Table 3.

Principal characteristics of the fMRI design and principal results obtained.

ID	Teslas	Design	Task	Task time	Main aim	Principal results
Anderson et al. (2013)	3T	Resting-state imaging with visualizing cartoons		50'	Compare fMRI scans of 15 individuals with Down syndrome to 14 typically developing control subjects while they viewed cartoon video clips	Measurements of subject motion were significantly higher in Down syndrome subjects than in controls. Down syndrome subjects showed higher levels of synchrony between distributed brain networks as well as between the vast majority of gray matter regions. Down syndrome subjects exhibited weaker correlations only for a relatively small subset of the most correlated regions, whether negatively or positively related. Regardless of the distance separating the regions, pairs of regions that showed anticorrelation in a large control sample showed increased correlation (reduced anticorrelation) in Down syndrome.
Anderson et al. (2015)	3T	Resting-state imaging with visualizing cartoons		50'	Examine functional brain activation in response to stylized violence stimuli in Down syndrome and in typically developing individuals to determine whether regional brain activation patterns could be characterized, as well as whether atypical neural activation might be present that could provide clues to a basis for the deficits seen in Down syndrome	In typically developing individuals, the brain's dorsal attention network was most active during violent scenes in the cartoons; this was significantly and specifically reduced in Down syndrome participants. Individuals with Down syndrome exhibited significantly reduced activation in the primary sensory cortices, and such perceptual impairments may constrain their ability to respond to more complex social cues such as violence.
Jacola et al. (2011)	3T	Block design	Paradigm that required participants to make a decision based on semantic information derived from visually presented stimuli	5'30”	Understand the relationship between cognitive processing and brain activation in individuals with Down syndrome on tasks that measured aspects of both verbal and visual-spatial abilities	A significant difference was present in task performance between the mean of DS and control individuals; the mean of DS individuals was inferior to that of controls. In relation to fMRI, controls had 13 areas activated, whereas DS had 20 areas activated.
Jacola et al. (2014)	3T	Block design	Language processing: a passive story listening paradigm	5'30”	Explore neural activation during language processing in participants with DS compared with typically developing groups matched for chronological and mental age	Random effects group analyses documented a reduced activation magnitude in the DS cohort than in both control groups. The pattern of activation within the DS cohort additionally included significantly greater activation in the midline frontal regions (BA 9 and 10) and cingulate gyri (BA 23, 24, 30 and 32).
Reynolds Losin et al. (2009)	3T	Block design	Passive story-listening task (Blocks: forward, backward and rest)	6'08”	Investigate whether individuals with DS exhibit aberrant language-related activation patterns compared to an approximately age-matched typically developing control group during an easily performed passive story-listening task	Control > DS: Forward > Backward—Right middle temporal gyrus. DS > Control: Forward > Rest—Right precuneus; Backward > Rest—Right precuneus.
Seyffert et al. (2002)	1.5T	Block design	Silent naming of pictures of common objects presented through fiber-optic goggles. As a control condition, subjects viewed pixilated images of the same objects with instructions to look without attempting to name them		Unspecific objective related to language deficits in Down syndrome	Greater activation was observed in the right inferior frontal and right superior temporal gyrus in the DS group than in the controls. Vega et al. (2015)
Vega et al. (2015)	3T	Resting state		5'	First aim: confirm previous findings of increased between-network connectivity in DS individuals compared with TD controls and determine whether such differences are specific to DS or are also observed in another developmental disability disorders, such as WS. Characterize how the within-network connectivity profiles of DS and WS could be compared with each other and with TD participants. Together, these aims are intended to support the replication of previous work while providing new insights into resting-state brain function across two different neurodevelopmental disorders.	The results showed that alterations of between-network connectivity, particularly in the DMN, are a characteristic of a number of neurodevelopmental disorders involving intellectual disability, including DS and WS. Perhaps within-network connectivity is a feature that shows more variable patterns across different neurodevelopmental disorders.
Wan et al. (2017)	3T	Block design	Two types of visual perceptual tasks: two-choice revised version of Hooper Visual Organization Test (T-HVOT) and Full Picture Matching Test (FPMT)	6'42”	(1) Develop and implement a one-year computerized visual perceptual training (CVPT) program for DS, (2) use a standardized visual perception assessment to evaluate the effectiveness of the CVPT program, and (3) examine the changes of cortical activation patterns of DS individuals after one-year of CVPT intervention by utilizing functional magnetic resonance imaging (fMRI)	The results showed that the DS intervention group had significant improvements in TVPS-3 after the intervention. The fMRI results indicated more activation in the superior and inferior parietal lobes (spatial manipulation), as well as the precentral gyrus and dorsal premotor cortex (motor imagery) in the DS intervention group. In the T-HVOT vs. FPMT comparison, TD individuals showed highly significant bilateral activations in the middle occipital gyrus, middle temporal gyrus, middle frontal gyrus, and inferior frontal gyrus.
Wilson et al. (2019)	3T	Resting state	Eyes closed while awake	10'	(a) Determine the potential functional connectivity alterations of the DMN in people with Down syndrome; (b) examine the relationship between DMN connectivity and age, IQ and performance on memory and executive function tasks in people with Down syndrome; and (c) investigate differences in DMN connectivity in people with Down syndrome with and without fibrillar Aβ accumulation, indicative of Alzheimer's disease neuropathology	The Down syndrome (all) group did not display a typical profile of DMN connectivity; almost no anti-correlation with other cortical regions was observed. Disrupted functional connectivity of the DMN is an early biomarker of Alzheimer's disease neuropathology.