Motion and color processing in school-age children and adults: an ERP study

A static paradigm based on illusion-induced VEP for brain-computer interfaces

OBJECTIVE

Visual evoked potentials (VEPs) have been commonly applied in brain-computer interfaces (BCIs) due to their satisfactory classification performance recently. However, most existing methods with flickering or oscillating stimuli will induce visual fatigue under long-term training, thus restricting the implementation of VEP-based BCIs. To address this issue, a novel paradigm adopting static motion illusion based on illusion-induced visual evoked potential (IVEP) is proposed for BCIs to enhance visual experience and practicality.

APPROACH

This study explored the responses to baseline and illusion tasks including the Rotating-Tilted-Lines (RTL) illusion and Rotating-Snakes (RS) illusion. The distinguishable features were examined between different illusions by analyzing the event-related potentials (ERPs) and amplitude modulation of evoked oscillatory responses.

MAIN RESULTS

The illusion stimuli elicited VEPs in an early time window encompassing a negative component (N1) from 110 to 200 ms and a positive component (P2) between 210 and 300 ms. Based on the feature analysis, a filter bank was designed to extract discriminative signals. The task-related component analysis (TRCA) was used to evaluate the binary classification task performance of the proposed method. Then the highest accuracy of 86.67% was achieved with a data length of 0.6 s.

SIGNIFICANCE

The results of this study demonstrate that the static motion illusion paradigm has the feasibility of implementation and is promising for VEP-based BCI applications.

Realistic (3D) looming of emotional visual stimuli: Attentional effects at neural and behavioral levels

Previous research shows that endogenous attention (the controlled selection of certain aspects of our environment) is enhanced toward emotional stimuli due to its biological relevance. Although looming affective stimuli such as threat seem even more critical for survival, little is known about their effect on endogenous attention. Here, we recorded neural (event-related potentials, ERPs) and behavioral responses (errors and reaction times) to explore the combined effect of emotion and looming motion. 3D-recreated static and moving animals assessed as emotionally positive, negative, and neutral, were presented to participants (n = 71), who performed an indirect categorization task (vertebrate vs. invertebrate). Behavioral results showed better task performance, as reflected by lower number of errors and reaction times, in response to threatening stimuli. Neural indices revealed significant early (P1p, 150 milliseconds), intermediate (P2p, 240), and late (LPP, 450) effects, the latter being more intensely associated with behavior, as revealed by regression analyses. In general, neural indexes of attention to both static and dynamic stimuli showed a positivity offset in early stages and a negativity bias in subsequent phases. However, and importantly, the progressive inclusion of negative stimuli in the attentional focus is produced earlier in the case of dynamic (at P2p latency) than in static versions (at LPP). These results point to an enhancement of attention, particularly in temporal terms, toward stimuli combining motion and biological significance.

Low Spatial Frequency Sensitivity and Emotional Face Processing in Adolescents: An Event-related Potential Study

Slow maturation of visual pathways transmitting low spatial frequency (LSF) information may contribute to inaccurate facial emotion recognition in adolescence. We recorded ERPs from adolescents and adults to upright and inverted happy faces, fearful faces, and chairs, which were unfiltered, contained only LSFs, or only high spatial frequencies. P100s and N170s were larger for adolescents than adults, with the greatest effect size for LSF stimuli. For LSFs only, adolescents showed a larger N170 inversion effect for happy than for fearful faces, but adults showed the opposite response. Thus, immaturities in LSF pathways appear to impact facial expression processing in adolescents.

