F.R. (Ruud) van der Weel

The functional significance of arm movements in neonates

Arm movements made by newborn babies are usually dismissed as unintentional, purposeless, or reflexive. Spontaneous arm-waving movements were recorded while newborns lay supine facing to one side. They were allowed to see only the arm they were facing, only the opposite arm on a video monitor, or neither arm. Small forces pulled on their wrists in the direction of the toes. The babies opposed the perturbing force so as to keep an arm up and moving normally, but only when they could see the arm, either directly or on the video monitor. The findings indicate that newborns can purposely control their arm movements in the face of external forces and that development of visual control of arm movement is underway soon after birth.

Measuring dysfunction of basic movement control in cerebral palsy

Abstract Devising effective therapy for movement disorder in the cerebral palsied child requires in-depth measures of the childs motor functioning. Current assessment mainly uses measures of surface behaviour, but these measures cannot reveal the underlying causes of movement disorder which therapy needs to address. This paper reviewed five different experiments from our laboratory which measured in detail the functioning and development of basic movement control mechanisms. In particular these experiments investigated the degree in which cerebral palsied children are capable of picking up and use prospective perceptual information for movement control. The research revealed several perceptuo-motor difficulties in these children which could be used towards developing better, more detailed assessment, diagnosis, and therapy procedures.

Seeing it coming: infants’ brain responses to looming danger

A fundamental property of most animals is the ability to see whether an object is approaching on a direct collision course and, if so, when it will collide. Using high-density electroencephalography in 5- to 11-month-old infants and a looming stimulus approaching under three different accelerations, we investigated how the young human nervous system extracts and processes information for impending collision. Here, we show that infants’ looming related brain activity is characterised by theta oscillations. Source analyses reveal clear localised activity in the visual cortex. Analysing the temporal dynamics of the source waveform, we provide evidence that the temporal structure of different looming stimuli is sustained during processing in the more mature infant brain, providing infants with increasingly veridical time-to-collision information about looming danger as they grow older and become more mobile.

Perception of structured optic flow and random visual motion in infants and adults: a high-density EEG study

Electroencephalogram (EEG) was used in 8-month-old infants and adults to study brain electrical activity as a function of perception of structured optic flow and random visual motion. A combination of visual evoked potential (VEP) analyses and analyses of temporal spectral evolution (TSE, time-dependent spectral power) was carried out. Significant differences were found for the N2 component of VEP for optic flow versus random visual motion within and between groups. Both adults and infants showed shorter latencies for structured optic flow than random visual motion, and infants showed longer latencies, particularly for random visual motion, and larger amplitudes than adults. Both groups also showed significant differences in induced activity when TSE of the two motion stimuli (optic flow and random visual motion) was compared with TSE of a static dot pattern. Infants showed an induced decrease in the amplitudes in theta-band frequency, while adults showed an induced increase in beta-band frequency. Differences in induced activity for the two motion stimuli could, however, not be observed. Brain activity related to motion stimuli is different for infants and adults and the differences are observed both in VEPs and in induced activity of the EEG. To investigate how changes in locomotor development are related to accompanying changes in brain activity associated with visual motion perception, more data of infants with different experiences in self-produced locomotion are required.

Auditory Guided Arm and Whole Body Movements in Young Infants

Can infants use auditory information to guide their movements adequately in space, and if so, to what degree? Perceptual development has mostly been considered through the visual system. Similar to vision, audition provides us with spatial information over extended distances. There is generally little research about the use of auditory information for guided movement in the environment, and the similarity between vision and hearing is narrowly attached to a theoretical framework. Effective action is prospective and supposes the pickup of predictive perceptual information, so as to prepare the body how, when, and where a movement is to be performed. Studies on the use of auditory information for action are rare. This chapter will describe two studies with young infants where it will be shown that the auditory system is equally important as the visual system to the performance of prospective action in the environment. It will be concluded that the auditory system is best conceived as a functional listening system where auditory information is used as a perceptual source for guiding behaviour in the environment.

Development of Visual Motion Perception for Prospective Control: Brain and Behavioral Studies in Infants

During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioral and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioral data when studying the neural correlates of prospective control.

A high-density EEG study of differences between three high speeds of simulated forward motion from optic flow in adult participants

A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant differences between alpha de-synchronizations for forward motion and alpha synchronizations in the static condition were found in the parietal midline (PM) source. It was suggested that the alpha de-synchronizations reflect an activated state related to the visual processing of simulated forward motion, whereas the alpha synchronizations in response to the static condition reflect a deactivated resting period.

