Influence of Primary Auditory Cortex in the Characterization of Autism Spectrum in Young Adults using Brain Connectivity Parameters and Deep Belief Networks: An fMRI Study

Abstract

Background: The spectrum of autism includes High Functioning Autism(HFA)and Low Functioning Autism(LFA). Brain mapping studies have revealed that, the autism individuals have overlaps in brain behavioural characteristics. Generally, the high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, the specific mechanisms associated with the functional capabilities are still under research. Objective: This paper attempts to address the overlapping phenomenon present in autism through functional connectivity patterns along with, brain connectivity parameters and distinguish the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involving in a defined language processing task. The language processing regions of the brain, along with the Default Mode Network (DMN) have been focussed. The functional connectivity maps have been plotted through graph theory. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the groups. These parameters have been fed to the Deep Belief Networks (DBN) to classify the input as either LFA or HFA. Results: Results showed an increased functional connectivity in high functioning subjects. It was found that, the additional interaction of the Primary Auditory Cortex with the 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 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 identified. Therefore, this work that signifies 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 the different groups in autism spectrum.

Quantitative assessment of cognitive profile and brain asymmetry in the characterization of autism spectrum in children: A task-based EEG study

“…There are literature suggesting significant differences in brain behavior among low and high-functioning autistic children utilizing fMRI. 49 Srinivasan et al used a procedure based on language processing capacities to distinguish autism spectrum disorders (LFA and HFA) utilizing functional connectivity patterns and brain connectivity characteristics. The study reported a significant measurable difference in EEG functional connectivity metrics between the two groups.…”

Loss of oligodendrocyte ErbB receptor signaling leads to hypomyelination, reduced density of parvalbumin‐expressing interneurons, and inhibitory function in the auditory cortex

“…The finding that hypomyelination leads to reduced PV + neuron density but normal density of VVA + cells is remarkably similar to what has been reported for several mutant mice that display autism spectrum disorder (ASD) endophenotypes, that is, PV +/− , Shank1 −/− and Shank3B −/− mice (Filice et al, 2016 ). Interestingly, myelin defects have been found in ASD patients (Graciarena et al, 2018 ; Steinman & Mankuta, 2019 ), which also display auditory processing deficits (Jones et al, 2020 ; Rotschafer, 2021 ; Srinivasan et al, 2020 ). Together, these observations raise the possibility that defects in myelination might contribute to some aspects of ASD by their negative impact on inhibitory networks.…”

Hypomyelination reduces parvalbumin interneuron density and auditory cortex inhibitory function

“…The finding that hypomyelination leads to reduced density of PV + neurons but normal density of VVA + cells is remarkably similar to what has been reported for several mutant mice that display autism spectrum disorder (ASD) endophenotypes, i.e., PV +/- , Shank1 -/- and Shank3B -/- mice (Filice, Vorckel, Sungur, Wohr, & Schwaller, 2016). Interestingly, myelin defects have been found in ASD patients (Graciarena, Seiffe, Nait-Oumesmar, & Depino, 2018; Steinman & Mankuta, 2019), which also display auditory processing deficits (Jones et al, 2020; Rotschafer, 2021; Srinivasan, Udayakumar, & Anandan, 2020). Together, these observations raise the possibility that defects in myelination might contribute to some aspects of ASD by their negative impact on inhibitory networks.…”