Neural activity-dependent brain changes in development: Implications for psychopathology

Taking Sides: Asymmetries in the Evolution of Human Brain Development in Better Understanding Autism Spectrum Disorder

Confirmation from structural, functional, and behavioral studies agree and suggest a configuration of atypical lateralization in individuals with autistic spectrum disorders (ASD). It is suggested that patterns of cortical and behavioral atypicality are evident in individuals with ASDs with atypical lateralization being common in individuals with ASDs. The paper endeavors to better understand the relationship between alterations in typical cortical asymmetries and functional lateralization in ASD in evolutionary terms. We have proposed that both early genetic and/or environmental influences can alter the developmental process of cortical lateralization. There invariably is a “chicken or egg” issue that arises whether atypical cortical anatomy associated with abnormal function, or alternatively whether functional atypicality generates abnormal structure.

Atypical Response to Caregiver Touch in Infants at High Risk for Autism Spectrum Disorder

Atypical response to tactile input is associated with greater socio-communicative impairments in individuals with autism spectrum disorder (ASD). The current study examined overt orienting to caregiver-initiated touch in 12-month-olds at high risk for ASD (HRA) with (HRA+) and without (HRA-) a later diagnosis of ASD compared to low-risk comparison infants. Findings indicate that infants that go on to receive a diagnosis of ASD may more frequently fail to shift their attention in response to caregiver touch and when they do, they may be more likely to orient away from touch. Additionally, failure to respond to touch predicts ADOS severity scores at outcome suggesting that atypical response to touch may be an early indicator of autism severity.

The impact of robotic intervention on joint attention in children with autism spectrum disorders

Background

A growing body of anecdotal evidence indicates that the use of robots may provide unique opportunities for assisting children with autism spectrum disorders (ASD). However, previous studies investigating the effects of interventions using robots on joint attention (JA) in children with ASD have shown insufficient results. The robots used in these studies could not turn their eyes, which was a limitation preventing the robot from resembling a human agent.

Methods

We compared the behavior of children with ASD with that of children with typical development (TD) during a JA elicitation task while the children interacted with either a human or a robotic agent. We used the robot "CommU," which has clear eyes and can turn its eyes, for the robotic intervention. The age range of the participants was limited to 5-6 years.

Results

Sixty-eight participants participated in this study, including 30 (10 females and 20 males) children with ASD and 38 (13 females and 25 males) children with TD. The participants were randomly assigned to one of the following two groups: the robotic intervention group or the control group. JA in the children with ASD was better during the robotic intervention than during the human agent intervention. These children exhibited improved performance in the JA task with human after interacting with the robot CommU. JA was differentially facilitated by the human and robotic agents between the ASD and TD children.

Conclusions

The findings of this study significantly contribute to the literature on the impact of robots on JA and provide information regarding the suitability of specific robot types for therapeutic use.

The effects of embodied rhythm and robotic interventions on the spontaneous and responsive social attention patterns of children with Autism Spectrum Disorder (ASD): A pilot randomized controlled trial

We compared the effects of 8-weeks of rhythm and robotic interventions with those of a comparison, standard-of-care intervention, on the spontaneous and responsive social attention patterns of school-age children with Autism Spectrum Disorder. Attention patterns were examined within a standardized pretest/posttest measure of joint attention (JA) and a training-specific social attention measure during early, mid, and late training sessions. The rhythm and comparison groups demonstrated improvements in JA. Social attention was greater in the rhythm followed by the robot and lastly the comparison group. The robot and comparison groups spent maximum time fixating on the robot and objects, respectively. Across sessions, the robot group decreased attention to the robot and increased attention to elsewhere. Overall, rhythmic movement contexts afford sustained social monitoring in children with autism.