Differentiating prospective control information for catching in at-risk and control adolescents.

This paper investigated the use of prospective control in catching and how the results can be used as a sensitive tool to detect diffuse signs of brain dysfunction. A detailed analysis of 286 catching movements of eight adolescents (two males, six females [four very‐low‐birth weight {VLBW}, one small for gestational age {SGA}, and three appropriate for gestational age]; mean age 14y 5mo [SD 6mo]; range 14–15y) was performed blind for this purpose. The moving target approached the participants from the side at three different, non‐constant accelerations. The results showed that three adolescents used less advanced timing strategies that involved the lower‐order variables of distance or velocity to govern movement initiation of at least one of their hands. Two of these were preterm VLBW and one was term SGA. The remaining adolescents, on the other hand, all relied on the higher‐order variable of time‐to‐contact to initiate their hand movements, and were, therefore, considered low‐risk. These results were compared with the cerebral magnetic resonance imaging results of the adolescents. The findings show that timing strategy pinpoints successfully those adolescents at risk of neurological problems. It was, therefore, concluded that the skill of using prospective information for catching can be used as a tool to detect diffuse signs of motor dysfunction, which are not readily detected by standard behavioural tests alone.

Only Three Fingers Write, but the Whole Brain Works†: A High-Density EEG Study Showing Advantages of Drawing Over Typing for Learning

Are different parts of the brain active when we type on a keyboard as opposed to when we draw visual images on a tablet? Electroencephalogram (EEG) was used in young adults to study brain electrical activity as they were typing or describing in words visually presented PictionaryTM words using a keyboard, or as they were drawing pictures of the same words on a tablet using a stylus. Analyses of temporal spectral evolution (time-dependent amplitude changes) were performed on EEG data recorded with a 256-channel sensor array. We found that when drawing, brain areas in the parietal and occipital regions showed event related desynchronization activity in the theta/alpha range. Existing literature suggests that such oscillatory neuronal activity provides the brain with optimal conditions for learning. When describing the words using the keyboard, upper alpha/beta/gamma range activity in the central and frontal brain regions were observed, especially during the ideation phase. However, since this activity was highly synchronized, its relation to learning remains unclear. We concluded that because of the benefits for sensory-motor integration and learning, traditional handwritten notes are preferably combined with visualizations (e.g., small drawings, shapes, arrows, symbols) to facilitate and optimize learning.Are different parts of the brain active when we type on a keyboard as opposed to when we draw visual images on a tablet? Electroencephalogram (EEG) was used in young adults to study brain electrical activity as they were typing or describing in words visually presented PictionaryTM words using a keyboard, or as they were drawing pictures of the same words on a tablet using a stylus. Analyses of temporal spectral evolution (time-dependent amplitude changes) were performed on EEG data recorded with a 256-channel sensor array. We found that when drawing, brain areas in the parietal and occipital regions showed event related desynchronization activity in the theta/alpha range. Existing literature suggests that such oscillatory neuronal activity provides the brain with optimal conditions for learning. When describing the words using the keyboard, upper alpha/beta/gamma range activity in the central and frontal brain regions were observed, especially during the ideation phase. However, since this activity was highly synchronized, its relation to learning remains unclear. We concluded that because of the benefits for sensory-motor integration and learning, traditional handwritten notes are preferably combined with visualizations (e.g., small drawings, shapes, arrows, symbols) to facilitate and optimize learning.

The specificity of action in the analysis of movements

We are pleased to have been invited to write a commentary on Alan Fogel’s paper in which he integrates sociocultural information into a dynamical systems approach to human movement. Working, as we both are, on perceptuo-motor development in infancy, we have developed a particular interest in an ecological approach to perception and action. Such an approach ‘seeks to account for order and variability in movement as emerging in evolution, development, and learning from physical and informational constraints, without assuming sources of organisation in cognitive or neural structures a priori’ (Warren 1990: 23). We are therefore delighted that Fogel proposes a theory of social communication and development which is not based on internalized schemes or codes to account for developmental change, but on the emergence of communicative forms following a dynamic process of mutual interaction between adult and child. We also agree with Fogel that movements play an important role in social communication. When Fogel reverses this claim, however, by arguing that all movements are to be understood socially, we must object.