scholarly journals Network coherence in autism spectrum disorder : a multimodal neuroimaging study of functional connectivity and spectroscopy MRI

2015 ◽  
Author(s):  
◽  
John P. II Hegarty

The underlying neuropathology and effects on neuronal activity in individuals with ASD are still being elucidated; as well as their impact on intervention and treatment outcomes. Frontal, temporal, parietal and cerebellar pathways exhibit disrupted structural and functional connectivity in individuals with ASD and we sought to investigate the potential clinical utility of altered network coherence. Beta-adrenergic antagonism improved information processing in a subset of individuals with ASD and improved performance was related to pharmacologicallymediated alterations in functional connectivity in the fronto-parietal control network. These findings support the potential utility of beta-adrenergic antagonists for some patients with ASD and the clinical significance of alterations in network coherence. There are also additional considerations for functional connectivity investigations in ASD. The cerebellum is interconnected via feedback loops to the neocortex and thus has some modulatory influences on cortical and subcortical neuronal circuits. The cerebellum is consistently implicated in the neuropathology of ASD but has been largely ignored in investigations of functional network coherence. Functional connectivity between the cerebellum and neocortex was anticorrelated in a subset of individuals with ASD. These individuals exhibited reduced glutamate levels in the cerebellum and diminished interpretive linguistic abilities, suggesting a potential mechanism underlying altered cerebrocerebellar connectivity in some individuals with ASD as well a cognitive outcome of alterations in cerebrocerebellar network coherence.

Autism ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 795-801
Author(s):  
John P Hegarty ◽  
Rachel M Zamzow ◽  
Bradley J Ferguson ◽  
Shawn E Christ ◽  
Eric C Porges ◽  
...  

Beta-adrenergic antagonism (e.g. propranolol) has been associated with cognitive/behavioral benefits following stress-induced impairments and for some cognitive/behavioral domains in individuals with autism spectrum disorder. In this preliminary investigation, we examined whether the benefits of propranolol are associated with functional properties in the brain. Adolescents/adults (mean age = 22.54 years) with (n = 13) and without autism spectrum disorder (n = 13) attended three sessions in which propranolol, nadolol ( beta-adrenergic antagonist that does not cross the blood–brain barrier), or placebo was administered before a semantic fluency task during functional magnetic resonance imaging. Autonomic nervous system measures and functional connectivity between language/associative processing regions and within the fronto-parietal control, dorsal attention, and default mode networks were examined. Propranolol was associated with improved semantic fluency performance, which was correlated with the baseline resting heart rate. Propranolol also altered network efficiency of regions associated with semantic processing and in an exploratory analysis reduced functional differences in the fronto-parietal control network in individuals with autism spectrum disorder. Thus, the cognitive benefits from beta-adrenergic antagonism may be generally associated with improved information processing in the brain in domain-specific networks, but individuals with autism spectrum disorder may also benefit from additional improvements in domain-general networks. The benefits from propranolol may also be able to be predicted from baseline autonomic nervous system measures, which warrants further investigation.


2016 ◽  
Vol 11 (5) ◽  
pp. 1278-1289 ◽  
Author(s):  
John P. Hegarty ◽  
Bradley J. Ferguson ◽  
Rachel M. Zamzow ◽  
Landon J. Rohowetz ◽  
Jeffrey D. Johnson ◽  
...  

Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.


Author(s):  
Vidhusha Srinivasan ◽  
N. Udayakumar ◽  
Kavitha Anandan

Background: The spectrum of autism encompasses High Functioning Autism (HFA) and Low Functioning Autism (LFA). Brain mapping studies have revealed that autism individuals have overlaps in brain behavioural characteristics. Generally, high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, specific mechanisms associated with their functional capabilities are still under research. Objective: This work addresses the overlapping phenomenon present in autism spectrum through functional connectivity patterns along with brain connectivity parameters and distinguishes the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both high and low functioning autistic groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involved in a defined language processing task. The language processing regions of the brain, along with Default Mode Network (DMN) have been considered for the analysis. The functional connectivity maps have been plotted through graph theory procedures. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the individual groups. These parameters have been fed to Deep Belief Networks (DBN) to classify the subjects under consideration as either LFA or HFA. Results: Results showed increased functional connectivity in high functioning subjects. It was found that the additional interaction of the Primary Auditory Cortex lying in the temporal lobe, with other regions of interest complimented their enhanced connectivity. Results were validated using DBN measuring the classification accuracy of 85.85% for high functioning and 81.71% for the low functioning group. Conclusion: Since it is known that autism involves enhanced, but imbalanced components of intelligence, the reason behind the supremacy of high functioning group in language processing and region responsible for enhanced connectivity has been recognized. Therefore, this work that suggests the effect of Primary Auditory Cortex in characterizing the dominance of language processing in high functioning young adults seems to be highly significant in discriminating different groups in autism spectrum.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Lichtman ◽  
Eyal Bergmann ◽  
Alexandra Kavushansky ◽  
Nadav Cohen ◽  
Nina S. Levy ◽  
...  

AbstractIQSEC2 is an X-linked gene that is associated with autism spectrum disorder (ASD), intellectual disability, and epilepsy. IQSEC2 is a postsynaptic density protein, localized on excitatory synapses as part of the NMDA receptor complex and is suggested to play a role in AMPA receptor trafficking and mediation of long-term depression. Here, we present brain-wide structural volumetric and functional connectivity characterization in a novel mouse model with a missense mutation in the IQ domain of IQSEC2 (A350V). Using high-resolution structural and functional MRI, we show that animals with the A350V mutation display increased whole-brain volume which was further found to be specific to the cerebral cortex and hippocampus. Moreover, using a data-driven approach we identify putative alterations in structure–function relations of the frontal, auditory, and visual networks in A350V mice. Examination of these alterations revealed an increase in functional connectivity between the anterior cingulate cortex and the dorsomedial striatum. We also show that corticostriatal functional connectivity is correlated with individual variability in social behavior only in A350V mice, as assessed using the three-chamber social preference test. Our results at the systems-level bridge the impact of previously reported changes in AMPA receptor trafficking to network-level disruption and impaired social behavior. Further, the A350V mouse model recapitulates similarly reported brain-wide changes in other ASD mouse models, with substantially different cellular-level pathologies that nonetheless result in similar brain-wide alterations, suggesting that novel therapeutic approaches in ASD that result in systems-level rescue will be relevant to IQSEC2 mutations.


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