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 Restoration of FMRP expression in adult V1 neurons rescues visual deficits in a mouse model of fragile X syndrome

2021 ◽  
Author(s):  
Chaojuan Yang ◽  
Yonglu Tian ◽  
Feng Su ◽  
Yangzhen Wang ◽  
Mengna Liu ◽  
...  
Keyword(s):  
Mouse Model ◽  
Fragile X Syndrome ◽  
Visual Processing ◽  
Fragile X ◽  
Autism Spectrum ◽  
Inhibitory Neurons ◽  
Local Network ◽  
V1 Neurons ◽  
Processing Deficits

AbstractMany people affected by fragile X syndrome (FXS) and autism spectrum disorders have sensory processing deficits, such as hypersensitivity to auditory, tactile, and visual stimuli. Like FXS in humans, loss of Fmr1 in rodents also cause sensory, behavioral, and cognitive deficits. However, the neural mechanisms underlying sensory impairment, especially vision impairment, remain unclear. It remains elusive whether the visual processing deficits originate from corrupted inputs, impaired perception in the primary sensory cortex, or altered integration in the higher cortex, and there is no effective treatment. In this study, we used a genetic knockout mouse model (Fmr1KO), in vivo imaging, and behavioral measurements to show that the loss of Fmr1 impaired signal processing in the primary visual cortex (V1). Specifically, Fmr1KO mice showed enhanced responses to low-intensity stimuli but normal responses to high-intensity stimuli. This abnormality was accompanied by enhancements in local network connectivity in V1 microcircuits and increased dendritic complexity of V1 neurons. These effects were ameliorated by the acute application of GABAA receptor activators, which enhanced the activity of inhibitory neurons, or by reintroducing Fmr1 gene expression in knockout V1 neurons in both juvenile and young-adult mice. Overall, V1 plays an important role in the visual abnormalities of Fmr1KO mice and it could be possible to rescue the sensory disturbances in developed FXS and autism patients.

scholarly journals Impaired hippocampal representation of place in the Fmr1-knockout mouse model of Fragile X syndrome

2017 ◽  
Author(s):  
Tara Arbab ◽  
Cyriel MA Pennartz ◽  
Francesco P Battaglia
Keyword(s):  
Mouse Model ◽  
Fragile X Syndrome ◽  
Hippocampal Neurons ◽  
Spatial Information ◽  
Fragile X ◽  
Memory Function ◽  
Autism Spectrum ◽  
Spatial Representations ◽  
Potential Biomarker

AbstractFragile X syndrome (FXS) is an X-chromosome linked intellectual disability and the most common genetic cause of autism spectrum disorder (ASD). Building upon demonstrated deficits in neuronal plasticity and spatial memory in FXS, we investigated how spatial information processing is affected in vivo in an FXS mouse model (Fmr1-KO). Healthy hippocampal neurons (so-called place cells) exhibit place-related activity during spatial exploration, and the stability of these spatial representations can be taken as an index of memory function. We find impaired stability and reduced specificity of Fmr1-KO spatial representations. This is a potential biomarker for the cognitive dysfunction observed in FXS, informative on the ability to integrate sensory information into an abstract representation and successfully retain this conceptual memory. Our results provide key insight into the biological mechanisms underlying cognitive disabilities in FXS and ASD, paving the way for a targeted approach to remedy these.

scholarly journals Autism in Fragile X Syndrome; A Functional MRI Study of Facial Emotion-Processing

Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1052
Author(s):  
Andrew G. McKechanie ◽  
Sonya Campbell ◽  
Sarah E. A. Eley ◽  
Andrew C. Stanfield
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X Syndrome ◽  
Fragile X ◽  
Emotion Processing ◽  
Autistic Traits ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Facial Emotion ◽  
Facial Emotion Processing ◽  
The Impact

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism spectrum disorder, and among those with fragile X syndrome, approximately 1/3rd meet a threshold for an autism spectrum disorder (ASD) diagnosis. Previous functional imaging studies of fragile X syndrome have typically focused on those with fragile X syndrome compared to either neurotypical or autism spectrum disorder control groups. Further, the majority of previous studies have tended to focus on those who are more intellectually able than is typical for fragile X syndrome. In this study, we examine the impact of autistic traits in individuals with fragile X syndrome on a paradigm looking at facial emotion processing. The study included 17 individuals with fragile X syndrome, of whom 10 met criteria for autism as measured by the Autism Diagnostic Observation Schedule (ADOS). Prior to the scan, participants rehearsed on a mock scanner to help acclimatize to the scanner environment and thus allow more severely affected individuals to participate. The task examined the blood-oxygen-level-dependent (BOLD) response to fearful and neutral faces taken from the Ekman faces series. Individuals in the autism group had a region of significantly reduced activity centered on the left superior temporal gyrus, compared to those with FXS alone, in response to the fearful faces. We suggest that autism in individuals with fragile X syndrome is associated with similar changes in the neurobiology of facial emotion processing as seen in idiopathic autism.

scholarly journals Abnormal intrinsic dynamics of dendritic spines in a fragile X syndrome mouse model in vivo

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Akira Nagaoka ◽  
Hiroaki Takehara ◽  
Akiko Hayashi-Takagi ◽  
Jun Noguchi ◽  
Kazuhiko Ishii ◽  
...  
Keyword(s):  
Mouse Model ◽  
Fragile X Syndrome ◽  
Dendritic Spines ◽  
Fragile X

