Elevated amygdala response to faces and gaze aversion in autism spectrum disorder

Autism spectrum disorders (ASD) are often associated with impairments in judgment of facial expressions. This impairment is often accompanied by diminished eye contact and atypical amygdala responses to face stimuli. The current study used a within-subjects design to examine the effects of natural viewing and an experimental eye-gaze manipulation on amygdala responses to faces. Individuals with ASD showed less gaze toward the eye region of faces relative to a control group. Among individuals with ASD, reduced eye gaze was associated with higher threat ratings of neutral faces. Amygdala signal was elevated in the ASD group relative to controls. This elevated response was further potentiated by experimentally manipulating gaze to the eye region. Potentiation by the gaze manipulation was largest for those individuals who exhibited the least amount of naturally occurring gaze toward the eye region and was associated with their subjective threat ratings. Effects were largest for neutral faces, highlighting the importance of examining neutral faces in the pathophysiology of autism and questioning their use as control stimuli with this population. Overall, our findings provide support for the notion that gaze direction modulates affective response to faces in ASD.

Effects of diagnosis, race, and puberty on platelet serotonin levels in autism and mental retardation

OBJECTIVE

To reevaluate platelet serotonin (5-HT) levels in autism, measuring and controlling for effects of race and puberty. The specificity of hyperserotonemia for autism versus cognitive impairment is also assessed.

METHOD

Platelet 5-HT levels were measured in 77 individuals, aged 2 through 37 years, with autistic disorder; 65 normal controls; and 22 mentally retarded or otherwise cognitively impaired (MR/CI) prepubertal children. Effects of diagnosis, race, and pubertal status were evaluated by analysis of variance in separate pre- and postpubertal groups. 5-HT levels were expressed as ng/mL blood and ng/microL platelet volume.

RESULTS

Among prepubertal children, significant effects of diagnosis (ng/mL; F2,109 = 5.9, p = .004) and race (F2,109 = 14.7, p < .0005) were found. Autistic youngsters had significantly higher 5-HT concentrations than controls, although the elevation (25%) was less than typically reported; MR/CI children had levels very similar to those of controls. White children had significantly lower 5-HT levels than black or Latino youngsters, regardless of diagnosis. Diagnosis and race effects were nonsignificant in the postpubertal group. Postpubertal subjects had lower 5-HT concentrations than prepubertal subjects (ng/mL; F1,114 = 28.5, p < .0005).

CONCLUSIONS

The data underscore the importance of matching for race and pubertal status in neuropsychiatric research and suggest that the prevalence of hyperserotonemia in autistic individuals may have been overestimated because of a failure to control for both variables. Hyperserotonemia was not found in MR/CI youngsters without autistic features.

Plasma beta-endorphin, adrenocorticotropin hormone, and cortisol in autism

Plasma levels of the hypothalamo-pituitary-adrenal axis hormones beta-endorphin (BE), adrenocorticotropin hormone (ACTH), and cortisol were measured in autistic (N = 48), mentally retarded/cognitively impaired (MR/CI, N = 16), and normal control (N = 26) individuals. Comparison of log transformed data from the three groups revealed that levels of BE and ACTH were significantly higher (p < .05) in the autistic individuals than in normal controls. The higher means in the autistic group were due to significantly higher plasma levels of BE and ACTH, indices of acute stress response, in the more severely affected individuals. The data support the idea that individuals with severe autism have a heightened response to acute stressors rather than chronic hyperarousal or elevated basal stress response system functioning.

