scholarly journals Neural Correlates of Auditory Hypersensitivity in Fragile X Syndrome

2021 ◽  
Vol 12 ◽  
Author(s):  
Khaleel A. Razak ◽  
Devin K. Binder ◽  
Iryna M. Ethell
Keyword(s):  
Fragile X Syndrome ◽  
Sensory Processing ◽  
Fragile X ◽  
Neural Correlates ◽  
Autism Spectrum ◽  
Gamma Band ◽  
Repetitive Behaviors ◽  
Neural Responses ◽  
Eeg Abnormalities ◽  
Eeg Recordings

The mechanisms underlying the common association between autism spectrum disorders (ASD) and sensory processing disorders (SPD) are unclear, and treatment options to reduce atypical sensory processing are limited. Fragile X Syndrome (FXS) is a leading genetic cause of intellectual disability and ASD behaviors. As in most children with ASD, atypical sensory processing is a common symptom in FXS, frequently manifesting as sensory hypersensitivity. Auditory hypersensitivity is a highly debilitating condition in FXS that may lead to language delays, social anxiety and ritualized repetitive behaviors. Animal models of FXS, including Fmr1 knock out (KO) mouse, also show auditory hypersensitivity, providing a translation relevant platform to study underlying pathophysiological mechanisms. The focus of this review is to summarize recent studies in the Fmr1 KO mouse that identified neural correlates of auditory hypersensitivity. We review results of electroencephalography (EEG) recordings in the Fmr1 KO mice and highlight EEG phenotypes that are remarkably similar to EEG findings in humans with FXS. The EEG phenotypes associated with the loss of FMRP include enhanced resting EEG gamma band power, reduced cross frequency coupling, reduced sound-evoked synchrony of neural responses at gamma band frequencies, increased event-related potential amplitudes, reduced habituation of neural responses and increased non-phase locked power. In addition, we highlight the postnatal period when the EEG phenotypes develop and show a strong association of the phenotypes with enhanced matrix-metalloproteinase-9 (MMP-9) activity, abnormal development of parvalbumin (PV)-expressing inhibitory interneurons and reduced formation of specialized extracellular matrix structures called perineuronal nets (PNNs). Finally, we discuss how dysfunctions of inhibitory PV interneurons may contribute to cortical hyperexcitability and EEG abnormalities observed in FXS. Taken together, the studies reviewed here indicate that EEG recordings can be utilized in both pre-clinical studies and clinical trials, while at the same time, used to identify cellular and circuit mechanisms of dysfunction in FXS. New therapeutic approaches that reduce MMP-9 activity and restore functions of PV interneurons may succeed in reducing FXS sensory symptoms. Future studies should examine long-lasting benefits of developmental vs. adult interventions on sensory phenotypes.

scholarly journals Delineating Repetitive Behavior Profiles across the Lifespan in Fragile X Syndrome

2020 ◽  
Vol 10 (4) ◽  
pp. 239
Author(s):  
Debra L. Reisinger ◽  
Rebecca C. Shaffer ◽  
Nicole Tartaglia ◽  
Elizabeth Berry-Kravis ◽  
Craig A. Erickson
Keyword(s):  
Fragile X Syndrome ◽  
Fragile X ◽  
Repetitive Behavior ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Motor Behaviors ◽  
Sensory Motor ◽  
Adolescents And Adults ◽  
Males And Females ◽  
The Impact

Restricted repetitive behaviors (RRBs) are a core area of impairment in autism spectrum disorder (ASD), but also affect several other neurodevelopmental disorders including fragile X syndrome (FXS). Current literature has begun to describe the RRB profile in FXS up through adolescence; however, little is known about the subtypes of RRBs in adolescents and adults. Further, literature on the RRB profile of females with FXS is limited. The present study examines the RRB profile across subtypes and specific items in both males and females with FXS while assessing for differences based on age, ASD diagnosis and the impact of IQ. Participants included 154 individuals with FXS (ages 2 to 50 years old). Results revealed a peak in RRB severity in FXS between 7–12 years for the majority of RRB subscales with the exception of Sensory-Motor behaviors peaking between 2 and 12 years before declining. Distinct RRB profiles in males and females with FXS emerged in addition to significant overlap among the item and subscale levels of RRBs across gender. Further, an added diagnosis of ASD significantly increased rates of RRBs across all subscale levels, but not necessarily across all items. Lastly, IQ did not solely account for the presence of RRBs in FXS, with Sensory-Motor behaviors being driven by comorbid ASD in males with FXS, and Restricted Interest behaviors being driven by comorbid ASD regardless of gender. These findings build on the current understanding of RRBs in FXS based on gender and comorbid ASD and lay important groundwork for the development of targeted behavioral and pharmacological treatments.

