Developmental changes in brain function underlying inhibitory control in autism spectrum disorders

Longitudinal changes in executive function in autism spectrum disorder: A systematic review and meta-analyses

Individuals with an autism spectrum disorder (ASD) diagnosis show impairment in executive function (EF). However, findings are mixed regarding differences in the age effect on EF between autistic individuals and persons with typical development (TD). Questions remain regarding whether the age-related trajectories of EF in ASD are the same as or different from those in TD. To bridge this knowledge gap, we conducted a systematic review and meta-analyses of longitudinal studies that compared age-related changes in EF between ASD and TD groups (preregistration: osf.io/j5764). A literature search was conducted using PubMed, PsycINFO, and Web of Science on January 29, 2024. After screening by two independent reviewers, 14 longitudinal studies were included. Random-effects meta-analyses of studies involving a maximum total of 518 autistic and 3558 TD children and adolescents (mean baseline ages: 5.7-12.0 years) showed that ASD had significantly poorer EF than TD at both baseline and follow-up. However, there was no significant group difference in the age-related change in EF across domains, including working memory, inhibition, shifting, and planning. Robust Bayesian meta-analyses also provided substantial evidence in favor of the null hypothesis that ASD and TD groups showed similar changes over time for most EF processes. Limitations of the literature included the limited number of longitudinal studies and a narrow range of developmental stages and EF constructs analyzed across studies. Altogether, these findings suggest that autistic children and adolescents generally can improve in EF over time similarly to their neurotypical peers. This has important implications for parents and educators, encouraging appropriate EF training and intervention for autistic children and adolescents at an early stage.

The effect of tDCS on inhibitory control and its transfer effect on sustained attention in children with autism spectrum disorder: An fNIRS study

BACKGROUND

Individuals with autism spectrum disorder (ASD) have inhibitory control deficits. The combination of transcranial direct current stimulation (tDCS) and inhibitory control training produces good transfer effects and improves neuroplasticity. However, no studies have explored whether applying tDCS over the dlPFC improves inhibitory control and produces transfer effects in children with ASD.

OBJECTIVE

To explore whether multisession tDCS could enhance inhibitory control training (response inhibition), near-transfer (interference control) and far-transfer effects (sustained attention; stability of attention) in children with ASD and the generalizability of training effects in daily life and the class, as reflected by behavioral performance and neural activity measured by functional near-infrared spectroscopy (fNIRS).

METHODS

Twenty-eight autistic children were randomly assigned to either the true or sham tDCS group. The experimental group received bifrontal tDCS stimulation at 1.5 mA, administered for 15 min daily across eight consecutive days. tDCS was delivered during a computerized Go/No-go training task. Behavioral performance in terms of inhibitory control (Dog/Monkey and Day/Night Stroop tasks), sustained attention (Continuous Performance and Cancellation tests), prefrontal cortex (PFC) neural activity and inhibitory control and sustained attention in the class and at home were evaluated.

RESULTS

Training (response inhibition) and transfer effects (interference control; sustained attention) were significantly greater after receiving tDCS during the Go/No-go training task than after receiving sham tDCS. Changes in oxyhemoglobin (HbO) concentrations in the dlPFC and FPA associated with consistent conditions in the Day/Night Stroop and Continuous Performance test were observed after applying tDCS during the inhibitory control training task. Notably, transfer effects can be generalized to classroom environments.

CONCLUSION

Inhibitory control training combined with tDCS may be a promising, safe, and effective method for improving inhibitory control and sustained attention in children with ASD.

