Marisa Tomoe Hebihara Fukuda

Early postnatal protein malnutrition affects learning and memory in the distal but not in the proximal cue version of the Morris water maze

Learning and memory of early postnatal protein malnourished rats were investigated in the Morris water maze. During the lactation period (21 days) each litter (mother plus six male and two female pups) was provided with 16% (well-nourished) or 6% (malnourished) protein diets. After weaning, rats remained on the same diet until 49 days of age. From day 50 on all animals were fed a commercial lab chow. Experiments started on day 70. In experiment I (proximal cue version) the animals were trained to escape from water to a visible platform (3 cm above the water level) in six trials daily for four consecutive days, completing 24 trials. In experiment II (distal cue version) the animals were trained to escape from water to a submerged platform using the same procedure as in experiment II. After the 24th trial, the platform was removed and the animals were submitted to a 60-s trial (probe trial). Seven and twenty-eight days after training, the retention test was conducted in one 180-s trial. The results showed no impairment of the learning or memory of malnourished animals tested in the proximal cue version but an increased latency and distance traveled to find the submerged platform in the distal cue version of the procedure. In the distal cue version the malnourished animals also showed increased latency to find the platform 7 and 28 days after the test training. No difference due to diet was found in the probe trial test indicating that, once the task is acquired, malnourished rats can manage extra-maze cues as easily as well-nourished rats. It is suggested that the present results can be due to alterations produced by protein malnutrition in the hippocampal formation or also to reflect the higher emotionality of rats following early malnutrition, specially considering the fact that postnatally malnourished animals are more reactive to unpleasant or aversive stimuli as cold water.

Effects of different malnutrition techniques on the behavior of rats tested in the elevated T-maze

The influence of different malnutrition techniques on the behavior of adult animals was investigated in the elevated T-maze (ETM). Control litters (C) were composed by eight pups constantly kept with their mother and fed by a 16%-protein diet ad libitum; protein malnutrition litters (PM) were fed by a 6%-protein diet; protein-calorie malnutrition litters (PCM) were fed with 50% of the 16%-protein diet ingested by C litters; malnutrition by increase in the size of the litter (LLM-number of pups was twice the number of pups in C litters), and malnutrition by separation (SM-litters spent half of the day with non-lactating females). After weaning, all groups received lab chow diet until the test day (70th day). During the test were recorded the basal, avoidance 1, avoidance 2 and escape latencies. The data showed that PM, PCM, LLM and SM animals showed lower increases in avoidance latencies, when compared to their control groups. However, malnutrition did not affect escape latencies. The nature of these alterations seems to be nutritional, as the extra-nutritional factors (i.e. maternal care) differ a lot among the malnutrition techniques. These results suggest that malnutrition, irrespective of the technique, altered the neural mechanisms believed to control defensive behaviors in the ETM.

Anxiolytic-like effects of short-term postnatal protein malnutrition in the elevated plus-maze test.

Given that protein malnutrition induces structural, neurochemical and functional changes in the CNS, the present study aimed to investigate the effects of short-term early protein malnutrition on the behavior and reactivity to diazepam (DZ) in the elevated plus-maze test (EPM). Male Wistar rats (n=176) from well-nourished (16%-protein) or malnourished litters (6%-protein) were distributed in five different groups: W (well-nourished), M7 (malnourished for 7 days), M14 (malnourished for 14 days), M21 (malnourished for 21 days) and M28 (malnourished for 28 days) since birthday. EPM results showed that the longer the exposition to the deficient diet, the lower the anxiety of malnourished animals, a result similar to that produced by the treatment with DZ. This anxiolytic-like effect suggested that short-term malnutrition may affect neural and/or neurochemical systems believed to underlie behavioral expression in anxiogenic experimental situations.