Neural dynamics underlying coherent motion perception in children and adults

Motion sensitivity increases during childhood, but little is known about the neural correlates. Most studies investigating children's evoked responses have not dissociated direction-specific and non-direction-specific responses. To isolate direction-specific responses, we presented coherently moving dot stimuli preceded by incoherent motion, to 6- to 7-year-olds (n = 34), 8- to 10-year-olds (n = 34), 10- to 12-year-olds (n = 34) and adults (n = 20). Participants reported the coherent motion direction while high-density EEG was recorded. Using a data-driven approach, we identified two stimulus-locked EEG components with distinct topographies: an early component with an occipital topography likely reflecting sensory encoding and a later, sustained positive component over centro-parietal electrodes that we attribute to decision-related processes. The component waveforms showed clear age-related differences. In the early, occipital component, all groups showed a negativity peaking at ˜300 ms, like the previously reported coherent-motion N2. However, the children, unlike adults, showed an additional positive peak at ˜200 ms, suggesting differential stimulus encoding. The later positivity in the centro-parietal component rose more steeply for adults than for the youngest children, likely reflecting age-related speeding of decision-making. We conclude that children's protracted development of coherent motion sensitivity is associated with maturation of both early sensory and later decision-related processes.

Visually Evoked Response Differences to Contrast and Motion in Children with Autism Spectrum Disorder

High-density electroencephalography (EEG) was used to examine the utility of the P1 event-related potential (ERP) as a marker of visual motion sensitivity to luminance defined low-spatial frequency drifting gratings in 16 children with autism and 16 neurotypical children. Children with autism displayed enhanced sensitivity to large, high-contrast low-spatial frequency stimuli as indexed by significantly shorter P1 response latencies to large vs. small gratings. The current study also found that children with autism had larger amplitude responses to large gratings irrespective of contrast. A linear regression established that P1 adaptive mean amplitude for large, high-contrast sinusoidal gratings significantly predicted hyperresponsiveness item mean scores on the Sensory Experiences Questionnaire for children with autism, but not for neurotypical children. We conclude that children with autism have differences in the mechanisms that underlie low-level visual processing potentially related to altered visual spatial suppression or contrast gain control.

An fMRI study of coherent visual motion processing in children and adults

There is a large corpus of brain imaging studies examining the dorsal visual pathway, especially area V5/MT during visual motion perception. However, despite evidence suggesting a protracted development of the dorsal visual stream, and a role of this pathway in neurodevelopmental disorders, V5/MT has not been characterized developmentally. Further, experiential factors such as reading acquisition may play a modulating role in any age-dependent changes. Here we used a coherent visual motion detection task to examine V5/MT activity and connectivity in typical participants in two studies: a Cross- Sectional Study comparing adults and children; and a Longitudinal Study of 2nd graders followed into 3rd grade. In the Cross-Sectional Study, a whole-brain analysis revealed no differences between the two groups, whereas a region of interest (ROI) approach identified greater activation in left (right trending) V5/MT in adults compared to children. However, when we measured V5/MT activation individually for each participant, children and adults showed no difference in the location or intensity of activation, although children did exhibit relatively larger extent of V5/MT activation bilaterally. There was also relatively greater functional connectivity in the children between left and right occipitotemporal cortex, including V5/MT. The Longitudinal Study revealed no changes in V5/MT activation for any measures of activation or functional connectivity from 2nd to 3rd grade. Finally, there was no evidence of an association between reading and V5/MT over time, nor predictive power of V5/MT activity for later reading. Together, our results indicate similar V5/MT activity across age groups, with relatively greater extent of V5/MT activation and functional connectivity in children relative to adults, bilaterally. These differences were not apparent over the time course of one year, suggesting that these developmental changes occur over a more protracted period.

Visual cortical activity before and after cochlear implantation: A follow up ERP prospective study in deaf children

ERPs were recorded in response to presentation of static colored patterned stimuli in 25 children (19 to 80months of age at cochlear implantation, CI) with very early prelingual profound deafness (PreLD), 21 postlingual profoundly deaf children (PostLD) (34 to 180months of age at CI) and gender- and age-matched control hearing children. Recording sessions were performed before CI, then 6 and 24months after CI. Results showed that prelingual and, at a lesser degree, postlingual auditory deprivation altered cortical visual neural activity associated to colored shapes from both P1 and N1 cortical processing stages. The P1 and N1 amplitude modifications vanished about 24months after CI in both PreLD and PostLD deaf children. In PreLD the visual processing pattern becomes similar to the typical one essentially by an amplitude decrease of P1 on the left hemisphere together with an amplitude increase of the N1 on the right hemisphere. Finally, in PreLD, increased LH advantage over the RH in N1 amplitude on the cerebellar-occipito-parietal region before CI showed a significant inverse relationship with speech perception outcomes 3years after CI. Investigating early visual processing development and its neural substrates in deaf children would help to understand the variability of CI outcome, because their cortical visual organization diverged from the one of typically developing hearing children, and cannot be predicted from what is observed in deaf adults.

