Media use, attention, mental health and academic performance among 8 to 12 year old children.

The rise in digital media consumption, especially among children, raises the societal question of its impact on cognition, mental health and academic achievement. Here, we investigate three different ways of measuring technology use--total hours of media consumed, hours of video game play and number of media used concurrently--in 118 eight-to-twelve year-old children. At stake is the question of whether different technology uses have different effects, which could explain some of the past mixed findings. We collected data about children's media uses as well as (i) attentional and behavioral control abilities, (ii) psychological distress, psychosocial functioning, and sleep, and (iii) academic achievement and motivation. While attentional control abilities were assessed using both cognitive tests and questionnaires, mental health and sleep were all questionnaire-based. Finally, academic performance was based on self-reported grades, with motivational variables being measured through the grit and the growth-mindset questionnaires. We present partial correlation analyses and construct a psychological network to assess the structural associations between different forms of media consumption and the three categories of measures. We observe that children consume large amounts of media and media multitask substantially. Partial correlation analyses show that media multitasking specifically was mostly correlated with negative mental health, while playing video games was associated with faster responding and better mental health. No significant partial correlations were observed for total hours on media. Psychological network analysis complement these first results by indicating that all three ways of consuming technology are only indirectly related to self-reported grades. Thus, technology uses appear to only indirectly relate to academic performance, while more directly affecting mental health. This work emphasizes the need to differentiate among technology uses if one is to understand how every day digital consumption impacts human behavior.

Implicit representation of the auditory space: contribution of the left and right hemispheres.

Spatial cues contribute to the ability to segregate sound sources and thus facilitate their detection and recognition. This implicit use of spatial cues can be preserved in cases of cortical spatial deafness, suggesting that partially distinct neural networks underlie the explicit sound localization and the implicit use of spatial cues. We addressed this issue by assessing 40 patients, 20 patients with left and 20 patients with right hemispheric damage, for their ability to use auditory spatial cues implicitly in a paradigm of spatial release from masking (SRM) and explicitly in sound localization. The anatomical correlates of their performance were determined with voxel-based lesion-symptom mapping (VLSM). During the SRM task, the target was always presented at the centre, whereas the masker was presented at the centre or at one of the two lateral positions on the right or left side. The SRM effect was absent in some but not all patients; the inability to perceive the target when the masker was at one of the lateral positions correlated with lesions of the left temporo-parieto-frontal cortex or of the right inferior parietal lobule and the underlying white matter. As previously reported, sound localization depended critically on the right parietal and opercular cortex. Thus, explicit and implicit use of spatial cues depends on at least partially distinct neural networks. Our results suggest that the implicit use may rely on the left-dominant position-linked representation of sound objects, which has been demonstrated in previous EEG and fMRI studies.

Remodelling the attentional system after left hemispheric stroke: Effect of leftward prismatic adaptation.

Left hemispheric stroke is known to be associated with right neglect and/or not lateralized attentional deficits. The former appears to respond favourably to leftward prismatic adaptation (L-PA), as reported in a case of a large left stroke. In normal subjects, brief exposure to L-PA was shown to enhance the representation of the right visual field within the right inferior parietal lobule, emphasizing thus right hemispheric dominance within the ventral attentional system. We have investigated whether L-PA does the same in left hemispheric stroke by comparing neural responses to left, central and right stimuli before and after a brief exposure to L-PA. Neural responses to visual stimuli were significantly modulated within a large part of the occipito-temporal cortex and in smaller clusters in the angular gyrus, the anterior temporal lobe and the insula, corresponding to decrease in activity. Within the occipito-temporal region the decrease concerned predominantly neural activity elicited by left stimuli, downregulating thus the representation of the contralateral visual field, which is characteristic of the higher-order visual areas in this region.

Exploring auditory neglect: Anatomo-clinical correlations of auditory extinction.