Child maltreatment, inflammation, and internalizing symptoms: Investigating the roles of C-reactive protein, gene variation, and neuroendocrine regulation

Prior research has found inconsistent evidence regarding the association among childhood adversity, inflammation, and internalizing symptoms, perhaps because previous studies have yet to adequately integrate important factors such as the timing of the adversity, genetic variation, and other relevant processes such as neuroendocrine regulation. The aims of the present study were threefold: (a) to determine whether the effect of the timing of child maltreatment on C-reactive protein (CRP), an inflammatory marker, varies by CRP gene variation; (b) to explore whether links between salivary CRP and childhood internalizing symptoms depend on the presence and timing of maltreatment experiences; and (c) to investigate the role of CRP in the relations between child neuroendocrine regulation and internalizing symptoms and examine whether these associations are moderated by the presence and timing of child maltreatment. Participants included a sample of 267 maltreated and 222 nonmaltreated children (M age = 9.72, SD = 0.99; 52.4% male; 66% African American) who attended a summer day camp research program designed for school-aged low-income children. Department of Human Services records were examined to determine the onset and recency of maltreatment for children in the maltreated group. The results indicated that among children with recent onset maltreatment, those with at least one A allele from CRP single nucleotide polymorphism rs1417938 evidenced significantly higher CRP levels compared to recently maltreated children carrying the TT genotype. Moreover, higher levels of CRP were associated with higher levels of internalizing symptoms only for recently maltreated children. Finally, we did not find support for salivary CRP as a mechanism in the relation between neuroendocrine regulation and childhood internalizing symptoms. Our findings highlight the importance of the timing of child maltreatment and have important implications for characterizing variability in inflammation and internalizing symptoms among youth.

Childhood maltreatment and its effect on neurocognitive functioning: Timing and chronicity matter

Childhood maltreatment represents a complex stressor, with the developmental timing, duration, frequency, and type of maltreatment varying with each child (Barnett, Manly, & Cicchetti, 1993; Cicchetti & Manly, 2001). Multiple brain regions and neural circuits are disrupted by the experience of child maltreatment (Cicchetti & Toth, in press; DeBellis et al., 2002; McCrory & Viding, 2010; Teicher, Anderson, & Polcari, 2012). These neurobiological compromises indicate the impairment of a number of important cognitive functions, including working memory and inhibitory control. The present study extends prior research by examining the effect of childhood maltreatment on neurocognitive functioning based on developmental timing of maltreatment, including onset, chronicity, and recency, in a sample of 3- to 9-year-old nonmaltreated (n = 136) and maltreated children (n = 223). Maltreated children performed more poorly on inhibitory control and working-memory tasks than did nonmaltreated children. Group differences between maltreated children based on the timing of maltreatment and the chronicity of maltreatment also were evident. Specifically, children who were maltreated during infancy, and children with a chronic history of maltreatment, exhibited significantly poorer inhibitory control and working-memory performance than did children without a history of maltreatment. The results suggest that maltreatment occurring during infancy, a period of major brain organization, disrupts normative structure and function, and these deficits are further instantiated by the prolonged stress of chronic maltreatment during the early years of life.

Prenatal tobacco exposure and self-regulation in early childhood: Implications for developmental psychopathology

Prenatal tobacco exposure (PTE) has a well-documented association with disruptive behavior in childhood, but the neurocognitive effects of exposure that underlie this link are not sufficiently understood. The present study was designed to address this gap, through longitudinal follow-up in early childhood of a prospectively enrolled cohort with well-characterized prenatal exposure. Three-year-old children (n = 151) were assessed using a developmentally sensitive battery capturing both cognitive and motivational aspects of self-regulation. PTE was related to motivational self-regulation, where children had to delay approach to attractive rewards, but not cognitive self-regulation, where children had to hold information in mind and inhibit prepotent motor responses. Furthermore, PTE predicted motivational self-regulation more strongly in boys than in girls, and when propensity scores were covaried to control for confounding risk factors, the effect of PTE on motivational self-regulation was significant only in boys. These findings suggest that PTE's impact on neurodevelopment may be greater in boys than in girls, perhaps reflecting vulnerability in neural circuits that subserve reward sensitivity and emotion regulation, and may also help to explain why PTE is more consistently related to disruptive behavior disorders than attention problems.