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Identification and analysis of autism spectrum disorder via large-scale dynamic functional network connectivity

Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder with severe cognitive impairment. Several studies have reported that brain functional network connectivity (FNC) has great potential for identifying ASD from healthy control (HC) and revealing the relationships between the brain and behaviors of ASD. However, few studies have explored dynamic large-scale FNC as a feature to identify individuals with ASD. This study used a time-sliding window method to study the dynamic FNC (dFNC) on the resting-state fMRI. To avoid arbitrarily determining the window length, we set a window length range of 10-75 TRs (TR = 2 s). We constructed linear support vector machine classifiers for all window length conditions. Using a nested 10-fold cross-validation framework, we obtained a grand average accuracy of 94.88% across window length conditions, which is higher than those reported in previous studies. In addition, we determined the optimal window length using the highest classification accuracy of 97.77%. Based on the optimal window length, we found that the dFNCs were located mainly in dorsal and ventral attention networks (DAN and VAN) and exhibited the highest weight in classification. Specifically, we found that the dFNC between DAN and temporal orbitofrontal network (TOFN) was significantly negatively correlated with social scores of ASD. Finally, using the dFNCs with high classification weights as features, we construct a model to predict the clinical score of ASD. Overall, our findings demonstrated that the dFNC could be a potential biomarker to identify ASD and provide new perspectives to detect cognitive changes in ASD.

Altered neural mechanisms of deception in individuals with autistic traits

A successful deception involves making a decision, acting on it, and evaluating results. Here, we investigated deception in a non-clinical sample (n = 36) with varying autism traits using a coin-toss paradigm of active deception. The subjects were asked to react to the instructions by clicking one of the two boxes that could mislead their opponents, followed by feedback on their success or failure. During this reaction, their EEG activity was recorded, and the results suggested that people with high autistic traits exhibited longer reaction times and lower amplitude of P3 in the decision-making stage compared to individuals with low autistic traits. The feedback evaluation stage in the high autistic trait group elicited lower amplitude of FRN and P3. Overall, these results indicated that people with high autistic traits experienced difficulties in deceiving, which could be related to atypical neural mechanisms.

Inhibitory Control Development: A Network Neuroscience Perspective

As one of the core executive functions, inhibition plays an important role in human life through development. Inhibitory control is defined as the ability to suppress actions when they are unlikely to accomplish valuable results. Contemporary neuroscience has investigated the underlying neural mechanisms of inhibitory control. The controversy started to arise, which resulted in two schools of thought: a modulatory and a network account of inhibitory control. In this systematic review, we survey developmental mechanisms in inhibitory control as well as neurodevelopmental diseases related to inhibitory dysfunctions. This evidence stands against the modulatory perspective of inhibitory control: the development of inhibitory control does not depend on a dedicated region such as the right inferior frontal gyrus (rIFG) but relies on a more broadly distributed network.

A developmental examination of medial frontal theta dynamics and inhibitory control

Medial frontal theta-band oscillations are a robust marker of action-outcome monitoring. In a large developmental sample (n = 432, 9-16 years), we examined whether phase and non-phase locked medial frontal theta power were related to inhibitory control among children and adolescents. Our results showed that the well-established increase in medial frontal theta power during inhibitory control was captured largely by non-phase locked dynamics, which partially mediated the positive effect of age on task performance. A person-centered approach also revealed latent classes of individuals based on their multivariate theta power dynamics (phase locked/non-phase locked, GO/NOGO). The class of individuals showing low phase locked and high non-phase locked medial frontal theta were significantly older, had better inhibitory control, scored higher on measures of general cognitive function, and were more efficient in their behavioural responses. The functional significance of phase and non-phase locked theta dynamics, and their potential changes, could have important implications for action-outcome monitoring and cognitive function in both typical and atypical development, as well as related psychopathology .

Visual attention and inhibitory control in children, teenagers and adults with autism without intellectual disability: results of oculomotor tasks from a 2-year longitudinal follow-up study (InFoR)

BACKGROUND

Inhibitory control and attention processing atypicalities are implicated in various diseases, including autism spectrum disorders (ASD). These cognitive functions can be tested by using visually guided saccade-based paradigms in children, adolescents and adults to determine the time course of such disorders.

METHODS

In this study, using Gap, Step, Overlap and Antisaccade tasks, we analyzed the oculomotor behavior of 82 children, teenagers and adults with high functioning ASD and their peer typically developing (TD) controls in a two-year follow-up study under the auspices of the InFoR-Autism project. Analysis of correlations between oculomotors task measurements and diagnostic assessment of attentional (ADHD-RS and ADHD comorbidity indices) and executive functioning (BRIEF scales) were conducted in order to evaluate their relationship with the oculomotor performance of participants with ASD.

