Kerstin Rosander

The iCub humanoid robot: An open-systems platform for research in cognitive development

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.

Development of Smooth Pursuit Tracking in Young Infants

Eye and head movements were measured in a group of infants at 2, 3, and 5 months of age as they were attentively tracking an object moving at 0.2 or 0.4 Hz in sinus or triangular mode. Smooth pursuit gain increased with age, especially until 3 months. At 2-3 months, the lag of the smooth pursuit was small for the sinusoidal motion but large for the triangular one. At 5 months, smooth pursuit was leading the sinusoidal motion and the lag for the triangular one was small. Head tracking increased substantially with age and its lag was always large.

The development of gaze control and predictive tracking in young infants

Eye and head tracking of an oscillating visual flow was studied in 1-, 2-, and 3-month-old infants using EOG and an opto-electronic system. A pronounced decrease in phaselag of gaze velocity was observed over this age period, from 170 to 70 msec, but gain changed only marginally. Latency of the onset of tracking decreased with age from 860 to 560 msec. During tracking, the velocity of the head showed high frequency components in the 1-6 Hz range, to which the eye movements were reciprocal and without systematic phase lag. This coordination improved with age.

The Development of Anticipatory Postural Adjustments in Infancy

Efficient voluntary action requires postural adjustments that compensate for potential balance disturbances before they occur. These anticipatory postural adjustments have been widely investigated in adults, but relatively little is known about their development, especially during infancy. This study examined the early development of anticipatory postural activity in support of pulling action while standing. A total of 34 infants between 10 and 17 months were tested. The task required infants to open a cabinet drawer to retrieve toys while a force resisting the pulling action was applied to the drawer. The experiment included between 9 and 13 pulling trials. The force resisting the pull was doubled after the first 4 initial trials and returned again to its original value after another 4 trials. Electromyographic activity from the gastrocnemius and biceps brachii muscles was recorded. The proportion of pulls involving anticipatory activity in the gastrocnemius muscles progressively increased between 10 and...

Cortical processing of visual motion in young infants.

High-density EEG was used to investigate the cortical processing of a rotating 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 V1 bypass at these ages. The results are in agreement with behavioural and psychophysical data in infants.

Movement Planning Reflects Skill Level and Age Changes in Toddlers

Kinematic measures of childrens 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.

Perception-action in children with ASD

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 peoples actions. This includes communicative actions as they are ultimately based on movements. Today there are two promising neurobiological interpretation of Autism Spectrum Disorder (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 premotor areas. Secondly, action prediction is accomplished through a system that includes a loop from the posterior parietal cortex (PPC) 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.

DNA damage in human endothelial cells after irradiation in anoxia

Endothelial cells and fibroblasts have been reported to respond differently to oxidative stress. Both the effects of high oxygen tension and radiation involve the action of free radicals. DNA damage (single strand breaks, SSB, and double strand breaks, DSB) was assayed in human umbilical cord vein (HUV) cells and in Chinese hamster fibroblasts (V79) after irradiation under oxic or anoxic conditions. The cells were exposed to single doses in the range of 2-18 Gy of gamma-radiation from 60Co. Significantly more DNA damage was induced in the V79 cells than in the HUV cells. As a consequence, a higher oxygen enhancement ratio was obtained for the HUV cells (6.3) as compared to the V79 cells (2.8). The repair of SSB was slower in the HUV cells than in the V79 cells, irrespective of oxic state. For the higher doses, the damage remaining at 60 min after anoxic irradiation, i.e. DSB, was only detected in the V79 cells.

Kinematic and gait similarities between crawling human infants and other quadruped mammals

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.

Development of smooth pursuit eye movements in very preterm infants: 1. General aspects

Aim:  To investigate early oculo‐motor development in a population‐based cohort of very preterm infants.