Pubmed du 26/07/21
1. Augustine F, Nebel MB, Mostofsky SH, Mahone EM, Singer HS. Aberrant prefrontal cortical-striatal functional connectivity in children with primary complex motor stereotypies. Cortex; a journal devoted to the study of the nervous system and behavior. 2021; 142: 272-82.
Motor stereotypies are rhythmic, repetitive, prolonged, predictable, and purposeless movements that stop with distraction. Although once believed to occur only in children with neurodevelopmental disorders such as autism, the presence and persistence of complex motor stereotypies (CMS) in otherwise typically developing children (primary CMS) has been well-established. Little, however, is known about the underlying pathophysiology of these unwanted actions. The aim of the present study was to use resting-state functional magnetic resonance imaging to evaluate functional connectivity within frontal-striatal circuits that are essential for goal-directed and habitual activity in children with primary complex motor stereotypies. Functional connectivity between prefrontal cortical and striatal regions, considered essential for developing goal-directed behaviors, was reduced in children with primary CMS compared to their typically developing peers. In contrast, functional connectivity between motor/premotor and striatal regions, critical for developing and regulating habitual behaviors, did not differ between groups. This documented alteration of prefrontal to striatal connectivity could provide the underlying mechanism for the presence and persistence of complex motor stereotypies in otherwise developmentally normal children.
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2. Gonzaga CN, Valente HB, Ricci-Vitor AL, Laurino MJL, Santos LA, Stoco-Oliveira MC, Rodrigues MV, Ribeiro AA, Bofi TC, de Carvalho AC, Vanderlei LCM. Autonomic responses to facial expression tasks in children with autism spectrum disorders: Cross-section study. Research in developmental disabilities. 2021; 116: 104034.
BACKGROUND: The autonomic nervous system has an influence on emotions and behavior modulation, however, the relationship between autonomic modulation impairment and the autism spectrum disorder (ASD) is yet to be fully described. AIMS: To evaluate the autonomic responses of children with and without ASD through the non-linear, and linear heart rate variability (HRV) measures, and assess the correlation between these responses, the severity and behavioral symptoms of autism. METHODS AND PROCEDURES: 27 children diagnosed with ASD (EG = experimental group) and 28 matching controls (CG = control group) were evaluated. The HRV was evaluated in 15 min sections at the following moments: I) Resting condition; II) During facial expression tasks; and III) Recovery. The severity and behavioral symptoms of autism were evaluated by the Childhood Autism Rating Scale (CARS) and Autistic Behaviors Checklist (ABC) scales. OUTCOMES AND RESULTS: The facial expression tasks influenced the activity of the autonomic nervous system in both groups, however the EG experienced more autonomic changes. These changes were mostly evidenced by the non-linear indices. Also, the CARS and ABC scales showed significant correlations with HRV indices. CONCLUSIONS AND IMPLICATIONS: Children with ASD presented an autonomic modulation impairment, mostly identified by the non-linear indices of HRV. Also, this autonomic impairment is associated with the severity and behavioral symptoms of autism.
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3. Liu DC, Lee KY, Lizarazo S, Cook JK, Tsai NP. ER stress-induced modulation of neural activity and seizure susceptibility is impaired in a fragile X syndrome mouse model. Neurobiology of disease. 2021; 158: 105450.
Imbalanced neuronal excitability homeostasis is commonly observed in patients with fragile X syndrome (FXS) and the animal model of FXS, the Fmr1 KO. While alterations of neuronal intrinsic excitability and synaptic activity at the steady state in FXS have been suggested to contribute to such a deficit and ultimately the increased susceptibility to seizures in FXS, it remains largely unclear whether and how the homeostatic response of neuronal excitability following extrinsic challenges is disrupted in FXS. Our previous work has shown that the acute response following induction of endoplasmic reticulum (ER) stress can reduce neural activity and seizure susceptibility. Because many signaling pathways associated with ER stress response are mediated by Fmr1, we asked whether acute ER stress-induced reduction of neural activity and seizure susceptibility are altered in FXS. Our results first revealed that acute ER stress can trigger a protein synthesis-dependent prevention of neural network synchronization in vitro and a reduction of susceptibility to kainic acid-induced seizures in vivo in wild-type but not in Fmr1 KO mice. Mechanistically, we found that acute ER stress-induced activation of murine double minute-2 (Mdm2), ubiquitination of p53, and the subsequent transient protein synthesis are all impaired in Fmr1 KO neurons. Employing a p53 inhibitor, Pifithrin-α, to mimic p53 inactivation, we were able to blunt the increase in neural network synchronization and reduce the seizure susceptibility in Fmr1 KO mice following ER stress induction. In summary, our data revealed a novel cellular defect in Fmr1 KO mice and suggest that an impaired response to common extrinsic challenges may contribute to imbalanced neuronal excitability homeostasis in FXS.
