What role does the presence of facial speech play for children with dyslexia? Current literature proposes two distinctive claims. One claim states that children with dyslexia make less use of visual ...information from the mouth during speech processing due to a deficit in recruitment of audiovisual areas. An opposing claim suggests that children with dyslexia are in fact
reliant
on such information in order to compensate for auditory/phonological impairments. The current paper aims at directly testing these contrasting hypotheses (here referred to as “mouth insensitivity” versus “mouth reliance”) in school-age children with and without dyslexia, matched on age and listening comprehension. Using eye tracking, in Study 1, we examined how children look at the mouth across conditions varying in speech processing demands. The results did not indicate significant group differences in looking at the mouth. However, correlation analyses suggest potentially important distinctions within the dyslexia group: those children with dyslexia who are better readers attended more to the mouth while presented with a person’s face in a phonologically demanding condition. In Study 2, we examined whether the presence of facial speech cues is functionally beneficial when a child is encoding written words. The results indicated lack of overall group differences on the task, although those with less severe reading problems in the dyslexia group were more accurate when reading words that were presented with articulatory facial speech cues. Collectively, our results suggest that children with dyslexia differ in their “mouth reliance” versus “mouth insensitivity,” a profile that seems to be related to the severity of their reading problems.
AbstractBackgroundDeletions and duplications of the 16p11.2 BP4-BP5 locus are prevalent copy number variations (CNVs), highly associated with autism spectrum disorder and schizophrenia. Beyond ...language and global cognition, neuropsychological assessments of these two CNVs have not yet been reported. MethodsThis study investigates the relationship between the number of genomic copies at the 16p11.2 locus and cognitive domains assessed in 62 deletion carriers, 44 duplication carriers, and 71 intrafamilial control subjects. ResultsIQ is decreased in deletion and duplication carriers, but we demonstrate contrasting cognitive profiles in these reciprocal CNVs. Deletion carriers present with severe impairments of phonology and of inhibition skills beyond what is expected for their IQ level. In contrast, for verbal memory and phonology, the data may suggest that duplication carriers outperform intrafamilial control subjects with the same IQ level. This finding is reminiscent of special isolated skills as well as contrasting language performance observed in autism spectrum disorder. Some domains, such as visuospatial and working memory, are unaffected by the 16p11.2 locus beyond the effect of decreased IQ. Neuroimaging analyses reveal that measures of inhibition covary with neuroanatomic structures previously identified as sensitive to 16p11.2 CNVs. ConclusionsThe simultaneous study of reciprocal CNVs suggests that the 16p11.2 genomic locus modulates specific cognitive skills according to the number of genomic copies. Further research is warranted to replicate these findings and elucidate the molecular mechanisms modulating these cognitive performances.
Research demonstrating responsiveness of the neural reward network to face trustworthiness has not assessed whether the effects are mediated by dopaminergic function. We filled this gap in the ...literature by investigating whether dietary dopamine depletion would blunt the sensitivity of neural activation to faces varying in trustworthiness across reward regions as well as the sensitivity of behavioral responses to those faces. As prolactin release is negatively regulated by dopamine, peripheral prolactin levels confirmed the efficacy of our manipulation. The dopamine depletion manipulation moderated neural activation to face trustworthiness in the amygdala, medial orbital frontal cortex, and ventral medial prefrontal cortex. Control participants (n=20) showed nonlinear and linear neural activation to face trustworthiness in the amygdala and ventral medial prefrontal cortex, and nonlinear activation in the medial orbital frontal cortex, while depleted participants (n=20) showed only a linear effect in the amygdala. Controls also showed stronger amygdala activation to high trustworthy faces than depleted participants. In contrast to effects on neural activation, dopamine depletion did not blunt the sensitivity of behavioral ratings. While this is the first study to demonstrate that dopamine depletion blunts the sensitivity of the neural reward system to social stimuli, namely faces varying in trustworthiness, future research should investigate behavioral measures that may be more responsive to dopaminergic effects than face ratings. Such research would shed further light on the possibility that individual differences in dopaminergic function that were simulated by our manipulation influence social interactions with people who vary in facial trustworthiness.
Judgment of trustworthiness is an important social ability. Many studies show neural activation differences to variations in face trustworthiness in brain reward regions. A previously published ...analysis of the present fMRI data showed that older adults’ (OA) reward region activation responded significantly to trustworthiness in a set of older and younger faces, whereas younger adults’ (YA) activation did not—a finding inconsistent with studies that used only younger faces. We hypothesized that voxel pattern analyses would be more sensitive to YA neural responses to trustworthiness in our set of faces, replicating YA neural discrimination in prior literature. Based on evidence for OA neural dedifferentiation, we also hypothesized that voxel pattern analyses would more accurately classify YA than OA neural responses to face trustworthiness. We reanalyzed the data with two pattern classification models and evaluated the models’ performance with permutation testing. Voxel patterns discriminated face trustworthiness levels in both YA and OA reward regions, while allowing better classification of face trustworthiness for YA than OA, the reverse of previous results for neural activation levels. The moderation of age differences by analytic method shines a light on the possibility that voxel patterns uniquely index neural representations of the stimulus information content, consistent with findings of impaired representation with age.