The notion of the motion: the neurocognition of motion lines in visual narratives

Motion lines appear ubiquitously in graphic representation to depict the path of a moving object, most popularly in comics. Some researchers have argued that these graphic signs directly tie to the "streaks" appearing in the visual system when a viewer tracks an object (Burr, 2000), despite the fact that previous studies have been limited to offline measurements. Here, we directly examine the cognition of motion lines by comparing images in comic strips that depicted normal motion lines with those that either had no lines or anomalous, reversed lines. In Experiment 1, shorter viewing times appeared to images with normal lines than those with no lines, which were shorter than those with anomalous lines. In Experiment 2, measurements of event-related potentials (ERPs) showed that, compared to normal lines, panels with no lines elicited a posterior positivity that was distinct from the frontal positivity evoked by anomalous lines. These results suggested that motion lines aid in the comprehension of depicted events. LORETA source localization implicated greater activation of visual and language areas when understanding was made more difficult by anomalous lines. Furthermore, in both experiments, participants' experience reading comics modulated these effects, suggesting motion lines are not tied to aspects of the visual system, but rather are conventionalized parts of the "vocabulary" of the visual language of comics.

Developmental changes in point-light walker processing during childhood: a two-year follow-up ERP study

Event-related potentials were measured in twenty-four children aged 6-15 years, at one-year intervals for two years, to investigate developmental changes in each subject's neural response to a point-light walker (PLW) and a scrambled PLW (sPLW) stimulus. One positive peak (P1) and two negative peaks (N1 and N2) were observed in both occipitotemporal regions at approximately 130, 200, and 300-400ms. The amplitude and latency of the P1 component measured by the occipital electrode decreased during development over the first one-year period. Negative amplitudes of both N1 and N2, induced by the PLW stimulus, were significantly larger than those induced by the sPLW stimulus. Moreover, for the P1-N1 amplitude, the values for the eight-year-old children were significantly larger than those for the twelve-year-old children. N1 and N2 latency at certain electrodes decreased with age, but no consistent changes were observed. These results suggest that enhanced electrophysiological responses to PLW can be observed in all age groups, and that the early components were changed even over the course of a single year at the age of twelve.

Electrophysiological indices of phonological impairments in dyslexia

PURPOSE

A range of studies have shown difficulties in perceiving acoustic and phonetic information in dyslexia; however, much less is known about how such difficulties relate to the perception of individual words. The authors present data from event-related potentials (ERPs) examining the hypothesis that children with dyslexia have difficulties with processing phonemic information within spoken words compared to age-matched readers with typical development.

METHOD

The authors monitored ERPs to auditory words during a simple picture-word matching task. The key manipulation was the inclusion of both matching stimuli and three types of mismatches (cohort, CONE-comb; rhyme, CONE-bone; and unrelated, CONE-fox).

RESULTS

Children with dyslexia showed atypical N400 ERP waveforms to both types of phonological mismatches, but not to phonologically unrelated mismatches, reflecting a relative insensitivity to phonological overlap among auditory words.

CONCLUSION

The data suggest that children with dyslexia have impairments in integrating phonological information into word-level representations. The results suggest that speech perception difficulties in dyslexia might have consequences for processing auditory words.