BACKGROUND: The key symptoms of auditory neglect include left extinction on tasks of dichotic and/or diotic listening and rightward shift in locating sounds. The anatomical correlates of the latter are relatively well understood, but no systematic studies have examined auditory extinction. Here, we performed a systematic study of anatomo-clinical correlates of extinction by using dichotic and/or diotic listening tasks. METHODS: In total, 20 patients with right hemispheric damage (RHD) and 19 with left hemispheric damage (LHD) performed dichotic and diotic listening tasks. Either task consists of the simultaneous presentation of word pairs; in the dichotic task, 1 word is presented to each ear, and in the diotic task, each word is lateralized by means of interaural time differences and presented to one side. RESULTS AND CONCLUSION: RHD was associated with exclusively contralesional extinction in dichotic or diotic listening, whereas in selected cases, LHD led to contra- or ipsilesional extinction. Bilateral symmetrical extinction occurred in RHD or LHD, with dichotic or diotic listening. The anatomical correlates of these extinction profiles offer an insight into the organisation of the auditory and attentional systems. First, left extinction in dichotic versus diotic listening involves different parts of the right hemisphere, which explains the double dissociation between these 2 neglect symptoms. Second, contralesional extinction in the dichotic task relies on homologous regions in either hemisphere. Third, ipsilesional extinction in dichotic listening after LHD was associated with lesions of the intrahemispheric white matter, interrupting callosal fibres outside their midsagittal or periventricular trajectory. Fourth, bilateral symmetrical extinction was associated with large parieto-fronto-temporal LHD or smaller parieto-temporal RHD, which suggests that divided attention, supported by the right hemisphere, and auditory streaming, supported by the left, likely play a critical role.

Supramodal effect of rightward prismatic adaptation on spatial representations within the ventral attentional system.

Rightward prismatic adaptation (R-PA) was shown to alleviate not only visuo-spatial but also auditory symptoms in neglect. The neural mechanisms underlying the effect of R-PA have been previously investigated in visual tasks, demonstrating a shift of hemispheric dominance for visuo-spatial attention from the right to the left hemisphere both in normal subjects and in patients. We have investigated whether the same neural mechanisms underlie the supramodal effect of R-PA on auditory attention. Normal subjects underwent a brief session of R-PA, which was preceded and followed by an fMRI evaluation during which subjects detected targets within the left, central and right space in the auditory or visual modality. R-PA-related changes in activation patterns were found bilaterally in the inferior parietal lobule. In either modality, the representation of the left, central and right space increased in the left IPL, whereas the representation of the right space decreased in the right IPL. Thus, a brief exposure to R-PA modulated the representation of the auditory and visual space within the ventral attentional system. This shift in hemispheric dominance for auditory spatial attention offers a parsimonious explanation for the previously reported effects of R-PA on auditory symptoms in neglect.

For Better or Worse: The Effect of Prismatic Adaptation on Auditory Neglect.

Patients with auditory neglect attend less to auditory stimuli on their left and/or make systematic directional errors when indicating sound positions. Rightward prismatic adaptation (R-PA) was repeatedly shown to alleviate symptoms of visuospatial neglect and once to restore partially spatial bias in dichotic listening. It is currently unknown whether R-PA affects only this ear-related symptom or also other aspects of auditory neglect. We have investigated the effect of R-PA on left ear extinction in dichotic listening, space-related inattention assessed by diotic listening, and directional errors in auditory localization in patients with auditory neglect. The most striking effect of R-PA was the alleviation of left ear extinction in dichotic listening, which occurred in half of the patients with initial deficit. In contrast to nonresponders, their lesions spared the right dorsal attentional system and posterior temporal cortex. The beneficial effect of R-PA on an ear-related performance contrasted with detrimental effects on diotic listening and auditory localization. The former can be parsimoniously explained by the SHD-VAS model (shift in hemispheric dominance within the ventral attentional system; Clarke and Crottaz-Herbette 2016), which is based on the R-PA-induced shift of the right-dominant ventral attentional system to the left hemisphere. The negative effects in space-related tasks may be due to the complex nature of auditory space encoding at a cortical level.

A Brief Exposure to Leftward Prismatic Adaptation Enhances the Representation of the Ipsilateral, Right Visual Field in the Right Inferior Parietal Lobule.

A brief exposure to rightward prismatic adaptation (PA) was shown to shift visual field representation within the inferior parietal lobule (IPL) from the right to the left hemisphere. This change in hemispheric dominance could be interpreted as (1) a general effect of discrepancy in visuomotor alignment caused by PA or (2) a direction-specific effect of rightward PA. To test these hypotheses, we compared the effects of rightward and leftward PA on visual representation in normal human subjects. Three groups of normal subjects underwent an fMRI evaluation using a simple visual detection task before and after brief PA exposure using leftward- or rightward-deviating prisms or no prisms (L-PA, R-PA, neutral groups). A two-way ANOVA group × session revealed a significant interaction suggesting that PA-induced modulation is direction specific. Post hoc analysis showed that L-PA enhanced the representation of the right visual field within the right IPL. Thus, a brief exposure to L-PA enhanced right hemispheric dominance within the ventral attentional system, which is the opposite effect of the previously described shift in hemispheric dominance following R-PA. The direction-specific effects suggest that the underlying neural mechanisms involve the fine-tuning of specific visuomotor networks. The enhancement of right hemispheric dominance following L-PA offers a parsimonious explanation for neglect-like symptoms described previously in normal subjects.