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Johansson, Roland S
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Publications (10 of 70) Show all publications
Pruszynski, J. A., Johansson, R. S. & Flanagan, J. R. (2016). A Rapid Tactile-Motor Reflex Automatically Guides Reaching toward Handheld Objects. Current Biology, 26(6), 788-792.
Open this publication in new window or tab >>A Rapid Tactile-Motor Reflex Automatically Guides Reaching toward Handheld Objects
2016 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 26, no 6, 788-792 p.Article in journal (Refereed) Published
Abstract [en]

The ability to respond quickly and effectively when objects in the world suddenly change position is essential for skilled action, and previous work has documented how unexpected changes in the location of a visually presented target during reaching can elicit rapid reflexive (i.e., automatic) corrections of the hand's trajectory [1-12]. In object manipulation and tool use, the sense of touch can also provide information about changes in the location of reach targets. Consider the many tasks where we reach with one hand to part of an object grasped by the other hand: reaching to a berry while holding a branch, reaching for a cap while grasping a bottle, and reaching toward a dog's collar while holding the dog's leash. In such cases, changes in the position of the reach target, due to wind, slip, or an active agent, can be detected, in principle, through touch. Here, we show that when people reach with their right hand to a target attached to the far end of a rod contacted, at the near end, by their left hand, an unexpected change in target location caused by rod rotation rapidly evokes an effective reach correction. That is, spatial information about a change in target location provided by tactile inputs to one hand elicits a rapid correction of the other hand's trajectory. In addition to uncovering a tactile-motor reflex that can support manipulatory actions, our results demonstrate that automatic reach corrections to moving targets are not unique to visually registered changes in target location.

National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-119280 (URN)10.1016/j.cub.2016.01.027 (DOI)000372411600023 ()26898466 (PubMedID)
Available from: 2016-06-02 Created: 2016-04-15 Last updated: 2018-01-10Bibliographically approved
Diamond, J. S., Nashed, J. Y., Johansson, R. S., Wolpert, D. M. & Flanagan, J. R. (2015). Rapid Visuomotor Corrective Responses during Transport of Hand-Held Objects Incorporate Novel Object Dynamics. Journal of Neuroscience, 35(29), 10572-10580.
Open this publication in new window or tab >>Rapid Visuomotor Corrective Responses during Transport of Hand-Held Objects Incorporate Novel Object Dynamics
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2015 (English)In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 35, no 29, 10572-10580 p.Article in journal (Refereed) Published
Abstract [en]

Numerous studies have shown that people are adept at learning novel object dynamics, linking applied force and motion, when performing reaching movements with hand-held objects. Here we investigated whether the control of rapid corrective arm responses, elicited in response to visual perturbations, has access to such newly acquired knowledge of object dynamics. Participants first learned to make reaching movements while grasping an object subjected to complex load forces that depended on the distance and angle of the hand from the start position. During a subsequent test phase, we examined grip and load force coordination during corrective arm movements elicited (within similar to 150 ms) in response to viewed sudden lateral shifts (1.5 cm) in target or object position. We hypothesized that, if knowledge of object dynamics is incorporated in the control of the corrective responses, grip force changes would anticipate the unusual load force changes associated with the corrective arm movements so as to support grasp stability. Indeed, we found that the participants generated grip force adjustments tightly coupled, both spatially and temporally, to the load force changes associated with the arm movement corrections. We submit that recently learned novel object dynamics are effectively integrated into sensorimotor control policies that support rapid visually driven arm corrective actions during transport of hand held objects.

Keyword
internal model, motor learning, object manipulation, reaching, visuomotor control
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-107162 (URN)10.1523/JNEUROSCI.1376-15.2015 (DOI)000358299500018 ()26203151 (PubMedID)
Available from: 2015-09-07 Created: 2015-08-19 Last updated: 2018-01-11Bibliographically approved
Pruszynski, J. A. & Johansson, R. S. (2014). Edge-orientation processing in first-order tactile neurons. Nature Neuroscience, 17(10), 1404-1409.
Open this publication in new window or tab >>Edge-orientation processing in first-order tactile neurons
2014 (English)In: Nature Neuroscience, ISSN 1097-6256, E-ISSN 1546-1726, Vol. 17, no 10, 1404-1409 p.Article in journal (Refereed) Published
Abstract [en]

A fundamental feature of first-order neurons in the tactile system is that their distal axon branches in the skin and forms many transduction sites, yielding complex receptive fields with many highly sensitive zones. We found that this arrangement constitutes a peripheral neural mechanism that allows individual neurons to signal geometric features of touched objects. Specifically, we observed that two types of first-order tactile neurons that densely innervate the glabrous skin of the human fingertips signaled edge orientation via both the intensity and the temporal structure of their responses. Moreover, we found that the spatial layout of a neuron's highly sensitive zones predicted its sensitivity to particular edge orientations. We submit that peripheral neurons in the touch-processing pathway, as with peripheral neurons in the visual-processing pathway, perform feature extraction computations that are typically attributed to neurons in the cerebral cortex.

