Desmurget & Grafton, 2000; Kawato, 1999; Shadmehr & Krakauer, 2008; Wolpert & Ghahramani, 2000).”

“Studies of human action dynamics have primarily focused on the dynamics within actions, such as how the motor control of reaching actions unfolds over time (20).”

“It requires continuous processing of hand and target position, comparing the predicted outcome of the movement with the intended target location and correcting for any error (Desmurget et al. 1998; Desmurget & Grafton, 2000).”

“Such models are given in a number of sources such as Sabes (2000) and Desmurget and Grafton (2000).”

“The impulse control discussed by Elliott et al. (2010) is similar in some ways to the type of early, continuous control discussed by Desmurget and Grafton (2000) in their hybrid model.”

“Their parameters, namely latencies of peak value, of onset and offset (defined as the time when the submovement went respectively above and below 5% of its peak value), as well as peak value and sigma or standard deviation were calculated.”

“…off-line have to be compatible with the on-line execution of action; how this is possible, and how off-line planning and on-line (feedback) control are integrated, are widely discussed topics that go beyond the scope of this paper (see e.g., Cisek, 2005; Desmurget & Grafton, 2000; Sabes, 2000).”

“the direction of previous errors, and proportional to prior error extents [5,6,7].”

“1995), as well as from ‘‘efference copy’’ and a forward model of the limb and its environment (Wolpert et al. 1995a; Nelson 1996; Desmurget and Grafton 2000; Gritsenko et al. 2007).”

“…however, no purely predictive strategies have been proposed for the interception of moving targets on foot, which should not lead one to discard the possibility that predictive information is used as part of an on-line regulation process (cf., Desmurget and Grafton 2000; Starkes et al. 2002).”

“In ongoing movements feedforward control and external and internal feedback control should interact to achieve the movement goal (e.g., Desmurget and Grafton 2000).”

“The digit individuation affords compensatory control through faster timescale feedback processes and this leads to reduced variability (Desmurget and Grafton 2000).”

“…and feedbackcoupled processes that minimize error and movement variability and are already ascribed to the dorsal sensorimotor system (Desmurget & Grafton, 2000; Flanagan & Beltzner, 2000; Whitwell, Ganel, Caitline, & Coodale, 2015; Whitwell, Milner, Cavina-Pratesi, Barat, & Goodale, 2015;…”

“During goal-directed movements, sensory information is continuously integrated into themotor plan in order to ensure and improve execution success (Desmurget and Grafton, 2000; Shadmehr et al., 2010; Wolpert et al., 1995).”

“The final position error was defined as the 2-D Euclidean distance from the final cursor location to the center of the target at movement offset and provides information on online error corrective mechanisms (Desmurget and Grafton 2000).”

“For motor control with continuous trajectories, such as reaching movements or articulation of single speech phonemes, it has been proposed that internal models estimate sensory consequences of motor commands, compare these estimates to actual sensory feedback, and use the difference as error signals to correct ongoing…”

“Moreover, there is a vast literature that show how prediction and internal models play an important role in (visuo)motor control (Kawato 1999; Miall and Wolpert 1996) and in the stabilization of perception (von Holst and Mittelstaedt 1950), allow to circumvent the problems caused by the delay with which sensory inform…”

“This information may then be used by the cerebellum to better predict or update the motor plan on subsequent trials, thus leading to trial-to-trial adaptation (Desmurget and Grafton 2000).”

“, 2009, 2011, 2020), we suggest it compares these two inputs, thus acting as a state estimator of the arm/hand movement (Kawato, 1999; Desmurget and Grafton, 2000; Shadmehr and Krakauer, 2008; Grafton, 2010; Shadmehr et al., 2010; Fattori et al., 2017).”

“There is continuing debate over the extent to which such goal-directed hand movements are programmed in advance or controlled online (Jeannerod 1984; Desmurget and Grafton 2000; Elliot et al.”