Plasma androgens in autism

Plasma levels of testosterone and the adrenal androgen dehydroepiandrosterone sulfate (DHEA-S) were measured in male autistic subjects (31 prepubertal, 8 postpubertal), mentally retarded/cognitively impaired subjects (MR, 12 prepubertal), and normal control subjects (NC, 10 prepubertal, 11 postpubertal). Mean levels of plasma testosterone were similar in the postpubertal autistic (4.54 +/- 1.12 ng/ml) and postpubertal NC (5.02 +/- 1.87 ng/ml) groups. Plasma DHEA-S levels in postpubertal autistic (2170 +/- 1020 ng/ml) and postpubertal NC (1850 +/- 777 ng/ml) groups also were not significantly different. Similarly, no significant group differences were seen for testosterone or DHEA-S in the prepubertal autistic, MR, or NC individuals, although prepubertal MR individuals with cerebral palsy did have increased plasma DHEA-S levels compared to age-matched MR or NC individuals. Significant negative correlations were found between testosterone and whole blood serotonin (5-HT) levels in the combined (all subjects, all ages) groups and in the autistic group, suggesting that the effect of puberty on whole blood 5-HT may deserve further study. Data indicate that altered secretion of the androgens is not a common feature of autism. However, abnormalities of adrenal androgen secretion may be present in individuals with cerebral palsy.

Social deviance in autism: a central integrative failure as a model for social nonengagement

Clinically, adult autistic and PDD individuals appear to have an uneasy relationship with their social environment no matter how much developmental progress they make. Many can work at modest jobs, many more do not, and even fewer are interested enough in the human environment to cohabitate and/or marry. A conversation with a young autistic man of 20 about a trip to visit a relative focuses more on the time the train left and how late it was in hypermnestic detail, including all details except the affective environment or the relationships to human beings. This is the human significance of the term autism. Autistics can speak and reference, but they seem not to understand the social requirements of a human interchange. If they do know it, they know it in a fragmentary or rudimentary way devoid of subtlety or nuance. Whatever we mean by social intercourse and whatever functions subsume it, they seem to emerge in interaction with cognition and language. They develop apace as human traverse those first 3 years of life and as they reach social maturity in adolescence. Autistic children appear not to integrate their knowledge of things in a representation that includes emotional and cognitive elements. They do not seem to understand that words necessarily refer to things of this world that others are also referencing in their words and sentences--shared reference is not natural to them. Intersubjectivity as a feature of common code use is not tacit or explicit in their behavior. They similarly do not use social referencing in the way in which normals do, and although they show some attachment to people, they seem to do so without benefit of affective display leading to reciprocity. There is little notion of the external that makes another human being distinguishable from a thing. Their treasured objects in early childhood are hard and lack comforting proximal receptor attractiveness as in normals. Hobson's extensive studies have elaborated a notion about the autistic child's knowledge of person. He comments on the lack of integration of the verbal and visual situational ties in which affective expression emerges and functions. He also comments on the deictic inabilities, inferring that the "I," "you," and "he" references do not have any significance for such children. We would like to note that while Vygotsky and others have observed that speech comes from the world of people, language comes from the maturing organism as an innate propensity.(ABSTRACT TRUNCATED AT 400 WORDS)

DSM-III and DSM-III-R diagnosis of autism and pervasive developmental disorder in nursery school children

DSM-III and DSM-III-R diagnoses of 112 developmentally disordered preschool children were compared. There was no significant difference between the DSM-III and DSM-III-R diagnosis of the inclusive category of pervasive developmental disorder, but nearly twice as many cases (58) were diagnosed as autistic disorder by DSM-III-R criteria as were diagnosed as infantile autism (31) by DSM-III. Thirty children met both DSM-III and DSM-III-R criteria for autism (IA/AD) and 23 received a DSM-III diagnosis of atypical PDD (A-PDD) and a DSM-III-R diagnosis of AD (A-PDD/AD). All of the IA/AD children and none of the A-PDD/AD group displayed a marked lack of awareness of others. DSM-III-R criteria have specifically broadened the concept of autism to include children who, although socially impaired, are not pervasively unresponsive to others.

Affect and cognition in autism

An array of six photographs of the same woman was used to assess the ability of 18 autistic, 14 nonautistic mentally retarded, and 18 normal preschool subjects to use affect- and activity-related concepts in the solution of cognitive tasks. The Total Performance Level of the autistic and mentally retarded subjects did not differ significantly. Autistic subjects performed imitation, directed action, and description tasks less well in the affect mode. The findings are consistent with other studies, suggesting an impairment in the expression of emotion in autism.

