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Smeets JBJ, Pennekamp I, van Amsterdam B, Schot WD. How prism adaptation reveals the distinct use of size and positions in grasping. Exp Brain Res 2023; 241:105-111. [PMID: 36370156 PMCID: PMC9870818 DOI: 10.1007/s00221-022-06506-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
The size of an object equals the distance between the positions of its opposite edges. However, human sensory processing for perceiving positions differs from that for perceiving size. Which of these two information sources is used to control grip aperture? In this paper, we answer this question by prism adaptation of single-digit movements of the index finger and thumb. We previously showed that it is possible to adapt the index finger and thumb in opposite directions and that this adaptation induces an aftereffect in grip aperture in grasping. This finding suggests that grasping is based on the perceived positions of the contact points. However, it might be compatible with grasping being controlled based on size provided that the opposing prism adaptation leads to changes in visually perceived size or proprioception of hand opening. In that case, one would predict a similar aftereffect in manually indicating the perceived size. In contrast, if grasping is controlled based on information about the positions of the edges, the aftereffect in grasping is due to altered position information, so one would predict no aftereffect in manually indicating the perceived size. Our present experiment shows that there was no aftereffect in manually indicating perceived size. We conclude that grip aperture during grasping is based on perceived positions rather than on perceived size.
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Affiliation(s)
- Jeroen B. J. Smeets
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, NL-1081 BT Amsterdam, The Netherlands
| | - Ian Pennekamp
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, NL-1081 BT Amsterdam, The Netherlands
| | - Bente van Amsterdam
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, NL-1081 BT Amsterdam, The Netherlands
| | - Willemijn D. Schot
- Educational Development and Training, Utrecht University, Utrecht, The Netherlands
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2
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Fan AWY, Guo LL, Frost A, Whitwell RL, Niemeier M, Cant JS. Grasping of Real-World Objects Is Not Biased by Ensemble Perception. Front Psychol 2021; 12:597691. [PMID: 33912099 PMCID: PMC8071954 DOI: 10.3389/fpsyg.2021.597691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 03/15/2021] [Indexed: 11/13/2022] Open
Abstract
The visual system is known to extract summary representations of visually similar objects which bias the perception of individual objects toward the ensemble average. Although vision plays a large role in guiding action, less is known about whether ensemble representation is informative for action. Motor behavior is tuned to the veridical dimensions of objects and generally considered resistant to perceptual biases. However, when the relevant grasp dimension is not available or is unconstrained, ensemble perception may be informative to behavior by providing gist information about surrounding objects. In the present study, we examined if summary representations of a surrounding ensemble display influenced grip aperture and orientation when participants reached-to-grasp a central circular target which had an explicit size but importantly no explicit orientation that the visuomotor system could selectively attend to. Maximum grip aperture and grip orientation were not biased by ensemble statistics during grasping, although participants were able to perceive and provide manual estimations of the average size and orientation of the ensemble display. Support vector machine classification of ensemble statistics achieved above-chance classification accuracy when trained on kinematic and electromyography data of the perceptual but not grasping conditions, supporting our univariate findings. These results suggest that even along unconstrained grasping dimensions, visually-guided behaviors toward real-world objects are not biased by ensemble processing.
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Affiliation(s)
- Annabel Wing-Yan Fan
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Lin Lawrence Guo
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Adam Frost
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Robert L. Whitwell
- The Department of Psychology, The University of British Columbia, Vancouver, BC, Canada
| | - Matthias Niemeier
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Jonathan S. Cant
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
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3
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Abstract
There is extensive literature debating whether perceived size is used to guide grasping. A possible reason for not using judged size is that using judged positions might lead to more precise movements. As this argument does not hold for small objects and all studies showing an effect of the Ebbinghaus illusion on grasping used small objects, we hypothesized that size information is used for small objects but not for large ones. Using a modified diagonal illusion, we obtained an effect of about 10% on perceptual judgements, without an effect on grasping, irrespective of object size. We therefore reject our precision hypothesis. We discuss the results in the framework of grasping as moving digits to positions on an object. We conclude that the reported disagreement on the effect of illusions is because the Ebbinghaus illusion not only affects size, but—unlike most size illusions—also affects perceived positions.
