| 1. |
- Brodd, Katarina Strand, et al.
(författare)
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Development of Smooth Pursuit Eye Movements in very preterm born infants : 3. Association to perinatal risk factors
- 2012
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 101:2, s. 164-171
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate the association between perinatal risk factors and neonatal complications and early oculo-motor development in very preterm infants. Methods: Perinatal risk factors were identified, and the potential association with early oculo-motor development was evaluated by measuring smooth pursuit eye movements (SP) at 2 and 4 months' corrected age (CA) in a population of very preterm infants born in Uppsala County 2004-2007 (n = 113). Results: Among the 15 tested factors, eight showed significant association in univariate analysis with lower levels of SP at 4 months' CA, namely administration of prenatal corticosteroids, gestational age, birthweight, bronchopulmonary dysplasia, retinopathy of prematurity, periventricular leukomalacia, intraventricular haemorrhage >grade 2, and persistent ductus arteriosus. At 2 months' CA, only retinopathy of prematurity >stage 2 was associated with lower levels of SP. When all factors significant in the univariate tests were included in multiple regressions aimed to assess each factor's independent relation to SP, periventricular leukomalacia was the only significant independent factor. When adding 2-5 of the significant factors using multiple regression analysis, the levels of SP became lower. Conclusion: Perinatal risk factors were associated with lower levels of SP. This could be interpreted as delayed or disturbed development of normal oculomotor ability.
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| 2. |
- Brodd, Katarina Strand, et al.
(författare)
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Development of smooth pursuit eye movements in very preterm infants : 1. General aspects
- 2011
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 100:7, s. 983-991
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate early oculo-motor development in a population-based cohort of very preterm infants.Methods: Early oculo-motor development was prospectively studied by measuring smooth pursuit eye movements at 2 and 4 months corrected age in a population of very preterm infants born in Uppsala County 2004–2007. Eighty-one preterm infants were studied, and 32 healthy term infants constituted the control group.Results: The study group consisted of infants with a mean gestational age of28 + 5 weeks. At 2 and 4 months corrected age, infants born very preterm showed lower gain (p < 0.001) and proportion of smooth pursuit eyemovements (p < 0.001) compared to the control group. The boys showed higher gain of smooth pursuit eye movements at both 2 and 4 months corrected age, compared to girls.Conclusions: Oculo-motor development measured by smooth pursuit eye movements is delayed in very preterm infants at 2 and 4 months corrected age. This might be a risk factor or early indicator of later perceptual and behavioural impairment.
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| 3. |
- Bäckström, Anna, et al.
(författare)
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Action planning in relation to movement performance in 6-year-old children with autism spectrum disorder
- 2019
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Konferensbidrag (refereegranskat)abstract
- Introduction: Recent research proposes problems with action planning as part of atypical motor functioning in children with autism spectrum disorder (ASD), although findings are inconsistent. This study investigated relations between action planning and movement performance in 6-year-old children with and without ASD.Patients and methods: 3D kinematic recordings of preferred arm/hand performance on a sequential peg rotation task with varying complexity of goal insertion (four endpoints and either visual or occluded goal display at onset) were conducted in 6 children with ASD (MAge = 6.4) and 6 typically developing (TD) controls (MAge = 6.5).Results: Analyses revealed significant (p < .05) group and task-endpoint differences for movement segmentation (number of movement units, MUs) and 3D movement distance. Children with ASD generally displayed more MUs and longer distances than controls and all children showed increased MUs and movement distance on more complex task-endpoints. TD controls showed significantly shorter movement initiation latency (MIL) durations than ASD in the visual condition and evidently longer MILs in the occluded than visual condition. In contrast, no difference between goal display conditions was shown for the ASD group.Conclusion: Children with ASD generally had longer movement distances and more segmented movements than controls, suggesting less efficient movement performance. Movement performance was not evidently affected by goal display condition in either group. However, the lack of MIL differences between goal display conditions within the ASD group indicates reduced pre-planning, possibly affecting movement execution efficiency.
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| 4. |
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| 5. |
- Bäckström, Anna, et al.
(författare)
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Atypical motor planning in an interpersonal context in 9-year-old children with autism spectrum disorder (ASD)
- 2023
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Ingår i: 35th EACD Annual meeting European Academy of Childhood Disability. - : European Academy of Childhood Disability. ; , s. 254-254
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Konferensbidrag (refereegranskat)abstract
- Introduction: Motor planning deviances may negatively affect interpersonal motor interactions in ASD, although detailed studies are sparse. This study examined motor planning kinematics in an interpersonal and non-interpersonal context in 9-year-old children with ASD and neurotypical peers.Patients and methods: Twelve children with ASD and 17 controls performed two different sequential manual tasks (preferred hand): grasping and placing a peg on a wooden disc (non-interpersonal) or in the hand of an examiner (interpersonal). Three-dimensional kinematic recordings of arm/hand movements were performed. Group and task differences were explored for total movement duration (MD), and for peak velocity (PV) and placement of peak velocity (PPV) during reach-to-grasp and transport-to-place movements, respectively.Results: Task differences were found in terms of longer MD and higher transport-to-place-PV in the disc- compared to hand-task. An interaction effect was evident for reach-to-grasp-PPV, where the control-group, but not ASD, had earlier reach-to-grasp-PPV and longer relative deceleration in the hand-task compared to the disc-task.Conclusion: Results show that the interpersonal context influenced initial reach-to-grasp motor planning in the control-group, but not the ASD-group. Later in the sequential movement (transport-to-place), the interpersonal context seemed to influence motor planning independent of group. Taken together, this indicates support towards a more careful peg-placing in the interpersonal hand-task in the control-group but much less clearly so in the ASD-group.Relevance for users and families: Atypical motor planning may influence motor interaction with peers. Investigations of motor planning and movement organization in ASD could thus inform interventions also targeting interpersonal exchange.
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| 6. |
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| 7. |
- Bäckström, Anna, et al.
