L. Clark Johnson

Abnormal functional connectivity in autism spectrum disorders during face processing

Abnormalities in the interactions between functionally linked brain regions have been suggested to be associated with the clinical impairments observed in autism spectrum disorders (ASD). We investigated functional connectivity within the limbic system during face identification; a primary component of social cognition, in 19 high-functioning adults with ASD and 21 age-and IQ-matched control adults. Activation during identification of previously viewed faces and houses using a one-back paradigm was compared. The fusiform face area (FFA) was individually localized in each participant and used as the seed point for functional connectivity analyses. The degree of correlation between FFA and the extended neural circuitry involved in face identification was tested. A whole brain analysis was also conducted in order to determine whether connectivity from the FFA to aberrant brain locations was present in the ASD group. Measures of clinical severity (ADOS social score and ADI-R social score) were included as independent variables into the functional connectivity analyses. Significant FFA-amygdala and FFA-superior temporal sulcus functional connectivity was found in both the ASD and control participants. However, the control group had significantly increased connectivity to the left amygdala and the posterior cingulate compared to ASD. Post hoc analyses additionally found increased connectivity to the thalamus in the controls. A significant relationship between abnormal functional connectivity and clinical severity in the ASD group was observed. Specifically, greater social impairment was associated with reduced FFA-amygdala connectivity and increased FFA-right inferior frontal connectivity. These results suggest that abnormal neural connections within the limbic system may contribute to the social impairments observed in ASD.

Reduced Neural Habituation in the Amygdala and Social Impairments in Autism Spectrum Disorders

OBJECTIVE Amygdala dysfunction has been proposed as a critical component in social impairment in autism spectrum disorders. This study was designed to investigate whether abnormal habituation characterizes amygdala dysfunction in autism spectrum disorders and whether the rate of amygdala habituation is related to social impairment. METHOD Using functional MRI, the authors measured change over time in activation of the amygdala and fusiform gyrus to neutral facial stimuli in adults with autism spectrum disorders and healthy comparison adults. RESULTS The comparison group evidenced significantly greater amygdala habituation bilaterally than the autism spectrum group. There were no group differences in overall fusiform habituation. For the autism spectrum group, lower levels of habituation of the amygdala to the face stimuli were associated with more severe social impairment. CONCLUSIONS These results suggest amygdala hyperarousal in autism spectrum disorders in response to socially relevant stimuli. Further, sustained amygdala arousal may contribute to the social deficits observed in autism spectrum disorders.

Association between amygdala response to emotional faces and social anxiety in autism spectrum disorders

Difficulty interpreting facial expressions has been reported in autism spectrum disorders (ASD) and is thought to be associated with amygdala abnormalities. To further explore the neural basis of abnormal emotional face processing in ASD, we conducted an fMRI study of emotional face matching in high-functioning adults with ASD and age, IQ, and gender matched controls. In addition, we investigated whether there was a relationship between self-reported social anxiety and fMRI activation. During fMRI scanning, study participants were instructed to match facial expressions depicting fear or anger. The control condition was a comparable shape-matching task. The control group evidenced significantly increased left prefrontal activation and decreased activation in the occipital lobes compared to the ASD group during emotional face matching. Further, within the ASD group, greater social anxiety was associated with increased activation in right amygdala and left middle temporal gyrus, and decreased activation in the fusiform face area. These results indicate that level of social anxiety mediates the neural response to emotional face perception in ASD.

fMRI evidence of neural abnormalities in the subcortical face processing system in ASD

Recent evidence suggests that a rapid, automatic face detection system is supported by subcortical structures including the amygdala, pulvinar, and superior colliculus. Early-emerging abnormalities in these structures may be related to reduced social orienting in children with autism, and subsequently, to aberrant development of cortical circuits involved in face processing. Our objective was to determine whether functional abnormalities in the subcortical face processing system are present in adults with autism spectrum disorders (ASD) during supraliminal fearful face processing. Participants included twenty-eight individuals with ASD and 25 controls group-matched on age, IQ, and behavioral performance. The ASD group met diagnostic criteria on the ADI-R, ADOS-G, and DSM-IV. Both the ASD and control groups showed significant activation in bilateral fusiform gyri. The control group exhibited additional significant responses in the right amygdala, right pulvinar, and bilateral superior colliculi. In the direct group comparison, the controls showed significantly greater activation in the left amygdala, bilateral fusiform gyrus, right pulvinar, and bilateral superior colliculi. No brain region showed significantly greater activation in the ASD group compared to the controls. Thus, basic rapid face identification mechanisms appear to be functional in ASD. However, individuals with ASD failed to engage the subcortical brain regions involved in face detection and automatic emotional face processing, suggesting a core mechanism for impaired socioemotional processing in ASD. Neural abnormalities in this system may contribute to early-emerging deficits in social orienting and attention, the putative precursors to abnormalities in social cognition and cortical face processing specialization.