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de la Malla C, Brenner E, de Haan EHF, Smeets JBJ. A visual illusion that influences perception and action through the dorsal pathway. Commun Biol 2019; 2:38. [PMID: 30701203 PMCID: PMC6349884 DOI: 10.1038/s42003-019-0293-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 01/08/2019] [Indexed: 11/09/2022] Open
Abstract
There are two main anatomically and physiologically defined visual pathways connecting the primary visual cortex with higher visual areas: the ventral and the dorsal pathway. The influential two-visual-systems hypothesis postulates that visual attributes are analyzed differently for different functions: in the dorsal pathway visual information is analyzed to guide actions, whereas in the ventral pathway visual information is analyzed for perceptual judgments. We here show that a person who cannot identify objects due to an extensive bilateral ventral brain lesion is able to judge the velocity at which an object moves. Moreover, both his velocity judgements and his interceptive actions are as susceptible to a motion illusion as those of people without brain lesions. These findings speak in favor of the idea that dorsal structures process information about attributes such as velocity, irrespective of whether such information is used for perceptual judgments or to guide actions.
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Affiliation(s)
- Cristina de la Malla
- Vision and Control of Action (VISCA) Group, Department of Cognition, Development and Psychology of Education, Institut de Neurociències, Universitat de Barcelona, Passeig de la Vall d’Hebron 171, 08035 Barcelona, Catalonia Spain
- Department of Human Movement Sciences, Institute for Brain and Behavior Amsterdam, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081BT Amsterdam, The Netherlands
| | - Eli Brenner
- Department of Human Movement Sciences, Institute for Brain and Behavior Amsterdam, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081BT Amsterdam, The Netherlands
| | - Edward H. F. de Haan
- Department of Psychology, Amsterdam Brain and Cognition, University of Amsterdam, Nieuwe Achtergracht 129, 1001NK Amsterdam, The Netherlands
| | - Jeroen B. J. Smeets
- Department of Human Movement Sciences, Institute for Brain and Behavior Amsterdam, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, 1081BT Amsterdam, The Netherlands
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5
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Mikula L, Gaveau V, Pisella L, Khan AZ, Blohm G. Learned rather than online relative weighting of visual-proprioceptive sensory cues. J Neurophysiol 2018; 119:1981-1992. [PMID: 29465322 DOI: 10.1152/jn.00338.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
When reaching to an object, information about the target location as well as the initial hand position is required to program the motor plan for the arm. The initial hand position can be determined by proprioceptive information as well as visual information, if available. Bayes-optimal integration posits that we utilize all information available, with greater weighting on the sense that is more reliable, thus generally weighting visual information more than the usually less reliable proprioceptive information. The criterion by which information is weighted has not been explicitly investigated; it has been assumed that the weights are based on task- and effector-dependent sensory reliability requiring an explicit neuronal representation of variability. However, the weights could also be determined implicitly through learned modality-specific integration weights and not on effector-dependent reliability. While the former hypothesis predicts different proprioceptive weights for left and right hands, e.g., due to different reliabilities of dominant vs. nondominant hand proprioception, we would expect the same integration weights if the latter hypothesis was true. We found that the proprioceptive weights for the left and right hands were extremely consistent regardless of differences in sensory variability for the two hands as measured in two separate complementary tasks. Thus we propose that proprioceptive weights during reaching are learned across both hands, with high interindividual range but independent of each hand's specific proprioceptive variability. NEW & NOTEWORTHY How visual and proprioceptive information about the hand are integrated to plan a reaching movement is still debated. The goal of this study was to clarify how the weights assigned to vision and proprioception during multisensory integration are determined. We found evidence that the integration weights are modality specific rather than based on the sensory reliabilities of the effectors.