(författare)
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Motor imagery ability in 7-year-old children with autism spectrum disorder
- 2020
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Knowledge about motor imagery (MI) ability in autism spectrum disorder (ASD) is limited and inconclusive in young children with ASD. The aim of the current study was to investigate MI ability in 7-year-old children with ASD.Patients and methods: Thirteen children with ASD and 13 typically developing (TD) children performed a computerized hand laterality judgement task (HLJ) and a non-corporeal visual imagery (VI) control task. All participants passing a criterion test performed the tasks with images at 4 different rotational increments to vary the MI biomechanical demands (HLJ task) or VI angle rotational demands (VI task). Response times (RT) and accuracy were extracted.Results: Four children with ASD did not pass the HLJ criterion test and one failed the VI criterion test. The ASD-group had evidently more incorrect responses than TD on both tasks. Analyses of RT showed a biomechanical effect in the MI task and an angle increment effect in the VI task in both groups. Children with ASD had longer RT than TD children on VI but not MI tasks. Conclusion: Findings suggest that both the ASD and control children used MI to solve the HLJ task. However, failures to pass the HLJ criterion test and the increased error rate in the ASD group indicate that MI ability is weaker in young children with autism than TD controls. Notably, a large individual variability in employment of MI within the ASD group was found, ranging from functional, fractional but existing, to absent MI ability.
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| 8. |
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| 9. |
- Bäckström, Anna, et al.
(författare)
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Motor planning and movement execution during goal-directed sequential manual movements in 6-year-old children with autism spectrum disorder : A kinematic analysis
- 2021
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Ingår i: Research in Developmental Disabilities. - : Elsevier. - 0891-4222 .- 1873-3379. ; 115
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Tidskriftsartikel (refereegranskat)abstract
- Background: Atypical motor functioning is prevalent in children with autism spectrum disorder (ASD). Knowledge of the underlying kinematic properties of these problems is sparse.Aims: To investigate characteristics of manual motor planning and performance difficulties/diversity in children with ASD by detailed kinematic measurements. Further, associations between movement parameters and cognitive functions were explored.Methods and procedures: Six-year-old children with ASD (N = 12) and typically developing (TD) peers (N = 12) performed a sequential manual task comprising grasping and fitting a semi-circular peg into a goal-slot. The goal-slot orientation was manipulated to impose different motor planning constraints. Movements were recorded by an optoelectronic system.Outcomes and results: The ASD-group displayed less efficient motor planning than the TD-group, evident in the reach-to-grasp and transport kinematics and less proactive adjustments of the peg to the goal-slot orientations. The intra-individual variation of movement kinematics was higher in the ASD-group compared to the TD-group. Further, in the ASD-group, movement performance associated negatively with cognitive functions.Conclusions and implications: Planning and execution of sequential manual movements proved challenging for children with ASD, likely contributing to problems in everyday actions. Detailed kinematic investigations contribute to the generation of specific knowledge about the nature of atypical motor performance/diversity in ASD. This is of potential clinical relevance.
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| 10. |
- Bäckström, Anna, et al.
(författare)
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Visuomotor integration in action planning in 7-year-old children with autism spectrum disorder
- 2022
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Ingår i: Specia issue: Abstracts of the 34th annual meeting of the European Academy of Childhood Disability (EACD) Barcelona, Spain 18-21 May 2022. - : Mac Keith Press. ; , s. 65-65
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Konferensbidrag (refereegranskat)abstract
- Introduction: Difficulties with action planning and visuomotor integration may contribute to atypical motorfunctioning in children with autism spectrum disorder (ASD), although detailed studies of sensorimotorintegration in action planning are sparse. This ongoing study investigates visuomotor integration in actionplanning in 7-year-old children with and without ASD.Patients and methods: A sub-sample of 6 children with ASD and 6 typically developing (TD) controls wereincluded. Recordings of gaze synchronized with 3D kinematic registration were made during performance of amanual sequential peg rotation task with variations in goal insertion complexity. Group differences and relations between movement duration and number of gaze shifts over the sequential movement phases(latency, reach-to-grasp, grasp, and transport-to-fit) were explored.Results: No significant group differences were found for either movement duration or number of gaze shifts.When controlling for the between-participants variance, total number of gaze shifts and number of gaze shiftsin reach-to-grasp were related to movement duration in the initial phases of the movement in the TD-group but not in the ASD-group.Conclusion: The results indicate that, whilst performance measures were similar between groups, the overallpattern of visuomotor integration was related to feed-forward movement processes in the sequentialmovement in the TD-group but not in the ASD-group. This finding adds support to previous suggestions thatvisuomotor integration underpinning action planning may operate differently in ASD. Synchronizedexamination of gaze and detailed movement registration appears as a promising methodology for detailed investigation of visuomotor integration in action planning.
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| 11. |
- Chen, Yu-ping, et al.
(författare)
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Movement Planning Reflects Skill Level and Age Changes in Toddlers
- 2010
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Ingår i: Child Development. - : Wiley. - 0009-3920 .- 1467-8624. ; 81:6, s. 1846-1858
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Tidskriftsartikel (refereegranskat)abstract
- Kinematic measures of children's reaching were found to reflect stable differences in skill level for planning for future actions. Thirty-five toddlers (18-21 months) were engaged in building block towers (precise task) and in placing blocks into an open container (imprecise task). Sixteen children were retested on the same tasks a year later. Longer deceleration as the hand approached the block for pickup was found in the tower task compared with the imprecise task, indicating planning for the second movement. More skillful toddlers who could build high towers had a longer deceleration phase when placing blocks on the tower than toddlers who built low towers. Kinematic differences between the groups remained a year later when all children could build high towers.
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| 12. |
- Cunha, Andrea Baraldi, et al.
(författare)
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Maturational and situational determinants of reaching at its onset
- 2015
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Ingår i: Infant Behavior and Development. - : Elsevier BV. - 0163-6383 .- 1879-0453. ; 41, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- At 3 months of age, reaching behavior was measured in a group of 10 girls and 10 boys born at term. The assessments were carried out on the average 2 days after reaching onset. Reaching kinematics was measured in both supine and reclined positions. Girls reached more than boys, had straighter reaching trajectories and movements of shorter durations as well as fewer movement units. The reclined position gave rise to straighter trajectories in both girls and boys. Several anthropometric parameters were measured. Girls had less length and volume of the forearm than boys but similar upper arm volumes. There was a weak relation between kinematic and anthropometric variables.