“The resulting model would be complex which does not fit with the results on how fast and adaptable the action decision-making process actually is (Desmurget and Grafton 2000).”

“Computational modeling in recent decades has consistently argued for the importance of accurate internal representations of movement to the efficient online monitoring and control of action (Desmurget & Grafton, 2000; Izawa & Shadmehr, 2011; Shadmehr & Krakauer, 2008; Wolpert et al., 2011).”

“The present results are in line with the notion of hybrid internal models of action, which postulate the formation of a ‘‘crude’’ motor plan before action onset, which gets constantly updated through feedback loops during movement execution (Desmurget & Grafton, 2000).”

“movements performed by the healthy adults and to some extend also by the healthy children suggests that they utilized well-learned feed-forward motor programs, whereas the slow unsteady movements performed by the CP children suggests that they were forced to use a feedback strategy in which the movement had to be corr…”

“However, there is mounting evidence that practical reaching movements are also infl uenced by the feedback (Botzer and Karniel, 2008; Desmurget and Grafton, 2000; Ma-Wyatt and McKee, 2007; Saunders and Knill, 2003, 2005).”

“It could be proposed that because of deficient forward modeling, patients rely more extensively on closed-loop monitoring, making the correction longer and possibly more variable (Desmurget and Grafton 2000).”

“Such a model may allow the central nervous system to adequately preplan and calibrate the force production (muscle activity) required for an individual with SCI to perform SPTs in both directions, even before motiondependent feedback becomes available, suggesting a feed-forward control strategy [19].”

“Protocols for measuring such ballistic kinematics are well established, and have been applied in a broad range of cognitive and visuomotor tasks (Desmurget and Grafton, 2000).”

“An unimpaired reach-to-grasp movement is characterized by high temporal efficiency given the pre-planning and execution of the movements [12, 48].”

“…motor system to estimate the effects of the motor commands sent to the effectors, compare these predicted effects with sensory feedback, and make adjustments if needed (for full descriptions of these models, see Desmurget & Grafton 2000; Wolpert, Ghahramani & Jordan 1995; Wolpert & Kawato 1998).”

“Desmurget and Grafton (2000) implicate both the IPS and the cerebellum as key regions for making feedback strategies viable processes for fast effective motor responses.”

“While it is possible that these influences primarily impact the initial motor program, some feedforward models of reaching suggest that feedback processes influence the integration of sensory and motor information during ongoing movements (Desmurget & Grafton, 2000 ).”

“This is achieved by integrating delayed sensory input and motor output through afferent and efferent internal feedback loops (Desmurget and Grafton 2000).”

“Behavioral experiments and simulations confirm that humans must use forward model information to stabilize behavioral control [21, 61].”

“by a forward model [33,34] because forward models could be used to determine spatial location when joint angles are given.”

“An alternative perspective is that visuomotor processing is composed of multiple processes that operate on unique timescales (Desmurget & Grafton, 2000; Sosnoff & Newell, in press), as revealed in the frequency structure of the force output.”

“Currently, the prevailing assumption is that feedback and feedforward control are combined in a forward model (Desmurget & Grafton, 2000; Miall & Wolpert, 1996).”

“Multiple sources of information are integrated when forming goals or during the control of ongoing movements [18, 47].”

“Moreover, when guiding the arm to a certain point one could benefit from efferent signals to overcome some of the sensorimotor delays that are encountered when dealing with visual or haptic feedback about the arm (Desmurget and Grafton 2000; Pickering and Clark 2014).”

“Specifically, the motor system is able to correct the deviation from the desired movement with the aid of feedback control, whilst feedforward control allows it to reconcile the interdependency of the involved effectors and preplan the response to the sensory incoming information [12]–[14].”

“Computationally, since the target remains stationary throughout the movement; discrepancy between the expected (according to the predictive model) and actual consequences of action is minimal, assuming that the initial motor command is accurate (Desmurget & Grafton, 2000).”