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Affiliation(s)
- Laura Mikula
- Centre de Recherche en Neurosciences de Lyon, ImpAct Team, INSERM U1028, CNRS UMR 5292, Lyon 1 University, Bron Cedex, France.,School of Optometry, University of Montreal , Montreal, Quebec , Canada
| | - Valérie Gaveau
- Centre de Recherche en Neurosciences de Lyon, ImpAct Team, INSERM U1028, CNRS UMR 5292, Lyon 1 University, Bron Cedex, France
| | - Laure Pisella
- Centre de Recherche en Neurosciences de Lyon, ImpAct Team, INSERM U1028, CNRS UMR 5292, Lyon 1 University, Bron Cedex, France
| | - Aarlenne Z Khan
- School of Optometry, University of Montreal , Montreal, Quebec , Canada
| | - Gunnar Blohm
- Centre for Neuroscience Studies, Queen's University , Kingston, Ontario , Canada
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6
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Gamble CM, Song JH. Dynamic modulation of illusory and physical target size on separate and coordinated eye and hand movements. J Vis 2017; 17:23. [PMID: 28362898 PMCID: PMC5381334 DOI: 10.1167/17.3.23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands.
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Affiliation(s)
- Christine M Gamble
- Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI,
| | - Joo-Hyun Song
- Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI, USABrown Institute for Brain Science, Brown University, Providence, RI, ://research.clps.brown.edu/songlab/
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7
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Knol H, Huys R, Sarrazin JC, Spiegler A, Jirsa VK. Ebbinghaus figures that deceive the eye do not necessarily deceive the hand. Sci Rep 2017; 7:3111. [PMID: 28596601 PMCID: PMC5465067 DOI: 10.1038/s41598-017-02925-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 04/27/2017] [Indexed: 11/09/2022] Open
Abstract
In support of the visual stream dissociation hypothesis, which states that distinct visual streams serve vision-for-perception and vision-for-action, visual size illusions were reported over 20 years ago to ‘deceive the eye but not the hand’. Ever since, inconclusive results and contradictory interpretations have accumulated. Therefore, we investigated the effects of the Ebbinghaus figure on repetitive aiming movements with distinct dynamics. Participants performed a Fitts’ task in which Ebbinghaus figures served as targets. We systematically varied the three parameters which have been shown to influence the perceived size of the Ebbinghaus figure’s target circle, namely the size of the target, its distance to the context circles and the size of the context circles. This paper shows that movement is significantly affected by the context size, but, in contrast to perception, not by the other two parameters. This is especially prominent in the approach phase of the movement towards the target, regardless of the dynamics. To reconcile the findings, we argue that different informational variables are used for size perception and the visual control of movements irrespective of whether certain variables induce (perceptual) illusions.
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Affiliation(s)
- Hester Knol
- Aix Marseille Université, CNRS, Institut des Sciences du Mouvement, UMR 7287, Marseille, France.
