Learning to See the Impossible

Perception ◽  
1981 ◽  
Vol 10 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Andrew W Young ◽  
Jan B Deregowski
Keyword(s):  
Mental Representation ◽  
Internal Model ◽  
Internal Models ◽  
Principal Factor ◽  
Picture Perception ◽  
Older Children ◽  
General Importance ◽  
Memory Experiment ◽  
Impossible Figures

Four experiments investigating children's ability to detect the impossibility of impossible figures are reported. In the first, children were required to identify the impossible figure from a pair of corresponding possible and impossible figures. Whilst seven-year-old children were able to detect the impossibility of certain impossible figures, their overall level of performance was lower than that of older children. Regardless of age, the impossibility of some types of figure was found to be relatively easy or difficult to detect. Experiment 2 confirmed this pattern of results using a task that required children to copy possible and impossible figures from memory. Experiment 3 showed that, when the impossibility of an impossible figure is not readily detected, this is not due to failure to understand the conventions used in that figure to represent depth and solidity. In experiment 4 predictions from different hypotheses concerning the principal factor responsible for the detection of impossibility were tested. Results support the view that the detection of impossibility requires the construction of a mental representation (internal model) of the interrelationships of the constituent parts of the depicted object. It is suggested that the construction of such internal models may be of general importance in picture perception.

scholarly journals An internal model approach for motor behavior

2021 ◽  
Vol 15 (5) ◽  
pp. 356-371
Author(s):  
Cláudio M. F. Leite ◽  
Carlos E. Campos ◽  
Crislaine R. Couto ◽  
Herbert Ugrinowitsch
Keyword(s):  
Motor Skills ◽  
Internal Model ◽  
Motor Behavior ◽  
External World ◽  
Internal Models ◽  
Sensory Inputs ◽  
Theoretical Approaches ◽  
Internal Coherence ◽  
Motor Actions ◽  
Model Approach

Interacting with the environment requires a remarkable ability to control, learn, and adapt motor skills to ever-changing conditions. The intriguing complexity involved in the process of controlling, learning, and adapting motor skills has led to the development of many theoretical approaches to explain and investigate motor behavior. This paper will present a theoretical approach built upon the top-down mode of motor control that shows substantial internal coherence and has a large and growing body of empirical evidence: The Internal Models. The Internal Models are representations of the external world within the CNS, which learn to predict this external world, simulate behaviors based on sensory inputs, and transform these predictions into motor actions. We present the Internal Models’ background based on two main structures, Inverse and Forward models, explain how they work, and present some applicability.

The Effect of An Internal Model on Subsequent Learning

1983 ◽  
Vol 27 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Ray E. Eberts
Keyword(s):  
System Dynamics ◽  
Internal Model ◽  
Prior Experience ◽  
Internal Models ◽  
The Other ◽  
Learning Performance ◽  
Continuous Control ◽  
Control Task ◽  
Discrete Task ◽  
Previous Training

The purpose of this experiment was to compare the learning performance on a discrete second order control task between an experienced group of subjects, who had generated both accurate and inaccurate internal models through prior experience, to a group of subjects who had little prior experience and no model of the system dynamics. The 48 subjects were divided into six groups of eight subjects each. Three of the groups, the experienced groups, had previous training in a continuous control task and the other three groups, the no experience groups, had only a few trials on the continuous control task. The results showed that all three experienced groups learned the new discrete task faster than the no experience groups; the no experience groups actually got slightly worse with practice. It was concluded that an internal model, even an inaccurate one, provides a reference for subjects which can be used to analyze and improve their performance.

scholarly journals Internal models for interpreting neural population activity during sensorimotor control

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthew D Golub ◽  
Byron M Yu ◽  
Steven M Chase
Keyword(s):  
Internal Model ◽  
Sensory Information ◽  
Internal Models ◽  
Neural Population ◽  
Prior Beliefs ◽  
Population Activity ◽  
Motor Commands ◽  
Machine Interface ◽  
The Brain ◽  
Neural Population Activity

