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PubMed2006

[Early development and learning conditions: the role of the executive functions].

INTRODUCTION: From the neuroconstructivist approach, cognitive development is understood and studied as a process of successive rearrangement, as are its mechanisms of change and its differential results. The early years of life are essential in being able to explain the differential cognitive, emotional and social competencies. Changes in the executive functions play a crucial role in this process. Understanding it calls for interdisciplinary research that relates neuroanatomical data about the brain with functional and psychological data. AIMS: To further our knowledge in a number of different disciplines about early executive functioning in infants with differential courses of development (typical infants, infants with Down syndrome, infants born with risk factors). We suggest the existence of an early differential gradient of executive functioning. SUBJECTS AND METHODS: A comparative and longitudinal study was conducted into the activity of typical infants (n = 10), infants with a risk factor (n = 6 infants with congenital hypothyroidism; n = 6 infants born underweight) and infants with Down syndrome (n = 6), using a stimulating material, at 1.3 years and again 9 months later. Data was analysed both qualitatively and quantitatively. RESULTS: The two groups that were studied showed different patterns of early executive functioning, and the biggest difference was observed between typical infants and infants with Down syndrome. The infants with risk factors were located on a gradient between these two, although closer to the former but with certain differences. It is also noted how the executive functions develop over the ages that were studied. CONCLUSION: These differences in executive functioning provide us with guidelines on interventions aimed at harmonising early cognitive development.

Child Development↗
PubMed1982

The effects of analgesics on quickly-learned conditioned suppression in mice.

Mice were found to exhibit a marked suppression of motor activity when placed into the same experimental chamber in which they had previously received electrical shocks. This suppression was found to be a stable response when mice, 6-8 weeks of age, received shocks of frequencies of 1/10 or 1/30 Hz, and their motility was examined 24 hr after the delivery of the shock in the same experimental chamber. Control experiments indicated that the mice exhibited similar degrees of locomotor activity, compared to non-shocked mice, that were placed into a different experimental chamber than from the one in which they had previously received electrical shocks. Thus, the suppression of motor activity appeared to be a conditioned emotional response to the environment previously associated with delivery of shock. Morphine, codeine, and pethidine, but not pentazocine and aminopyrine, attenuated the conditioned suppression in a dose-related manner in the shocked mice. The effect of morphine was completely antagonized by pretreatment with naloxone or levallorphan. Thus, it is possible that the opiate-induced reduction of conditioned suppression is mediated by opiate receptor sites.

Aging↗
PubMed1982

Effects of apomorphine and diazepam on a quickly learned conditioned suppression in rats.

Electric shock experienced rats exhibited a marked suppression of motor activity when placed in the same environment in which the animal received shocks. At 24 hr after electrical shocks, the shock frequencies of 1/10 Hz to 1/180 Hz equally produced a marked suppression of motility. However, electric shock experienced rats exhibited a similar degree of locomotor activity that was seen with the non-shocked rats, when the motility of the animals was measured by using Animex system at 24 hr after electrical shocks. Therefore, this suppression of motility was found to be a consistent response and to be a conditioned response to the environment. Diazepam (1.2.5 or 5 mg/kg, IP) did not show any effect on the conditioned suppression. Apomorphine-HCl (0.1, 0.5 or 1 mg/kg, IP) caused attenuation of the conditioned suppression in relation to dose, but did not increase motor activity of the non-shocked rats. Thus, conditioned suppression caused by a quick conditioning technique may not be associated with anxiety.

Animals↗
PubMed1983

Effects of diazepam, meprobamate, chlorpromazine and apomorphine on a quickly learned conditioned suppression in mice.

Mice exhibited a marked suppression of motor activity when placed into the same environment in which they had previously received electric foot shocks. Apomorphine-HCl (0.1 - 10 mg/kg) produced a dose-dependent reduction of the conditioned suppression of activity, but did not increase activity in non-shocked mice. Diazepam (0.2, 1, and 5 mg/kg), meprobamate (25 and 50 mg/kg), and chlorpromazine-HCl (2 and 5 mg/kg) did not reduce conditioned suppression. Thus, the conditioned suppression caused by a quick conditioning technique does not produce similar results to those using the conditioned emotional response involving suppression of operant lever-pressing behavior.

Animals↗
PubMed1984

A mode of action of morphine on a quickly learned conditioned suppression in mice.

Mice exhibited marked suppression of motor activity when placed in the same environment where they had previously received electric shocks. Morphine-HCl (20 mg/kg) markedly attenuated such a conditioned suppression in mice. The morphine-induced reduction of the conditioned suppression was antagonized by pretreatment with reserpine (0.1 and 0.5 mg/kg), haloperiodol, pimozide and alpha-methyl-p-tyrosine, but not atropine-sulfate, p-chlorophenylalanine, phenoxybenzamine-HCl or propranolol. Thus, it is possible that the potentiation of the dopaminergic neurotransmission in the brain is involved in the morphine-induced reduction of the conditioned suppression in mice.

Animals↗
PubMed1998

[Report from the conference on "safe and hygienic learning conditions as indispensable elements of elementary schools' functioning"].