RESULTS

As indicated by the presence of a Gap and Overlap effects in all age groups, the oculomotor performances of ASD participants showed a preserved capability in overt attention switching. In contrast, the difference in performances of ASD participants in the Antisaccade task, compared to their TD peers, indicated an atypical development of inhibition and executive functions. From correlation analysis between our oculomotor data and ADHD comorbidity index, and scores of attention and executive function difficulties, our findings support the hypothesis that a specific dysfunction of inhibition skills occurs in ASD participants that is independent of the presence of ADHD comorbidity.

LIMITATIONS

These include the relatively small sample size of the ASD group over the study's two-year period, the absence of an ADHD-only control group and the evaluation of a TD control group solely at the study's inception.

CONCLUSIONS

Children and teenagers with ASD have greater difficulty in attention switching and inhibiting prepotent stimuli. Adults with ASD can overcome these difficulties, but, similar to teenagers and children with ASD, they make more erroneous and anticipatory saccades and display a greater trial-to-trial variability in all oculomotor tasks compared to their peers. Our results are indicative of a developmental delay in the maturation of executive and attentional functioning in ASD and of a specific impairment in inhibitory control.

Reduced Proactive Control Processes Associated With Behavioral Response Inhibition Deficits in Autism Spectrum Disorder

Impairments in inhibitory control are common in individuals with autism spectrum disorder (ASD) and associated with multiple clinical issues. Proactive (i.e., delaying response onset) and reactive control mechanisms (i.e., stopping quickly) contribute to successful inhibitory control in typically developing individuals and may be compromised in ASD. We assessed inhibitory control in 58 individuals with ASD and 63 typically developing controls aged 5-29 years using an oculomotor stop-signal task during which participants made rapid eye movements (i.e., saccades) toward peripheral targets (i.e., GO trials) or inhibited saccades (i.e., STOP trials). Individuals with ASD exhibited reduced ability to inhibit saccades, reduced reaction time slowing (GO RT slowing), and faster stop-signal reaction times (SSRT) compared to controls. Across participants, stopping accuracy was positively related to GO RT slowing, and increased age was associated with higher stopping accuracy and GO RT slowing. Our results indicate that failures to proactively delay prepotent responses in ASD underpin deficits of inhibitory control and may contribute to difficulties modifying their behavior according to changes in contextual demands. These findings implicate frontostriatal brain networks in inhibitory control and core symptoms of ASD. LAY SUMMARY: Difficulties stopping actions are common in individuals with autism spectrum disorder (ASD) and are related to repetitive behaviors. This study compared the ability to stop eye movements in individuals with ASD and healthy peers. We found that individuals with ASD were less able to stop eye movements and that this difficulty was related to a reduced ability to delay their eye movements before seeing the cue to stop, not their ability to react quickly to this cue.

Alpha connectivity and inhibitory control in adults with autism spectrum disorder

BACKGROUND

Individuals with autism spectrum disorder (ASD) often report difficulties with inhibition in everyday life. During inhibition tasks, adults with ASD show reduced activation of and connectivity between brain areas implicated in inhibition, suggesting impairments in inhibitory control at the neural level. Our study further investigated these differences by using magnetoencephalography (MEG) to examine the frequency band(s) in which functional connectivity underlying response inhibition occurs, as brain functions are frequency specific, and whether connectivity in certain frequency bands differs between adults with and without ASD.

METHODS

We analysed MEG data from 40 adults with ASD (27 males; 26.94 ± 6.08 years old) and 39 control adults (27 males; 27.29 ± 5.94 years old) who performed a Go/No-go task. The task involved two blocks with different proportions of No-go trials: Inhibition (25% No-go) and Vigilance (75% No-go). We compared whole-brain connectivity in the two groups during correct No-go trials in the Inhibition vs. Vigilance blocks between 0 and 400 ms.