Electrophysiological correlates of automatic visual change detection in school-age children

Automatic stimulus-change detection is usually investigated in the auditory modality by studying Mismatch Negativity (MMN). Although the change-detection process occurs in all sensory modalities, little is known about visual deviance detection, particularly regarding the development of this brain function throughout childhood. The aim of the present study was to examine the maturation of the electrophysiological response to unattended deviant visual stimuli in 11-year-old children. Twelve children and 12 adults were presented with a passive visual oddball paradigm using dynamic stimuli involving changes in form and motion. Visual Mismatch responses were identified over occipito-parietal sites in both groups but they displayed several differences. In adults the response clearly culminated at around 210 ms whereas in children three successive negative deflections were evidenced between 150 and 330 ms. Moreover, the main mismatch response in children was characterized by a positive component peaking over occipito-parieto-temporal regions around 450 ms after deviant stimulus onset. The findings showed that the organization of the vMMN response is not mature in 11-year-old children and that a longer time is still necessary to process simple visual deviancy at this late stage of child development.

Keep your eyes on development: the behavioral and neurophysiological development of visual mechanisms underlying form processing

Visual form perception is essential for correct interpretation of, and interaction with, our environment. Form perception depends on visual acuity and processing of specific form characteristics, such as luminance contrast, spatial frequency, color, orientation, depth, and even motion information. As other cognitive processes, form perception matures with age. This paper aims at providing a concise overview of our current understanding of the typical development, from birth to adulthood, of form-characteristic processing, as measured both behaviorally and neurophysiologically. Two main conclusions can be drawn. First, the current literature conveys that for most reviewed characteristics a developmental pattern is apparent. These trajectories are discussed in relation to the organization of the visual system. The second conclusion is that significant gaps in the literature exist for several age-ranges. To complete our understanding of the typical and, by consequence, atypical development of visual mechanisms underlying form processing, future research should uncover these missing segments.

Identification of a novel dynamic red blindness in human by event-related brain potentials

Dynamic color is an important carrier that takes information in some special occupations. However, up to the present, there are no available and objective tests to evaluate dynamic color processing. To investigate the characteristics of dynamic color processing, we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group). ERPs were recorded by Neuroscan system. The results showed that in the normal group, ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms, a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms. In the abnormal group, ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms. No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P>0.05). ERPs of the two groups in response to the static red, green and blue stimulus were not much different, showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms. Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs, which was called "dynamic red blindness". Furthermore, these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.

Early Visually Evoked Electrophysiological Responses Over the Human Brain (P1, N170) Show Stable Patterns of Face-Sensitivity from 4 years to Adulthood

Whether the development of face recognition abilities truly reflects changes in how faces, specifically, are perceived, or rather can be attributed to more general perceptual or cognitive development, is debated. Event-related potential (ERP) recordings on the scalp offer promise for this issue because they allow brain responses to complex visual stimuli to be relatively well isolated from other sensory, cognitive and motor processes. ERP studies in 5- to 16-year-old children report large age-related changes in amplitude, latency (decreases) and topographical distribution of the early visual components, the P1 and the occipito-temporal N170. To test the face specificity of these effects, we recorded high-density ERPs to pictures of faces, cars, and their phase-scrambled versions from 72 children between the ages of 4 and 17, and a group of adults. We found that none of the previously reported age-dependent changes in amplitude, latency or topography of the P1 or N170 were specific to faces. Most importantly, when we controlled for age-related variations of the P1, the N170 appeared remarkably similar in amplitude and topography across development, with much smaller age-related decreases in latencies than previously reported. At all ages the N170 showed equivalent face-sensitivity: it had the same topography and right hemisphere dominance, it was absent for meaningless (scrambled) stimuli, and larger and earlier for faces than cars. The data also illustrate the large amount of inter-individual and inter-trial variance in young children's data, which causes the N170 to merge with a later component, the N250, in grand-averaged data. Based on our observations, we suggest that the previously reported “bi-fid” N170 of young children is in fact the N250. Overall, our data indicate that the electrophysiological markers of face-sensitive perceptual processes are present from 4 years of age and do not appear to change throughout development.

