Visual search for feature conjunctions: an fMRI study comparing alcohol-related neurodevelopmental disorder (ARND) to ADHD

Abstract Background Alcohol-related neurodevelopmental disorder (ARND) falls under the umbrella of fetal alcohol spectrum disorder (FASD). Diagnosis of ARND is difficult because individuals do not demonstrate the characteristic facial features associated with fetal alcohol syndrome (FAS). While attentional problems in ARND are similar to those found in attention-deficit/hyperactivity disorder (ADHD), the underlying impairment in attention pathways may be different. Methods Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) was conducted at 3 T. Sixty-three children aged 10 to 14 years diagnosed with ARND, ADHD, and typically developing (TD) controls performed a single-feature and a feature-conjunction visual search task. Results Dorsal and ventral attention pathways were activated during both attention tasks in all groups. Significantly greater activation was observed in ARND subjects during a single-feature search as compared to TD and ADHD groups, suggesting ARND subjects require greater neural recruitment to perform this simple task. ARND subjects appear unable to effectively use the very efficient automatic perceptual ‘pop-out’ mechanism employed by TD and ADHD groups during presentation of the disjunction array. By comparison, activation was lower in ARND compared to TD and ADHD subjects during the more difficult conjunction search task as compared to the single-feature search. Analysis of DTI data using tract-based spatial statistics (TBSS) showed areas of significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) in the right inferior longitudinal fasciculus (ILF) in ARND compared to TD subjects. Damage to the white matter of the ILF may compromise the ventral attention pathway and may require subjects to use the dorsal attention pathway, which is associated with effortful top-down processing, for tasks that should be automatic. Decreased functional activity in the right temporoparietal junction (TPJ) of ARND subjects may be due to a reduction in the white matter tract’s ability to efficiently convey information critical to performance of the attention tasks. Conclusions Limited activation patterns in ARND suggest problems in information processing along the ventral frontoparietal attention pathway. Poor integrity of the ILF, which connects the functional components of the ventral attention network, in ARND subjects may contribute to the attention deficits characteristic of the disorder

Motion and Attention in a Kinetic Videoconferencing Proxy

Abstract. Compared to collocated interaction, videoconferencing disrupts the ability to use gaze and gestures to mediate interaction, direct reactions to specific people, and provide a sense of presence for the satellite (i.e., remote) participant. We developed a kinetic videoconferencing proxy with a swiveling display screen to indicate which direction that the satellite participant was looking. Our goal was to compare two alternative motion control conditions, in which the satellite participant directed the display screen’s motion either explicitly (aiming the direction of the display with a mouse) or implicitly (with the screen following the satellite participant’s head turns). We then explored the effectiveness of this prototype compared to a typical stationary video display in a lab study. We found that both motion conditions resulted in communication patterns that indicate higher engagement in conversation, more accurate responses to the satellite participant’s deictic questions (i.e., “What do you think?”), and higher user rankings. We also discovered tradeoffs in attention and clarity between explicit versus implicit control, a tension in how motion toward one person can exclude other people, and ways that swiveling motion provides attention awareness, even without direct eye contact. Keywords: Video-mediated communication, videoconferencing, gaze awareness, proxy, telepresence.