RESULTS

Despite comparable performance on the Go/No-go task, adults with ASD showed reduced connectivity compared to controls in the alpha band (8-14 Hz) in a network with a main hub in the right inferior frontal gyrus. Decreased connectivity in this network predicted more self-reported difficulties on a measure of inhibition in everyday life.

LIMITATIONS

Measures of everyday inhibitory control were not available for all participants, so this relationship between reduced network connectivity and inhibitory control abilities may not be necessarily representative of all adults with ASD or the larger ASD population. Further research with independent samples of adults with ASD, including those with a wider range of cognitive abilities, would be valuable.

CONCLUSIONS

Our findings demonstrate reduced functional brain connectivity during response inhibition in adults with ASD. As alpha-band synchrony has been linked to top-down control mechanisms, we propose that the lack of alpha synchrony observed in our ASD group may reflect difficulties in suppressing task-irrelevant information, interfering with inhibition in real-life situations.

Components of Executive Control in Autism Spectrum Disorder: A Functional Magnetic Resonance Imaging Examination of Dual-Mechanism Accounts

BACKGROUND

It remains unclear whether executive control (EC) deficits in autism spectrum disorder (ASD) represent a failure in proactive EC (engaged and maintained before a cognitively demanding event) or in reactive EC (engaged transiently as the event occurs). We addressed this question by administering a paradigm investigating components of EC in a sample of individuals with ASD and typically developing individuals during functional magnetic resonance imaging.

METHODS

During functional magnetic resonance imaging, 141 participants (64 ASD, 77 typically developing) completed a rapid preparing to overcome prepotency task that required participants to respond to an arrow probe based on the color of an initially presented cue. We examined functional recruitment and connectivity in the frontoparietal task control, cingulo-opercular task control, salience, and default mode networks during cue and probe phases of the task.

RESULTS

ASD participants showed evidence of behavioral EC impairment. Analyses of functional recruitment and connectivity revealed that ASD participants showed significantly greater activity during the cue in networks associated with proactive control processes, but on the less cognitively demanding trials. On the more cognitively demanding trials, cue activity was similar across groups. During the probe, connectivity between regions associated with reactive control processes was uniquely enhanced on more-demanding (relative to less-demanding) trials in individuals with ASD but not in typically developing individuals.

CONCLUSIONS

The current data suggest that rather than arising from a specific failure to engage proactive or reactive forms of EC, the deficits in EC commonly observed in ASD may be due to reduced proactive EC and a consequent overreliance on reactive EC on more cognitively demanding tasks.

Parental report of cognitive and social-emotionality traits in school-age children with autism and Williams syndrome

The majority of the research examining children with Autism Spectrum Disorder (ASD) and Williams Syndrome (WS) focus on the social domain while few have examined cognitive style and emotionality. Accordingly, this current study assessed the day-to-day cognitive and behavioral functioning of school-age children with ASD, WS, and neurotypical development (ND) through caregiver-report inventories to further delineate commonalities and disparities in cognitive and social-emotional traits. Two caregiver-report inventories, the Children's Behavior Questionnaire and the Multidimensional Personality Questionnaire were employed to assess the day-to-day functioning of children ages 7-14 years. Participants included 64 caregivers of children, of these, 25 were caregivers of children with high functioning autism (HFA), 14 with WS, and 25 with ND. Multivariate analysis of covariance was computed to assess between-group differences for each subscale within a questionnaire. Covariates included age and full-scale IQ. For cognitive traits, group differences were observed across two categories while seven were present within the social-emotional categories. The majority of the group effects reflected differences in social-emotional traits between ND and both neurodevelopmental groups, while limited distinctions were found between the two clinical groups. This brief report provides additional evidence that HFA and WS may show similarities in cognitive traits but more divergent social-emotional tendencies, despite controlling for age and intellect. This study highlights the large social-emotional differences that supports prior phenotypic descriptions of both neurodevelopmental groups. Future research in these domains are needed to determine focused interventions to address social impairment.