To successfully guide limb movements, the brain takes in sensory information about the limb, internally tracks the state of the limb, and produces appropriate motor commands. It is widely believed that this process uses an internal model, which describes our prior beliefs about how the limb responds to motor commands. Here, we leveraged a brain-machine interface (BMI) paradigm in rhesus monkeys and novel statistical analyses of neural population activity to gain insight into moment-by-moment internal model computations. We discovered that a mismatch between subjects’ internal models and the actual BMI explains roughly 65% of movement errors, as well as long-standing deficiencies in BMI speed control. We then used the internal models to characterize how the neural population activity changes during BMI learning. More broadly, this work provides an approach for interpreting neural population activity in the context of how prior beliefs guide the transformation of sensory input to motor output.

scholarly journals A cerebellar internal model calibrates a feedback controller involved in sensorimotor control

2020 ◽  
Author(s):  
Daniil A. Markov ◽  
Luigi Petrucco ◽  
Andreas M. Kist ◽  
Ruben Portugues
Keyword(s):  
Feedback Control ◽  
Visual Feedback ◽  
Internal Model ◽  
Control Mechanism ◽  
Internal Models ◽  
List Type ◽  
Optomotor Response ◽  
Larval Zebrafish ◽  
Sensory State ◽  
Control Feedback

AbstractAnimals must adapt their behavior to survive in a changing environment. Behavioral adaptations can be evoked by two mechanisms: feedback control and internal-model-based control. Feedback controllers can maintain the sensory state of the animal at a desired level under different environmental conditions. In turn, internal models learn the relationship between behavior and resulting sensory consequences in order to modify the behavior when this relationship changes. Here, we present multiple perturbations in visual feedback to larval zebrafish performing the optomotor response and show that they react to these perturbations through a feedback control mechanism. In contrast, if a perturbation is long-lasting, fish adapt their behavior by updating a cerebellum-dependent internal model. We use modelling and functional imaging to show that neuronal requirements for these mechanisms are met in the larval zebrafish brain. Our results illustrate the role of the cerebellum in encoding internal models and how these can calibrate neuronal circuits involved in reactive behaviors depending on the interactions between animal and environment.HighlightsBehavioral reactions to unexpected changes in visual feedback are implemented by a feedback control mechanismA long-lasting change in visual feedback updates the state of the neuronal controllerThe cerebellar internal model mediates this recalibration

scholarly journals Learning to shape virtual patient locomotor patterns: internal representations adapt to exploit interactive dynamics

2019 ◽  
Vol 121 (1) ◽  
pp. 321-335 ◽  
Author(s):  
Christopher J. Hasson ◽  
Sarah E. Goodman
Keyword(s):  
Internal Model ◽  
Rhythmic Activity ◽  
Virtual Patient ◽  
Internal Models ◽  
Target Pattern ◽  
Locomotor Pattern ◽  
Model Free ◽  
Interactive Dynamics ◽  
Locomotor Patterns ◽  
Locomotor Rehabilitation

This work aimed to understand the sensorimotor processes used by humans when learning how to manipulate a virtual model of locomotor dynamics. Prior research shows that when interacting with novel dynamics humans develop internal models that map neural commands to limb motion and vice versa. Whether this can be extrapolated to locomotor rehabilitation, a continuous and rhythmic activity that involves dynamically complex interactions, is unknown. In this case, humans could default to model-free strategies. These competing hypotheses were tested with a novel interactive locomotor simulator that reproduced the dynamics of hemiparetic gait. A group of 16 healthy subjects practiced using a small robotic manipulandum to alter the gait of a virtual patient (VP) that had an asymmetric locomotor pattern modeled after stroke survivors. The point of interaction was the ankle of the VP’s affected leg, and the goal was to make the VP’s gait symmetric. Internal model formation was probed with unexpected force channels and null force fields. Generalization was assessed by changing the target locomotor pattern and comparing outcomes with a second group of 10 naive subjects who did not practice the initial symmetric target pattern. Results supported the internal model hypothesis with aftereffects and generalization of manipulation skill. Internal models demonstrated refinements that capitalized on the natural pendular dynamics of human locomotion. This work shows that despite the complex interactive dynamics involved in shaping locomotor patterns, humans nevertheless develop and use internal models that are refined with experience.NEW & NOTEWORTHY This study aimed to understand how humans manipulate the physics of locomotion, a common task for physical therapists during locomotor rehabilitation. To achieve this aim, a novel locomotor simulator was developed that allowed participants to feel like they were manipulating the leg of a miniature virtual stroke survivor walking on a treadmill. As participants practiced improving the simulated patient’s gait, they developed generalizable internal models that capitalized on the natural pendular dynamics of locomotion.

