[Social cognition in autism. A survey of functional imaging studies]

Enhanced cognitive processing by viewing snakes in children with autism spectrum disorder. A preliminary study

BACKGROUND

Prioritization of the processing of threatening stimuli induces deleterious effects on task performance. However, emotion evoked by viewing images of snakes exerts a facilitating effect upon making judgments of their color in neurotypical adults and schoolchildren. We attempted to confirm this in school and preschool children with and without Autism Spectrum Disorder (ASD).

METHODS

Forty French children participated and corresponded to two age groups: a group of schoolchildren and a group of preschool children, each group including 10 children with typical development and 10 children with ASD. Each participant was exposed to 120 trials composed of 20 photographs of snakes and 20 photographs of flowers, each of which appeared 3 times (in red, green and blue). Participants were asked to indicate the color of each image as quickly as possible via key-press. A three-way analysis of variance test for reaction time (RT) considering image type (IMAGE), participant group (PARTICIPANT), and age (AGE) as main effects and its interaction terms was performed for each subject.

RESULTS

When the reaction time required to respond to presented stimuli was measured, schoolchildren tended to respond faster when stimuli were snake images than when stimuli were flower images whether the children had or did not have ASD. For the 5-to-6-year-old preschool participants, the difference between reaction time for the color-naming of snake images and flower images was ambiguous overall.

CONCLUSIONS

There were possible odd color-specific effects in children with ASD when images were presented to the children in green. Implications of the findings are argued with respect to active avoidance or attraction as one of the behavioral characteristics commonly noted in children with ASD.

Neural networks related to dysfunctional face processing in autism spectrum disorder

One of the most consistent neuropsychological findings in autism spectrum disorders (ASD) is a reduced interest in and impaired processing of human faces. We conducted an activation likelihood estimation meta-analysis on 14 functional imaging studies on neural correlates of face processing enrolling a total of 164 ASD patients. Subsequently, normative whole-brain functional connectivity maps for the identified regions of significant convergence were computed for the task-independent (resting-state) and task-dependent (co-activations) state in healthy subjects. Quantitative functional decoding was performed by reference to the BrainMap database. Finally, we examined the overlap of the delineated network with the results of a previous meta-analysis on structural abnormalities in ASD as well as with brain regions involved in human action observation/imitation. We found a single cluster in the left fusiform gyrus showing significantly reduced activation during face processing in ASD across all studies. Both task-dependent and task-independent analyses indicated significant functional connectivity of this region with the temporo-occipital and lateral occipital cortex, the inferior frontal and parietal cortices, the thalamus and the amygdala. Quantitative reverse inference then indicated an association of these regions mainly with face processing, affective processing, and language-related tasks. Moreover, we found that the cortex in the region of right area V5 displaying structural changes in ASD patients showed consistent connectivity with the region showing aberrant responses in the context of face processing. Finally, this network was also implicated in the human action observation/imitation network. In summary, our findings thus suggest a functionally and structurally disturbed network of occipital regions related primarily to face (but potentially also language) processing, which interact with inferior frontal as well as limbic regions and may be the core of aberrant face processing and reduced interest in faces in ASD.

ADHD and autism: differential diagnosis or overlapping traits? A selective review

According to DSM-IV TR and ICD-10, a diagnosis of autism or Asperger Syndrome precludes a diagnosis of attention-deficit/hyperactivity disorder (ADHD). However, despite the different conceptualization, population-based twin studies reported symptom overlap, and a recent epidemiologically based study reported a high rate of ADHD in autism and autism spectrum disorders (ASD). In the planned revision of the DSM-IV TR, dsm5 (www.dsm5.org), the diagnoses of autistic disorder and ADHD will not be mutually exclusive any longer. This provides the basis of more differentiated studies on overlap and distinction between both disorders. This review presents data on comorbidity rates and symptom overlap and discusses common and disorder-specific risk factors, including recent proteomic studies. Neuropsychological findings in the areas of attention, reward processing, and social cognition are then compared between both disorders, as these cognitive abilities show overlapping as well as specific impairment for one of both disorders. In addition, selective brain imaging findings are reported. Therapeutic options are summarized, and new approaches are discussed. The review concludes with a prospectus on open questions for research and clinical practice.