Neurological Correlates of Reward Responding in Adolescents With and Without Externalizing Behavior Disorders

Opposing theories of striatal hyper- and hypodopaminergic functioning have been suggested in the pathophysiology of externalizing behavior disorders. To test these competing theories, the authors used functional MRI to evaluate neural activity during a simple reward task in 12- to 16-year-old boys with attention-deficit/hyperactivity disorder and/or conduct disorder (n = 19) and in controls with no psychiatric condition (n = 11). The task proceeded in blocks during which participants received either (a) monetary incentives for correct responses or (b) no rewards for correct responses. Controls exhibited striatal activation only during reward, shifting to anterior cingulate activation during nonreward. In contrast, externalizing adolescents exhibited striatal activation during both reward and nonreward. Externalizing psychopathology appears to be characterized by deficits in processing the omission of predicted reward, which may render behaviors that are acquired through environmental contingencies difficult to extinguish when those contingencies change.

Altered medial temporal lobe responses during visuospatial encoding in healthy APOE*4 carriers

The apolipoprotein varepsilon4 allele (APOE*4) is a major genetic risk factor for Alzheimers disease (AD) and has been associated with altered cortical activation as assessed by functional neuroimaging in cognitively normal younger and older carriers. We chose to evaluate medial temporal lobe (MTL) activation during encoding and recognition using a perspective-dependent (route or survey) visuospatial memory task by monitoring the blood-oxygen-level-dependent (BOLD) fMRI response in older, non-demented APOE*4 carriers (APOE*4+) and non-carriers (APOE*4-). During encoding, the APOE*4- group had greater average task-associated BOLD responses in ventral visual pathways, including the MTLs, as compared to the APOE*4+ group. Furthermore, MTL activation was greater during route encoding than survey encoding on average in APOE*4-, but not APOE*4+, subjects. During recognition, both groups performed similarly and no BOLD signal differences were found. Finally, within-group analysis revealed MTL activation during encoding was correlated with recognition performance in APOE*4-, but not APOE*4+ subjects. Reduced task-associated MTL activation that does not correlate with either visuospatial perspective or task performance suggests that MTL dysregulation occurs prior to clinical symptoms of dementia in APOE*4 carriers.

Recidivism of Supermax Prisoners in Washington State

This study of recidivism among Washington supermax prisoners used a retrospective matched control design, matching supermax prisoners one-to-one with nonsupermax prisoners on mental illness status and up to eight recidivism predictors. Supermax prisoners committed new felonies at a higher rate than nonsupermax controls, but the difference was not statistically significant. Prisoners released directly from supermax to the community, however, showed significantly higher felony recidivism rates than their nonsupermax controls and committed new offenses sooner than supermax prisoners who left supermax 3 months or more before prison release. Limitations, methodological issues, and policy implications are considered.

Suicide Ideation Among Parents Bereaved by the Violent Deaths of Their Children

Suicidal behaviors of parents bereaved by a childs suicide have received considerable attention by researchers, but deaths by other violent causes have not. We observed 175 bereaved parents for five years following three types of violent death: accidents, homicides, and suicides. The results showed that the incidence of suicidal ideation (SI) among the study parents was 13% ( n = 34) over the 5 years and 9% ( n = 24) at the initial data collection four months after the death of an adolescent or young adult child. Comparisons of study parents grouped by the presence or absence of SI showed that after corrections were made for the number of t -tests conducted, statistically significant differences on three of four outcome variables remained (mental distress, depression, and posttraumatic stress disorder [PTSD], but not on acceptance of the childs death). The groups also differed significantly on four of seven mediating variables examined. The hypothesis that parents whose children died by suicide would report the highest incidence of suicidal ideation was not supported. Regression analyses showed that SI was a significant predictor of depression one year, but not five years, after the violent death of a child. The hypothesis that SI would predict both depression and PTSD one year postdeath was not supported. Clinical and policy recommendations are offered.

Sampling Bias and Other Methodological Threats to the Validity of Health Survey Research

Data from a longitudinal occupational health survey of professional fire fighters were used to explore the potential impact of two types of methodological bias: sample selection and reactivity. No significant differences on demographic variables were observed between the group who first responded after a within-study change in survey administration format (Delayed) and respondents who had completed surveys since the studys inception (Initial). However, statistically significant differences in the studys 26 outcome measures provided some evidence that between-group differences did exist and that an “administration format” type of response bias was also potentially present. The effect sizes associated with the 37 observed significant differences ranged from small to medium. These results provide a context for a reexamination of standard techniques for the identification and interpretation of survey research biases. Methods are suggested to strengthen tests for selection bias and to minimize the impact of response biases.

Home-Based Peer Social Networks of Young Children With Down Syndrome: A Developmental Perspective

Numerous dimensions of the peer social networks of children with Down syndrome were examined within a developmental framework. Results revealed that for many key measures, particularly involvement in play, linkages to other settings, and control of play, children with Down syndrome have less well-developed peer networks even in comparison to a mental age matched group of typically developing children. This suggests both an absence of any social advantage in the peer context for children with Down syndrome and the existence of unusual difficulties that may be traced to underlying problems in peer-related social competence. The need for future observational studies of peer interactions for this group of children was emphasized.