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| 13. |
- Domellöf, Erik, et al.
(författare)
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Kinematic characteristics of second‐order motor planning and performance in 6‐ and 10‐year‐old children and adults : Effects of age and task constraints
- 2020
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Ingår i: Developmental Psychobiology. - : John Wiley & Sons. - 0012-1630 .- 1098-2302 .- 0012-1649 .- 1939-0599. ; 62:2, s. 250-265
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Tidskriftsartikel (refereegranskat)abstract
- This study explored age‐related differences in motor planning as expressed in arm‐hand kinematics during a sequential peg moving task with varying demands on goal insertion complexity (second‐order planning). The peg was a vertical cylinder with either a circular or semicircular base. The task was to transport the peg between two positions and rotate it various amounts horizontally before fitting into its final position. The amount of rotation required was either 0°, 90°, 180°, or −90°. The reaching for the peg, the displacement of it, and the way the rotation was accomplished was analyzed. Assessments of end state comfort, goal interpretation errors, and type of grip used were also included. Participants were two groups of typically developing children, one younger (Mage = 6.7 years) and one older (Mage = 10.3 years), and one adult group (Mage = 34.9 years). The children, particularly 6‐year‐olds, displayed less efficient prehensile movement organization than adults. Related to less efficient motor planning, 6‐year‐olds, mainly, had shorter reach‐to‐grasp onset latencies, higher velocities, and shorter time to peak velocities, and longer grasp durations than adults. Importantly, the adults rotated the peg during transport. In contrast, the children made corrective rotations after the hand had arrived at the goal.
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| 14. |
- Domellöf, Erik, et al.
(författare)
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Sequential upper-limb action planning in children with autism spectrum disorder : a kinematic pilot study
- 2018
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Ingår i: Developmental Medicine & Child Neurology. - : Mac Keith Press. - 0012-1622 .- 1469-8749. ; 60:S2, s. 34-34
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Recent research on sensory-motor skill in children with autism spectrum disorder (ASD) suggest that problems with planning sequential actions may explain difficulties with motor execution in this population. The present pilot study investigated upper-limb movement kinematics during a goal-directed manual task requiring sequential action planning in children with and without ASD at 6-7 years.Patients and method: 3D kinematic recordings of performance with the preferred arm/hand during a sequential peg moving task with varying complexity of goal insertion (five endpoint conditions, open/revealed goal presentation) were carried out in 3 children with ASD (2 girls, mean age 6.3 years) and 3 typically developing children (3 girls, mean age 7 years). End state comfort and trial errors were also assessed.Results: Preliminary analyses of whole movement spatiotemporal segmentation (movement units, MUs) at trial level revealed significant main effects for group and endpoint condition. Overall, children with ASD consistently performed less proficiently (more MUs) than controls for all conditions across hand/arm and head. Independent of group, all children displayed increased MUs for the more complex endpoints. Children with ASD also showed evidently poorer planning behavior (less end state comfort and increased trial errors) than controls.Conclusion: Findings suggest difficulties with sequential movement planning in children with ASD in terms of suboptimal movement organization together with reduced end state comfort and inaccurate goal interpretations. In contrast to controls, children with ASD did not seem to have planned the onward action prior to action execution, contributing to the observed less proficient movement kinematics.
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| 15. |
- Ekberg, Therese L., et al.
(författare)
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Dynamic reaching in infants during binocular and monocular viewing
- 2013
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 229:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- This study examined reaching in 6-, 8-, and 10-month-olds during binocular and monocular viewing in a dynamic reaching situation. Infants were rotated toward a flat vertical board and reached for objects at one of seven positions along a horizontal line at shoulder height. Hand selection, time to contact the object, and reaching accuracy were examined in both viewing conditions. Hand selection was strongly dependent on object location, not on infants' age or whether one eye was covered. Monocular viewing and age did, however, affect time to object contact and contact errors: Infants showed longer contact times when one eye was covered, and 6-month-olds made more contact errors in the monocular condition. For right-hand selection, contact times were longer when the covered right eye was leading during the chair rotation. For left-hand selection, there were no differences in contact time due to whether the covered eye was leading during rotation.
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| 16. |
- Falck-Ytter, Terje, 1979-
(författare)
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From Actions to Faces : Studies of Social Perception in Typical and Atypical Development
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three eye-tracking studies of social perception in children. Study I and Study II investigated action perception in typically developing infants and preschoolers with Autism Spectrum Disorder (ASD), respectively. Study III investigated face perception in children with ASD. Do infants come to understand others’ actions by a Mirror Neuron System (MNS) that maps others’ actions onto motor plans for similar actions? In Study I, we measured the eye movements while participants observed video clips of an actor's hand placing toys into a bucket. Adults and twelve-month-old infants looked at the bucket before the hand reached it, predicting the goal of the action. This predictive performance was linked to seeing a hand-object interaction. Six-month-olds failed to predict the goal of the action. The development in prediction skills coincides with the age at which infants learn to perform the action themselves. This supports the view that the MNS forms the basis of important social competences such as predicting others' actions. According to the MNS theory of ASD, a failure to map others’ actions onto motor plans for similar actions underlies the social symptoms defining the disorder. In Study II, children with ASD as well as typically developing children and adults were shown the same stimuli as used in Study I. At odds with the theory, all groups used strikingly similar predictive eye movements in action observation. Gaze was reactive in a self-propelled condition, suggesting that prediction is linked to seeing a hand-object interaction. This study does not support the view that ASD is characterized by a global dysfunction in the MNS. Face processing is another core social competence, and research has suggested that many individuals with ASD have face processing impairments. In Study III, we showed faces to young children with ASD and related their looking performance to their behavioural symptoms. Our findings suggest that the socio-communicative information transmitted from faces is processed in a piecemeal fashion in young children with ASD. Much of the variability in face scanning could be explained by individual differences in socio-communicative skills.
