Faculty Bibliography

The psychometric properties of the Alabama Parenting Questionnaire-Preschool Revision (APQ-PR) were explored in a sample of hyperactive-inattentive preschool children (N = 47) and nonimpaired controls (N = 113). A subset of parents completed the questionnaire on 2 occasions, approximately 1 year apart. Factor analysis revealed a 3-factor solution, accounting for 32.28% of the variance. The resultant Positive Parenting, Negative/Inconsistent Parenting, and Punitive Parenting factors demonstrated good internal consistency and temporal stability. At baseline, parents of hyperactive-inattentive and control children did not differ on any APQ-PR subscale. However, over time parents of controls increased their use of positive parenting techniques, whereas the use of positive parenting practices decreased over time in the hyperactive-inattentive group.

Throughout adulthood, new neurons are continuously added to the dentate gyrus, a hippocampal subregion that is important in spatial learning. Whether these adult-generated granule cells become functionally integrated into memory networks is not known. We used immunohistochemical approaches to visualize the recruitment of new neurons into circuits supporting water maze memory in intact mice. We show that as new granule cells mature, they are increasingly likely to be incorporated into circuits supporting spatial memory. By the time the cells are 4 or more weeks of age, they are more likely than existing granule cells to be recruited into circuits supporting spatial memory. This preferential recruitment supports the idea that new neurons make a unique contribution to memory processing in the dentate gyrus.

The study aimed to assess the psychometric properties of the Indigenous Risk Impact Screen (IRIS) as a screening instrument for determining (i) the presence of alcohol and drug and mental health risk in Indigenous adult Australians and (ii) the cut-off scores that discriminate most effectively between the presence and absence of risk. A cross-sectional survey was used in clinical and non-clinical Indigenous and non-Indigenous services across Queensland Australia. A total of 175 Aboriginal and Torres Strait Islander people from urban, rural, regional and remote locations in Queensland took part in the study. Measures included the Indigenous Risk Impact Screen (IRIS), the Severity of Dependence Scale (SDS), the Alcohol Use Disorders Identification Test (AUDIT) and the Leeds Dependence Questionnaire (LDQ). Additional Mental Health measures included the Depression Anxiety and Stress Scale (DASS-21) and the Self-Report Questionnaire (SRQ). Principle axis factoring analysis of the IRIS revealed two factors corresponding with (i) alcohol and drug and (ii) mental health. The IRIS alcohol and drug and mental health subscales demonstrated good convergent validity with other well-established screening instruments and both subscales showed high internal consistency. A receiver operating characteristics (ROC) curve analysis was used to generate cut-offs for the two subscales and t-tests validated the utility of these cut-offs for determining risky levels of drinking. The study validated statistically the utility of the IRIS as a screen for alcohol and drug and mental health risk. The instrument is therefore recommended as a brief screening instrument for Aboriginal and Torres Strait Islander people.

Synapses onto dendritic spines in the lateral amygdala formed by afferents from the auditory thalamus represent a site of plasticity in Pavlovian fear conditioning. Previous work has demonstrated that thalamic afferents synapse onto LA spines expressing glutamate receptor (GluR) subunits, but the GluR subunit distribution at the synapse and within the cytoplasm has not been characterized. Therefore, we performed a quantitative analysis for alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits GluR2 and GluR3 and N-methyl-D-aspartate (NMDA) receptor subunits NR1 and NR2B by combining anterograde labeling of thalamo-amygdaloid afferents with postembedding immunoelectron microscopy for the GluRs in adult rats. A high percentage of thalamo-amygdaloid spines was immunoreactive for GluR2 (80%), GluR3 (83%), and NR1 (83%), while a smaller proportion of spines expressed NR2B (59%). To compare across the various subunits, the cytoplasmic to synaptic ratios of GluRs were measured within thalamo-amygdaloid spines. Analyses revealed that the cytoplasmic pool of GluR2 receptors was twice as large compared to the GluR3, NR1, and NR2B subunits. Our data also show that in the adult brain, the NR2B subunit is expressed in the majority of in thalamo-amygdaloid spines and that within these spines, the various GluRs are differentially distributed between synaptic and non-synaptic sites. The prevalence of the NR2B subunit in thalamo-amygdaloid spines provides morphological evidence supporting its role in the fear conditioning circuit while the differential distribution of the GluR subtypes may reflect distinct roles for their involvement in this circuitry and synaptic plasticity