Variation in restricted and repetitive behaviors and interests relates to inhibitory control and shifting in children with autism spectrum disorder

Symptoms of restricted and repetitive behaviors and interests in autism are theoretically linked to executive functioning, which includes problem-solving abilities such as inhibition and cognitive flexibility. This study examined whether inhibition and flexibility are related to higher order restricted and repetitive behaviors and interests (e.g. circumscribed interests and ritualistic behavior) and sensorimotor behaviors (e.g. stereotyped and repetitive movements and sensory preoccupations) among 102 school-aged children with autism spectrum disorder who had cognitive abilities in the average or above average range. The ability to inhibit interfering information and shifting ability were related to higher order restricted and repetitive behaviors and interests, and each uniquely accounted for variance. This suggests that the ability to suppress interfering information as well as the ability to flexibly shift between patterns of responding is protective against higher order restricted and repetitive behaviors and interest symptoms in autism. In addition, the ability to proactively slow one's reaction time in order to respond more carefully was related to sensorimotor restricted and repetitive behaviors. These results support the importance of distinguishing between higher order and sensorimotor symptoms due to their distinct relationships to executive functioning abilities.

Aberrant functional connectivity of inhibitory control networks in children with autism spectrum disorder

Development of inhibitory control is a core component of executive function processes and a key aspect of healthy development. Children with autism spectrum disorder (ASD) show impairments in performance on inhibitory control tasks. Nevertheless, the research on the neural correlates of these impairments is inconclusive. Here, we explore the integrity of inhibitory control networks in children with ASD and typically developing (TD) children using resting state functional Magnetic Resonance Imagaing (MRI). In a large multisite sample, we find evidence for significantly greater functional connectivity (FC) of the right inferior frontal junction (rIFJ) with the posterior cingulate gyrus, and left and right frontal poles in children with ASD compared with TD children. Additionally, TD children show greater FC of rIFJ with the superior parietal lobule (SPL) compared with children with ASD. Furthermore, although higher rIFJ-SPL and rIFJ-IPL FC was related to better inhibitory control behaviors in both ASD and TD children, rIFJ-dACC FC was only associated with inhibitory control behaviors in TD children. These results provide preliminary evidence of differences in intrinsic functional networks supporting inhibitory control in children with ASD, and provide a basis for further exploration of the development of inhibitory control in children with the disorder. Autism Research 2018, 11: 1468-1478. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Inhibitory control is an important process in healthy cognitive development. Behavioral studies suggest that inhibitory control is impaired in autism spectrum disorder (ASD). However, research examining the neural correlates underlying inhibitory control differences in children with ASD is inconclusive. This study reveals differences in functional connectivity of brain networks important for inhibitory control in children with ASD compared with typically developing children. Furthermore, it relates brain network differences to parent-reported inhibitory control behaviors in children with ASD. These findings provide support for the hypothesis that differences in brain connectivity may underlie observable behavioral deficits in inhibitory control in children with the disorder.

Cognitive mechanisms of inhibitory control deficits in autism spectrum disorder

BACKGROUND

Inhibitory control deficits are common in autism spectrum disorder (ASD) and associated with more severe repetitive behaviors. Inhibitory control deficits may reflect slower execution of stopping processes, or a reduced ability to delay the onset of behavioral responses in contexts of uncertainty. Previous studies have documented relatively spared stopping processes in ASD, but whether inhibitory control deficits in ASD reflect failures to delay response onset has not been systematically assessed. Further, while improvements in stopping abilities and response slowing are seen through adolescence/early adulthood in health, their development in ASD is less clear.

METHODS

A stop-signal test (SST) was administered to 121 individuals with ASD and 76 age and IQ-matched healthy controls (ages 5-28). This test included 'GO trials' in which participants pressed a button when a peripheral target appeared and interleaved 'STOP trials' in which they were cued to inhibit button-presses when a stop-signal appeared at variable times following the GO cue. STOP trial accuracy, RT of the stopping process (SSRT), and reaction time (RT) slowing during GO trials were examined.