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| 17. |
- Fredriksson Kaul, Ylva
(författare)
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From Eye to Mind : Early Visuomotor Performance and Developmental Trajectories in Children Born Preterm
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Children born very preterm, at less than 32 weeks of gestation, have an increased risk of developing problems with attention, cognition, perception and motor function. Despite this, the developmental trajectories leading from preterm birth to later impairments are not fully understood.This thesis focused on investigating the development of the visuomotor system in infants born very preterm, in relation to neurodevelopment at 2.5-3 years (including cognitive, language and motor functions) and 6.5 years (including cognitive functions and attention). Two early visuomotor functions were investigated: at 4 months of corrected age we looked at their visual tracking of moving objects and at 8 months of corrected age we examined how they reached for moving objects. Visual tracking performance is the ability to follow, sustain attention on and predict the future positions of a moving object. When infants reach for moving objects, these requirements are enhanced by movements of the arm and hand.This was a prospective, population-based cohort study of children born very preterm in 2004-2007, who were longitudinally assessed from the neonatal period until 6.5 years of age. The results showed that the two most important early visual tracking parameters were gaze gain, which is effectively combining eye and head movements to follow the trajectory of the object, and timing of gaze to the motion of the object. Gaze gain correlated with neurodevelopment at 2.5-3 years and with cognition and attention at 6.5 years. Early reaching was also related to outcomes at 2.5-3 years, but the pattern differed for children born before and after 28 weeks of gestation. Parameters of prediction and movement planning were the most important factors for the children of the lowest gestational age, but strategies and success had greater associations with later function in those who were less premature.The results confirmed that children born very preterm in the first decade of the 2000’s still faced increased risks of developmental delays. Early visual tracking performance, and reaching for moving objects, were shown to be important visuomotor functions in the developmental process of children born very preterm. The studies in this thesis illustrate how early basic functions were related to different neurodevelopmental areas at a later stage and offer important new insights into developmental trajectories of children at risk of developmental impairments. These findings suggest that attention and predictive elements of adjusting one´s movements to motion, may be key mechanisms and possible targets in future intervention studies.
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| 18. |
- Fredriksson Kaul, Ylva, et al.
(författare)
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Visual tracking at 4 months in preterm infants predicts 6.5-year cognition and attention
- 2022
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Ingår i: Pediatric Research. - : Springer Nature. - 0031-3998 .- 1530-0447. ; 92:4, s. 1082-1089
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Visual tracking of moving objects requires sustained attention and prediction of the object’s trajectory. We tested the hypothesis that measures of eye-head tracking of moving objects are associated to long-term neurodevelopment in very preterm infants.METHODS: Visual tracking performance was assessed at 4 month’s corrected age in 57 infants with gestational age <32 weeks. An object moved in front of the infant with sinusoidal or triangular (i.e. abrupt) turns of the direction. Gaze gain, smooth pursuit gain, and timing of gaze to object motion were analyzed. At 6.5 years the Wechsler Intelligence Scale for Children (WISC-IV), the Brown Attention Deficit Disorder (Brown ADD), and visual examination were performed. RESULTS: Gaze gain and smooth pursuit gain at 4 months were strongly related to all WISC-IV parameters at 6.5 years. Gaze gain for the triangular and sinusoidal motion patterns related similarly to the cognitive scores. For the sinusoidal motion pattern, timing related to most Brown ADD parameters. There were no statistically significant differences in associations dependent on motion pattern. Visual function did not influence the results. CONCLUSION: The ability to attend to and smoothly track a moving object in infancy is an early marker of cognition and attention at 6.5 years.
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| 19. |
- Gredebäck, Gustaf, et al.
(författare)
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Action Type and Goal Type Modulate Goal-Directed Gaze Shifts in 14-Month-Old Infants
- 2009
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Ingår i: Developmental Psychology. - : American Psychological Association (APA). - 0012-1649 .- 1939-0599. ; 45:4, s. 1190-1194
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Tidskriftsartikel (refereegranskat)abstract
- Ten- and 14-month-old infants' gaze was recorded as the infants observed videos of different hand actions directed toward multiple goals. Infants observed an actor who (a) reached for objects and displaced them, (b) reached for objects and placed them inside containers, or (c) moved his fisted hand. Fourteen-month-olds, but not 10-month-olds, anticipated the goal of reaching actions but tracked all the other actions reactively. Fourteen-month-olds also produced more anticipatory gaze shifts during containment compared with displacement and differentiated between reaching actions dependent on whether the overall goal was to displace objects or place objects inside containers. These results demonstrate that action type and goal type modulate the latency of goal-directed gaze shifts in infants.
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| 20. |
- Grönqvist, Helena, et al.
(författare)
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Development of smooth pursuit eye movements in very prematurely born infants : 2. The low-risk subgroup.
- 2011
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 100:7, s. e5-e11
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate the impact of premature birth on visual tracking in a group of 37 infants, born before the 32nd gestational weeks (mean 29 + 6 weeks) and diagnosed as being without major neonatal complications. This paper is a part of the LOVIS study (Strand Brodd, Ewald, Grönqvist, Holmström, Strömberg, Von Hofsten, et al. Acta Pediatrica, 2011). Methods: At 2 and 4 months corrected age, eye and head movements were measured when the infant tracked a moving object. The eye movements were analysed in terms of smooth pursuit and saccades (Vision Res, 37, 1997, 1799; Exp Brain Res, 146, 2002, 257). Accuracy of gaze, proportion of smooth pursuit, head movements and saccades were calculated. Results: Between 2 and 4 months of age, all infants improved their ability to smoothly pursue a moving object. However, at both occasions, the preterm infants had less proportion smooth pursuit than the full-term infants. The groups did not differ with respect to gaze and head movements, but the saccade frequency was higher for the very preterms in some of the conditions. Conclusion: The development of smooth pursuit in the low-risk preterm infant group was strongly delayed compared to typically developed infants. Thus, the 2 months or more extra visual experience did not have a distinguishable positive effect on visuo-motor development as expressed in smooth pursuit.