scholarly journals Contextual cuing contributes to the independent modification of multiple internal models for vocal control

2011 ◽  
Vol 105 (5) ◽  
pp. 2448-2456 ◽  
Author(s):  
Dwayne Keough ◽  
Jeffery A. Jones
Keyword(s):  
Auditory Feedback ◽  
Internal Model ◽  
Sensory Feedback ◽  
Motor Command ◽  
Internal Models ◽  
Motor Commands ◽  
Arm Reaching ◽  
Vocal Control ◽  
Vocal Productions ◽  
The Brain

Research on the control of visually guided limb movements indicates that the brain learns and continuously updates an internal model that maps the relationship between motor commands and sensory feedback. A growing body of work suggests that an internal model that relates motor commands to sensory feedback also supports vocal control. There is evidence from arm-reaching studies that shows that when provided with a contextual cue, the motor system can acquire multiple internal models, which allows an animal to adapt to different perturbations in diverse contexts. In this study we show that trained singers can rapidly acquire multiple internal models regarding voice fundamental frequency ( F0). These models accommodate different perturbations to ongoing auditory feedback. Participants heard three musical notes and reproduced each one in succession. The musical targets could serve as a contextual cue to indicate which direction (up or down) feedback would be altered on each trial; however, participants were not explicitly instructed to use this strategy. When participants were gradually exposed to altered feedback adaptation was observed immediately following vocal onset. Aftereffects were target specific and did not influence vocal productions on subsequent trials. When target notes were no longer a contextual cue, adaptation occurred during altered feedback trials and evidence for trial-by-trial adaptation was found. These findings indicate that the brain is exceptionally sensitive to the deviations between auditory feedback and the predicted consequence of a motor command during vocalization. Moreover, these results indicate that, with contextual cues, the vocal control system may maintain multiple internal models that are capable of independent modification during different tasks or environments.

Internal Models and Contextual Cues: Encoding Serial Order and Direction of Movement

2005 ◽  
Vol 93 (2) ◽  
pp. 786-800 ◽  
Author(s):  
Stephanie K. Wainscott ◽  
Opher Donchin ◽  
Reza Shadmehr
Keyword(s):  
Internal Model ◽  
Serial Order ◽  
Internal Models ◽  
General Mechanism ◽  
Sources Of Information ◽  
Contextual Cues ◽  
Reaching Task ◽  
Motor Commands ◽  
Preferred Direction ◽  
Direction Of Movement

During reaching, the brain may rely on internal models to transform desired sensory outcomes into motor commands. This transformation depends on both the state of the limb and the cues that can identify the context of the movement. How are contextual cues and information about state of the limb combined in the computations of internal models? We considered a reaching task where forces on the hand depended on both the direction of movement (state of the limb) and order of that movement in a predefined sequence (contextual cue). When the cue was available, the motor system formed an internal model that used both serial order and target direction to program motor commands. Assuming that the internal model was formed by a population code through a combination of unknown basis elements, the sensitivity of the bases with respect to state of the limb and contextual cue should dictate how error in one type of movement affected all other movement types. Using a state-space theory, we estimated this generalization function and identified the adaptive system from trial-by-trial changes in performance. The results implied that the basis elements were tuned to direction of movement but output of each basis at its preferred direction was multiplicatively modulated by a weak tuning with respect to the contextual cue. Activity fields that multiplicatively encode diverse sources of information may serve as a general mechanism for a single network to produce context-dependent motor output.