Place, publisher, year, edition, pages
Nature Publishing Group, 2014
National Category
Physiology Neurosciences
Identifiers
urn:nbn:se:umu:diva-92698 (URN)10.1038/nn.3804 (DOI)000342327000021 ()25174006 (PubMedID)
Available from: 2014-09-01 Created: 2014-09-01 Last updated: 2018-01-11Bibliographically approved
Säfström, D., Johansson, R. S. & Flanagan, J. R. (2014). Gaze behavior when learning to link sequential action phases in a manual task. Journal of Vision, 14(4).
Open this publication in new window or tab >>Gaze behavior when learning to link sequential action phases in a manual task
2014 (English)In: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 14, no 4Article in journal (Refereed) Published
Abstract [en]

Most manual tasks comprise a sequence of action phases. Skill acquisition in such tasks involves a transition from reactive control, whereby motor commands for the next phase are triggered by sensory events signaling completion of the current phase, to predictive control, whereby commands for the next phase are launched in anticipation of these events. Here we investigated gaze behavior associated with such learning. Participants moved a cursor to successively acquire visual targets, as quickly as possible, by actively keeping the cursor within the target zone (hold phase) for a required duration, before moving to the next target (transport phase). Distinct visual and auditory events marked completion of each phase and, with learning, the launching of the transport phase shifted from being reactively to predictively controlled. Initially, gaze was directed to the current target throughout the hold phase, allowing visual feedback control of the cursor position, and shifted to the next target in synchrony with the cursor. However, with learning, two distinct gaze behaviors emerged. Gaze either shifted to the next target well before the end of the hold phase, facilitating planning of the forthcoming cursor movement, or shifted to the next target after the cursor, enabling cursor exits to be monitored in central vision. These results suggest that, with learning, gaze behavior changes to support evolving task demands, and that people distribute different gaze behaviors across repetitions of the task.

National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-88072 (URN)10.1167/14.4.3 (DOI)000337169900003 ()24695992 (PubMedID)
Available from: 2014-04-23 Created: 2014-04-23 Last updated: 2018-01-11Bibliographically approved
Grigoriadis, A., Johansson, R. S. & Trulsson, M. (2014). Temporal profile and amplitude of human masseter muscle activity is adapted to food properties during individual chewing cycles. Journal of Oral Rehabilitation, 41(5), 367-373.
Open this publication in new window or tab >>Temporal profile and amplitude of human masseter muscle activity is adapted to food properties during individual chewing cycles
2014 (English)In: Journal of Oral Rehabilitation, ISSN 0305-182X, E-ISSN 1365-2842, Vol. 41, no 5, 367-373 p.Article in journal (Refereed) Published
Abstract [en]

Jaw actions adapt to the changing properties of food that occur during a masticatory sequence. In the present study, we investigated how the time-varying activation profile of the masseter muscle changes during natural chewing in humans and how food hardness affects the profile. We recorded surface electromyography (EMG) of the masseter muscle together with the movement of the lower jaw in 14 healthy young adults (mean age 22) when chewing gelatin-based model food of two different hardness. The muscle activity and the jaw kinematics were analysed for different phases of the chewing cycles. The increase in the excitatory drive of the masseter muscle was biphasic during the jaw-closing phase showing early and late components. The transition between these components occurred approximately at the time of tooth-food contact. During the masticatory sequence, when the food was particularised, the size of the early component as well as the peak amplitude of the EMG significantly decreased along with a reduction in the duration of the jaw-closing phase. Except for amplitude scaling, food hardness did not appreciably affect the muscle's activation profile. In conclusion, when chewing food during natural conditions, masseter muscle activation adapted throughout the masticatory sequence, principally during the jaw-closing phase and influenced both early and late muscle activation components. Furthermore, the adaptation of jaw actions to food hardness was affected by amplitude scaling of the magnitude of the muscle activity throughout the masticatory sequence.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2014
Keyword
electromyography; food; kinematics; masseter muscle; mastication; neurophysiology
National Category
Dentistry
Identifiers
urn:nbn:se:umu:diva-88662 (URN)10.1111/joor.12155 (DOI)000334050900006 ()
Available from: 2014-05-19 Created: 2014-05-12 Last updated: 2017-12-05Bibliographically approved
Reichelt, A. F., Ash, A. M., Baugh, L. A., Johansson, R. S. & Flanagan, J. R. (2013). Adaptation of lift forces in object manipulation through action observation.. Experimental Brain Research, 228(2), 221-234.
Open this publication in new window or tab >>Adaptation of lift forces in object manipulation through action observation.
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2013 (English)In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 228, no 2, 221-234 p.Article in journal (Refereed) Published
Abstract [en]