A Point of Departure in the Comparison of Social and Nonsocial Visual Orienting Among Persons With Autism Spectrum Disorders

Endogenous visual orienting among children with autism spectrum disorders (ASDs) and among typically developing (TD) children was examined using a Posner-type task that was modified to include social and nonsocial cues and targets to test hypotheses regarding information (social or nonsocial) and cue processing (long or short stimulus onset asynchronies (SOAs)). The findings suggest intact endogenous orienting to face and mixed face targets using hand and arrow cues among children with ASDs who were matched to typically developing children (TDC) on the basis of nonverbal mental age (MA) at approximately 8.5 years. The findings from this study challenge the notions of a social orienting impairment and of mechanical social orienting as the children with ASDs in this study demonstrated strong orienting effects in all conditions and social sensitivity in the long stimulus onset asynchrony (SOA) condition.

Interest towards human, animal and object in children with autism spectrum disorders: an ethological approach at home

Autistic spectrum disorders (ASD) are characterised by attention deficits in communication and social interactions and a lack of interest in people. Data are mostly based on clinical situations. However, recent studies have shown a more mixed situation where children with ASD (ASD children) displayed interest towards humans, in both experimental and natural settings. The aim of this study was to assess the interest of ASD children in a natural standardised home setting. Here, we hypothesised that ASD children would display more interest towards animate stimuli-human and pet-when in the child's home than in the lab experimental setting. We used an ethological approach involving observations, a methodological alternative to lab static techniques, to investigate the behaviour of ninety 6- to 12-year-old ASD and typical development (TD) children. Our results were consistent with those of the literature revealing that the ASD children displayed interest towards animate stimuli as did children with TD children. Interestingly, while the ASD children showed higher interest towards humans, e.g. their parent, than the TD children did, they showed less interest towards pet compared to the TD children. Our results suggested that animals are not inherently easy to decode for ASD children, in contrast with previous experiences where a pet was regarded as a more attractive partner, easier to be understood. At last, the ASD children changed more frequently their focus point than the TD children did. These differences may be explained by the reduced attention skills in ASD or the study's context. To conclude, larger exploratory studies in natural settings conducted beyond ordinary human to human interactions are crucial for better understanding of the underlying mechanisms involved in social interactions in ASD.

Affective facial expression processing in young children who have experienced maltreatment during the first year of life: an event-related potential study

This study employed event-related potentials (ERPs) to investigate the neural correlates of facial affect processing in maltreated and nonmaltreated children at 42 months of age. ERPs elicited while children passively viewed standardized pictures of female models posing angry, happy, and neutral facial expressions were examined, and differences between maltreated (N = 46) and nonmaltreated (N = 25) children were reported. Three occipital components (P1, N170, and P400) and four frontal-central components (N150, P240, Nc, and a positive slow wave [PSW]) were identified. Findings revealed that maltreated children had greater P1 and P400 amplitude in response to angry facial affect compared to other emotions, and compared to nonmaltreated children. N170 amplitude was greater in response to happy compared to angry in the maltreated group. For the P240 component, maltreated children had greater amplitude in response to angry facial expressions relative to happy, whereas children in the nonmaltreated group had greater P240 amplitude in response to happy relative to angry facial affect. Further, the nonmaltreated group had greater PSW amplitude in response to angry facial affect, whereas those in the maltreated group showed greater PSW amplitude to happy facial expressions. The results provided further support for the hypothesis that the experience of maltreatment and the predominantly negative emotional tone in maltreating families alters the functioning of neural systems associated with the identification and processing of facial emotion. These results exemplify the importance of early preventive interventions focused on emotion for children who have experienced maltreatment early in life.

