Correlates of Mental Disorders in the Quebec General Population of 6 to 14-Year Olds

Previous epidemiological studies of correlates of child and adolescent mental disorders in the general population have focused more on child/adolescent and socioeconomic/sociodemographic characteristics than on family characteristics. Moreover, there are no generally accepted methods to analyze and interpret correlates. The purpose of the Quebec Child Mental Health Survey in this regard was twofold: (1) to identify correlates of DSM-III-R internalizing and externalizing disorders according to informant (youth, parent, teacher), for three age groups (6–8, 9–11, and 12–14 years), including relevant family characteristics not considered in previous studies; and (2) to interpret the relative importance of risk indicators by ranking correlates according to strength and consistency of association across age groups. Logistic regression models suggest the inconsistency of correlates across informants. The ranking of correlates reveals that individual and family characteristics make a more important contribution than do socioeconomic characteristics, thereby supporting the relevance of proximal variables in the development of psychopathology.     

Selective attention and interhemispheric response competition in the split-brain

The interfering effect of an unattended stimulus on processing of an attended item was studied in a single split-brain participant (LB) and in normal controls. Pairs of letters were presented to the left visual field (LVF), right visual field (RVF), or bilaterally. Participants attended to the rightmost letter while attempting to ignore the leftmost letter. Responses associated with the attended and to-be-ignored letters could be compatible or incompatible. Manual response latencies were generally slower on Response Incompatible compared to Response Compatible trials. Notably, LB displayed this effect on Bilateral trials, where target and distractor were presented to opposite visual fields. LB was unable to perform a same-different matching task with bilateral letter stimuli, but was able to name bilateral letters accurately. Hence, in the bilateral condition, the ability to cross-compare letters was dissociated from attentional interference and from letter naming. Implications of these findings are discussed.     

Activity-stress increases density of GFAP-immunoreactive astrocytes in the rat hippocampus

Although past research has indicated that stress and the accompanying increase in glucocorticoids compromises hippocampal neurons, little is known about the effect of stress on hippocampal glial cells. In the current study, male rats were exposed to activity-stress (A-S) for six days; this comprised housing with an activity wheel and restricted access (1h/day) to food. Physiological data (e.g., relative adrenal and thymus weights, gastric ulceration) suggested that the A-S rats experienced more stress than pair-fed (no wheel) and control (fed ad libitum, no wheel) rats. Whereas stress did not influence the quantitative morphology of glial fibrillary acidic protein (GFAP)-immunoreactive cells, a semi-quantitative analysis revealed that the A-S rats had significantly more (30%) GFAP-immunoreactive cells in the hippocampal CA3 region than the control rats. Based on the present findings, it appears that the hippocampal astrocytic response to chronic stress may be similar to the response found in endangered, or challenged hippocampal environments, such as in ischemia.     

Selective attention and performance with a multidimensional visual display

Selective attention was studied in four experiments in which stimuli varied in both spatial location and visual form. In Experiment 1 the likely location and likely form of targets were both precued. An advantage was found for cued over uncued forms at both cued and uncued locations. In Experiments 2, 3, and 4, different forms tended to occur at different locations. Regardless of whether a location was cued or uncued, form selective effects were found in accordance with form probability for that location. It was not the case that selective attention simply favored certain locations or certain stimulus forms in preference to others. Rather, selective attention was sensitive to precise combinations of form and location. These results could not be reconciled with mental spotlight notions of spatial selectivity.     

Cartoons varying in low-level pain ratings,not aggression ratings,correlate positively with funniness ratings

In three studies, cartoons were rated for aggression, pain, and funniness in order to determine whether aggression, pain, or both correlated with funniness and whether a positive or inverted-U function described the relationship. Pain correlated more reliably with funniness than did aggression. A probable explanation for this is that cartoons showed greater variability in pain than in aggression ratings, since pain could be self-inflicted or could result from a mishap or from another's aggression. Funniness increased to asymptote within the first third of the pain dimension and was unaffected by further pain increases. No significant downward trend in funniness was observed with increased pain ratings. The results were interpreted by assuming that cartoon violence is a salient dimension, in which to create discrepancies, and that the discrepancies were reflected in the pain ratings.These studies were supported by Ball State University Research Grants.     

Regional cerebral blood flow during comprehension and speech (in cerebrally healthy subjects)

Regional cerebral blood flow (rCBF) was measured by the xenon-133 inhalation method in 10 cerebrally healthy subjects at rest and during linguistic activation tests. These consisted of a comprehension test (binaural listening to a narrative text) and a speech test (making sentences from a list of words presented orally at 30-s intervals). The comprehension task induced a moderate increase in the mean right CBF and in both inferior parietal areas, whereas the speech test resulted in a diffuse increase in the mean CBF of both hemispheres, predominating regionally in both inferior parietal, left operculary, and right upper motor and premotor areas. It is proposed that the activation pattern induced by linguistic stimulation depends on not only specific factors, such as syntactic and semantic aspects of language, but also the contents of the material proposed and the attention required by the test situation.