| | - Raoul Huys
- Centre de Recherche Cerveau & Cognition, Université Paul Sabatier, Université de Toulouse, Toulouse, France.,CerCo, CNRS UMR 5549, Toulouse, France
| | | | - Andreas Spiegler
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Viktor K Jirsa
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
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8
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Knol H, Huys R, Sarrazin JC, Jirsa VK. Quantifying the Ebbinghaus figure effect: target size, context size, and target-context distance determine the presence and direction of the illusion. Front Psychol 2015; 6:1679. [PMID: 26583002 PMCID: PMC4631937 DOI: 10.3389/fpsyg.2015.01679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 10/19/2015] [Indexed: 11/13/2022] Open
Abstract
Over the last 20 years, visual illusions, like the Ebbinghaus figure, have become widespread to investigate functional segregation of the visual system. This segregation reveals itself, so it is claimed, in the insensitivity of movement to optical illusions. This claim, however, faces contradictory results (and interpretations) in the literature. These contradictions may be due to methodological weaknesses in, and differences across studies, some of which may hide a lack of perceptual illusion effects. Indeed, despite the long history of research with the Ebbinghaus figure, standardized configurations to predict the illusion effect are missing. Here, we present a complete geometrical description of the Ebbinghaus figure with three target sizes compatible with Fitts' task. Each trial consisted of a stimulus and an isolated probe. The probe was controlled by the participant's response through a staircase procedure. The participant was asked whether the probe or target appeared bigger. The factors target size, context size, target-context distance, and a control condition resulted in a 3 × 3 × 3+3 factorial design. The results indicate that the illusion magnitude, the perceptual distinctiveness, and the response time depend on the context size, distance, and especially, target size. In 33% of the factor combinations there was no illusion effect. The illusion magnitude ranged from zero to (exceptionally) 10% of the target size. The small (or absent) illusion effects on perception and its possible influence on motor tasks might have been overlooked or misinterpreted in previous studies. Our results provide a basis for the application of the Ebbinghaus figure in psychophysical and motor control studies.
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Affiliation(s)
- Hester Knol
- Institut de Neurosciences des Systèmes, Aix-Marseille Université Marseille, France ; Institut de la Santé et de la Recherche Médical, UMR_S 1106 Marseille, France ; Systems Control and Flight Dynamics Department, Office National d'Etudes et de Recherches Aérospatiales (ONERA) Salon de Provence, France
| | - Raoul Huys
- Centre National de la Recherche Scientifique Paris, France ; Centre de Recherche Cerveau & Cognition - UMR5549, Université Toulouse III - Paul Sabatier Toulouse, France
| | - Jean-Christophe Sarrazin
- Systems Control and Flight Dynamics Department, Office National d'Etudes et de Recherches Aérospatiales (ONERA) Salon de Provence, France
| | - Viktor K Jirsa
- Institut de Neurosciences des Systèmes, Aix-Marseille Université Marseille, France ; Institut de la Santé et de la Recherche Médical, UMR_S 1106 Marseille, France ; Centre National de la Recherche Scientifique Paris, France
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9
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Christensen A, Borchers S, Himmelbach M. Effects of pictorial cues on reaching depend on the distinctiveness of target objects. PLoS One 2013; 8:e54230. [PMID: 23382882 PMCID: PMC3559638 DOI: 10.1371/journal.pone.0054230] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 12/11/2012] [Indexed: 11/18/2022] Open
Abstract
There is an ongoing debate under what conditions learned object sizes influence visuomotor control under preserved stereovision. Using meaningful objects (matchboxes of locally well-known brands in the UK) a previous study has nicely shown that the recognition of these objects influences action programming by means of reach amplitude and grasp pre-shaping even under binocular vision. Using the same paradigm, we demonstrated that short-term learning of colour-size associations was not sufficient to induce any visuomotor effects under binocular viewing conditions. Now we used the same matchboxes, for which the familiarity effect was shown in the UK, with German participants who have never seen these objects before. We addressed the question whether simply a high degree of distinctness, or whether instead actual prior familiarity of these objects, are required to affect motor computations. We found that under monocular and binocular viewing conditions the learned size and location influenced the amplitude of the reaching component significantly. In contrast, the maximum grip aperture remained unaffected for binocular vision. We conclude that visual distinctness is sufficient to form reliable associations in short-term learning to influence reaching even for preserved stereovision. Grasp pre-shaping instead seems to be less susceptible to such perceptual effects.