Annual Research Review: Parenting and children's brain development: the end of the beginning

After questioning the practical significance of evidence that parenting influences brain development - while highlighting the scientific importance of such work for understanding how family experience shapes human development - this paper reviews evidence suggesting that brain structure and function are 'chiselled' by parenting. Although the generalisability of most findings is limited due to a disproportionate, but understandable focus on clinical samples (e.g., maltreated children with post-traumatic stress disorder (PTSD)) and causal inferences are difficult to draw because of the observational nature of most of the evidence, it is noteworthy that some work with community samples and very new experimental work (e.g., parent training) suggests that tentative conclusions regarding effects of parenting on the developing brain may well be substantiated in future research. Such efforts should focus on parenting in the normal range, experimental manipulations of parenting, differential susceptibility to parenting effects and pathway models linking parenting to brain development and, thereby, to behavioural development. Research on parenting and children's brain development may be regarded as at 'the end of the beginning'.

Slowed orienting of covert visual-spatial attention in autism: Specific deficits associated with cerebellar and parietal abnormality

The most commonly reported finding from structural brain studies in autism is abnormality of the cerebellum. Autopsy and magnetic resonance imaging (MR) studies from nine independent research groups have found developmental abnormality of the cerebellar vermis or hemispheres in the majority of the more than 240 subjects with autism who were studied. We reported previously that patients with autism and those with acquired damage to the cerebellum were slow to shift attention between and within sensory modalities. In this study, we found that patients with autism who come from a group with significant cerebellar abnormality were also slow to orient attention in space.

A subgroup of these patients who have additional or corollary parietal abnormality, like previously studied patients with acquired parietal damage, were also slow to detect and respond to information outside an attended location. Posner, Walker, Friedrich, and Rafal (1984) showed that patients with parietal lesions were slow to respond to contralesional information if they were attending an ipsilesional location. This study has replicated that finding in patients with autism who have developmental bilateral parietal abnormality, and found a strong correlation between the attentional deficits and the amount of neuroanatomic parietal abnormality in these patients. This is the first time in the study of autism that there is evidence for a statistically significant association of the size of a specific brain structural abnormality with a specific behavioral deficit.

These findings illustrate that in autism different patterns of underlying brain pathology may result in different patterns of functional deficits. In conjunction with previous studies of patients with acquired lesions, these data have implications for the brain bases of normal attention. The cerebellum may affect the speed with which attentional resources can be activated, while the parietal cortex affects the ability to use those resources for efficient information processing at locations outside an attended focus. Deficits in the speed and efficiency with which neural activity can be modulated to facilitate processing can clearly influence cognitive function. Such deficits may contribute to the behavioral disabilities that characterize autism.

An event-related potential study of the processing of affective facial expressions in young children who experienced maltreatment during the first year of life

This investigation examined the effects of maltreatment during the first year of life on the neural correlates of processing facial expressions of emotion at 30 months of age. Event-related potentials (ERPs) in response to children passively viewing standardized pictures of female models posing angry, happy, and neutral facial expressions were examined. Four ERP waveform components were derived: early negative (N150), early positive (P260), negative central (Nc), and positive slow wave (PSW). Differences in these waveforms between a group of 35 maltreated and 24 nonmaltreated children were reported. The groups did not differ on the early perceptual negative component (N150), whereas the maltreated children had greater P260 amplitude at frontal leads compared to the nonmaltreated children in response to viewing angry facial expressions. For the Nc component, the nonmaltreated comparison children exhibited greater amplitude while viewing pictures of happy faces compared to angry and neutral faces, whereas the maltreated children showed greater Nc amplitude at central sites while viewing angry faces. For the PSW, the nonmaltreated group showed a greater area score in the right hemisphere in response to viewing angry facial expressions compared to the maltreated group. The results are discussed in terms of brain development and function, as well as their implications for the design and evaluation of preventive interventions.