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| 21. |
- Grönqvist, Helena, 1975-
(författare)
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Visual motor development in full term and preterm infants
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Smooth tracking and efficient reaching for moving objects require the ability to predict the velocity and trajectory of the object. This skill is important to be able to perceive human action and object motion in the world. This thesis explores early visual motor development in full term and preterm infants.Study I showed that horizontal eye tracking develops ahead of vertical (full term infants at 5, 7 and 9 months of age). The vertical component is also more affected when a second dimension is added during circular pursuit. It is concluded that different mechanisms appear to underlie vertical and horizontal eye movementsStudy II-IV compared the development of the ability to visually track and reach for moving objects in very preterm infants born <32 gestational weeks to healthy infants born at term. The development of horizontal smooth pursuit at 2 and 4 months of corrected age was delayed for the preterm group (Study II). Some infants were catching up whereas others were not improving at all. A question raised by the results was whether the delay was caused by specific injuries as a result of the prematurity. However, the delays persisted when all infants with known neonatal complications and infants born small for gestational age were excluded (Study III), indicating that they were caused by prematurity per se. At 8 months corrected age preterm and full term infants were equally good at aiming reaches and successfully catching a moving object. Nevertheless, the preterm group used a bimanual strategy more often and had a more jerky and circuitous path than the full term group (Study IV). In summary, preterm infants showed a delayed visual motor development compared to infants born at term.The results of these studies suggest that there is additional diffuse damage to the visual motor system that is not related to neonatal complications as diagnosed today. Measuring smooth pursuit could potentially be a new method for early non-invasive diagnosis of impaired visual function.
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| 22. |
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| 23. |
- Hreinsdottir, Jonina, et al.
(författare)
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Impaired cognitive ability at 2.5 years predicts later visual and ophthalmological problems in children born very preterm
- 2018
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 107:5, s. 822-830
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To identify possible predictive factors for visual problems at 6.5 years in children born very preterm.Methods: During 2004–2007, all very preterm infants (gestational age [GA] <32 weeks) in Uppsala County, Sweden were screened for retinopathy of prematurity (ROP) neonatally; at four months, visual tracking was tested; at 2.5 years, visuospatial and cognitive tests were carried out. At 6.5 years, 84 preterm children and a reference group of 64 full‐term children underwent ophthalmological testing.Results: Mean visual acuity (VA) did not differ between the groups, but subnormal VA (≤0.8) was more common in the preterm group (31% vs 14%; p < 0.05). More often than full‐term children, preterm children had impaired contrast sensitivity (<0.5) (36% vs 19%; p < 0.05) and strabismus (8% vs 0%; p < 0.05). Low GA, ROP, intraventricular haemorrhage 3‐4/periventricular leukomalacia and cognitive disability at 2.5 years predicted ophthalmological and visual problems at 6.5 years. Visual tracking ability at four months was not predictive of ophthalmological outcome.Conclusion: Children born preterm had more ophthalmological problems at 6.5 years of age, including subtle dysfunctions. ROP, early brain injury and impaired cognitive function around 2.5 years predicted later ophthalmological dysfunctions.
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| 24. |
- Johansson, Anna-Maria, 1981-, et al.
(författare)
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Development of motor imagery in school-aged children with autism spectrum disorder : a longitudinal study
- 2022
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Ingår i: Brain Sciences. - : MDPI. - 2076-3425. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorder (ASD) is a diagnosis based on social communication deficits and prevalence of repetitive stereotyped behaviors, but sensorimotor disturbances are commonly exhibited. This longitudinal study aimed at exploring the development of the ability to form mental motor representations (motor imagery; MI) in 14 children with ASD and 17 typically developing (TD) children at 7, 8 and 9 years of age. MI was investigated using a hand laterality paradigm from which response times (RT) and error rates were extracted and compared with performance on a visually based mental rotation task (VI). A criterion task was used to ensure that the children could perform the task. The results showed wide performance variability in the ASD group with more failures than TD in the MI criterion task, especially at 7 years. For all age levels and both the MI and VI tasks, the error rates were significantly higher and RTs longer for the ASD group compared with TD. Signs of MI strategies were however noted in the ASD group as biomechanically constrained orientations had longer RTs than less constrained orientations, a RT pattern that differed from the VI task. The presence of MI in the ASD group was most evident at 9 years, but the error rates remained high at all ages, both in the MI and VI task. In comparison, the TD group showed stable MI strategies at all ages. These findings indicate that MI ability is delayed and/or impaired in children with ASD which may be related to difficulties performing required mental rotations.
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| 25. |
- Kaul, Ylva Fredriksson, et al.
(författare)
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Reaching skills of infants born very preterm predict neurodevelopment at 2.5 years
- 2019
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Ingår i: Infant Behavior and Development. - : Elsevier. - 0163-6383 .- 1879-0453. ; 57
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate associations between quality of reaching for moving objects at 8 months corrected age and neurodevelopment at 2.5 years in children born very preterm (gestational age (GA), 24–31 weeks). Thirtysix infants were assessed while reaching for moving objects. The movements were recorded by a 3D motion capture system. Reaching parameters included aiming, relative length of the reach, number of movement units, proportion of bimanual coupled reaches and number of hits. Neurodevelopment was assessed at 2.5 years by the Bayley Scales of Infant Development III. There were strong associations between infant reaching kinematics and neurodevelopment of cognition and language but the patterns differed: in children born extremely preterm (GA < 28 weeks), planning and control of reaching was strongly related to outcome, while in children born very preterm (GA 28–31 weeks) number of hits and bimanual strategies were of greater relevance. In conclusion, for extremely preterm infants, basic problems on how motion information is incorporated with action planning prevail, while in very preterm infants the coordination of bimanual reaches is more at the focus. We conclude that the results reflect GA related differences in neural vulnerability and that early motor coordination deficits have a cascading effect on neurodevelopment.
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| 26. |
- Kaul, Ylva Fredriksson, et al.
(författare)
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Visual tracking in very preterm infants at 4 mo predicts neurodevelopment at 3 y of age
- 2016
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Ingår i: Pediatric Research. - : Springer Science and Business Media LLC. - 0031-3998 .- 1530-0447. ; 80:1, s. 35-42
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Typically developing infants track moving objects with eye and head movements in a smooth and predictive way at 4 mo of age, but this ability is delayed in very preterm infants. We hypothesized that visual tracking ability in very preterm infants predicts later neurodevelopment. METHOD: In 67 very preterm infants (gestational age<32wk), eye and head movements were assessed at 4 mo corrected age while the infant tracked a moving object. Gaze gain, smooth pursuit, head movements, and timing of gaze relative the object were analyzed off line. Results of the five subscales included in the Bayley Scales of Infant Development (BSID-III) at 3 y of age were evaluated in relation to the visual tracking data and to perinatal risk factors. RESULTS: Significant correlations were obtained between gaze gain and cognition, receptive and expressive language, and fine motor function, respectively, also after controlling for gestational age, severe brain damage, retinopathy of prematurity, and bronchopulmonary dysplasia. CONCLUSION: This is the first study demonstrating that the basic ability to visually track a moving object at 4 mo robustly predicts neurodevelopment at 3 y of age in children born very preterm.