scholarly journals Effect of muscle fatigue on internal model formation and retention during reaching with the arm

2006 ◽  
Vol 100 (2) ◽  
pp. 695-706 ◽  
Author(s):  
Craig D. Takahashi ◽  
Dan Nemet ◽  
Christie M. Rose-Gottron ◽  
Jennifer K. Larson ◽  
Dan M. Cooper ◽  
...  
Keyword(s):  
Force Field ◽  
Muscle Fatigue ◽  
Internal Model ◽  
Motor System ◽  
Arm Movement ◽  
Internal Models ◽  
Viscous Force ◽  
Adaptive Ability ◽  
Model Formation ◽  
Level Of Effort

The motor system adapts to novel dynamic environments by forming internal models that predict the muscle forces needed to move skillfully. The goal of this study was to determine how muscle fatigue affects internal model formation during arm movement and whether an internal model acquired while fatigued could be recalled accurately after rest. Twelve subjects adapted to a viscous force field applied by a lightweight robot as they reached to a target. They then reached while being resisted by elastic bands until they could no longer touch the target. This protocol reduced the strength of the muscles used to resist the force field by ∼20%. The bands were removed, and subjects adapted again to the viscous force field. Their adaptive ability, quantified by the amount and time constant of adaptation, was not significantly impaired following fatigue. The subjects then rested, recovering ∼70% of their lost force-generation ability. When they reached in the force field again, their prediction of the force field strength was different than in a nonfatigued state. This alteration was consistent with the use of a higher level of effort than normally used to counteract the force field. These results suggest that recovery from fatigue can affect recall of an internal model, even when the fatigue did not substantially affect the motor system’s ability to form the model. Recovery from fatigue apparently affects recall because the motor system represents internal models as a mapping between effort and movement and relies on practice to recalibrate this mapping.

scholarly journals Developmental onset of a cerebellar-dependent forward model of movement in motor thalamus

2021 ◽  
Author(s):  
James C Dooley ◽  
Greta Sokoloff ◽  
Mark S Blumberg
Keyword(s):  
Sensory Processing ◽  
Neural Activity ◽  
Internal Model ◽  
Internal Models ◽  
Active Sleep ◽  
Related Activity ◽  
Discrete Movements ◽  
Temporal Precision ◽  
Somatosensory Input ◽  
Motor Thalamus

To execute complex behavior with temporal precision, adult animals use internal models to predict the sensory consequences of self-generated movement. Here, taking advantage of the unique kinematic features of twitches-the brief, discrete movements of active sleep-we captured the developmental onset of a cerebellar-dependent internal model. Using rats at postnatal days (P) 12, P16, and P20, we compared neural activity in two thalamic structures: the ventral posterior (VP) and ventral lateral (VL) nuclei, both of which receive somatosensory input but only the latter of which receives cerebellar input. At all ages, twitch-related activity in VP lagged behind movement, consistent with sensory processing; similar activity was observed in VL through P16. At P20, however, VL activity precisely mimicked the twitch itself, a pattern of activity that depended on cerebellar input. Altogether, these findings implicate twitches in the development and refinement of internal models of movement.

Anticipating synchronization as an alternative to the internal model

2008 ◽  
Vol 31 (2) ◽  
pp. 216-217 ◽  
Author(s):  
Nigel Stepp ◽  
Michael T. Turvey
Keyword(s):  
Internal Model ◽  
Internal Models ◽  
Delay Compensation ◽  
Compensatory Mechanisms ◽  
Fundamental Assumption

AbstractThe fundamental assumption of compensation for visual delays states that, since delays are dealt with, there must be compensatory mechanisms. These mechanisms are taken to be internal models. Alternatives for delay compensation exist, suggesting that this assumption may not be fundamental, and nor should the existence of internal models be assumed. Delays may even be employed in their own compensation.

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