scholarly journals Deletion of Fmr1 from Forebrain Excitatory Neurons Triggers Abnormal Cellular, EEG, and Behavioral Phenotypes in the Auditory Cortex of a Mouse Model of Fragile X Syndrome

2019 ◽  
Vol 30 (3) ◽  
pp. 969-988 ◽  
Author(s):  
Jonathan W Lovelace ◽  
Maham Rais ◽  
Arnold R Palacios ◽  
Xinghao S Shuai ◽  
Steven Bishay ◽  
...  
Keyword(s):  
Mouse Model ◽  
Auditory Cortex ◽  
Fragile X Syndrome ◽  
Sensory Processing ◽  
Fragile X ◽  
Autism Spectrum ◽  
Behavioral Phenotypes ◽  
Excitatory Neurons ◽  
Gamma Power ◽  
Processing Deficits

Abstract Fragile X syndrome (FXS) is a leading genetic cause of autism with symptoms that include sensory processing deficits. In both humans with FXS and a mouse model [Fmr1 knockout (KO) mouse], electroencephalographic (EEG) recordings show enhanced resting state gamma power and reduced sound-evoked gamma synchrony. We previously showed that elevated levels of matrix metalloproteinase-9 (MMP-9) may contribute to these phenotypes by affecting perineuronal nets (PNNs) around parvalbumin (PV) interneurons in the auditory cortex of Fmr1 KO mice. However, how different cell types within local cortical circuits contribute to these deficits is not known. Here, we examined whether Fmr1 deletion in forebrain excitatory neurons affects neural oscillations, MMP-9 activity, and PV/PNN expression in the auditory cortex. We found that cortical MMP-9 gelatinase activity, mTOR/Akt phosphorylation, and resting EEG gamma power were enhanced in CreNex1/Fmr1Flox/y conditional KO (cKO) mice, whereas the density of PV/PNN cells was reduced. The CreNex1/Fmr1Flox/y cKO mice also show increased locomotor activity, but not the anxiety-like behaviors. These results indicate that fragile X mental retardation protein changes in excitatory neurons in the cortex are sufficient to elicit cellular, electrophysiological, and behavioral phenotypes in Fmr1 KO mice. More broadly, these results indicate that local cortical circuit abnormalities contribute to sensory processing deficits in autism spectrum disorders.

scholarly journals Local Protein Translation and RNA Processing of Synaptic Proteins in Autism Spectrum Disorder

2021 ◽  
Vol 22 (6) ◽  
pp. 2811
Author(s):  
Yuyoung Joo ◽  
David R. Benavides
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X ◽  
Single Gene ◽  
Protein Translation ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Spectrum Disorder ◽  
Synaptic Proteins ◽  
Local Translation ◽  
Translation Control

Autism spectrum disorder (ASD) is a heritable neurodevelopmental condition associated with impairments in social interaction, communication and repetitive behaviors. While the underlying disease mechanisms remain to be fully elucidated, dysfunction of neuronal plasticity and local translation control have emerged as key points of interest. Translation of mRNAs for critical synaptic proteins are negatively regulated by Fragile X mental retardation protein (FMRP), which is lost in the most common single-gene disorder associated with ASD. Numerous studies have shown that mRNA transport, RNA metabolism, and translation of synaptic proteins are important for neuronal health, synaptic plasticity, and learning and memory. Accordingly, dysfunction of these mechanisms may contribute to the abnormal brain function observed in individuals with autism spectrum disorder (ASD). In this review, we summarize recent studies about local translation and mRNA processing of synaptic proteins and discuss how perturbations of these processes may be related to the pathophysiology of ASD.

scholarly journals The PDE10A Inhibitor TAK-063 Reverses Sound-Evoked EEG Abnormalities in a Mouse Model of Fragile X Syndrome