Effects of postnatal protein malnutrition on learning and memory procedures

Abstract Protein malnutrition induces structural, neurochemical and functional changes in the central nervous system leading to alterations in cognitive and behavioral development of rats. The aim of this work was to investigate the effects of postnatal protein malnutrition on learning and memory tasks. Previously malnourished (6% protein) and well-nourished rats (16% protein) were tested in three experiments: working memory tasks in the Morris water maze (Experiment I), recognition memory of objects (Experiment II), and working memory in the water T-maze (Experiment III). The results showed higher escape latencies in malnourished animals in Experiment I, lower recognition indexes of malnourished animals in Experiment II, and no differences due to diet in Experiment III. It is suggested that protein malnutrition imposed on early life of rats can produce impairments on both working memory in the Morris maze and recognition memory in the open field tests.

Effects of early protein malnutrition and scopolamine on learning and memory in the Morris water maze

Abstract The present study investigated the effects of early protein malnutrition on the spatial learning and memory processes. The consequences of malnutrition for the cholinergic system were evaluated by comparing the performance of malnourished and control animals in the Morris water maze after treatment with scopolamine. The learning test consisted of placing the animal in the maze to escape to a submerged platform with 12 trials per day for two consecutive days. After 24 trials, the platform was removed, the rats were placed in the maze and the time spent by them in each quadrant was recorded. After 28 days the animals were tested in a single trial to verify the retention of the spatial information. In the first Experiment, scopolamine (0.0, 0.2, 0.4 and 0.6 mg/kg per ml. i.p.) was administered 20 min before the experimental sessions. In the second experiment, a dose of 0.6 mg/kg was administered after the sessions, during the period in which learning consolidation occurs. In the first experiment, there was a significant effect of the drug, with scopolamine impairing, learning in both nutritional conditions. In the saline condition, control animals presented a better performance when compared with malnourished animals. However, 28 days later, both groups increased their latencies. With 0.2 and 0.4 mg/kg of scopolamine, the performance of both nutritional groups was similar and with 0.6 mg/kg malnourished animals performed better than controls. In the second experiment, malnourished animals were also less reactive to the effects of scopolamine, resulting in lower impairments as compared to control animals. These data suggest long-term changes in learning and memory as the result of changes produced by protein malnutrition in the cholinergic neurotransmitter system.

Deficits in working memory, reading comprehension and arithmetic skills in children with mouth breathing syndrome: analytical cross-sectional study

CONTEXT AND OBJECTIVE Mouth breathing syndrome is very common among school-age children, and it is possibly related to learning difficulties and low academic achievement. In this study, we investigated working memory, reading comprehension and arithmetic skills in children with nasal and mouth breathing. DESIGN AND SETTING Analytical cross-sectional study with control group conducted in a public university hospital. METHODS 42 children (mean age = 8.7 years) who had been identified as mouth breathers were compared with a control group (mean age = 8.4 years) matched for age and schooling. All the participants underwent a clinical interview, tone audiometry, otorhinolaryngological evaluation and cognitive assessment of phonological working memory (numbers and pseudowords), reading comprehension and arithmetic skills. RESULTS Children with mouth breathing had poorer performance than controls, regarding reading comprehension (P = 0.006), arithmetic (P = 0.025) and working memory for pseudowords (P = 0.002), but not for numbers (P = 0.76). CONCLUSION Children with mouth breathing have low academic achievement and poorer phonological working memory than controls. Teachers and healthcare professionals should be aware of the association of mouth breathing with childrens physical and cognitive health.

Memory, learning, and participation of the cholinergic system in young rats exposed to environmental enrichment.

