Amplitude of low frequency fluctuations during resting state fMRI in autistic children

Abstract

Resting state fMRI (rs-fMRI) provides an excellent platform for examining the amplitude of low frequency fluctuations (ALFF) and fractional amplitude of low frequency fluctuations (fALFF), which are key indices of brain functioning. However, ALFF and fALFF have been used only sporadically to study autism. rs-fMRI data from 69 children (40 autistic, mean age = 8.47 AE 2.20 years; age range: 5.2 to 13.2; and 29 non-autistic, mean age = 9.02 AE 1.97 years; age range 5.9 to 12.9) were obtained from the Autism Brain Imaging Data Exchange (ABIDE II). ALFF and fALFF were measured using CONN connectivity toolbox and SPM12, at whole-brain & network-levels. A two-sampled t-test and a 2 Group (autistic, nonautistic) Â 7 Networks ANOVA were conducted to test group differences in ALFF and fALFF. The whole-brain analysis identified significantly reduced ALFF values for autistic participants in left parietal opercular cortex, precuneus, and right insula. At the network level, there was a significant effect of diagnostic group and brain network on ALFF values, and only significant effect of network, not group, on fALFF values. Regression analyses indicated a significant effect of age on ALFF values of certain networks in autistic participants. Such intrinsically different network-level responses in autistic participants may have implications for task-level recruitment and synchronization of brain areas, which may in turn impact optimal cognitive functioning. Moreover, differences in low frequency fluctuations of key networks, such as the DMN and SN, may underlie alterations in brain responses in autism that are frequently reported in the literature. Lay SummaryThe human brain while at rest (when a person is not doing any specific task) is a key venue for examining its makeup. Scientists can use resting-state functional MRI (rs-fMRI) to study how the brain functions at rest. This rs-fMRI study found differences between autistic and non-autistic children in the way that certain parts of the brain activate during rest. The study's findings could help people understand what aspects of brain function make autistic and non-autistic people different from each other.

Glutamate Dysregulation in Cingulated Cortices Is Associated with Autism Spectrum Disorder Traits

“…The interest in the different resonance magnetic modalities highlights specific brain areas such as the involvement of the ACC, and posterior cingulate cortex (PCC) in ASD symptoms, specifically magnetic resonance spectroscopy which relates cingulated cortices dysfunction to deficits in joint attention and social skills in ASD [13][14][15][16][17][18][19][20][21]. Increasing of these, neuropathology advances [22][23][24][25][26][27], structural MRI [28][29][30][31][32], fMRI [33][34][35][36][37][38][39][40], PET [41,42], and SPECT [43,44], including EEG-evoked potentials [45][46][47][48] indicate the cingulated cortices as one of the most affected areas of the brain responsible for the symptoms of the autism triad mainly [49].…”

Decreased functional concordance in male children with autism spectrum disorder

“…It is temporally stable (Kublbock et al, 2014) and is considered to be a valid metric for assessing SNA variations associated with neuropsychiatric disorders (Zhou et al, 2010). The study has shown significantly lower ALFF in the left parietal cortex, precuneus, and right insula in ASD (Karavallil Achuthan et al, 2023). Regional homogeneity (ReHo) measures the regional homogeneity of SNA (Kendall, 1990) with high testretest reliability (Zuo & Xing, 2014).…”

“…That is, functional concordance had the potential to capture commonalities between different metrics and provided new insights into temporal dynamics for the study of intrinsic brain activity in related disorders. To date, abundant studies on ASD have discovered that ALFF (Karavallil Achuthan et al, 2023), ReHo (Dajani & Uddin, 2016), dALFF, and dReHo (Wu et al, 2022) are altered in multiple brain regions. However, these explorations were performed from a single aspect, and the findings were incompatible.…”

Distinguishing functional and structural MRI abnormalities between bipolar and unipolar depression

“…Particularly, resting-state fMRI has been widely used to analyze the differences in spontaneous brain activity and functional connectivity of various brain regions through various measures, including fractional Amplitude of Low-Frequency Fluctuations (fALFF) and Regional Homogeneity (ReHo) ( 16 ). The fALFF is a method for quantifying spontaneous brain activity by measuring the intensity fluctuation of fMRI signals with specific frequencies in a given region of interest ( 17 ). It reflects the synchronization of neuronal oscillations within a region and has been used to investigate various neurological and psychiatric disorders ( 18 ).…”