The ability to predict accurately the weights of objects is essential for skilled and dexterous manipulation. A potentially important source of information about object weight is through the observation of other people lifting objects. Here, we tested the hypothesis that when watching an actor lift an object, people naturally learn the object's weight and use this information to scale forces when they subsequently lift the object themselves. Participants repeatedly lifted an object in turn with an actor. Object weight unpredictably changed between 2 and 7 N every 5th to 9th of the actor's lifts, and the weight lifted by the participant always matched that previously lifted by the actor. Even though the participants were uninformed about the structure of the experiment, they appropriately adapted their lifting force in the first trial after a weight change. Thus, participants updated their internal representation about the object's weight, for use in action, when watching a single lift performed by the actor. This ability presumably involves the comparison of predicted and actual sensory information related to actor's actions, a comparison process that is also fundamental in action.

Place, publisher, year, edition, pages
Springer, 2013
Keyword
Action observation, Object manipulation, Motor learning, Human
National Category
Neurosciences Neurology
Identifiers
urn:nbn:se:umu:diva-73229 (URN)10.1007/s00221-013-3554-9 (DOI)000320820900009 ()23681295 (PubMedID)
Funder
Swedish Research Council, 08667
Note

This work was supported by a grant from the Canadian Institutes of Health Research, the Swedish Research Council Project 08667, and the Strategic Research Program in Neuroscience at the Karolinska Institute.

Available from: 2013-06-19 Created: 2013-06-19 Last updated: 2018-01-11Bibliographically approved
Bengtsson, F., Brasselet, R., Johansson, R. S., Arleo, A. & Jörntell, H. (2013). Integration of sensory quanta in cuneate nucleus neurons in vivo. PLoS ONE, 8(2), e56630.
Open this publication in new window or tab >>Integration of sensory quanta in cuneate nucleus neurons in vivo
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2013 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 2, e56630- p.Article in journal (Refereed) Published
Abstract [en]

Discriminative touch relies on afferent information carried to the central nervous system by action potentials (spikes) in ensembles of primary afferents bundled in peripheral nerves. These sensory quanta are first processed by the cuneate nucleus before the afferent information is transmitted to brain networks serving specific perceptual and sensorimotor functions. Here we report data on the integration of primary afferent synaptic inputs obtained with in vivo whole cell patch clamp recordings from the neurons of this nucleus. We find that the synaptic integration in individual cuneate neurons is dominated by 4-8 primary afferent inputs with large synaptic weights. In a simulation we show that the arrangement with a low number of primary afferent inputs can maximize transfer over the cuneate nucleus of information encoded in the spatiotemporal patterns of spikes generated when a human fingertip contact objects. Hence, the observed distributions of synaptic weights support high fidelity transfer of signals from ensembles of tactile afferents. Various anatomical estimates suggest that a cuneate neuron may receive hundreds of primary afferents rather than 4-8. Therefore, we discuss the possibility that adaptation of synaptic weight distribution, possibly involving silent synapses, may function to maximize information transfer in somatosensory pathways.

National Category
Neurosciences Physiology
Identifiers
urn:nbn:se:umu:diva-67394 (URN)10.1371/journal.pone.0056630 (DOI)000314660300078 ()
Available from: 2013-04-11 Created: 2013-03-18 Last updated: 2018-01-11Bibliographically approved
Säfström, D., Flanagan, J. R. & Johansson, R. S. (2013). Skill learning involves optimizing the linking of action phases. Journal of Neurophysiology, 110(6), 1291-1300.
Open this publication in new window or tab >>Skill learning involves optimizing the linking of action phases
2013 (English)In: Journal of Neurophysiology, ISSN 0022-3077, E-ISSN 1522-1598, Vol. 110, no 6, 1291-1300 p.Article in journal (Refereed) Published
Abstract [en]

Many manual tasks involve object manipulation and are achieved by an evolving series of actions, or action phases, recruited to achieve task subgoals. The ability to effectively link action phases is an important component of manual dexterity. However, our understanding of how the effective linking of sequential action phases develops with skill learning is limited. Here, we addressed this issue using a task in which participants applied forces to a handle to move a cursor on a computer screen to successively acquire visual targets. Target acquisition required actively holding the cursor within the target zone (hold phase) for a required duration, before moving to the next target (transport phase). If the transport phase was initiated prematurely, before the end of the required hold duration, participants had to return to the target to acquire it. The goal was to acquire targets as quickly as possible. Distinct visual and auditory sensory events marked goal completion of each action phase. During initial task performance, the transport phase was reactively triggered by sensory events signaling hold phase completion. However, with practice, participants learned to initiate the transport phase based on a prediction of the time of hold phase completion. Simulations revealed that participants learned to near-optimally compensate for temporal uncertainty, presumably related to estimation of time intervals and execution of motor commands, so as to reduce the average latency between the end of the required hold phase duration and the start of the transport phase, while avoiding an excess of premature exits.

