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Johansson, Roland S.
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Publications (10 of 74) Show all publications
Pruszynski, J. A., Flanagan, J. R. & Johansson, R. S. (2018). Fast and accurate edge orientation processing during object manipulation. eLIFE, 7, Article ID e31200.
Open this publication in new window or tab >>Fast and accurate edge orientation processing during object manipulation
2018 (English)In: eLIFE, E-ISSN 2050-084X, Vol. 7, article id e31200Article in journal (Refereed) Published
Abstract [en]

Quickly and accurately extracting information about a touched object’s orientation is a critical aspect of dexterous object manipulation. However, the speed and acuity of tactile edge orientation processing with respect to the fingertips as reported in previous perceptual studies appear inadequate in these respects. Here we directly establish the tactile system’s capacity to process edge-orientation information during dexterous manipulation. Participants extracted tactile information about edge orientation very quickly, using it within 200 ms of first touching the object. Participants were also strikingly accurate. With edges spanning the entire fingertip, edge-orientation resolution was better than 3° in our object manipulation task, which is several times better than reported in previous perceptual studies. Performance remained impressive even with edges as short as 2 mm, consistent with our ability to precisely manipulate very small objects. Taken together, our results radically redefine the spatial processing capacity of the tactile system.

Place, publisher, year, edition, pages
ELIFE SCIENCES PUBLICATIONS LTD, 2018
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-151176 (URN)10.7554/eLife.31200 (DOI)000431038000001 ()29611804 (PubMedID)2-s2.0-85051947543 (Scopus ID)
Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-09-05Bibliographically approved
Nordmark, P. F., Ljungberg, C. & Johansson, R. S. (2018). Structural changes in hand related cortical areas after median nerve injury and repair. Scientific Reports, 8, Article ID 4485.
Open this publication in new window or tab >>Structural changes in hand related cortical areas after median nerve injury and repair
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 4485Article in journal (Refereed) Published
Abstract [en]

Transection of the median nerve typically causes lifelong restriction of fine sensory and motor skills of the affected hand despite the best available surgical treatment. Inspired by recent findings on activity-dependent structural plasticity of the adult brain, we used voxel-based morphometry to analyze the brains of 16 right-handed adults who more than two years earlier had suffered injury to the left or right median nerve followed by microsurgical repair. Healthy individuals served as matched controls. Irrespective of side of injury, we observed gray matter reductions in left ventral and right dorsal premotor cortex, and white matter reductions in commissural pathways interconnecting those motor areas. Only left-side injured participants showed gray matter reduction in the hand area of the contralesional primary motor cortex. We interpret these effects as structural manifestations of reduced neural processing linked to restrictions in the diversity of the natural manual dexterity repertoire. Furthermore, irrespective of side of injury, we observed gray matter increases bilaterally in a motion-processing visual area. We interpret this finding as a consequence of increased neural processing linked to greater dependence on vision for control of manual dexterity after median nerve injury because of a compromised somatosensory innervation of the affected hand.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-146441 (URN)10.1038/s41598-018-22792-x (DOI)000427366200015 ()29540748 (PubMedID)
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2019-05-20Bibliographically approved
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, p. 788-792Article 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: 2018-06-07Bibliographically approved
Baugh, L. A., Yak, A., Johansson, R. S. & Flanagan, J. R. (2016). Representing multiple object weights: competing priors and sensorimotor memories. Journal of Neurophysiology, 116(4), 1615-1625
Open this publication in new window or tab >>Representing multiple object weights: competing priors and sensorimotor memories
2016 (English)In: Journal of Neurophysiology, ISSN 0022-3077, E-ISSN 1522-1598, Vol. 116, no 4, p. 1615-1625Article in journal (Refereed) Published
Abstract [en]

When lifting an object, individuals scale lifting forces based on long-term priors relating external object properties (such as material and size) to object weight. When experiencing objects that are poorly predicted by priors, people rapidly form and update sensorimotor memories that can be used to predict an object's atypical size-weight relation in support of predictively scaling lift forces. With extensive experience in lifting such objects, long-term priors, assessed with weight judgments, are gradually updated. The aim of the present study was to understand the formation and updating of these memory processes. Participants lifted, over multiple days, a set of black cubes with a normal size-weight mapping and green cubes with an inverse size-weight mapping. Sensorimotor memory was assessed with lifting forces, and priors associated with the black and green cubes were assessed with the size-weight illusion (SWI). Interference was observed in terms of adaptation of the SWI, indicating that priors were not independently adjusted. Half of the participants rapidly learned to scale lift forces appropriately, whereas reduced learning was observed in the others, suggesting that individual differences may be affecting sensorimotor memory abilities. A follow-up experiment showed that lifting forces are not accurately scaled to objects when concurrently performing a visuomotor association task, suggesting that sensorimotor memory formation involves cognitive resources to instantiate the mapping between object identity and weight, potentially explaining the results of experiment 1. These results provide novel insight into the formation and updating of sensorimotor memories and provide support for the independent adjustment of sensorimotor memory and priors.

Keywords
object lifting, sensorimotor integration, sensorimotor memory, weight prediction
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-128472 (URN)10.1152/jn.00282.2016 (DOI)000386828400009 ()27385795 (PubMedID)
Available from: 2016-12-15 Created: 2016-12-05 Last updated: 2018-06-09Bibliographically 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, p. 10572-10580Article 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.

Keywords
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: 2018-06-07Bibliographically 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, p. 1404-1409Article 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: 2018-06-07Bibliographically 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: 2018-06-08Bibliographically 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, p. 367-373Article 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
Keywords
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: 2018-06-07Bibliographically 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, p. 221-234Article 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
Keywords
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: 2018-06-08Bibliographically 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, p. e56630-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: 2018-06-08Bibliographically approved
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