scholarly journals Development of motion speed perception from infancy to early adulthood: a high-density EEG study of simulated forward motion through optic flow

Author(s):  
Stefania Rasulo ◽  
Kenneth Vilhelmsen ◽  
F. R. van der Weel ◽  
Audrey L. H. van der Meer

AbstractThis study investigated evoked and oscillatory brain activity in response to forward visual motion at three different ecologically valid speeds, simulated through an optic flow pattern consisting of a virtual road with moving poles at either side of it. Participants were prelocomotor infants at 4–5 months, crawling infants at 9–11 months, primary school children at 6 years, adolescents at 12 years, and young adults. N2 latencies for motion decreased significantly with age from around 400 ms in prelocomotor infants to 325 ms in crawling infants, and from 300 and 275 ms in 6- and 12-year-olds, respectively, to 250 ms in adults. Infants at 4–5 months displayed the longest latencies and appeared unable to differentiate between motion speeds. In contrast, crawling infants at 9–11 months and 6-year-old children differentiated between low, medium and high speeds, with shortest latency for low speed. Adolescents and adults displayed similar short latencies for the three motion speeds, indicating that they perceived them as equally easy to detect. Time–frequency analyses indicated that with increasing age, participants showed a progression from low- to high-frequency desynchronized oscillatory brain activity in response to visual motion. The developmental differences in motion speed perception are interpreted in terms of a combination of neurobiological development and increased experience with self-produced locomotion. Our findings suggest that motion speed perception is not fully developed until adolescence, which has implications for children’s road traffic safety.

2012 ◽  
Vol 25 (0) ◽  
pp. 192
Author(s):  
Davide Bottari ◽  
Sophie Rohlf ◽  
Marlene Hense ◽  
Boukje Habets ◽  
Brigitte Roeder

Event-related potentials (ERP) to the second stimulus of a pair are known to be reduced in amplitude. The magnitude of this ‘refractoriness’ is modulated by both the interstimulus interval and the similarity between the two stimuli. Intramodal refractoriness is interpreted as an index of a temporary decrement in neural responsiveness. So, cross-modal refractoriness might be an indicator of shared neural generators between modalities. We analysed oscillatory neuronal activity while participants were engaged in an oddball paradigm with auditory (4000 Hz, 50 ms-long, 90 db, bilateral) and tactile stimuli (50 ms-long, 125 Hz-vibrations, index fingers) presented in a random order with an ISI of either 1000 or 2000 ms. Participants were required to detect rare tactile (middle fingers) and auditory deviants (600 Hz). A time–frequency analysis of the brain response to the second stimulus of each pair (T-T, A-A, T-A and A-T) contrasting Short and Long ISIs revealed a reduced refractory effect after Long ISI with respect to Short ISI, in all pairs (both intramodal and cross-modal). This emerged as a broadly distributed increase of evoked theta activity (3–7 Hz, 100–500 ms). Only in intramodal tactile pairs and cross-modal tactile-auditory pairs we also observed that Long ISI with respect to Short ISI determined a decrease of induced alpha (8–12 Hz, 200–700 ms), a typical sign of enhanced neural excitability and thus decreased refractoriness. These data suggest that somatosensory and auditory cortices display different neural markers of refractoriness and that the auditory cortex might have a stronger low level degree of influence on the tactile cortex than vice-versa.


2012 ◽  
Vol 24 (2) ◽  
pp. 337-350 ◽  
Author(s):  
Álvaro Darriba ◽  
Paula Pazo-Álvarez ◽  
Almudena Capilla ◽  
Elena Amenedo

Despite the importance of change detection (CD) for visual perception and for performance in our environment, observers often miss changes that should be easily noticed. In the present study, we employed time–frequency analysis to investigate the neural activity associated with CD and change blindness (CB). Observers were presented with two successive visual displays and had to look for a change in orientation in any one of four sinusoid gratings between both displays. Theta power increased widely over the scalp after the second display when a change was consciously detected. Relative to no-change and CD, CB was associated with a pronounced theta power enhancement at parietal-occipital and occipital sites and broadly distributed alpha power suppression during the processing of the prechange display. Finally, power suppressions in the beta band following the second display show that, even when a change is not consciously detected, it might be represented to a certain degree. These results show the potential of time–frequency analysis to deepen our knowledge of the temporal curse of the neural events underlying CD. The results further reveal that the process resulting in CB begins even before the occurrence of the change itself.