Keyword
object manipulation, sensorimotor control, motor learning, multisensory, optimality
National Category
Neurosciences Physiology
Identifiers
urn:nbn:se:umu:diva-73230 (URN)10.1152/jn.00019.2013 (DOI)000324756100004 ()23741046 (PubMedID)
Available from: 2013-06-19 Created: 2013-06-19 Last updated: 2018-01-11Bibliographically approved
Flanagan, J. R., Rotman, G., Reichelt, A. F. & Johansson, R. S. (2013). The role of observers' gaze behaviour when watching object manipulation tasks: predicting and evaluating the consequences of action. Philosophical Transactions of the Royal Society of London. Biological Sciences, 368(1628), 20130063.
Open this publication in new window or tab >>The role of observers' gaze behaviour when watching object manipulation tasks: predicting and evaluating the consequences of action
2013 (English)In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 368, no 1628, 20130063- p.Article in journal (Refereed) Published
Abstract [en]

When watching an actor manipulate objects, observers, like the actor, naturally direct their gaze to each object as the hand approaches and typically maintain gaze on the object until the hand departs. Here, we probed the function of observers' eye movements, focusing on two possibilities: (i) that observers' gaze behaviour arises from processes involved in the prediction of the target object of the actor's reaching movement and (ii) that this gaze behaviour supports the evaluation of mechanical events that arise from interactions between the actor's hand and objects. Observers watched an actor reach for and lift one of two presented objects. The observers' task was either to predict the target object or judge its weight. Proactive gaze behaviour, similar to that seen in self-guided action-observation, was seen in the weight judgement task, which requires evaluating mechanical events associated with lifting, but not in the target prediction task. We submit that an important function of gaze behaviour in self-guided action observation is the evaluation of mechanical events associated with interactions between the hand and object. By comparing predicted and actual mechanical events, observers, like actors, can gain knowledge about the world, including information about objects they may subsequently act upon.

Keyword
gaze behaviour, action – observation, object manipulation
National Category
Physiology Neurosciences
Identifiers
urn:nbn:se:umu:diva-83715 (URN)10.1098/rstb.2013.0063 (DOI)000331224600011 ()24018725 (PubMedID)
Available from: 2013-12-05 Created: 2013-12-05 Last updated: 2018-01-11Bibliographically approved
Armstrong, I. T., Judson, M., Munoz, D. P., Johansson, R. S. & Flanagan, J. R. (2013). Waiting for a hand: saccadic reaction time increases in proportion to hand reaction time when reaching under a visuomotor reversal. Frontiers in Human Neuroscience, 7, 319.
Open this publication in new window or tab >>Waiting for a hand: saccadic reaction time increases in proportion to hand reaction time when reaching under a visuomotor reversal
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2013 (English)In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 7, 319- p.Article in journal (Refereed) Published
Abstract [en]

Although eye movement onset typically precedes hand movement onset when reaching to targets presented in peripheral vision, arm motor commands appear to be issued at around the same time, and possibly in advance, of eye motor commands. A fundamental question, therefore, is whether eye movement initiation is linked or yoked to hand movement. We addressed this issue by having participants reach to targets after adapting to a visuomotor reversal (or 180° rotation) between the position of the unseen hand and the position of a cursor controlled by the hand. We asked whether this reversal, which we expected to increase hand reaction time (HRT), would also increase saccadic reaction time (SRT). As predicted, when moving the cursor to targets under the reversal, HRT increased in all participants. SRT also increased in all but one participant, even though the task for the eyes-shifting gaze to the target-was unaltered by the reversal of hand position feedback. Moreover, the effects of the reversal on SRT and HRT were positively correlated across participants; those who exhibited the greatest increases in HRT also showed the greatest increases in SRT. These results indicate that the mechanisms underlying the initiation of eye and hand movements are linked. In particular, the results suggest that the initiation of an eye movement to a manual target depends, at least in part, on the specification of hand movement.

National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-83714 (URN)10.3389/fnhum.2013.00319 (DOI)000321249800001 ()23847494 (PubMedID)
Available from: 2013-12-05 Created: 2013-12-05 Last updated: 2018-01-11Bibliographically approved
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