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Affiliation(s)
- Andrea Christensen
- Division of Neuropsychology, Hertie-Institute for Clinical Brain Research and Centre for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany
- Section Computational Sensomotorics, Hertie-Institute for Clinical Brain Research and Centre for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany
| | - Svenja Borchers
- Division of Neuropsychology, Hertie-Institute for Clinical Brain Research and Centre for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany
| | - Marc Himmelbach
- Division of Neuropsychology, Hertie-Institute for Clinical Brain Research and Centre for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany
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10
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Thomaschke R, Hopkins B, Miall RC. The planning and control model (PCM) of motorvisual priming: reconciling motorvisual impairment and facilitation effects. Psychol Rev 2012; 119:388-407. [PMID: 22369178 PMCID: PMC3936358 DOI: 10.1037/a0027453] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 01/04/2012] [Accepted: 01/20/2012] [Indexed: 11/08/2022]
Abstract
Previous research on dual-tasks has shown that, under some circumstances, actions impair the perception of action-consistent stimuli, whereas, under other conditions, actions facilitate the perception of action-consistent stimuli. We propose a new model to reconcile these contrasting findings. The planning and control model (PCM) of motorvisual priming proposes that action planning binds categorical representations of action features so that their availability for perceptual processing is inhibited. Thus, the perception of categorically action-consistent stimuli is impaired during action planning. Movement control processes, on the other hand, integrate multi-sensory spatial information about the movement and, therefore, facilitate perceptual processing of spatially movement-consistent stimuli. We show that the PCM is consistent with a wider range of empirical data than previous models on motorvisual priming. Furthermore, the model yields previously untested empirical predictions. We also discuss how the PCM relates to motorvisual research paradigms other than dual-tasks.
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Affiliation(s)
- Roland Thomaschke
- Department of Psychology, University of Regensburg, 93053 Regensburg, Germany.
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11
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Sartori L, Straulino E, Castiello U. How objects are grasped: the interplay between affordances and end-goals. PLoS One 2011; 6:e25203. [PMID: 21980396 PMCID: PMC3182194 DOI: 10.1371/journal.pone.0025203] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 08/29/2011] [Indexed: 01/08/2023] Open
Abstract
Background Substantial literature has demonstrated that how the hand approaches an object depends on the manipulative action that will follow object contact. Little is known about how the placement of individual fingers on objects is affected by the end-goal of the action. Methodology/Principal Findings Hand movement kinematics were measured during reaching for and grasping movements towards two objects (stimuli): a bottle with an ordinary cylindrical shape and a bottle with a concave constriction. The effects of the stimuli's weight (half full or completely full of water) and the end-goals (pouring, moving) of the action were also assessed. Analysis of key kinematic landmarks measured during reaching movements indicate that object affordance facilitates the end-goal of the action regardless of accuracy constraints. Furthermore, the placement of individual digits at contact is modulated by the shape of the object and the end-goal of the action. Conclusions/Significance These findings offer a substantial contribution to the current debate about the role played by affordances and end-goals in determining the structure of reach-to-grasp movements.