[Brain imaging in autism spectrum disorders. A review]

In the past two decades, an increasing number of functional and structural brain imaging studies has provided insights into the neurobiological basis of autism spectrum disorders (ASD). This article summarizes pertinent functional brain imaging studies addressing the neuronal underpinnings of ASD symptomatology (impairments in social interaction and communication, repetitive and restrictive behavior) and associated neuropsychological deficits (theory of mind, executive functions, central coherence), complemented by relevant structural imaging findings. The results of these studies show that although cognitive functions in ASD are generally mediated by the same brain regions as in typically developed individuals, the degree and especially the patterns of brain activation often differ. Therefore, a hypothesis of aberrant network connectivity has increasingly been favored over one of focal brain dysfunction.

Neuropsychologische Modelle von Autismus-Spektrum-Störungen

Fragestellung: Der Artikel gibt einen Überblick über die Modelle der Theory of Mind (ToM), Exekutivfunktionen (EF) und Zentralen Kohärenz (ZK), welche die neuropsychologischen Auffälligkeiten bei Menschen mit Autismus-Spektrum Störungen (ASS) treffend zu beschreiben vermögen. Methodik: In einem selektiven Review werden Ergebnisse behavioraler und funktionell-bildgebender Arbeiten zu den sozial-kognitiven, emotionalen und exekutiven Funktionen sowie der lokal-orientierten Wahrnehmung bei ASS berichtet. Ergebnisse: Beeinträchtigungen in ToM und EF sowie Besonderheiten in ZK sind vielfach replizierte Phänomene bei ASS. Vor allem soziale Wahrnehmungsprobleme und ToM haben einen hohen Erklärungswert für die klinische Symptomatik von ASS. Cerebrale Aktivierungsmuster unterscheiden sich bei Menschen mit und ohne ASS für ToM, EF und ZK. Als übergeordnetes neurales Erklärungsmodell scheint sich verringerte Konnektivität rekrutierter kortikaler Netzwerke gegen das Konzept einzelner betroffener Gehirnareale durchzusetzen. Schlussfolgerungen: Für ein besseres Verständnis der komplexen Zusammenhänge bei ASS ist eine zukünftige Integration klinischer, neuropsychologischer, funktionell-bildgebender und molekulargenetischer Befunde essenziell. Schwächen bei ToM und EF sowie Stärken in den Bereichen detail-orientierte Wahrnehmung sollten bei der individuellen Interventionsplanung verstärkt Eingang finden.

Autismus-Spektrum-Störungen

Dem Thema Autismus-Spektrum-Störungen (ASD) wurde in den letzten Jahren sowohl in der empirischen Forschung als auch in der Öffentlichkeit deutlich mehr Aufmerksamkeit gewidmet. Im vorliegenden Themenschwerpunkt werden neben klinischen auch relevante Forschungsfragen dieser Thematik aufgegriffen und diskutiert. Außer diagnostischen werden sowohl neuropsychologische Konzepte als auch therapeutische Betrachtungsweisen und Perspektiven aufgezeigt. Ein Ziel ist dabei, neben einem umfangreichen Verständnis und Wissen um die Störung, eine möglichst frühe und exakte diagnostische Einschätzung auch von milderen Varianten, um frühzeitig gezielte therapeutische Schritte einzuleiten. In zukünftigen Studien sollte darüber hinaus der Entwicklungsaspekt über die Lebensspanne stärker berücksichtigt werden.

[Autism and autistic disorders. Historical and current aspects]

Since its first use in medical literature the meaning of the term autism has constantly changed. An historical overview indicates that in both adult and child psychiatry autism was first used to refer to a symptom of schizophrenia. Later on the use of the term in child psychiatry took a different independent course, which led to present-day conceptualization of autism, mainly due to the work of Leo Kanner and Hans Asperger. Currently autism and autistic disorders are regarded as severe developmental disorders and, due to their stable nature, have gained considerable attention in adult psychiatry. In order to better understand this development, the path from onset to reception is traced via Kanner and Asperger. In the search for central characteristics of autism, one finds restrictions in social communication and interaction, which can be explained by fundamental deficits in social cognition. These restrictions in social cognition can be considered the central characteristic of autism - one which has been a constant since the phenomenon was first described. Our historical review considers to what extent experimental psychopathological research can deepen our understanding of the disorder.