The conference was organized in Warsaw on the 14th of November 1997, by the Main Section of School Hygiene of the Polish Society of Hygiene. 202 people took part in the conference. They represented following institutions: a sanitary inspection, a health care service, academy institutes, pedagogical institutions, community councils. The purpose of the meeting was to point out and widespread local initiatives and ideas, appearing in various regions of Poland, that concern the following topics: 1: improvement of health conditions in schools, 2) improvement of conditions and realization's methods of increased number of physical training lessons in schools (a gradual increase from 3 hours a week at the present time to 5 in the year 2000), 3) providing actions to minimize the number of accidents among children and adolescents. There were panel discussions concerning the problems mentioned above. Many conclusions were formulated as the result of the discussion, out of which the most important are: ad 1) Maintaining the conditions of proper education demands cooperation between schools' headquarters and community councils and an initiative in seeking allies and sponsors. Examples of the activities of community councils to maintain proper safe and hygienic conditions in education should be propagated. These examples can be applied in another areas. ad 2) There is a dramatic shortage of facilities. Schools try to fulfil the increased requirements by: utilizing elements of natural environment, profiting from the spontaneous activity of children and parents, extending a traditional curriculum offered by new elements of physical culture. Increasing the number of physical training classes gives a chance to create social attitudes during these classes and health behaviour. ad 3) Accident risk in schools should be eliminated by carrying out a systematic many-sided and preventive activity. The coordination of actions should exist on all levels of local and national administration. In schools decisions concerning organizational solutions should be taken up, with the active involvement of headquarters, teachers, administrative workers and parents.

Accident Prevention↗
PubMed2002

[Assessment of learning conditions in urban and county secondary schools in the first year of education's system reform].

The study was conducted in spring 2000 on the representative national sample of 266 secondary schools. Collected data included information about the organisation of schools, hygienic conditions of classrooms, conditions of regular travelling to schools, using of day-rooms, base for physical education range of supplementary alimentation. It was established that on the contrary to the reforms program (education in different sites) secondary schools were located in 2/3 of cases in the same site with primary schools. Analysis of data from independent secondary schools showed that ensuring appropriate conditions for education was more difficult that in case of secondary schools located with primary school. A lot of problems were not solved with a such consequences like crowded schools, poor ventilation, inappropriate lighting, inconvenient furniture, Significantly better base of physical education and wide range of supplementary alimentation may be regarded as the positive aspects of created system. Unfortunately only a part of children took the possibility of supplementary alimentation. Both positive and negative aspects of education's conditions in urban and country secondary schools were similar with the exception of better technical status of buildings, more frequently taking offers of supplementary alimentation and more frequently organisation of breakfast at country schools. Urban schools had better conditions at day rooms and frequently owned the physical education halls. Presenting results may serve as a basis for planning activities to support health needs of children at urban and country secondary schools.

Adolescent↗
PubMed1991

Analysis of aversively conditioned learning and memory in rats recovered from pyrithiamine-induced thiamine deficiency.

Rats that had recovered from pyrithiamine-induced thiamine deficiency (PTD) were trained on tasks motivated by escape from mild footshock. On postmortem examination, the PTD model showed two consistent lesions: a bilaterally symmetrical lesion of the medial thalamus, which was centered on the internal medullary lamina (IML), and a lesion centered on the medial mammillary nuclei. PTD rats with IML lesions were impaired in learning a spatial nonmatching-to-sample (NMTS) task that was mastered without error by controls and PTD animals without IML lesions. These same animals were able to perform as well as controls on discrimination tasks based on either place or visual (light-dark) cues, although they made more errors than controls in reaching criterion in the initial place discrimination problem. These findings are consistent with findings from appetitively motivated tasks that PTD rats with IML lesions have an impaired capacity for working memory but not for reference memory.

Alcohol Amnestic Disorder↗
PubMed2000

The cerebellum and cognition: cerebellar lesions impair sequence learning but not conditional visuomotor learning in monkeys.

Claims that the cerebellum contributes to cognitive processing in humans have arisen from both functional neuroimaging and patient studies. These claims challenge traditional theories of cerebellar function that ascribe motor functions to this structure. We trained monkeys to perform both a visuomotor conditional associative learning task and a visually guided sequence task, and studied the effects of bilateral excitotoxic lesions in the lateral cerebellar nuclei. In the first experiment three operated monkeys showed a small impairment in post-operative retention of a visuomotor associative task (A) but were then not impaired in learning a new task (B). However, the impairment on A could have been due to a problem in making the movements themselves. In a second experiment we therefore gave the three control animals a further pre-operative retest on both A and B and then tested after surgery on retention of both tasks. Though again the animals showed motor problems on task A, they reached criterion, and at this stage could clearly make both movements satisfactorily. The critical test was then retention of task B, and they were not impaired. In the final experiment (serial reaction time task) the monkeys response times on a repeating visuomotor sequence were compared with those for a pseudo-random control sequence. After bilateral nuclei lesions they were slow to execute the pre-operatively learned sequence but were still faster on this than on the control task. However, when they were then given a new repeating sequence to learn, they never performed the sequence as quickly as they had on retention of the first sequence. We conclude that the cerebellum is not essential for the learning or recall of stimulus-response associations but that it is crucially involved in the process by which motor sequences become automatic with extended practice.

Animals↗