Serotonergic responsivity in male young adults with autistic disorder. Results of a pilot study

Altered serotonergic function has been postulated to exist in autistic disorder. Central serotonergic responsivity was assessed with a neuroendocrine challenge test in seven male young adults with autistic disorder and in seven age- and gender-matched healthy controls. Binding indexes and physiologic responsivity of the platelet serotonin-2 (5-HT2) receptor complex were also measured, as was whole-blood serotonin content. Compared with controls, autistic subjects had substantially blunted prolactin release in response to a 60-mg oral dose of fenfluramine hydrochloride, an indirect serotonin agonist [corrected]. Furthermore, the magnitude of serotonin-amplified platelet aggregation, mediated by the platelet 5-HT2 receptor complex, was reduced in the autistic group, as was the mean number of platelet 5-HT2 receptor sites. Among autistic subjects, fenfluramine-induced prolactin release correlated positively with the serotonin-amplified platelet aggregation response and negatively with whole-blood serotonin content. The results of the present study are compatible with the hypothesis that central serotonergic responsivity is decreased in male autistic young adults. Correlations between central and peripheral serotonergic measures in autistic subjects suggest that systemic alterations in serotonergic function may occur in autism.

Sleep and bedtime behavior in preschool-aged children

Age stage-specific changes in patterns of sleep and bedtime behavior were examined in 109 normally developing preschool-aged children who were the subjects of the New York Longitudinal Study of Temperament and Development. The data were derived from information abstracted from interviews conducted with parents about the behavior of their children in daily life situations at 1, 2, 3, 4, and 5 years of age. The following age trends were found: older children were significantly more likely to exhibit a prolongation of bedtime routine, insist on sleeping with the light on, take a treasured object to bed, request parental attention after being told good night, and experience delays in falling asleep than were younger children. The frequency of occurrence of night awakening was not different at the different age levels examined, although older children were significantly more likely to experience nightmares. The fathers of older children were significantly more likely to participate in bedtime routines, and older children were also significantly more likely to share a bedroom with a sibling. No sex differences were found.

Neurological 'soft' signs in low-birthweight children

Sixty-six longitudinally studied prematurely born children who had weighed between 1000 and 1750g at birth were examined neurologically at eight years of age. 13 of these children had localizing neurological findings and another 20 were found to have two or more non-localizing ('soft') signs of CNS dysfunction. These 33 children were significantly more likely to have sustained perinatal complications than were children whose neurological examinations were normal. However, a history of prenatal complications was significantly more frequent among children who subsequently developed 'soft' signs, while children with localizing findings were significantly more likely to have experienced postnatal complications. No significant differences in IQ or reading and arithmetic achievement test-score levels were found between children with 'soft' signs and those who were neurologically normal. Nevertheless, children with 'soft' signs were significantly more likely to have received special education and to have been referred for psychiatric consultation than were children who were neurologically normal.

Symptom formation as an expression of disordered information processing in schizophrenic children

The possible mechanisms that underlie symptom formation in childhood schizophrenia are discussed. A body of research evidence has been reviewed in which dissociation in relation to information processing was examined for its possible consequence in the formation and expression of symptomatology. Schizophrenic children have been found to exhibit dissociation of integrative processes among the sense systems at a level which is several years below normal expectation, and they usually fail to improve as age increases. The clinical manifestations of schizophrenia are considered to be the consequence of the conflict, distortion, and deprivation that derive from failure in information processing. These consequences can best be understood within a developmental framework which encompasses the different age-stages of function. This approach to the understanding of symptom formation is discussed in relationship to other evidence which suggests that primary neurological abnormality is present in schizophrenic children. Thus the identification of abnormality of intersensory integrative function may increase our understanding of etiology as well as of the mechanisms of symptom formation in schizophrenic children.