Altered Behaviour Associated With Autism in a Mouse Model of Fragile X Syndrome Treated With Bacteroides Fragilis BF839

2020 ◽  
Author(s):  
Chu-Hui Lin ◽  
Ting Zeng ◽  
Jian-Hong Lin ◽  
Feng Xiao ◽  
Bing-Mei Li ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Escape Latency ◽  
Fragile X ◽  
Bacteroides Fragilis ◽  
Autism Spectrum ◽  
Cognitive Capacity ◽  
Surrounding Environment ◽  
Maze Test ◽  
Plus Maze ◽  
The Impact

Abstract Background: Fragile X syndrome (FXS), tightly related to the morbidity of Autism spectrum disorder (ASD), is a common hereditary syndrome often associated with retardation of intelligence. Some key symptoms of ASD such as anxiety, cognitive impairment and social anxiety disorder are also the predominant features in FXS. Children with ASD are often performed with gastrointestinal symptoms. According to the existing research, with the treatment with Bacteroides Fragilis BF839, mice with ASD will have better performance in communication and social behaviours with less anxiety and perceptual disorder. In this article, we have observed the impact of Bacteroides Fragilis BF839, a well-established Chinese bacteria strain with the human intestine origin, on mice with FXS and their behavioural disorders accordingly. Result: Based on the Open Field test, compared to the Fmr1KO group, mice treated with BF839 showed prolonged staying time in the center of the container. This finding suggests that BF839 can improve Fmr1KO mice's self-exploration behaviour and dented their anxiety. The Elevated Plus Maze test indicated BF839 treated mice presented more activities in entering open arms, prolonged time of staying and significantly less distance travelled at the plus-maze, along with less entering behaviours in the closed arms with less time of staying and more distance travelled. This result proved that with the treatment of BF839, Fmr1KO mice have improved ability in recognizing the surrounding environment and greater senses at detecting danger. Three-box Social Interaction test confirmed that BF839 strengthens the social novelty preference of the Fmr1KO mice, proven by their increasing duration and frequency in social interacting with the stranger mouse. The final experiment named the Pool Maze test presented the result that on the fourth day, BF839 treated mice have shown significantly shortened escape latency. Meanwhile, on Day 5, BF839 treated group performed increasing frequency in passing through the platform, which, along with the shortened escape latency, demonstrated BF839 has the function of improving Fmr1KO mice's cognitive capacity and their ability to extract information from the surrounding environment.Conclusion: Based on the outcome of each test performed, Bacteroides Fragilis BF839 can successfully improve Autism related abnormal behaviours in mice with FXS. Bacteroides Fragilis BF839 can be a potential intervention strategy in treating FXS and ASD safely and effectively.

scholarly journals Cascade Testing for Fragile X Syndrome in a Rural Setting in Cameroon (Sub-Saharan Africa)

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 136
Author(s):  
Karen Kengne Kamga ◽  
Séraphin Nguefack ◽  
Khuthala Minka ◽  
Edmond Wonkam Tingang ◽  
Alina Esterhuizen ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Fragile X ◽  
Autism Spectrum ◽  
Sub Saharan Africa ◽  
Rural Setting ◽  
Premature Menopause ◽  
Molecular Testing ◽  
Full Mutation ◽  
Cgg Repeat ◽  
Cgg Repeats

Fragile X Syndrome (FXS), an X-linked dominant monogenic condition, is the main genetic cause of intellectual disability (ID) and autism spectrum disorder (ASD). FXS is associated with an expansion of CGG repeat sequence in the Fragile X Mental Retardation gene 1 (FMR1) on chromosome X. Following a neuropediatric assessment of two male siblings who presented with signs of FXS that was confirmed with molecular testing, we provided cascade counselling and testing to the extended family. A total of 46 individuals were tested for FXS; among them, 58.70% (n = 27) were females. The mean age was 9.4 (±5) years for children and 45.9 (±15.9) years for adults. Pedigree analysis suggested that the founder of these families was likely a normal transmitting male. Four out of 19 males with clinical ID were confirmed to have a full mutation for FXS, while 14/27 females had a pathologic CGG expansion (>56 CGG repeats) on one of their X chromosomes. Two women with premature menopause were confirmed of being carriers of premutation (91 and 101 CGG repeats). We also identified maternal alleles (91 and 126 CGG repeats) which expanded to a full mutation in their offspring (>200 CGG repeats). This study is a rare report on FXS from Africa and illustrates the case scenario of implementing genetic medicine for a neurogenetic condition in a rural setting.

scholarly journals Towards Mechanism-Based Treatments for Fragile X Syndrome

2019 ◽  
Vol 9 (8) ◽  
pp. 202
Author(s):  
Daman Kumari ◽  
Inbal Gazy
Keyword(s):  
Autism Spectrum Disorder ◽  
Intellectual Disability ◽  
Fragile X Syndrome ◽  
Fragile X ◽  
Autism Spectrum ◽  
Spectrum Disorder

Fragile X syndrome (FXS) is the most common heritable form of intellectual disability, as well as the most common known monogenic cause of autism spectrum disorder (ASD), affecting 1 in 4000–8000 people worldwide [...]

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