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| 27. |
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| 28. |
- Kochukhova, Olga, et al.
(författare)
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Integrated global motion influences smooth pursuit in infants
- 2008
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Ingår i: Journal of Vision. - : Association for Research in Vision and Ophthalmology (ARVO). - 1534-7362. ; 8:11, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Smooth pursuit eye movements (SP) were studied in 5- and 9-month-old infants and adults in response to a rhombusoscillating horizontally behind three spatially separated vertical occluders. During motion, the rhombus vertices were nevervisible. Thus the perception of the global motion of the rhombus required integration of its moving visible segments. Wetested whether infants were able to use such perceived global motion for SP in two different occluder conditions; one inwhich the occluder was clearly visible to the observer and one in which it was invisible. In adults, the presence of a visibleoccluder hiding the vertices of the rhombus strongly facilitates the perception of the global motion. It was found that adultsand 9-month-olds performed significantly more horizontal SP in the presence of a visible occluder but not 5-month-olds.Furthermore, this tendency was strengthened over single trials, and this temporal pattern was very similar in all age groups.In the invisible occluder condition both adults and infants tracked the segments of the rhombus primarily with vertical SP. Itwas concluded that the ability to integrate moving object fragments into perceived global motion and use that to regulate SPdevelops into adult performance by 9 months of age.
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| 29. |
- Metta, Giorgio, et al.
(författare)
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The iCub humanoid robot : An open-systems platform for research in cognitive development
- 2010
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Ingår i: Neural Networks. - : Elsevier BV. - 0893-6080 .- 1879-2782. ; 23:8-9, s. 1125-1134
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Tidskriftsartikel (refereegranskat)abstract
- We describe a humanoid robot platform - the iCub - which was designed to support collaborative research in cognitive development through autonomous exploration and social interaction. The motivation for this effort is the conviction that significantly greater impact can be leveraged by adopting an open systems policy for software and hardware development. This creates the need for a robust humanoid robot that offers rich perceptuo-motor capabilities with many degrees of freedom, a cognitive capacity for learning and development, a software architecture that encourages reuse & easy integration, and a support infrastructure that fosters collaboration and sharing of resources. The iCub satisfies all of these needs in the guise of an open-system platform which is freely available and which has attracted a growing community of users and developers. To date, twenty iCubs each comprising approximately 5000 mechanical and electrical parts have been delivered to several research labs in Europe and to one in the USA.
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| 30. |
- Nyström, Pär, et al.
(författare)
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Using mu rhythm desynchronization to measure mirror neuron activity in infants
- 2011
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Ingår i: Developmental Science. - : Wiley. - 1363-755X .- 1467-7687. ; 14:2, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- The Mirror Neuron System hypothesis stating that observed actions are projected onto the observer's own action system assigns an important role to development, because only actions mastered by the observer can be mirrored. The purpose of the present study was to investigate whether there is evidence of a functioning mirror neuron system (MNS) in 8-month-old infants. High-density EEG was used to assess the mu rhythm desynchronization in an action observation task where the infants observed a live model. To reduce noise, ICA decompositions were used. The results show a higher desynchronization of the mu rhythm when infants observed a goal-directed action than when they observed a spatially similar non-goal-directed movement. The localizations of the sources are in agreement with those proposed by the MNS hypothesis. This indicates that the MNS is functioning at this age.
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| 31. |
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| 32. |
- Righetti, Ludovic, et al.
(författare)
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Kinematic and gait similarities between crawling human infants and other quadruped mammals
- 2015
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Crawling on hands and knees is an early pattern of human infant locomotion, which offers an interesting way of studying quadrupedalism in one of its simplest form. We investigate how crawling human infants compare to other quadruped mammals, especially primates. We present quantitative data on both the gait and kinematics of seven 10-month-old crawling infants. Body movements were measured with an optoelectronic system giving precise data on 3-dimensional limb movements. Crawling on hands and knees is very similar to the locomotion of non-human primates in terms of the quite protracted arm at touch-down, the coordination between the spine movements in the lateral plane and the limbs, the relatively extended limbs during locomotion and the strong correlation between stance duration and speed of locomotion. However, there are important differences compared to primates, such as the choice of a lateral-sequence walking gait, which is similar to most non-primate mammals and the relatively stiff elbows during stance as opposed to the quite compliant gaits of primates. These finding raise the question of the role of both the mechanical structure of the body and neural control on the determination of these characteristics.
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| 33. |
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| 34. |
- Rosander, Kerstin, et al.
(författare)
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Cortical processing of visual motion in young infants
- 2007
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Ingår i: Vision Research. - : Elsevier BV. - 0042-6989 .- 1878-5646. ; 47:12, s. 1614-1623
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Tidskriftsartikel (refereegranskat)abstract
- High-density EEG was used to investigate the cortical processing of a rotatirig visual pattern in 2-, 3-, and 5-month-old infants and in adults. Motion induced ERP in the parietal and the temporal-occipital border regions (OT) was elicited at all ages. The ERP was discernable in the 2-months-olds, significant and unilateral in the 3-month-olds and significantly bilateral in the 5-month-olds and adults. The motion induced ERP in the primary visual area was absent in the 2-month-olds and later than in the OT area for the 3-month-olds indicating that information to OT may be supplied by the VI bypass at these ages. The results are in agreement with behavioural and psychophysical. data in infants.
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| 35. |
- Rosander, Kerstin
(författare)
-
Development of Gaze Control in Early Infancy
- 2020
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Ingår i: Oxford Research Encyclopedia of Psychology. - : Oxford University Press.