2012 ◽  
Vol 107 (9) ◽  
pp. 2475-2484 ◽  
Author(s):  
Paolo Manganotti ◽  
Emanuela Formaggio ◽  
Silvia Francesca Storti ◽  
Daniele De Massari ◽  
Alessandro Zamboni ◽  
...  

Dynamic changes in spontaneous electroencephalogram (EEG) rhythms can be seen to occur with a high rate of variability. An innovative method to study brain function is by triggering oscillatory brain activity with transcranial magnetic stimulation (TMS). EEG-TMS coregistration was performed on five healthy subjects during a 1-day experimental session that involved four steps: baseline acquisition, unconditioned single-pulse TMS, intracortical inhibition (ICI, 3 ms) paired-pulse TMS, and transcallosal stimulation over left and right primary motor cortex (M1). A time-frequency analysis based on the wavelet method was used to characterize rapid modifications of oscillatory EEG rhythms induced by TMS. Single, paired, and transcallosal TMS applied on the sensorimotor areas induced rapid desynchronization over the frontal and central-parietal electrodes mainly in the alpha and beta bands, followed by a rebound of synchronization, and rapid synchronization of delta and theta activity. Wavelet analysis after a perturbation approach is a novel way to investigate modulation of oscillatory brain activity. The main findings are consistent with the concept that the human motor system may be based on networklike oscillatory cortical activity and might be modulated by single, paired, and transcallosal magnetic pulses applied to M1, suggesting a phenomenon of fast brain activity resetting and triggering of slow activity.


Author(s):  
Niklas Grabbe ◽  
Michael Höcher ◽  
Alexander Thanos ◽  
Klaus Bengler

Automated driving offers great possibilities in traffic safety advancement. However, evidence of safety cannot be provided by current validation methods. One promising solution to overcome the approval trap (Winner, 2015) could be the scenario-based approach. Unfortunately, this approach still results in a huge number of test cases. One possible way out is to show the current, incorrect path in the argumentation and strategy of vehicle automation, and focus on the systemic mechanisms of road traffic safety. This paper therefore argues the case for defining relevant scenarios and analysing them systemically in order to ultimately reduce the test cases. The relevant scenarios are based on the strengths and weaknesses, in terms of the driving task, for both the human driver and automation. Finally, scenarios as criteria for exclusion are being proposed in order to systemically assess the contribution of the human driver and automation to road safety.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lei Lin ◽  
Feng Shi ◽  
Weizi Li

AbstractCOVID-19 has affected every sector of our society, among which human mobility is taking a dramatic change due to quarantine and social distancing. We investigate the impact of the pandemic and subsequent mobility changes on road traffic safety. Using traffic accident data from the city of Los Angeles and New York City, we find that the impact is not merely a blunt reduction in traffic and accidents; rather, (1) the proportion of accidents unexpectedly increases for “Hispanic” and “Male” groups; (2) the “hot spots” of accidents have shifted in both time and space and are likely moved from higher-income areas (e.g., Hollywood and Lower Manhattan) to lower-income areas (e.g., southern LA and southern Brooklyn); (3) the severity level of accidents decreases with the number of accidents regardless of transportation modes. Understanding those variations of traffic accidents not only sheds a light on the heterogeneous impact of COVID-19 across demographic and geographic factors, but also helps policymakers and planners design more effective safety policies and interventions during critical conditions such as the pandemic.


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