The objective of this study was to determine the association between lung function and mental health problems among adults in the United States. Data were drawn from the First National Health and Nutrition Examination Survey (1971-1975), with available information on a representative sample of US adults aged 25-74 years. Lung function was assessed by spirometry, and provisional diagnoses of restrictive and obstructive airway disease were assigned based on percentage of expected forced expiratory volume. Mental health problems were assessed with the General Well-Being scales. Restrictive lung function and obstructive lung function, compared with normal lung function, were each associated with a significantly increased likelihood of mental health problems. After adjustment for differences in demographic characteristics, obstructive lung function was associated with significantly lower overall well-being (p = 0.025), and restrictive lung function was associated with significantly lower overall well-being (p < 0.001), general health (p < 0.0001), vitality (p < 0.0001), and self-control (p = 0.001) and with higher depression (p = 0.002) subscale scores compared with no lung function problems. Consistent with previous findings from clinical and community-based studies, these results extend available data by providing evidence of a link between objectively measured lung function and self-reported mental health problems in a representative sample of community adults. Future studies are needed to determine the mechanisms of these associations.

BACKGROUND: Many chromosomal regions for susceptibility to autism spectrum disorders (ASDs) have been identified, but few have reached genomewide significance. In response, researchers have attempted to increase the power of their analyses by stratifying samples to increase phenotypic homogeneity. Although homogeneity has typically been defined by a single variable, resultant groups often differ in other dimensions that may be directly pertinent. Group differences in age, gender, IQ, and measures of autism severity are examined as related to Autism Diagnostic Interview-Revised (ADI-R) domains previously used for subsetting or Quantitative Trait Analysis (QTL). METHODS: Participants were research participants and clinic referrals for assessment of possible autism. Assessments included the ADI-R, Autism Diagnostic Observation Schedule, Vineland Adaptive Behavior Scales, and a developmental or cognitive test. Data were collected for 983 individuals, ages 4 to 52 years, with diagnoses of autism and ASDs. RESULTS: Findings suggest that, of several potential grouping variables, only restricted and repetitive behaviors associated with Insistence on Sameness were independent of age, IQ, and autism severity. CONCLUSIONS: Results emphasize the potential unintended effects of stratification and the importance of understanding such interrelationships between phenotypic characteristics when defining subgroups or performing QTL

Despite a remarkably precise spatial representation of odorant stimuli in the early stages of olfactory processing, the projections to the olfactory (piriform) cortex are more diffuse and show characteristics of a combinatorial array, with extensive overlap of afferent inputs and widespread intracortical association connections. Furthermore, although there is increasing evidence for the importance of temporal structure in olfactory bulb odorant-evoked output, little is known about how this temporal patterning is translated within cortical neural ensembles. The present study used multichannel electrode arrays and paired single-unit recordings in rat anterior piriform cortex to test several predictions regarding ensemble coding in this system. The results indicate that odorants evoke activity in a spatially scattered ensemble of anterior piriform cortex neurons, and the ensemble activity includes a rich temporal structure. The most pronounced discrimination between different odorants by cortical ensembles occurs during the first inhalation of a 2 s stimulus. The distributed spatial and temporal structure of cortical activity is present at both global and local scales, with neighboring single units contributing to coding of different odorants and active at different phases of the respiratory cycle. Finally, cross-correlogram analyses suggest that cortical unit activity reflects not only afferent input from the olfactory bulb but also intrinsic activity within the intracortical association fiber system. These results provide direct evidence for predictions stemming from anatomical- and theoretical-based models of piriform cortex