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4. Pehere NK, Dutton GN. Perceptual visual dysfunction in children – An Indian perspective. Indian journal of ophthalmology. 2021; 69(8): 2004-11.
Perceptual visual dysfunction (PVD) comprises a group of vision disorders resulting from dysfunction of the posterior parietal and/or temporal lobes. Often, affected children have normal/near normal visual acuities and/or visual fields, but have difficulties in activities of daily living involving the use of vision. PVDs are known to be common among children with risk factors such as a history of prematurity and/or neurodevelopmental disorders. The inferior temporal lobes and ventral stream transform visual signals into perception, while the posterior parietal lobes and dorsal stream transform visual signals to non-consciously map the scene to guide action and facilitate attention. Dysfunction of these can lead to specific visual impairments that need to be identified during history taking, triggering ascertainment of further details by a structured inventory approach. Clinical tests to elicit dorsal and ventral stream visual dysfunctions have good specificity but low sensitivity. Neuropsychologists are rarely available in the developing world to perform detailed assessments, but there are a few tests that can be used by eye care professionals with some training. Optical coherence tomography (OCT) showing thinning of the ganglion cell layer and retinal nerve fiber layer is being explored as a potential tool for rapid assessment in the clinic. The behavioral outcomes of PVD can mimic psychological conditions including autism spectrum disorder, attention deficit hyperactivity disorder, specific learning disability, and intellectual impairment, and one needs to be aware of overlap among these differential diagnoses. A practical functional approach providing working solutions for each child’s set of difficulties in day-to-day activities is needed.
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5. Shaw SCK, McCowan S, Doherty M, Grosjean B, Kinnear M. The neurodiversity concept viewed through an autistic lens. The lancet Psychiatry. 2021; 8(8): 654-5.
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6. Siper PM, Rowe MA, Guillory SB, Rouhandeh AA, George-Jones JL, Tavassoli T, Lurie S, Zweifach J, Weissman J, Foss-Feig J, Halpern D, Trelles MP, Mulhern MS, Brittenham C, Gordon J, Zemon V, Buxbaum JD, Kolevzon A. Visual Evoked Potential Abnormalities in Phelan-McDermid Syndrome. Journal of the American Academy of Child and Adolescent Psychiatry. 2022; 61(4): 565-74.e1.
OBJECTIVE: The current study used visual evoked potentials (VEPs) to examine excitatory and inhibitory postsynaptic activity in children with Phelan-McDermid syndrome (PMS) and the association with genetic factors. PMS is caused by haploinsufficiency of SHANK3 on chromosome 22 and represents a common single-gene cause of autism spectrum disorder (ASD) and intellectual disability. METHOD: Transient VEPs were obtained from 175 children, including 31 with PMS, 79 with idiopathic ASD, 45 typically developing controls, and 20 unaffected siblings of children with PMS. Stimuli included standard and short-duration contrast-reversing checkerboard conditions, and the reliability between these 2 conditions was assessed. Test-retest reliability and correlations with deletion size were explored in the group with PMS. RESULTS: Children with PMS and, to a lesser extent, those with idiopathic ASD displayed significantly smaller amplitudes and decreased beta and gamma band activity relative to TD controls and PMS siblings. Across groups, high intraclass correlation coefficients were obtained between standard and short-duration conditions. In children with PMS, test-retest reliability was strong. Deletion size was significantly correlated with P(60)-N(75) amplitude for both conditions. CONCLUSION: Children with PMS displayed distinct transient VEP waveform abnormalities in both time and frequency domains that might reflect underlying glutamatergic deficits that were associated with deletion size. A similar response pattern was observed in a subset of children with idiopathic ASD. VEPs offer a noninvasive measure of excitatory and inhibitory neurotransmission that holds promise for stratification and surrogate endpoints in ongoing clinical trials in PMS and ASD.