Autism: a window onto the development of the social and the analytic brain

Although the neurobiological understanding of autism has been increasing exponentially, the diagnosis of autism spectrum conditions still rests entirely on behavioral criteria. Autism is therefore most productively approached using a combination of biological and psychological theory. The triad of behavioral abnormalities in social function, communication, and restricted and repetitive behaviors and interests can be explained psychologically by an impaired capacity for empathizing, or modeling the mental states governing the behavior of people, along with a superior capacity for systemizing, or inferring the rules governing the behavior of objects. This empathizing-systemizing theory explains other psychological models such as impairments of executive function or central coherence, and may have a neurobiological basis in abnormally low activity of brain regions subserving social cognition, along with abnormally high activity of regions subserving lower-level, perceptual processing--a pattern that may result from a skewed balance of local versus long-range functional connectivity.

The orbitofrontal-amygdala circuit and self-regulation of social-emotional behavior in autism

Individuals with an autistic spectrum disorder are impaired not only in understanding others' mental states, but also in self-regulation of social-emotional behavior. Therefore, a model of the brain in autism must encompass not only those brain systems that subserve social-cognitive and emotional functioning, but also those that subserve the self-regulation of behavior in response to a changing social environment. We present evidence to support the hypothesis that developmental dysfunction of the orbitofrontal-amygdala circuit of the brain is a critical factor in the development of autism and that some of the characteristic deficits of persons with autism in socio-emotional cognition and behavioral self-regulation are related to early dysfunction of different components of this circuit. A secondary hypothesis posits that the degree of intellectual impairment present in individuals with autism is directly related to the integrity of the dorsolateral prefrontal-hippocampal circuit of the brain. Together, these hypotheses have the potential to help explain the neurodevelopmental basis of some of the primary manifestations of autism as well as the heterogeneity of outcomes.

Early social attention impairments in autism: social orienting, joint attention, and attention to distress

This study investigated social attention impairments in autism (social orienting, joint attention, and attention to another's distress) and their relations to language ability. Three- to four-year-old children with autism spectrum disorder (ASD; n = 72), 3- to 4-year-old developmentally delayed children (n = 34), and 12- to 46-month-old typically developing children (n = 39), matched on mental age, were compared on measures of social orienting, joint attention, and attention to another's distress. Children with autism performed significantly worse than the comparison groups in all of these domains. Combined impairments in joint attention and social orienting were found to best distinguish young children with ASD from those without ASD. Structural equation modeling indicated that joint attention was the best predictor of concurrent language ability. Social orienting and attention to distress were indirectly related to language through their relations with joint attention. These results help to clarify the nature of social attention impairments in autism, offer clues to developmental mechanisms, and suggest targets for early intervention.

Autism as a disorder of neural information processing: directions for research and targets for therapy

The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which they feed, is hampered by the large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging, and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself.

Functional anatomy of impaired selective attention and compensatory processing in autism

In autism, physiological indices of selective attention have been shown to be abnormal even in situations where behaviour is intact. This divergence between behaviour and physiology suggests the action of some compensatory process of attention, one which may hold clues to the aetiology of autism's characteristic cognitive phenotype. Six subjects with autism spectrum disorders and six normal control subjects were studied with functional magnetic resonance imaging while performing a bilateral visual spatial attention task. In normal subjects, the task evoked activation in a network of cortical regions including the superior parietal lobe (P<0.001), left middle temporal gyrus (P=0.002), left inferior (P<0.001) and middle (P<0.02) frontal gyri, and medial frontal gyrus (P<0.02). Autistic subjects, in contrast, showed activation in the bilateral ventral occipital cortex (P<0.03) and striate cortex (P<0.05). Within the task condition, a region-of-interest comparison of attend-left versus attend-right conditions indicated that modulation of activation in the autistic brain as a function of the lateral focus of spatial attention was abnormally decreased in the left ventral occipital cortex (P<0.03), abnormally increased in the left intraparietal sulcus (P<0.01), and abnormally variable in the superior parietal lobe (P<0.03). These results are discussed in terms of a model of autism in which a pervasive defect of neural and synaptic development produces over-connected neural systems prone to noise and crosstalk, resulting in hyper-arousal and reduced selectivity. These low-level attentional traits may be the developmental basis for higher-order cognitive styles such as weak central coherence.