Developmental changes in point-light walker processing during childhood and adolescence: an event-related potential study

To investigate developmental changes in the neural responses to a biological motion stimulus, we measured event-related potentials (ERPs) in 50 children aged from 7 to 14 years, and 10 adults. Two kinds of visual stimuli were presented: a point-light walker (PLW) stimulus and a scrambled point-light walker (sPLW) stimulus as a control. The sPLW stimulus had the same number of point-lights and the same velocity vector of point-lights as the PLW stimulus, but the initial starting positions were randomized. Consistent with previous ERP studies, one positive peak (P1) and two negative peaks (N1 and N2) were observed at around 130, 200 and 330 ms, respectively, in bilateral occipitotemporal regions, in all age groups. The latency of the P1 component was significantly shorter for the PLW than sPLW stimulus in all age groups, whereas the amplitude was significantly larger for the PLW than sPLW stimulus only for the 7-year-old group. The P1 amplitude and N1 latency were linearly decreased with age. The negative amplitudes of both N1 and N2 components of the PLW stimulus were significantly larger than those of the sPLW stimulus in all age groups. P1-N1 amplitude was changed by development, but not N2 amplitude. These results suggest that the intensity (P1) and timing (N1) of early visual processing for the PLW stimulus changed linearly throughout childhood and P1-N1 amplitude at occipitotemporal electrodes and N1 latency in 10-year-olds, but not 11-year-olds, was significantly larger than that in adults. For the amplitudes of the N2 component in response to PLW and sPLW stimuli in 7-8-year-old subjects were not statistically different from those in adults at occipitotemporal electrodes. These results suggest that the neural response to the PLW stimulus has developed by 10 years of age at the occipitotemporal electrode.

The processing of non-symbolic numerical magnitudes as indexed by ERPs

Previous research has shown that, in the context of event-related potential (ERP) prime-target experiments, processing meaningful stimuli such as words, phonemes, numbers, pictures of objects, and faces elicit negativities around 400 ms. However, there is little information on whether non-symbolic numerical magnitudes elicit this negative component. The present experiments recorded ERPs while adults made same/different judgments to serially presented prime-target pairs of non-symbolic numerical stimuli containing the same, close, or distant quantities. In Experiment 1, a negativity between 350 and 450 ms was elicited for targets preceded by primes of unequal quantity, and this was greater for close than for distant quantities. Change direction (decreasing or increasing) also modulated a similar negativity: a greater negativity was elicited by targets preceded by larger than by smaller quantities. Experiment 2 replicated the numerical distance and change direction effects for numerical judgments, but found no negative distance effect in a color comparison task when the same stimuli were used. Additionally, ERP effects of numerical distance were found under implicit conditions, and task proficiency in the number condition modulated implicit and explicit numerical distance ERP effects. These results suggest that the neural systems involved with processing numerical magnitudes contribute to the construction of meaningful, contextual representations, are partly automatic, and display marked individual differences.

Young infants readily use proximity to organize visual pattern information

Four experiments relying on novelty and spontaneous preference procedures were performed to determine whether 3-4-month-old infants utilize the Gestalt principle of proximity to organize visual pattern information. In Experiment 1, infants familiarized with arrays of elements that could be organized into either columns or rows were tested for their preference between vertical and horizontal bars. The infants preferred the novel organization of bars. Experiments 2 and 3 showed that the novelty preference could not be attributed to an a priori preference or an inability to discriminate between the elements comprising the patterns. Experiment 4 replicated the results of Experiment 1 in a bars --> elements version of the task, indicating that extended exposure is not necessary for infants to organize based on proximity. The results suggest that infants readily organize visual pattern information in accord with proximity. Implications of this finding for models of the ontogenesis and microgenesis of object perception in infants and adults are discussed.

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.

A primer on motion visual evoked potentials

Motion visual evoked potentials (motion VEPs) have been used since the late 1960s to investigate the properties of human visual motion processing, and continue to be a popular tool with a possible future in clinical diagnosis. This review first provides a synopsis of the characteristics of motion VEPs and then summarizes important methodological aspects. A subsequent overview illustrates how motion VEPs have been applied to study basic functions of human motion processing and shows perspectives for their use as a diagnostic tool.