Although there has been recent interest in the study of childhood and adolescent brain development, very little is known about normal brain development in the first few months of life. In older children, there are regional differences in cortical gray matter development, whereas cortical gray and white matter growth after birth has not been studied to a great extent. The adult human brain is also characterized by cerebral asymmetries and sexual dimorphisms, although very little is known about how these asymmetries and dimorphisms develop. We used magnetic resonance imaging and an automatic segmentation methodology to study brain structure in 74 neonates in the first few weeks after birth. We found robust cortical gray matter growth compared with white matter growth, with occipital regions growing much faster than prefrontal regions. Sexual dimorphism is present at birth, with males having larger total brain cortical gray and white matter volumes than females. In contrast to adults and older children, the left hemisphere is larger than the right hemisphere, and the normal pattern of fronto-occipital asymmetry described in older children and adults is not present. Regional differences in cortical gray matter growth are likely related to differential maturation of sensory and motor systems compared with prefrontal executive function after birth. These findings also indicate that whereas some adult patterns of sexual dimorphism and cerebral asymmetries are present at birth, others develop after birth.

BACKGROUND: Despite the wealth of information in adult posttraumatic stress disorder (PTSD) literature, few studies have explored the memory and learning performance of trauma-exposed youth. This study examined if memory deficits are associated with PTSD or with trauma exposure in the absence of PTSD. METHODS: Youth exposed to traumatic incidents underwent clinical interviews to diagnose PTSD and exclude major comorbid disorders. Youth with conditions that could impede performance on a memory scale (e.g., limited intellectual functioning, current substance abuse, psychopharmacological treatment) were excluded. Three groups of participants were identified (PTSD positives [n = 29], traumatized PTSD negatives [n = 62], and nontraumatized control subjects [n = 40]). Participants completed the Wide Range Assessment of Memory and Learning (WRAML). RESULTS: Youth with PTSD evidenced significantly lower scores on the WRAML General Memory, Verbal Memory, and Learning indices compared with nontraumatized control subjects. With the exception of Verbal Memory, youth with and without PTSD performed comparably on all other indices. Nonsignificant differences were noted on the Visual Memory Index. CONCLUSIONS: General memory and verbal memory impairments as evidenced in adult populations were observed among this sample of youth. Given the developmental trajectory of memory capabilities, the implications of such early trauma exposure and memory deficits are considered

Attention deficit hyperactivity disorder (ADHD) is the most frequent psychiatric disorder in children, yet data are sparse on its pathophysiology. Particularly relevant are the dopamine transporters since these are the main targets of stimulant medications used for ADHD treatment. Though some imaging studies have shown increases in dopamine transporters in ADHD others have not and their role in the neurobiology of ADHD remains unclear. Here we investigate dopamine transporters in ADHD subjects with control of potentially confounding factors (previous medication and/or drug histories, comorbidity) and their association with clinical symptoms. Positron emission tomography and [11C]cocaine were used to measure dopamine transporters in 20 never medicated adults with ADHD and 25 controls. Dopamine transporters were lower in left caudate (13%, p < 0.05) and in left nucleus accumbens (p < 0.005) in ADHD subjects than in controls. In putamen dopamine transporters did not differ between groups but were associated with scores of inattention (Conners Adult Attention Rating Scale) both in ADHD subjects (p < 0.005) and in controls (p < 0.005). Thus, for a given transporter level the scores for inattention were on average five times greater in ADHD subjects than in controls. These results do not corroborate increases in dopamine transporters in ADHD subjects and show that in some they are reduced. It also provides evidence that dopamine transporter levels modulate attention but suggest that additional pathology (e.g., prefrontal or cingulostriatal pathways, noradrenergic neurotransmission) is necessary to account for the large differences in inattention observed between controls and ADHD subjects