RESULTS

Relative to controls, individuals with ASD had reduced accuracy on STOP trials. SSRTs were similar across control and ASD participants, but RT slowing was reduced in patients compared to controls. Age-related increases in stopping ability and RT slowing were attenuated in ASD. Reduced stopping accuracy and RT slowing were associated with more severe repetitive behaviors in ASD.

DISCUSSION

Our findings show that inhibitory control deficits in ASD involve failures to strategically delay behavioral response onset. These results suggest that reduced preparatory behavioral control may underpin inhibitory control deficits as well as repetitive behaviors in ASD. Typical age-related improvements in inhibitory control during late childhood/early adolescence are reduced in ASD, highlighting an important developmental window during which treatments may mitigate cognitive alterations contributing to repetitive behaviors.

Auditory attention in autism spectrum disorder: An exploration of volumetric magnetic resonance imaging findings

Studies have shown that individuals with autism spectrum disorder (ASD) tend to perform significantly below typically developing individuals on standardized measures of attention, even when controlling for IQ. The current study sought to examine within ASD whether anatomical correlates of attention performance differed between those with average to above-average IQ (AIQ group) and those with low-average to borderline ability (LIQ group) as well as in comparison to typically developing controls (TDC). Using automated volumetric analyses, we examined regional volume of classic attention areas including the superior frontal gyrus, anterior cingulate cortex, and precuneus in ASD AIQ (n = 38) and LIQ (n = 18) individuals along with 30 TDC. Auditory attention performance was assessed using subtests of the Test of Memory and Learning (TOMAL) compared among the groups and then correlated with regional brain volumes. Analyses revealed group differences in attention. The three groups did not differ significantly on any auditory attention-related brain volumes; however, trends toward significant size-attention function interactions were observed. Negative correlations were found between the volume of the precuneus and auditory attention performance for the AIQ ASD group, indicating larger volume related to poorer performance. Implications for general attention functioning and dysfunctional neural connectivity in ASD are discussed.

An altered scaffold for information processing: Cognitive control development in adolescents with autism

We investigated how cognitive neuroscientific studies during the last decade have advanced understanding of cognitive control from adolescence to young adulthood in individuals with autism spectrum disorder (ASD). To do so, we conducted a selective review of the larger structural, resting state, and diffusion imaging studies of brain regions and networks related to cognitive control that have been conducted since 2007 in individuals with ASD and typical development (TYP) ages 10 to 30 years that examined how these regions and networks support behavioral and task-based fMRI performance on tasks assessing cognitive control during this period. Longitudinal structural studies reveal overgrowth of the anterior cingulate (ACC) and slower white matter development in the parietal cortex in adolescents with ASD versus TYP. Cross-sectional studies of the salience, executive control and default mode resting state functional connectivity networks, which mediate cognitive control, demonstrate patterns of connectivity that differ from TYP through adolescence. Finally, white matter tracts underlying these control-related brain regions continue to show reduced diffusion properties compared to TYP. It is thus not surprising that cognitive control tasks performance improves less during adolescence in ASD versus TYP. This review illustrates that a cognitive neuroscientific approach produces insights about the mechanisms of persistent cognitive control deficits in individuals with ASD from adolescence into young adulthood not apparent with neuropsychological methods alone, and draws attention to the great need for longitudinal studies of this period in those with ASD. Further investigation of ACC and fronto-parietal neural circuits may help specify pathophysiology and treatment options.

Visual Attention Processes and Oculomotor Control in Autism Spectrum Disorder: A Brief Review and Future Directions

Autism spectrum disorder (ASD) is defined as persistent deficits in social communication and social interaction, and restricted, repetitive patterns of behavior, interests or activities Diagnostic and Statistical Manual of Mental Disorders (5th ed., DSM-5; American Psychiatric Association, 2013). However, individuals with ASD show clearly atypical visual patterns. So far, indications of abnormal visual attention and oculomotor control concerning stimuli independent of social function in ASD have been found. The same findings have been shown in individuals suffering of other neurodevelopmental disorders (e.g., developmental coordination disorder and developmental dyslexia [DD]). Furthermore, visual attention processes and oculomotor control are supposed to be subserved by the magnocellular visual system, which has been found, in turn, to be dysfunctional in ASD and other neurodevelopmental disabilities (i.e., DD). The purpose of this article is to briefly review the link between oculomotor control and visual attention processes and ASD, and to discuss the specificity and overlap of eye movement findings between ASD and other neurodevelopmental disorders.