Impact of trauma on children

Millions of children are affected by physical and sexual abuse, natural and technological disasters, transportation accidents, invasive medical procedures, exposure to community violence, violence in the home, assault, and terrorism. Unfortunately, the emotional impact of exposure to trauma on children is often unappreciated and therefore untreated, and yet the impact of exposures to disaster and violence is profound and long-lasting. This article first briefly discusses the epidemiology of trauma in children, and then reviews the psychiatric and neurodevelopmental impact of trauma on children as well as the effects of trauma on children's emotional development. Trauma in children can lead to the development of posttraumatic stress disorder as well as to a variety of other psychiatric disorders, including depression, generalized anxiety disorder, panic attacks, borderline personality disorder, and substance abuse in adult survivors of trauma. Research has found that early exposure to stress and trauma causes physical effects on neurodevelopment which may lead to changes in the individual's long-term response to stress and vulnerability to psychiatric disorders. Exposure to trauma also affects children's ability to regulate, identify, and express emotions, and may have a negative effect on the individual's core identity and ability to relate to others. The authors also discuss what has been learned, based on recent experiences such as the World Trade Center catastrophe, about the role of television viewing in increasing the effects of traumatic events. The last section of the article provides guidance concerning the identification and clinical treatment of children and adolescents who are having emotional problems as a result of exposure to trauma.

Forensic evaluation of trauma syndromes in children

There are significant differences between a clinical evaluation and a forensic evaluation [289-291]. These differences must be kept solidly in mind in performing the evaluation. The forensic evaluator needs to assess the validity of complaints, including the possibility of malingering and the child's ability to describe symptoms accurately, the connection between the symptoms and a given incident, and the potential long-term sequelae of a trauma. The goal of the interview is not to treat, but to obtain information. Assessing the validity of complaints is perhaps the greatest challenge. This requires obtaining and reconciling data from numerous sources, including interviews with the child and parents, and information from other sources, as well as rating scales and validity testing. One must be very cautious in asking leading questions and using standardized PTSD protocols, lest they teach the parents and child about the symptoms of PTSD and thereby distort the information they provide as a result. The forensic interviewer should consider what will be needed when called to testify in court. What data will convince the jury? How might the opposing attorney challenge the assessment? What scientific studies support the findings and conclusions concerning the diagnosis, functional impairment, and validity. The precise DSM-IV-TR diagnosis is not always key in a forensic evaluation. What is essential is establishing the connection between the trauma and ensuing emotional problems. All of the symptoms the individual has as a result of the trauma become important, whether or not they contribute to fulfillment of DSM-IV-TR criteria. This contrasts with a clinical evaluation in which one needs to demonstrate the existence of a DSM-IV-TR diagnosis for reimbursement purposes. Finally, the forensic evaluator should be familiar with current practice guidelines for examination of children with PTSD. Any deviation may need to be explained in court [264,292].