-
Bokkapitel (refereegranskat)abstract
- Gaze control involves eyes, head, and body movements and is guided by mainly three types of information: visual, vestibular, and proprioceptive. Appropriate gaze control is a basis for actions such as reaching, grasping, eating, and manipulation, all of which develop during the first year of life. The development of gaze control is about how young infants gain access to these different kinds of information, how they come to use them, and how they come to coordinate head and eyes to accomplish it. This control develops during the first few weeks of life. A major challenge for the gaze controlling system is how gaze is stabilized on a moving target to keep vision clear, including during self-motion or the compensation of other sudden movements. Furthermore, the tracking has to be timed relative to the object motion. This requires prediction, which is a part of smooth pursuit that emerges at around six weeks and is in full function at three months. The smooth eye and head movements must add up in time and space to the object motion. Then the vestibular and visual neural signals must be properly added. Catch-up saccades compensate when the smooth pursuit is insufficient. In other situations, saccades shift the gaze between objects or situations. Moreover, if a moving object temporarily disappears out of view, one or several saccades predictively recapture the object at the reappearance position (four months). The complex and fast development of gaze has inspired the design of robotic vision (iCub) through processes similar to human development, thus increasing the robot’s flexibility and learning abilities.
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| 36. |
- Rosander, Kerstin, et al.
(författare)
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Development of gaze tracking of small and large objects
- 2002
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 146:2, s. 257-264
-
Tidskriftsartikel (refereegranskat)abstract
- A longitudinal study was designed to address the relationships between the smooth pursuit (SP) and the optokinetic response (OKR). Eye and head movements were measured in infants between 7 and 14 weeks of age. They were placed in front of a moving object subtending visual angles of 2.5, 5, 7, 14, 21, 28, and 35°. The object oscillated sinusoidally along a horizontal path with a frequency of 0.25 Hz and an amplitude of ±25° visual angle. It was found that the number of saccades was dependent on object size: at 6 and 9 weeks of age there were more saccades for the smallest objects. With increasing age, the number of saccades decreased. The composite eye movement gain (smooth tracking + saccades) did not change with age but for the 6.5-week group the gain was higher for smaller objects. The gain of the smooth eye tracking increased with age and showed no dependency on object size. In conclusion, the results do not support the concept of two separate systems, the OKR and the SP, each of them processing eye tracking of small and large objects. Finally, it was observed that two infants at 6.5 weeks of age who used considerable head movements did not inhibit the vestibular-ocular response.
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| 37. |
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| 38. |
- Rosander, Kerstin, et al.
(författare)
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Predictive gaze shifts elicited during observed and performed actions in 10-month-old infants and adults
- 2011
-
Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 49:10, s. 2911-2917
-
Tidskriftsartikel (refereegranskat)abstract
- We asked whether people's actions are understood by projecting them onto one's own action programs, according to the direct matching hypothesis, and whether this mode of control functions in infants. Adults' and infants' gaze and hand movements were measured in two live situations. The task was either to move an object between two places in the visual field, or to observe the corresponding action performed by another person. When performing the action, infants and adults behaved strikingly similar. Hand and gaze movements were simultaneously initiated and gaze arrived at the goal ahead of the hand. When observing the actions, the initiation of the gaze shift was delayed relative to the observed hand movement in both infants and adults, but it still arrived at the goal ahead of the hand. For both the performance and observation of actions the proactiveness of gaze shifts was associated with saccades ahead of the velocity peak of the hand. The close similarity between adults' and infants' actions when performing the movements and the great advantage of the adults when observing them support the conclusion that one's own motor actions develop ahead of the ability to predict other people's actions.
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| 39. |
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| 40. |
- Rosander, Kerstin
(författare)
-
Visual tracking and its relationship to cortical development
- 2007
-
Ingår i: From action to cognition. - 9780444530165 ; , s. 105-122
-
Konferensbidrag (refereegranskat)abstract
- Measurements of visual tracking in infants have been performed from 2 weeks of age. Although directed appropriately, the eye movements are saccadic at this age. Over the first 4 months of life, a rapid transition to successively smoother eye movements takes place. Timing develops first and at 7 weeks of age the smooth pursuit is well timed to a sinusoidal motion of 0.25 Hz. From this age, the gain of the smooth pursuit improves rapidly and from 4 months of age, smooth pursuit dominates visual tracking in combination with head movements. This development reflects massive cortical and cerebellar changes. The coordination between eyes-head-body and the external events to be tracked presumes predictive control. One common type of model for explaining the acquisition of such control focuses on the maturation of the cerebellar circuits. A problem with such models, however, is that although Purkinje cells and climbing fibers are present in the newborn, the parallel and mossy fibers, essential for predictive control, grow and mature at 4-7 months postnatally. Therefore, an alternative model that also includes the prefrontal cerebral cortex might better explain the early development of predictive control. The prefrontal cortex functions by 3-4 months of age and provides a site for prediction of eye movements as a part of cerebro-cerebellar nets.
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| 41. |
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| 42. |
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| 43. |
- von Hofsten, Claes, et al.
(författare)
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Perception-action in children with ASD
- 2012
-
Ingår i: Frontiers in Integrative Neuroscience. - : Frontiers Media SA. - 1662-5145. ; :NOV
-
Forskningsöversikt (refereegranskat)abstract
- How do disturbances to perception and action relate to the deficiencies expressed by children with autism? The ability to predict what is going to happen next is crucial for the construction of all actions and children develop these predictive abilities early in development. Children with autism, however, are deficient in the ability to foresee future events and to plan movements and movement sequences. They are also deficient in the understanding of other people's actions. This includes communicative actions as they are ultimately based on movements. Today there are two promising neurobiological interpretation of ASD. First, there is strong evidence that the Mirror Neuron System (MNS) is impaired. As stated by this hypothesis, action production and action understanding are intimately related. Both these functions rely on predictive models of the sensory consequences of actions and depend on connectivity between the parietal and pre-motor areas. Secondly, action prediction is accomplished through a system that includes a loop from the posterior parietal cortex through the cerebellum and back to the premotor and motor areas of the brain. Impairment of this loop is probably also part of the explanation of the prediction problems in children with ASD. Both the cortico-cerebellar loop and the MNS rely on distant neural connections. There are multiple evidence that such connections are weak in children with autism.
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| 44. |
- von Hofsten, Claes, et al.
