Relationship between Autistic Spectrum Trait and Regional Cerebral Blood Flow in Healthy Male Subjects

OBJECTIVE: Autistic spectrum traits are postulated to lie on a continuum that extends between individuals with autism and individuals with typical development. The present study was carried out to investigate functional and network abnormalities associated with autistic spectrum trait in healthy male subjects. METHODS: Subjects were 41 healthy male subjects who underwent the social responsiveness scale-adult (SRS-A) and magnetic resonance imaging. RESULTS: There was significant positive correlation between the total score of SRS-A and the regional cerebral blood flow (CBF) in posterior cingulate cortex (PCC). Also, there were changes in functional network such as in cingulate corti, insula and fusiform cortex. Further, we also found the significant difference of functional networks between the healthy male subjects with high or low autistic spectrum trait, and these points were congruent with the previous perceptions derived from autistic-spectrum disorders. CONCLUSION: These findings suggest a biological basis for the autistic spectrum trait and may be useful for the imaging marker of autism symptomatology.

Neuropsychiatric comorbidities in autism spectrum disorders without intellectual disability

Epilepsy and autism spectrum disorder tend to co-occur in the population with intellectual disability. However, in the autistic population without intellectual disability, the prevalence of epilepsy is also much greater than in the general population. The special health needs in children having autism spectrum disorder without intellectual disability, namely those with high-functioning autism spectrum disorder have become recognized in recent years, yet comorbid neuropsychiatric symptoms such as anxiety, attention-defi cit/hyperactivity disorder, and epilepsy still sometimes remain undiagnosed and untreated. Heightened awareness of such comorbidities will help these children to access appropriate treatment. Whether the epilepsy associated with high-functioning autism spectrum disorder is the same or different from that associated with intellectual disability, and whether the autistic profi le associated with epilepsy in high-functioning autism spectrum disorder is the same or different from that without epilepsy, should be answered by future studies.

Prepulse Inhibition of Startle Response: Recent Advances in Human Studies of Psychiatric Disease

Prepulse inhibition (PPI) is considered to be one of the most promising neurophysiological indexes for translational research in psychiatry. Impairment of PPI has been reported in several psychiatric diseases, particularly schizophrenia, where PPI is considered a candidate intermediate phenotype (endophenotype) of the disease. Recent findings from a variety of research areas have provided important evidence regarding PPI impairment. Human brain imaging studies have demonstrated the involvement of the striatum, hippocampus, thalamus and frontal and parietal cortical regions in PPI. In addition, several genetic polymorphisms, including variations in the genes coding for Catechol O-methyltransferase, Neuregulin 1, nuclear factor kappa-B subunit 3 and serotonin-2A receptor were related to PPI; and these findings support PPI as a polygenetic trait that involves several neurotransmitter pathways. Early psychosis studies suggest that PPI disruption is present before the onset of psychosis. Also, discrepancy of PPI impairment between children and adults can be found in other psychiatric diseases, such as autistic spectrum disorders and posttraumatic stress disorder, and comprehensive investigation of startle response might contribute to understand the impairment of the neural circuitry in psychiatric diseases. Finally, recent studies with both Asian and Caucasian subjects indicate that patients with schizophrenia exhibit impaired PPI, and impaired sensorimotor gating might be a global common psychophysiological feature of schizophrenia. In conclusion, studies of PPI have successfully contributed to a better understanding of the fundamental neural mechanisms underlying sensorimotor gating and will certainly be most valuable in devising future approaches that aim to investigate the complex pathogenesis of psychiatric diseases.