Gilberto N. O. Brito

Septohippocampal system and the prelimbic sector of frontal cortex: A neuropsychological battery analysis in the rat

Rats with lesions in the posterodorsal septal area (aimed at transecting the precommissural fornix) and rats with lesions in the prelimbic sector of the medial frontal cortex were tested postoperatively on a neuropsychological test battery comprised of the following tasks: time-spent-eating in two adaptation boxes, time-to-emerge and ambulation in an open field, general activity, contingently-reinforced (continuous) and schedule-specific (delayed non-matching-to-sample) T-maze alternation, visual and olfactory discrimination in a T-maze, temporal alternation (response patterning) and tactile Go/No-Go discrimination in a runway, approach-avoidance conflict in the runway, step-through inhibitory avoidance, one-way active avoidance, two-way active avoidance, and conditioned taste aversion. It was found that: (1) rats with septal (SEP) lesions spent more time eating than control (CON) rats and rats with lesions in prelimbic cortex (PRE). PRE rats did not differ from CON rats; (2) PRE rats emerged into an open field faster, and spent less time in home cage than CON and SEP rats. SEP rats stayed in home cage less than CON rats. PRE and SEP rats crossed more squares in the open field than CON rats; (3) SEP and PRE rats were more active than CON rats; (4) SEP rats performed the contigently-reinforced and schedule-specific T-maze alternation tasks worse than PRE rats, and PRE rats performed these tasks worse than CON rats. PRE, but not SEP, rats showed improvement with continued practice at brief intertrial and interrun intervals.(ABSTRACT TRUNCATED AT 400 WORDS)

The Conners Abbreviated Teacher Rating Scale: Development of Norms in Brazil

Normative data for the Conners Abbreviated (10-item) Teacher Rating Scale (CATRS-10) derived from 1,068 children in Brazil are presented. Ratings of boys were higher than ratings of girls, and younger children had higher ratings than older children. Test-retest reliability data indicate that the CATRS-10 has acceptable reliability in Brazil but only when the same teacher rates the child at both test and retest (interval of 1 to 3 months). This study found that ratings at retest were significantly lower than ratings at first test whether or not the same teacher rated the child on both occasions. The CATRS-10 was shown to be a valid instrument in Brazil since children with behavioral problems requiring medical or psychological treatment were rated higher than children without such problems.

A behavioral assessment scale for attention deficit disorder in Brazilian children based on DSM-IIIR criteria

A teacher scale based on DSM-III-R diagnostic criteria for attention deficit hyperactivity disorder (ADHD) was developed for the behavioral assessment of children in Brazil. A total of 2, 082 children (782 males and 1,300 females) with a mean age of 11.2 years who were attending a public school in the greater Rio de Janeiro area were the subjects of this study. Two factors (Hyperactivity-Impulsivity and Inattention) were extracted from a principal-factor analysis conducted on the data, and the factor structure of the scale was found to be stable. Ratings of boys were higher than ratings of girls, and younger children had higher ratings than older children for both factors. Test-retest reliability for each item of the scale ranged from .56 to .70. The data are discussed in view of current controversies in the factor structure of teacher ratings of DSM-III-R ADHD symptoms.

Behavioral and neuropsychological correlates of hyperactivity and inattention in Brazilian school children

Attempts at subtyping attention‐deficit‐hyperactivity disorder (ADHD) along the hyperactivity dimension are considered controversial. This study addresses this issue by dividing a non‐clinical sample of Brazilian children (mean age, 9.4 years; SD, 2.9), who were attending a mainstream school in the Greater Rio de Janeiro area, into four behavioral domain groups (normal [NO, N=324], hyperactive/impulsive [HI, N=17], inattentive [IA, N=48], and combined [C,N=13]) on the basis of teacher ratings on an ADHD scale. The groups did not differ in intellectual level as determined by the Human Figure Drawing test. Comparisons were made between groups along the factorial dimensions extracted from the Composite Teacher Rating Scale, academic performance and neuropsychological measures were then performed. Our data showed that IA and C children are less independent and more prone to socialization problems than NO children, and that HI and C children are less anxious and fearful than IA children. Furthermore, the groups differed in academic and neuropsychological performance. The results could be considered consistent with the hypothesis that ADD with hyperactivity (ADD/+) and ADD without hyperactivity (ADD/‐) represent singular nosological entities.

Hand preference in 4‐ to 7‐year‐old children: An analysis with the edinburgh inventory in Brazil

The hand preference of 761 Brazilian schoolchildren (349 boys and 412 girls) with ages ranging from 4 to 7 years was assessed with the Edinburgh Handed‐ness Inventory (Oldfield, 1971). We found significant effects due to sex, but not to age within the age range of this sample. Factor analysis of the Edinburgh Handedness Inventory (Oldfield, 1971) revealed a single factor. Comparison of the present results with data on hand preference of Brazilian adults that we reported previously confirmed an effect of sex on the distribution of handedness. Additionally, the distribution of handedness categories in children tends to be different than that found in adults, and removal of items with limited factorial validity (opening a box for children and broom for adults) accentuates these differences. Children are more mixed‐handed and less right‐handed than adults. Furthermore, we found that differences in hand preference between children and adults do not depend on the degree of novelty of the tasks included in the i...