The present study demonstrates the consequences of animal exposure to an enriched environment compared to animals living in a standard environment regarding learning and space memory. Male albino Wistar rats were exposed to an enriched environment for 4 weeks after the lactation period and tested in the Morris water maze in the distal and proximal clue version and in the arena. In the former test, the animals were tested at 50 days of age with 12 daily trials on two consecutive days. At the end of each session, scopolamine at the dose of 0.6 mg/kg/ml or saline solution was injected intraperitoneally. Twenty-eight days after the first phase, a new test consisting of a single trial was held (retest). An independent group of animals receiving no drug was subjected to the arena test and to the proximal clue version of the Morris maze. In the distal clue version the results did not show differences between groups in the first phase of the experiment. After 28 days (retest), the animals reared in a standard environment and treated with scopolamine exhibited a significant increase in latency compared to the group receiving the same drug and stimulated and to the group receiving saline. The arena data demonstrated a significant increase in exploratory activity in the group of animals reared in an enriched environment. The proximal clue version of the Morris maze did not show differences between groups. The results of the present study indicate that animals exposed to environmental enrichment react less to the amnesic effects of scopolamine and show an increase in exploratory activity.

Characterization of language and phonological working memory in patients with myoclonic astatic epileptic syndrome

The course of myoclonic astatic epileptic syndrome (MAES) is variable and little information is available about cortical functions in the presence of the disease. The objective of the present study was to assess the phonological working memory (PWM) and the verbal language of six patients between 8 and 18 years old, on treatment for at least 5 years, and good control of seizures, diagnosed in the Service of Epilepsy of Hospital of Clinics of Ribeirão Preto, São Paulo University in Brazil. The Test of Repetition of Meaningless Words was used to assess PWM. Video-recorded of language samples were collected during spontaneous and directed activities for the study of verbal language and pragmatics. A qualitative analysis showed that all patients presented deficits in the execution of the PWM test and only one patient showed poor mastery of all aspects studied. These finds contribute to strategies of treatment for language problems of patients with MAES, focusing on PWA.

Language aspects of children infected with HIV

Purpose: to assess the lexical proficiency and the incidence of phonologic disorders in the language of children infected with HIV. Methods: the study population consisted of 31 children between three and seven year-old. For evaluation purposes the Test of Infantile Language – ABFW was applied in the areas of phonology and vocabulary. Results: the results obtained were analyzed according to the clinical criteria for the classification of the disease proposed by the CDC and regarding the immunological profile and the viral burden using the Mann-Whitney test for statistical analysis. In the vocabulary evaluation, 100% of the children presented an inappropriate response for their age in at least two distinct conceptual fields. In the phonologic evaluation, 67.7% of the assessed children were considered to be affected by some phonologic disorder. When we compared adequate and inadequate results of phonologic evaluation to the clinical and immunological parameters of AIDS such as clinical classification (p=0,16), CD4 count (p=0,37) and viral burden (p=0,82), we did not detect a statistically significant relation between language alterations and disease severity. Conclusion: this research has shown that the studied group presents a high risk for language disorders and that constant phonoaudiological follow-up is essential to identify the alterations in early stage.

Aspectos perinatais, cognitivos e sociais e suas relações com as dificuldades de aprendizagem

PURPOSE: the main purpose of this study is to analyze the social, cognition and perinatal aspects that increase the risk of a child in reading, writing or arithmetic alterations. METHOD: we analyzed 45 children (about 8.3 year old), in average, and observed their reading, writing, arithmetic, phonological awareness, memory and auditory processing skills. In addition, the childrens parents answered a questionnaire about the childs gestation, birth, life and social aspects. In order to check the relationship among the independent and dependent variables (reading, writing, arithmetic), we used the logistic regression. RESULTS: we observed that alterations in phonological awareness increase the risk of a child in reading (OD = 42; p-value 0.02), writing (OD = 10.8; p-value 0.01) or arithmetic (OD = 42; p-value 0.002) alterations. Alterations in phonological memory increase the risk of a child in reading (OD = 24; p-value 0.04) or arithmetic (OD = 42; p-value 0.04). In the study we also observed that high education level of childrens mother reduce the risk for childrens school problems (OD = 0,3; p-value > 0.001) and mothers low level education (OD = 2.3; p-value > 0.001) affect the childrens reading. The weight in birth or prematurity is not related with school performance. CONCLUSIONS: children who have phonological awareness and phonological memory alterations or children who also have low education level mothers have increased the risk as for learning problems.