“…the prediction of human movement can tap into internal models of the body, including hierarchical limb structure, the dynamics of muscles, limitations on joint angles, and the forces involved in movement control (e.g. Desmurget & Grafton, 2000; Ito, 2008; Kawato, 1999; Wolpert & Flanagan, 2001).”

“In this study, we recorded from the posterior parietal cortex (PPC), which is thought to compute an internal forward model for sensorimotor control (Mulliken et al., 2008; Wolpert et al., 1998; Desmurget and Grafton, 2000; Li et al., 2022).”

“Recent studies have shown that comparison between motor intention and proprioception is critical for motor learning (Desmurget and Grafton, 2000; Panouilleres et al., 2015; Wolpert et al., 2011; Wolpert and Ghahramani, 2000) and motor-related cognitive functions, such as motor awareness (Berti and…”

“The forward model can predict the sensory consequences of an action by integrating information about the current state of the system and this efference copy (Wolpert et al., 1995; Desmurget and Grafton, 2000).”

“In summary, the literature regarding peripheral and entral visuo-motor processes reveals a complex picture ith many seemingly discrepant findings (for more comlete reviews see Desmurget et al., 1998; Lacquaniti and aminiti, 1998; Desmurget and Grafton, 2000; Todorov, 004).”

“, sensory feedback is essential for the forward model [86].”

“This enables the detection of potential action errors even before an action is executed [20], and can modulate the motor command [21].”

“…based on the environmental and task demands of the situation, along with the positions of the performer's body (Glover, 2004), and depends on feedforward processes involving discrepancies between predicted and actual sensory consequences (Desmurget & Grafton, 2000; Wolpert, Miall, & Kawato, 1998).”

“For creating a TJR within a short latency, the current hand position is estimated by comparing sensory feedback with forward model predictions to minimize delay times associated with the sensory feedback loop (Kawato, 1999; Desmurget and Grafton, 2000; Sabes, 2000).”

“This is done using sensory (e.g., visual and prioceptive) and non-sensory (e.g., efferent motor commands) information (Desmurget & Grafton, 2000; Todorov, 2004).”

“…refine future motor commands by generating an internal training signal that modifies plastic neural processes (Wolpert et al., 1995; Kawato, 1999; Desmurget and Grafton, 2000) and the same may hold during MP as well, only that the training signal may be less accurate and precise due to the lack…”

“Current models of sensorimotor control suggest that movements are executed through a combination of feedforward and feedback control mechanisms (Kawato and Wolpert, 1998; Desmurget and Grafton, 2000; Wolpert and Flanagan, 2001, 2010).”

“It has been suggested that a copy of the motor signal, known as an efference copy, is created so that sensory signals generated from external stimuli can be distinguished from reafferent signals from body movement [2,35,36].”

“feedforward motor commands [40, 41, 51, 169, 175], and their adaptation to changing environments [33, 71] have suggested “cues” of optimality principles in sensori-motor control.”

“There is considerable literature, based on kinematic analyses, visual and proprioceptive processing, brain imaging, and TMS, supporting an internal model for fast reaching movements, with a feedforward component (motor planning) and a feedback component (sensory processing; Desmurget and Grafton 2000).”

“Such mental simulation may operate according to the details of an internal model for actual action (e.g., Kawato 1999; Desmurget and Grafton 2000; Wolpert and Flanagan 2001; Blakemore et al. 2002), but with the actual output inhibited (Schwoebel et al. 2002).”

“…and control of muscular forces required to generate (i.e., an inverse model, see Wolpert & Kawato, 1998) and update (i.e., feedforward control; see Desmurget & Grafton, 2000; Wolpert & Flanagan, 2010) the motor command for goal-directed movement [Glazebrook et al., 2006; Hughes, 1996; Mari,…”

“The complex nature of dynamic walking leads to the idea that ambulation is driven by a combination of feed-forward and feedback signaling, simultaneously combining internal models and sensory feedback [17, 18].”

“determining how the motor control or coordination of arm movements has changed.(30,31)”