Ocular Fixation Abnormality in Patients with Autism Spectrum Disorder

We examined the factors that influence ocular fixation control in adults with autism spectrum disorder (ASD) including sensory information, individuals' motor characteristics, and inhibitory control. The ASD group showed difficulty in maintaining fixation especially when there was no fixation target. The fixational eye movement characteristics of individuals were consistent regardless of the presence or absence of a fixation target in the controls, but not in the ASD group. Additionally, fixation stability did not correlate with an ability to suppress reflexive saccades measured by an antisaccade task. These findings suggest that ASD adults have deficits in converting alternative sensory information, such as retinal signals in the peripheral visual field or extraretinal signals, to motor commands when the foveal information is unavailable.

Adolescents' inhibitory control: keep it cool or lose control

Inhibitory control (i.e., the ability to resist automatisms, temptations, distractions, or interference and to adapt to conflicting situations) is a determinant of cognitive and socio-emotional development. In light of the discrepancies of previous findings on the development of inhibitory control in affectively charged contexts, two important issues need to be addressed. We need to determine (a) whether cool inhibitory control (in affectively neutral contexts) and hot inhibitory control (in affectively charged contexts) follow the same developmental pattern and (b) the degree of specificity of these two types of inhibitory control at different ages. Thus, in the present study, we investigated the developmental patterns of cool and hot inhibitory control and the degree of specificity of these abilities in children, adolescents and adults. Typically developing children, adolescents, and adults performed two Stroop-like tasks: an affectively neutral one (Cool Stroop task) and an affectively charged one (Hot Stroop task). In the Cool Stroop task, the participants were asked to identify the ink color of the words independent of color that the words named; in the Hot Stroop task, the participants were asked to identify the emotional expression of a face independent of the emotion named by a simultaneously displayed written word. We found that cool inhibitory control abilities develop linearly with age, whereas hot inhibitory control abilities follow a quadratic developmental pattern, with adolescents displaying worse hot inhibitory control abilities than children and adults. In addition, cool and hot inhibitory control abilities were correlated in children but not in adolescents and adults. The present study suggests (a) that cool and hot inhibitory control abilities develop differently from childhood to adulthood - i.e., that cool inhibition follows a linear developmental pattern and hot inhibition follows an adolescent-specific pattern - and (b) that they become progressively more domain-specific with age.

Brain imaging research in autism spectrum disorders: in search of neuropathology and health across the lifespan

PURPOSE OF REVIEW

Advances in brain imaging research in autism spectrum disorders (ASD) are rapidly occurring, and the amount of neuroimaging research has dramatically increased over the past 5 years. In this review, advances during the past 12 months and longitudinal studies are highlighted.

RECENT FINDINGS

Cross-sectional neuroimaging research provides evidence that the neural underpinnings of the behavioral signs of ASD involve not only dysfunctional integration of information across distributed brain networks but also basic dysfunction in primary cortices.Longitudinal studies of ASD show abnormally enlarged brain volumes and increased rates of brain growth during early childhood in only a small minority of ASD children. There is evidence of disordered development of white matter microstructure and amygdala growth, and at 2 years of age, network inefficiencies in posterior cerebral regions.From older childhood into adulthood, atypical age-variant and age-invariant changes in the trajectories of total and regional brain volumes and cortical thickness are apparent at the group level.

SUMMARY

There is evidence of abnormalities in posterior lobes and posterior brain networks during the first 2 years of life in ASD and, even in older children and adults, dysfunction in primary cortical areas.