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Affiliation(s)
- Luisa Sartori
- Dipartimento di Psicologia Generale, Università di Padova, Padova, Italy
| | - Elisa Straulino
- Dipartimento di Psicologia Generale, Università di Padova, Padova, Italy
| | - Umberto Castiello
- Dipartimento di Psicologia Generale, Università di Padova, Padova, Italy
- * E-mail:
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12
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Pagano CC, Grutzmacher RP, Jenkins JC. Comparing Verbal and Reaching Responses to Visually Perceived Egocentric Distances. ECOLOGICAL PSYCHOLOGY 2010. [DOI: 10.1207/s15326969eco1303_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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13
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Hendrix CM, Mason CR, Ebner TJ. Signaling of grasp dimension and grasp force in dorsal premotor cortex and primary motor cortex neurons during reach to grasp in the monkey. J Neurophysiol 2009; 102:132-45. [PMID: 19403752 DOI: 10.1152/jn.00016.2009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A fundamental question is how the CNS controls the hand with its many degrees of freedom. Several motor cortical areas, including the dorsal premotor cortex (PMd) and primary motor cortex (M1), are involved in reach to grasp. Although neurons in PMd are known to modulate in relation to the type of grasp and neurons in M1 in relation to grasp force and finger movements, whether specific parameters of whole hand shaping are encoded in the discharge of these cells has not been studied. In this study, two monkeys were trained to reach and grasp 16 objects varying in shape, size, and orientation. Grasp force was explicitly controlled, requiring the monkeys to exert either three or five levels of grasp force on each object. The animals were unable to see the objects or their hands. Single PMd and M1 neurons were recorded during the task, and cell firing was examined for modulation with object properties and grasp force. The firing of the vast majority of PMd and M1 neurons varied significantly as a function of the object presented as well as the object grasp dimension. Grasp dimension of the object was an important determinant of the firing of cells in both PMd and M1. A smaller percentage of PMd and M1 neurons were modulated by grasp force. Linear encoding was prominent with grasp force but less so with grasp dimension. The correlations with grasp dimension and grasp force were stronger in the firing of M1 than PMd neurons and across both regions the modulation with these parameters increased as reach to grasp proceeded. All PMd and M1 neurons that signaled grasp force also signaled grasp dimension, yet the two signals showed limited interactions, providing a neural substrate for the independent control of these two parameters at the behavioral level.
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Affiliation(s)
- Claudia M Hendrix
- Department of Neuroscience, University of Minnesota, Lions Research Bldg., Rm. 421, 2001 Sixth St. SE, Minneapolis, MN 55455, USA
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14
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Brouwer AM, Georgiou I, Glover S, Castiello U. Adjusting reach to lift movements to sudden visible changes in target's weight. Exp Brain Res 2006; 173:629-36. [PMID: 16525801 DOI: 10.1007/s00221-006-0406-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 02/08/2006] [Indexed: 10/24/2022]
Abstract
People can adjust their reach-to-grasp movements online to sudden changes in the spatial properties of a target. We investigated whether they can also do this when a non-spatial property, weight, suddenly changes. Guiding your movement by using visual cues about an object's weight depends heavily on experience and is expected to be processed by the (slow) ventral stream rather than the (fast) 'online control' dorsal stream. In the first experiment, participants reached out and lifted an object with an expected or an unexpected weight. As predicted, there was an effect of expected weight on the time between the end of the reaching phase and the object's lift-off. In the second experiment, the object sometimes visibly changed weight after the participants had started their movement. The lifting time did not depend on whether the object had changed weight. Thus, participants can make online adjustments to a visually indicated change in weight. These results are interpreted as being contrary to existing theories of online control.
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Affiliation(s)
- Anne-Marie Brouwer
- Department Bülthoff, Max Planck Institute for Biological Cybernetics, P.O. Box 2169, 72012, Tübingen, Germany.
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15
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Repp BH. Does an auditory perceptual illusion affect on-line auditory action control? The case of (de)accentuation and synchronization. Exp Brain Res 2005; 168:493-504. [PMID: 16177833 DOI: 10.1007/s00221-005-0108-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 04/06/2005] [Indexed: 11/29/2022]
Abstract
Many recent studies have investigated whether visual (spatial) illusions affect visual (spatio-temporal) action control, with results that are far from simple. The present study asks the analogous question with regard to auditory temporal perception and action timing. The auditory illusion chosen for this particular study is the effect of increasing or decreasing the intensity of a tone in a sequence (i.e., accentuation or deaccentuation) on its perceived relative time of occurrence. The motor task is sensorimotor synchronization (finger tapping), specifically the automatic phase correction response to an advanced or delayed tone in a sequence. The strong hypothesis was that (de)accentuation would affect perceptual judgments of the tone's relative time of occurrence, but would have no effect at all on the phase correction response. The results of two experiments, if averaged across participants, confirm these predictions and furthermore suggest that individual perceptual and sensorimotor effects of (de)accentuation are uncorrelated. It is argued that perception and motor control in this case probably rely on different kinds of temporal information: relative versus absolute time of occurrence. Two unexpected findings complicate the results, however: the perceptual illusion was asymmetric, occurring only for delayed tones; and many individual participants did show significant differences in their phase correction response to accented and deaccented tones, although the direction of that difference varied.
