Coordinated brain development: exploring the synchrony between changes in grey and white matter during childhood maturation.

Brain development during childhood and early adolescence is characterized by global changes in brain architecture. Neuroimaging studies have revealed overall decreases in cortical thickness (CT) and increases in fractional anisotropy (FA). Furthermore, previous studies have shown that certain cortical regions display coordinated growth during development. However, there is significant heterogeneity in the timing and speed of these developmental transformations, and it is still unclear whether white and grey matter changes are co-localized. In this multimodal neuroimaging study, we investigated the relationship between grey and white matter developmental changes and asynchronous maturation within brain regions in 249 normally developing children between the ages 7-14. We used structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to analyze CT and FA, respectively, as well as their covariance across development. Consistent with previous studies, we observed overall cortical thinning with age, which was accompanied by increased FA. We then compared the coordinated development of grey and white matter as indexed by covariance measures. Covariance between grey matter regions and the microstructure of white matter tracts connecting those regions were highly similar, suggesting that coordinated changes in the cortex were mirrored by coordinated changes in their respective tracts. Examining within-brain divergent trajectories, we found significant structural decoupling (decreased covariance) between several brain regions and tracts in the 9- to 11-year-old group, particularly involving the forceps minor and the regions that it connects to. We argue that this decoupling could reflect a developmental pattern within the prefrontal region in 9- and 11-year-old children, possibly related to the significant changes in cognitive control observed at this age.

Illusory memories in amnesic patients: conceptual and perceptual false recognition.

Little is known about the neuropsychology of false recognition. D.L. Schacter, M. Verfaellie, and D. Pradere (1996) induced false recognition in amnesic patients and normal controls by exposing them to numerous semantic associates of a nonstudied word and found that amnesics showed significantly reduced levels of false recognition. To determine whether this outcome is specific to the semantic domain, the authors examined false recognition after exposure to lists of conceptually and perceptually related words. In the control group, conceptual false recognition was associated with "remember" responses and perceptual false recognition was associated with "know" responses. Amnesic patients showed reduced levels of conceptual and perceptual false recognition that were approximately equally divided between remember and know responses.

Roles of object-file review and type priming in visual identification within and across eye fixations.

Dynamic visual identification was investigated in 4 experiments. In Experiments 1 and 2, 2 perceptual objects (2 frames, each containing a letter or 1 containing a letter and the other a plus sign) were previewed in the periphery. A saccade brought these objects to central vision. During the saccade the display was changed so that 1 frame contained a letter and the other a plus sign, and the subject identified the letter by naming it aloud as rapidly as possible. In Experiment 3, the retinal events of Experiments 1 and 2 were simulated. In Experiment 4, both the preview and the target were presented centrally within a single fixation. In all experiments both object-specific and nonspecific preview benefits were observed. These results support a theory in which the preview benefits observed during visual identification arise from 2 processes, object file review and type priming.

[Brucellar orchitis. Report of a series of 16 cases]. / Orquitis brucelar. Aportación de una serie de 16 casos.

A retrospective study of orchiepididymitis, diagnosed and admitted to our Unit over the 1989-94 period was conducted. there were 125 orchiepididymitis, of which 16 (12.8%) had a brucellar etiology, and three had simultaneously become abscessified (18.75%). Considering that our working area is located within an endemic region, and even more, our province has the country's highest incidence rate (112.8/100000 inh.), this prompted us to study the conditions' morbidity in the testicular location, while we make a superficial revision of this disease. Brucellar orchitis is a diagnostic option to be taken into account in endemic regions, and the clinical picture associated to the orchiepididymal process should make us suspect its diagnosis and trigger follow-up of these patients.

Exploring the use of prosody during language comprehension using the auditory moving window technique.

Researchers in psycholinguistics have speculated about the possible role of prosody in resolving syntactic ambiguities. We argue in this paper that the issue is complicated by the following considerations: first, prosody may be even more effective at conveying semantic information than syntactic structure, yet the question how prosody signals meaning is essentially unstudied. Second, the one-to-many relation between syntactic and prosodic structure leads to a great deal of variability across speakers and contexts in the way a given sentence will be produced. The parser must somehow deal with this variability. Third, resolution of architectural debates in the parsing literature requires the use of sensitive, online techniques for measuring processing load during comprehension. In the auditory domain, no optimal technique is presently available. We discuss the strengths and weaknesses of a technique we introduced in previous work, which is an analogue of the visual moving window. We present the results of an experiment demonstrating that the technique preserves some aspects of the prosody of a spoken sentence but disrupts others, and we discuss ways of dealing with this problem. We conclude that the technique is useful for studying language processing, including the use of prosody during parsing. However, we also argue that researchers should study not just the role of prosody in parsing, but also its role in establishing sentence meaning.

Active enforcement of cigarette control laws in the prevention of cigarette sales to minors.

OBJECTIVE: To assess the effect that cigarette legislation would have on reducing merchant sales rates of cigarettes to minors and the affect on adolescent smoking behavior. DESIGN: Observational survey of merchant selling behaviors and adolescent smoking habits before and after passage of legislation. SETTING: The setting for the merchant survey was Woodridge, Ill (population 25,200), a suburban community of Chicago. The surveys were distributed to adolescents in the local junior high school. PARTICIPANTS: Convenience sample of both merchants and adolescent students. INTERVENTION: Passage of community antismoking legislation. MAIN OUTCOME MEASURES: Percentage of stores selling cigarettes to minors in Woodridge and percentage of students who had experimented with cigarettes or were regular smokers. RESULTS: Merchant sales rates in Woodridge decreased from a baseline of 70% before legislation to less than 5% in 1.5 years of compliance checking after legislation. Student surveys showed that the rates of cigarette experimentation and regular use of cigarettes by adolescents were reduced by over 50%. CONCLUSION: Cigarette control laws can be effective in significantly reducing the rate of cigarettes sold by merchants and rates of cigarette use by adolescents. Key elements of successful legislation implementation are consistent compliance checking and heightened community awareness of the problems and prevalence of adolescent smoking.

When true recognition suppresses false recognition: evidence from amnesic patients.

False recognition occurs when people mistakenly claim that a novel item is familiar. After studying lists of semantically related words, healthy controls show extraordinarily high levels of false recognition to nonstudied lures that are semantic associates of study list words. In previous experiments, we found that both Korsakoff and non-Korsakoff amnesic patients show reduced levels of false recognition to semantic associates, implying that the medial temporal/diencephalic structures that are damaged in amnesic patients are involved in the encoding and/or retrieval of information that underlies false recognition. These data contrast with earlier results indicating greater false recognition in Korsakoff amnesics than in control subjects. The present experiment tests the hypothesis that greater or lesser false recognition of semantic associates in amnesic patients, relative to normal controls, can be demonstrated by creating conditions that are more or less conducive to allowing true recognition to suppress false recognition. With repeated presentation and testing of lists of semantic associates, control subjects and both Korsakoff and non-Korsakoff amnesics showed increasing levels of true recognition across trials. However, control subjects exhibited decreasing levels of false recognition across trials, whereas Korsakoff amnesic patients showed increases across trials and non-Korsakoff amnesics showed a fluctuating pattern. Consideration of signal detection analyses and differences between the two types of amnesic patients provides insight into how mechanisms of veridical episodic memory can be used to suppress false recognition.