Vision Research special issue on the “On-line Visual Control of Action”

http://dx.doi.org/10.1016/j.visres.2014.12.017 0042-6989/ 2015 Elsevier Ltd. All rights reserved. It has been long known that on-going movements of the body can be adjusted when necessary, but the full implications of continuous visual control for the relationship between visual processing and the control of action, and the mechanisms by which this is achieved, have only just begun to be explored systematically. The on-line control of action is studied from diverse behavioural angles, including the control of eye movements, of goal directed arm and leg movements, and of locomotion and postural control. Furthermore, on-line control is probably essential for a variety of movement-control processes in the brain, such as updating coordinate transformations, optimising the interaction between eye and hand movements, and various other aspects of movement adaptation and learning. The aim of this special issue was to bring together perspectives on different effectors, control processes and neural circuitry in order to provide a state of the art overview of the on-line visual control of action. This is done with a combination of reviews, opinion papers, and some of the newest experimental findings on this topic. The on-line visual control of movements has probably been most widely studied in manual reaching. The issue therefore starts with a review by Sarlegna and Mutha of the use of visual target information for the continuous control of reaching movements. Next, Kuang and Gail report how rapid on-line control of the hand was reduced after short exposure to mirror-reversed vision of the hand, and then partly regained after prolonged exposure to the mirror-reversal. In another reaching experiment, Aivar, Brenner and Smeets show that movement corrections are initiated faster when a target is displaced than when an obstacle is displaced. Sandoval, Similä and McIntosh show that diverting participants’ attention influences the number of corrections that they make when performing a reaching task, implying that action and perception share attentional resources. On-line visual control of action has also been demonstrated for other movements than reaching. Zhao and Warren review some ideas about the extent to which the visual control of locomotion and of manual actions relies on continuous adjustments to on-going movements rather than on planning the movement in advance on the basis of internal models. In an experimental study, Valsecchi and Gegenfurtner examined the execution and possible role of binocular microsaccades during the last stages of precision reaching. Vision is not the only sensory modality involved in the on-line visual control of action. Cluff, Crevecoeur and Scott review online responses to visual perturbations of the target or hand as well as in response to mechanical perturbations of the reaching hand. Mackrous and Proteau adapted participants’ arms to a new inertia, and found that the influence of vision of the hand during the first part of their movements was reduced while adapting to the new inertia. Cameron and Lopez-Moliner examined whether the sensory modality (visual or proprioceptive) in which the target is specified matters for the on-line control of reaching. They find that the sensory modality in which the target is specified influences how much vision of the hand influences such on-line control. The last part of this issue deals with the neurophysiological bases of the on-line control of action, starting with a review by Archambault, Ferrari-Toniolo, Caminiti and Battaglia-Mayer, who make a clear distinction between adjusting a movement and replacing it by a new movement. Ono reviews the neuronal basis of on-line visual control in smooth pursuit eye movements. Whitwell, Milner, Cavina-Pratesi, Barat and Goodale present grasping data of patient DF, who is unable to indicate an object’s width with her thumb and index finger, but scales her hand aperture to the object’s size when reaching for the object. She even does so without on-line visual or haptic feedback. Krigolson, Cheng and Binsted provide a review on the use of EEG to study on-line movement adjustments. Finally, Pelah, Barbur, Thurrell and Hock examined the influence of optic flow on locomotion in a cortically blind patient, showing that optic flow information from the cortically blind hemifield influences behaviour. This implicates a visuo-locomotor coupling that does not involve V1.