(författare)
-
Predictive action in infancy : tracking and reaching for moving objects
- 1998
-
Ingår i: Cognition. - : Elsevier. - 0010-0277 .- 1873-7838. ; 67:3, s. 255-285
-
Tidskriftsartikel (refereegranskat)abstract
- Because action plans must anticipate the states of the world which will be obtained when the actions take place, effective actions depend on predictions. The present experiments begin to explore the principles underlying early-developing predictions of object motion, by focusing on 6-month-old infants' head tracking and reaching for moving objects. Infants were presented with an object that moved into reaching space on four trajectories: two linear trajectories that intersected at the center of a display and two trajectories containing a sudden turn at the point of intersection. In two studies, infants' tracking and reaching provided evidence for an extrapolation of the object motion on linear paths, in accord with the principle of inertia. This tendency was remarkably resistant to counter-evidence, for it was observed even after repeated presentations of an object that violated the principle of inertia by spontaneously stopping and then moving in a new direction. In contrast to the present findings, infants fail to extrapolate linear object motion in preferential looking experiments, suggesting that early-developing knowledge of object motion, like mature knowledge, is embedded in multiple systems of representation.
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| 45. |
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| 46. |
- Von Hofsten, Claes, et al.
(författare)
-
Predictive tracking over occlusions by 4-month-old infants
- 2007
-
Ingår i: Developmental Science. - : Wiley. - 1363-755X .- 1467-7687. ; 10:5, s. 625-640
-
Tidskriftsartikel (refereegranskat)abstract
- Two experiments investigated how 16-20-week-old infants visually tracked an object that oscillated on a horizontal trajectory with a centrally placed occluder. To determine the principles underlying infants' tendency to shift gaze to the exiting side before the object arrives, occluder width, oscillation frequency, and motion amplitude were manipulated resulting in occlusion durations between 0.20 and 1.66 s. Through these manipulations, we were able to distinguish between several possible modes of behavior underlying 'predictive' actions at occluders. Four such modes were tested. First, if passage-of-time determines when saccades are made, the tendency to shift gaze over the occluder is expected to be a function of time since disappearance. Second, if visual salience of the exiting occluder edge determines when saccades are made, occluder width would determine the pre-reappearance gaze shifts but not oscillation frequency, amplitude, or velocity. Third, if memory of the duration of the previous occlusion determines when the subjects shift gaze over the occluder, it is expected that the gaze will shift after the same latency at the next occlusion irrespective of whether occlusion duration is changed or not. Finally, if infants base their pre-reapperance gaze shifts on their ability to represent object motion (cognitive mode), it is expected that the latency of the gaze shifts over the occluder is scaled to occlusion duration. Eye and head movements as well as object motion were measured at 240 Hz. In 49% of the passages, the infants shifted gaze to the opposite side of the occluder before the object arrived there. The tendency to make such gaze shifts could not be explained by the passage of time since disappearance. Neither could it be fully explained in terms of visual information present during occlusion, i.e. occluder width. On the contrary, it was found that the latency of the pre-reappearance gaze shifts was determined by the time of object reappearance and that it was a function of all three factors manipulated. The results suggest that object velocity is represented during occlusion and that infants track the object behind the occluder in their 'mind's eye'.
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| 47. |
- von Hofsten, Claes, 1943-, et al.
(författare)
-
The Development of Sensorimotor Intelligence in Infants
- 2018
-
Ingår i: Studying The Perception-Action System As A Model System For Understanding Development. - : Elsevier. - 9780128147634 ; , s. 73-106
-
Bokkapitel (refereegranskat)abstract
- Infancy is the most dynamic part of human development. During this period, all basic sensorimotor and cognitive abilities are established. In this chapter, we will trace some of the important achievements of this development with a focus on how infants achieve predictive control of actions, i.e., how they come to coordinate their behavior with the ongoing events in the world without lagging behind. With the maturation of the brain, new possibilities that have profound effects on cognition open up. Some of them are core abilities, i.e., they function at birth or very early in development. Important examples are the structured perception of objects and surfaces and the control of arm movements. Closely after birth, infants move their arms to the vicinity of objects in front of them demonstrating that they have some control of their arms and indicating that they perceive objects as such. Another example is the rapid onset of smooth-pursuit eye movements during the second month of life and the emerging ability to predict when and where an occluded moving object will reappear. At 4 months of age, out of sight is no longer of mind. The child's sensorimotor system is especially designed to facilitate the extraction of knowledge about the world including other people. In addition, the infant is endowed with motives that ensure that the innate predispositions are transformed into a system of knowledge for guiding actions predictively. By perceiving and acting on the world, infants develop their cognition and through developmental studies; we can learn more about these processes.
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| 48. |
- von Hofsten, Claes, et al.
(författare)
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The establishment of gaze control in early infancy.
- 1998
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Ingår i: The Development of Sensory, Motor, and Cognitive Capacities in Early Infancy: From sensation to Cognition. ; , s. 49-66
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 49. |
- Wattam-Bell, John, et al.
(författare)
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Reorganization of Global Form and Motion Processing during Human Visual Development
- 2010
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 20:5, s. 411-415
-
Tidskriftsartikel (refereegranskat)abstract
- The functional selectivity of human primary visual cortex (Vi) for orientation and motion direction is established by around 3 months of age [1-3], but there have been few studies of the development of extrastriate visual areas that integrate outputs from V1 [4-8]. We investigated sensitivity and topographical organization for global form and motion with high-density visual event-related potentials (VERPs) in 4- to 5-month-old infants and adults. Responses were measured to transitions between concentrically organized elements (short arc segments for form, dot trajectories for motion) and random arrangements. Adults showed topographically separate responses, with midline motion and more lateral form responses. Of 26 infants, 25 showed significant motion responses but only 13 showed form responses, suggesting more advanced development for extrastriate motion areas than form. Infants' form and motion responses were topographically distinct but contrasted with the corresponding adult topographies, with infants' motion responses more lateral than form responses. These results imply distinct neural sources at both ages and raise the possibility of substantial reorganization of extrastriate networks between infancy and adulthood. We speculate that global motion responses arise from area V5 in infants but are dominated by more medial areas such as V3/V3A and V6 in adults.
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| 50. |
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