2021 ◽  
Author(s):  
Carrie R. Jonak ◽  
Manbir S. Sandhu ◽  
Samantha A. Assad ◽  
Jacqueline A. Barbosa ◽  
Mahindra Makhija ◽  
...  
Keyword(s):  
Mouse Model ◽  
Fragile X Syndrome ◽  
Fragile X ◽  
Eeg Abnormalities

scholarly journals Impaired perceptual learning in Fragile X syndrome is mediated by parvalbumin neuron dysfunction in V1 and is reversible

2017 ◽  
Author(s):  
Anubhuti Goel ◽  
Daniel A. Cantu ◽  
Janna Guilfoyle ◽  
Gunvant R. Chaudhari ◽  
Aditi Newadkar ◽  
...  
Keyword(s):  
Perceptual Learning ◽  
Fragile X Syndrome ◽  
Visual Discrimination ◽  
Fragile X ◽  
Human Subjects ◽  
Autistic Traits ◽  
Autism Spectrum ◽  
Orientation Tuning ◽  
Mechanistic Basis

Atypical sensory processing is a core characteristic in autism spectrum disorders1 that negatively impacts virtually all activities of daily living. Sensory symptoms are predictive of the subsequent appearance of impaired social behavior and other autistic traits2, 3. Thus, a better understanding of the changes in neural circuitry that disrupt perceptual learning in autism could shed light into the mechanistic basis and potential therapeutic avenues for a range of autistic symptoms2. Likewise, the lack of directly comparable behavioral paradigms in both humans and animal models currently limits the translational potential of discoveries in the latter. We adopted a symptom-to-circuit approach to uncover the circuit-level alterations in the Fmr1-/- mouse model of Fragile X syndrome (FXS) that underlie atypical visual discrimination in this disorder4, 5. Using a go/no-go task and in vivo 2-photon calcium imaging in primary visual cortex (V1), we find that impaired discrimination in Fmr1-/- mice correlates with marked deficits in orientation tuning of principal neurons, and a decrease in the activity of parvalbumin (PV) interneurons in V1. Restoring visually evoked activity in PV cells in Fmr1-/- mice with a chemogenetic (DREADD) strategy was sufficient to rescue their behavioral performance. Finally, we found that human subjects with FXS exhibit strikingly similar impairments in visual discrimination as Fmr1-/- mice. We conclude that manipulating orientation tuning in autism could improve visually guided behaviors that are critical for playing sports, driving or judging emotions.

scholarly journals SENP1 in the retrosplenial agranular cortex regulates core autistic-like symptoms in mice

2021 ◽  
Author(s):  
Kan Yang ◽  
Yuhan Shi ◽  
Xiujuan Du ◽  
Yuefang Zhang ◽  
Shifang Shan ◽  
...  
Keyword(s):  
Social Interaction ◽  
De Novo ◽  
Fragile X ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Genetic Components ◽  
Truncating Mutation ◽  
Synaptic Functions ◽  
Core Symptoms

AbstractAutism spectrum disorder (ASD) is a highly heritable complex neurodevelopmental disorder. While the core symptoms of ASD are defects of social interaction and repetitive behaviors, over 50% of ASD patients have comorbidity of intellectual disabilities (ID) or developmental delay (DD), raising the question whether there are genetic components and neural circuits specific for core symptoms of ASD. Here, by focusing on ASD patients who do not show compound ID or DD, we identified a de novo heterozygous gene-truncating mutation of the Sentrin-specific peptidase1 (SENP1) gene, coding the small ubiquitin-like modifiers (SUMO) deconjugating enzyme, as a potentially new candidate gene for ASD. We found that Senp1 haploinsufficient mice exhibited core symptoms of autism such as deficits in social interaction and repetitive behaviors, but normal learning and memory ability. Moreover, we found that the inhibitory and excitatory synaptic functions were severely affected in the retrosplenial agranular (RSA) cortex of Senp1 haploinsufficient mice. Lack of Senp1 led to over SUMOylation and degradation of fragile X mental retardation protein (FMRP) proteins, which is coded by the FMR1 gene, also implicated in syndromic autism. Importantly, re-introducing SENP1 or FMRP specifically in RSA fully rescued the defects of synaptic functions and core autistic-like symptoms of Senp1 haploinsufficient mice. Taken together, these results elucidate that disruption of the SENP1-FMRP regulatory axis in the RSA may cause core autistic symptoms, which further provide a candidate brain region for therapeutic intervene of ASD by neural modulation approaches.

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