A reconceptualization of learning disabilities via a self-organizing systems paradigm

A dilemma exists regarding the interpretation of learning disabilities. A self-organizing systems (SOS) paradigm suggests widespread, diffuse outcomes, whereas a specific learning disability concept suggests more localized dysfunction. There may be very good reason to doubt the veridicality of the concept of a specific learning disability, not because the construct of learning disabilities itself is a frivolous concept, as some have held, but because the biological or neurological events that underlie a learning disability do not remain focal and constrained only to specific dysfunction. It is important to know whether an identified learning disability remains contained or whether processing disorders might be found in other areas. The assessment profiles of school-age children identified with nonverbal learning disabilities (NLD), assumed to have primarily right-hemispheric brain dysfunctions, and children with language-based learning disabilities (LLD), assumed to have primarily left-hemispheric brain dysfunctions, were examined to explore learning disabilities using an SOS paradigm. The pilot study reported here is used as an exemplar of how a self-organizing systems paradigm is conceptualized. Although a more comprehensive study is needed to confirm the data, this exemplar suggests that overflow into areas not typically associated with each disability subtype may occur. Concerns regarding ways of determining discrepancy for diagnostic purposes are noted, and remediation strategies designed for specific disabilities are questioned.

Neuroanatomic contributions to slowed orienting of attention in children with autism

Previous research has demonstrated that adult autistic patients are abnormally slow to orient attention, with degree of slowed orienting associated with severity of cerebellar hypoplasia. This research was extended to children who, at ages two through six, met diagnostic criteria for autism and underwent magnetic resonance imaging (MRI). An average of 3 years later, when old enough to participate in behavioral experiments, the children returned to the laboratory and completed a spatial attention paradigm. Degree of slowed attentional orienting to visual cues was significantly correlated with degree of cerebellar hypoplasia, but not with size of other neuroanatomic regions. Additionally, there was a trend for orienting speed to differ between diagnostic outcome subgroups; children with confirmed diagnoses of autism at time of behavioral testing had larger orienting deficits than those who no longer met diagnostic criteria for autism. This research is among the first to establish a specific brain-behavior link in autistic children.

Attention coordination and anticipatory control

The coordination of the direction of selective attention is an adaptive function that may be one of the many anticipatory tools under cerebellar control. This chapter presents neurobehavioral, neurophysiological, and neuroimaging data to support our hypothesis that the cerebellum plays a role in attentional functions. We discuss the idea that the cerebellum is a master computational system that anticipates and adjusts responsiveness in a variety of brain systems (e.g., sensory, attention, memory, language, affect) to efficiently achieve goals determined by cerebral and other subcortical systems.

Brainstem, cerebellar and limbic neuroanatomical abnormalities in autism

Recent autopsy and/or quantitative magnetic resonance imaging studies of autistic patients have identified agenesis of the superior olive, dysgenesis of the facial nucleus, reduced numbers of Purkinje neurons, hypoplasia of the brainstem and posterior cerebellum, and increased neuron-packing density of the medial, cortical and central nuclei of the amygdala and the medial septum. As neurogenesis occurs for these different neuron types during approximately the fifth week of gestation, the possibility is raised that this may be a 'window of vulnerability' for autism; the likely etiologic heterogeneity of autism suggests that other windows of vulnerability are also possible.

Visual attention abnormalities in autism: delayed orienting to location

These studies provide evidence for slowed spatial orienting of attention in autism. A group of well-defined adult autistic subjects and age-matched normal controls performed a traditional spatial cueing task in which attention-related response facilitation is indexed by speed of target detection. To address the concern that motor impairment may interfere with interpretation of response time measures in those with neurologic abnormality, we also used a new adaptation of the traditional task that depended on accuracy of response (target discrimination) rather than speed of response. This design allowed separation of time to process and respond to target information from the time to move and engage (orient) attention. Results from both tasks were strikingly similar. Normal subjects oriented attention very quickly, and showed maximal performance facilitation at a cued location within 100 ms. Autistic subjects oriented attention much more slowly and showed increasing benefits of a spatial cue with increasing cue-to-target delays. These results are consistent with previous reports that patients with autism, the majority of whom have developmental abnormalities of the cerebellum, as well as those with acquired damage to the cerebellum, are slow to shift attention between and within modalities. This paper also addresses the variability in behavioral findings in autism, and suggests that many of the apparently contradictory findings may actually reflect sampling differences in patterns of brain pathology.