Developmental norms for eight instruments used in the neuropsychological assessment of children: studies in Brazil

Norms for a battery of instruments, including Dencklas and Garfields tests of Motor Persistence, Bentons Right-Left Discrimination, two recall modalities (Immediate and Delayed) of the Bender Test, Wechslers Digit Span, the Color Span Test and the Human Figure Drawing Test, were developed for the neuropsychological assessment of children in the greater Rio de Janeiro area. Additionally, the behavior of each child was assessed with the Composite Teacher Rating Scale (Brito GNO and Pinto RCA (1991) Journal of Clinical and Experimental Neuropsychology, 13: 417-418). A total of 398 children (199 boys and 199 girls balanced for age) with a mean age of 9.3 years (SD = 2.8), who were attending a public school in Niterói, were the subjects of this study. Gender and age had significant effects on performance which depended on the instrument. Nonachievers performed worse than achievers in most neuropsychological tests. Comparison of our data to the available counterparts in the United States revealed that American children outperformed Brazilian children on the Right-Left Discrimination, Forward Digit Span, Color Span and Human Figure Drawing Tests. Further analysis showed that the neurobehavioral data consist of different factorial dimensions, including Human Body Representation, Motor Persistence of the Legs, Orbito-Orobuccal Motor Persistence, Attention-Memory, Visuospatial Memory, Neuropsychomotor Speed, Hyperactivity-Inattention, and Anxiety-Negative Socialization. We conclude that gender and age should be taken into account when using the normative data for most of the instruments studied in the present report. Furthermore, we stress the need for major changes in the Brazilian public school system in order to foster the development of secondary cognitive abilities in our children.

Lateral Preferences in 8- to 15-Year-Old Brazilian Children Assessed With the Edinburgh Inventory: Different Measures of Handedness and Comparison With Younger Children and Adults

This article completes a series of 3 studies on the lateral preferences of Brazilians of different age ranges. In previous reports, we assessed the lateral preferences of adults ranging in age from 20 to 72 years (Brito, Brito, Paumgartten, & Lins, 1989) and 4- to 7-year-old schoolchildren (Brito, Lins, Paumgartten, & Brito, 1992). In this study, we evaluated the lateral preferences of 625 children with ages ranging from 8 to 15 years with different measures of handedness derived from the Edinburgh Inventory (Oldfield, 1971). We found significant age and sex effects which depended on the measure of handedness. Factor analysis of the inventory revealed a single factor. Comparison of the data with those reported previously confirmed a sex effect on the distribution of handedness categories. Additionally, we found that the distribution of handedness categories in 4- to 7-year-old children and 8- to 15-year-old children differs from that found in adults, and removal of inventory items with reduced factorial v...

A neurobiological model for Tourette syndrome centered on the nucleus accumbens

Tourette syndrome is a genetic disorder characterized by chronic multiple motor and vocal tics with a fluctuating course and modulated by internal and external environmental events. Tourette syndrome is more prevalent in males than females, and is associated with behavioural disorders such as obsessive-compulsive disorder and attention deficit hyperactivity disorder. Tourette syndrome symptoms are commonly attenuated by dopaminergic antagonists and adrenergic agonists, and usually exacerbated by psychostimulants. In this paper, I propose that dysfunction centered on the nucleus accumbens represents the neurobiological basis of Tourette syndrome. Recent evidence indicates that nucleus accumbens has a micro-organization characterized by modules of distinct neurochemical and neuroanatomical features. Our model assumes that external and internal events occurring during the development of the nervous system interact with products derived from the expression of the putative gene for Tourette syndrome, thereby inducing modular changes in nucleus accumbens. The clinical presentation, associated behavioural disturbances and response to drugs would depend on the pattern of modular dysfunction.

Developmental norms for the Gardner Steadiness Test and the Purdue Pegboard: a study with children of a metropolitan school in Brazil

Norms for the Gardner Steadiness Test and the Purdue Pegboard were developed for the neuropsychological assessment of children in the metropolitan area of Rio de Janeiro. A computer-generated unbiased sample of 346 children with a mean age of 9.4 years (SD = 2.76), who were attending a large normal public school in this urban area, was the subject of this study. Two boys were removed from the study, one for refusing to participate and the other due to severe strabismus. Therefore, the final sample contained 344 children (173 boys and 171 girls). Sex and age of the child and hand preferred for writing, but not ethnic membership or social class, had significant effects on performance in the Gardner Steadiness Test and the Purdue Pegboard. Girls outperformed boys. Older children performed better than younger children. However, the predictive relationship between age of the child and neuropsychological performance included linear and curvilinear components. Comparison of the present results to data gathered in the United States revealed that the performance of this group of Brazilian children is equivalent to that of US children after Bonferronis correction of the alpha level of significance. It is concluded that sex and age of the child and hand preferred for writing should be taken into account when using the normative data for the two instruments evaluated in the present study. Furthermore, the relevance of neurobehavioral antidotes for the obliteration of some of the probable neuropsychological effects of cultural deprivation in Brazilian public school children is hypothesized.

Exercise and cognitive function: a hypothesis for the association of type II diabetes mellitus and Alzheimer's disease from an evolutionary perspective

The association of type II diabetes mellitus (DM2) with Alzheimers disease (AD) has received considerable attention in recent years. In the present paper, a hypothesis for this association from an evolutionary perspective, with emphasis on the close interplay between exercise and cognitive function, will be advanced in order to provide a biological rationale for the notion that the fundamental metabolic features of DM2 act in the brain over a protracted time span to induce the neuropathological characteristics of Alzheimers disease thereby producing cognitive impairment. It is hoped that this hypothesis puts the association of DM2 and AD on firm conceptual grounds from a biological perspective and offers directions for further research.