Motion-onset VEPs: Characteristics, methods, and diagnostic use

This review article summarises the research on the motion-onset visual evoked potentials (VEPs) and important motion stimulus parameters which have been clarified. For activation of the visual motion processing system and evocation of the motion-onset specific N2 peak (with latency of 160-200ms) from the extra-striate temporo-occipital and/or parietal cortex, the following stimulus parameters can be recently recommended: low luminance (<ca. 20cd/m(2)) and low contrast (<ca. 10%-sinusoidally modulated) of a moving structure with low velocity and temporal frequency (<ca. 6Hz). A short (up to 200ms) duration of motion and a long (at least 1s) inter-stimulus interval reduce adaptation to motion and predominance of a pattern-related P1 peak. Radial motion (with increasing velocity and decreasing spatial frequency towards the periphery) produces larger reactions as compared to a unidirectional translation. In view of the slow maturation (up to the age of 18 years) and early ageing of the visual motion processing system, the use of age-dependent latency norms may be necessary. Since early or selective involvement of the motion processing system is suspected in some CNS disorders, we suggest an evaluation of the utility of motion-onset VEPs as part of the electrophysiological CNS examination since this method may recognise motion processing involvement better than other methods. Motion-onset VEPs might increase the sensitivity of this examination for diagnosing CNS diseases including Multiple Sclerosis, Neuroborreliosis, Glaucoma, Dyslexia and Encephalopathies.

Neuroplasticity as a Double-edged Sword: Deaf Enhancements and Dyslexic Deficits in Motion Processing

We examined the hypothesis that aspects of processing that are most modifiable by experience (i.e., “plastic”) display the most vulnerability in developmental disorders and the most compensatory enhancement after sensory deprivation. A large literature reports that motion processing and magnocellular visual function is selectively deficient in dyslexia. A smaller literature reports enhancements in such functions in deaf individuals. However, studies with dyslexic and deaf individuals have used different experimental paradigms to assess visual function, and no research has yet examined both sides of modifiability (i.e., enhancements and deficits) using the same experimental paradigm. In the present research, visual function was compared in dyslexic (n = 15), deaf (n = 17), and control adults by using automated peripheral kinetic and foveal static perimetry. In the kinetic perimetry task, the dyslexic group showed deficits ( p &lt; .003), whereas the deaf group showed enhancements ( p &lt; .001) for detecting moving light points in the periphery. In the foveal static perimetry task, neither the dyslexic ( p = .866) nor the deaf ( p = .632) group differed significantly from controls in foveal contrast sensitivity thresholds, and no group or individual approached ceiling performance on this task. Taken together, the present data bridge previous literatures and suggest that motion processing tasks are selectively modifiable, either to decrement or enhancement, whereas foveal contrast sensitivity does not differ in dyslexic or deaf groups.

Maturation of luminance- and motion-defined form perception beyond adolescence: a combined ERP and fMRI study

Abilities to discriminate forms defined by motion continue to develop throughout childhood. To investigate late development of the visual motion system, we measured brain activity with event-related EEG potentials (ERPs) and functional magnetic resonance imaging (fMRI) in groups of adolescents (15-17 years) and adults (20-30 years) during a visual form discrimination task--with forms being either defined by motion or luminance contrast. We further explored whether possible developmental changes varied with the degree of motion coherence reflecting maturation specific to global motion processing. Both the fMRI activation patterns and ERP topographies were very similar between adolescents and adults, suggesting that the basic visual networks for processing motion and form are established by the age of 15-17. The ERP response to luminance- and motion-defined forms was dominated by a posterior negativity (N1: 120-270 ms). The N1 of the motion contrast was delayed in adolescents, whereas the N1 of the static condition did not differ between groups. Since the motion-evoked N1 is thought to arise in the middle temporal area MT/V5, our results indicate that visual motion processing in MT continues to get faster, becoming still more efficient during late development. Neither the ERP nor the fMRI results revealed maturation effects specific to motion coherence. This indicates that the specific mechanisms to process global dot motion are already mature in adolescence. The present findings support the view that static perception matures earlier than dynamic perception, and that these visual systems have different developmental courses.