The cerebellum is a complex structure that can be affected by several congenital and acquired diseases leading to alteration of its function and neuronal circuits. Identifying the structural bases of ...cerebellar neuronal networks in humans in vivo may provide biomarkers for diagnosis and management of cerebellar diseases.
To define the anatomy of intrinsic and extrinsic cerebellar circuits using high-angular resolution diffusion spectrum imaging (DSI).
We acquired high-resolution structural MRI and DSI of the cerebellum in four healthy female subjects at 3T. DSI tractography based on a streamline algorithm was performed to identify the circuits connecting the cerebellar cortex with the deep cerebellar nuclei, selected brainstem nuclei, and the thalamus.
Using in-vivo DSI in humans we were able to demonstrate the structure of the following cerebellar neuronal circuits: (1) connections of the inferior olivary nucleus with the cerebellar cortex, and with the deep cerebellar nuclei (2) connections between the cerebellar cortex and the deep cerebellar nuclei, (3) connections of the deep cerebellar nuclei conveyed in the superior (SCP), middle (MCP) and inferior (ICP) cerebellar peduncles, (4) complex intersections of fibers in the SCP, MCP and ICP, and (5) connections between the deep cerebellar nuclei and the red nucleus and the thalamus.
For the first time, we show that DSI tractography in humans in vivo is capable of revealing the structural bases of complex cerebellar networks. DSI thus appears to be a promising imaging method for characterizing anatomical disruptions that occur in cerebellar diseases, and for monitoring response to therapeutic interventions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We examined older adult (OA) and younger adult (YA) neural sensitivity to face trustworthiness in reward circuit regions, previously found to respond to trustworthiness in YA. Interactions of face ...trustworthiness with age revealed effects exclusive to OA in the amygdala and caudate, and an effect that was not moderated by age in the dorsal anterior cingulate cortex (dACC). OA, but not YA, showed a nonlinear amygdala response to face trustworthiness, with significantly stronger activation response to high than to medium trustworthy faces, and no difference between low and medium or high. This may explain why an earlier study investigating OA amygdala activation to trustworthiness failed to find a significant effect, since only the linear low versus high trustworthiness difference was assessed. OA, but not YA, also showed significantly stronger activation to high than to low trustworthy faces in the right caudate, indicating a positive linear effect, consistent with previous YA research, as well as significantly stronger activation to high than to medium but not low trustworthy faces in the left caudate, indicating a nonlinear effect. Activation in dACC across both age groups showed a positive linear effect consistent with previous YA research. Finally, OA rated the faces as more trustworthy than did YA across all levels of trustworthiness. Future research should examine whether the null effects for YA were due to our inclusion of older faces. Research also should investigate possible implications of our findings for more ecologically valid OA responses to people who vary in facial trustworthiness.
Background Despite the prevalence of Autism Spectrum Disorder (ASD) globally, there's a knowledge gap pertaining to autism in Arabic nations. Recognizing the need for validated biomarkers for ASD, ...our study leverages eye-tracking technology to understand gaze patterns associated with ASD, focusing on joint attention (JA) and atypical gaze patterns during face perception. While previous studies typically evaluate a single eye-tracking metric, our research combines multiple metrics to capture the multidimensional nature of autism, focusing on dwell times on eyes, left facial side, and joint attention. Methods We recorded data from 104 participants (41 neurotypical, mean age: 8.21 + or - 4.12 years; 63 with ASD, mean age 8 + or - 3.89 years). The data collection consisted of a series of visual stimuli of cartoon faces of humans and animals, presented to the participants in a controlled environment. During each stimulus, the eye movements of the participants were recorded and analyzed, extracting metrics such as time to first fixation and dwell time. We then used these data to train a number of machine learning classification algorithms, to determine if these biomarkers can be used to diagnose ASD. Results We found no significant difference in eye-dwell time between autistic and control groups on human or animal eyes. However, autistic individuals focused less on the left side of both human and animal faces, indicating reduced left visual field (LVF) bias. They also showed slower response times and shorter dwell times on congruent objects during joint attention (JA) tasks, indicating diminished reflexive joint attention. No significant difference was found in time spent on incongruent objects during JA tasks. These results suggest potential eye-tracking biomarkers for autism. The best-performing algorithm was the random forest one, which achieved accuracy = 0.76 + or - 0.08, precision = 0.78 + or - 0.13, recall = 0.84 + or - 0.07, and F1 = 0.80 + or - 0.09. Conclusions Although the autism group displayed notable differences in reflexive joint attention and left visual field bias, the dwell time on eyes was not significantly different. Nevertheless, the machine algorithm model trained on these data proved effective at diagnosing ASD, showing the potential of these biomarkers. Our study shows promising results and opens up potential for further exploration in this under-researched geographical context. Keywords: Autism spectrum disorder, Eye-tracking, Face Processing, Prediction, Screening
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