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Affiliation(s)
- Bruno H Repp
- Haskins Laboratories, 300 George Street, New Haven, CT 06511-6624, USA.
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Heath M, Rival C, Neely K. Visual feedback schedules influence visuomotor resistance to the Müller-Lyer figures. Exp Brain Res 2005; 168:348-56. [PMID: 16175361 DOI: 10.1007/s00221-005-0095-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 05/26/2005] [Indexed: 10/25/2022]
Abstract
We examined whether blocked or random visual feedback schedules influence visuomotor resistance to the Müller-Lyer (ML) illusion. Participants completed closed-loop (CL) and open-loop (OL) grasping movements to an object embedded within fins-in and fins-out ML configurations. In the blocked feedback schedule, CL and OL trials were completed in separate blocks of trials, whereas visual conditions were randomly interleaved in the random feedback schedule. The results of the blocked feedback schedule showed that OL, but not CL, trials were influenced in a direction consistent with the perceptual effects of the ML illusion. For the random feedback schedule, however, both CL and OL trials were influenced by the illusion. We have interpreted these results to reflect the fact that participants evoked distinct control strategies based on the predicted availability of visual feedback. Specifically, the refractory nature of CL trials in the blocked feedback schedule suggests that advance knowledge that visual feedback would be available during a response encouraged an online control strategy wherein metrical visual information supported grasping. When visual feedback was unavailable (i.e., blocked OL trials), or could not be predicted in advance of a response (i.e., random CL and OL trials), it is proposed that movements were structured offline via perception-based visual information that was "tricked" by the cognitive properties of the ML illusion.
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Affiliation(s)
- Matthew Heath
- Department of Kinesiology and Program in Neural Science, Indiana University, Bloomington, IN 47405, USA.
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Dassonville P, Bala JK. Perception, action, and Roelofs effect: a mere illusion of dissociation. PLoS Biol 2004; 2:e364. [PMID: 15510224 PMCID: PMC524248 DOI: 10.1371/journal.pbio.0020364] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Accepted: 08/23/2004] [Indexed: 11/19/2022] Open
Abstract
A prominent and influential hypothesis of vision suggests the existence of two separate visual systems within the brain, one creating our perception of the world and another guiding our actions within it. The induced Roelofs effect has been described as providing strong evidence for this perception/action dissociation: When a small visual target is surrounded by a large frame positioned so that the frame's center is offset from the observer's midline, the perceived location of the target is shifted in the direction opposite the frame's offset. In spite of this perceptual mislocalization, however, the observer can accurately guide movements to the target location. Thus, perception is prone to the illusion while actions seem immune. Here we demonstrate that the Roelofs illusion is caused by a frame-induced transient distortion of the observer's apparent midline. We further demonstrate that actions guided to targets within this same distorted egocentric reference frame are fully expected to be accurate, since the errors of target localization will exactly cancel the errors of motor guidance. These findings provide a mechanistic explanation for the various perceptual and motor effects of the induced Roelofs illusion without requiring the existence of separate neural systems for perception and action. Given this, the behavioral dissociation that accompanies the Roelofs effect cannot be considered evidence of a dissociation of perception and action. This indicates a general need to re-evaluate the broad class of evidence purported to support this hypothesized dissociation. Paul Dassonville and Jagdeep Bala challenge a prominent hypothesis that proposes the existence of two separate visual systems within the brain, one creating perception and the other guiding action
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Affiliation(s)
- Paul Dassonville
- Department of Psychology and Institute of Neuroscience, University of Oregon, Eugene, Oregon, USA.
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