RESUMEN
This study investigated the interaction between motorcortical excitability (short interval cortical inhibition, intracortical facilitation and long interval cortical inhibition), different requirement conditions [choice reaction test (CRT), attention/go/nogo], and their pharmacological modulation by methylphenidate (MPH) in normal healthy adults (n = 31) using a transcranial magnetic stimulation paradigm. MPH was administered in a dosage of 1 mg/kg body weight, maximum 60 mg. Additionally, serum level and clearance of MPH were controlled. The statistical analysis of variance revealed a significant three-way interaction of 2 (MPH) x 3 (CRT) x 6 (ISI) predicting motor evoked potential amplitudes (P = 0.032, MPH none and full dose, n = 31). In order to compare effects of dosage an additional between-subjects factor (half vs. full MPH dose) was introduced. None of the interactions involving this between-subject factor reached statistical significance. Exploring interactions with MPH only, a 3 (MPH none, half and full dose) x 3 (CRT) x 6 (ISI) analysis of variance revealed significant two-way interactions for MPH x ISI (P = 0.040) and condition x ISI (P < 0.001, n = 18). Effects observed for MPH were strongest on facilitatory processes, weaker for intracortical inhibition. In sum, MPH seems to interact via striato-thalamo-cortical pathways with original motorcortical processes (ISI), to a lesser extent with task-dependent or behavioral parameters (CRT).
Asunto(s)
Inhibidores de Captación de Dopamina/farmacología , Función Ejecutiva/efectos de los fármacos , Metilfenidato/farmacología , Actividad Motora/efectos de los fármacos , Corteza Motora/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Análisis de Varianza , Atención/efectos de los fármacos , Atención/fisiología , Inhibidores de Captación de Dopamina/administración & dosificación , Inhibidores de Captación de Dopamina/sangre , Relación Dosis-Respuesta a Droga , Potenciales Evocados Motores/efectos de los fármacos , Función Ejecutiva/fisiología , Humanos , Metilfenidato/administración & dosificación , Metilfenidato/sangre , Actividad Motora/fisiología , Corteza Motora/fisiología , Inhibición Neural/efectos de los fármacos , Vías Nerviosas/efectos de los fármacos , Vías Nerviosas/fisiología , Pruebas Neuropsicológicas , Desempeño Psicomotor/fisiología , Análisis y Desempeño de Tareas , Factores de Tiempo , Estimulación Magnética Transcraneal , VoliciónRESUMEN
Sleep disturbances belong to the most frequent symptoms of depression. Low concentrations of n-3-fatty acids might represent one determinant within that process. Therefore, the aim of the study was to examine the relationships between serum fatty acid concentrations and severity of sleep disturbances in depressives. Serum fatty acids were measured gaschromatographically in 118 depressive inpatients (51 males; 67 females; age 45.4+/-12.0 years), divided into subgroups according to three degrees of sleep disturbances (BDI-item). At admission and discharge, we found significant negative correlations between the degree of sleep disturbances and fatty acid concentrations (myristic, palmitic, palmitoleic, oleic, linoleic, eicosadienoic and docosahexaenoic acid). At both assessments palmitoleic and eicosadienoic acids had the strongest connections with sleep performance. Palmitoleic and oleic acid seem to be especially important for sleep disorders, may be due to their function as precursors of the sleep inducing oleamide. Linoleic and eicosadienoic acid could be helpful for maintaining sleep because they are precursors of the sleep mediator PGD2. In contrast to our hypothesis, there is not only a significant lack of n-3 fatty acids but also of special monoenoic and n-6 fatty acids in sleep-disturbed depressives.
Asunto(s)
Trastorno Depresivo/metabolismo , Ácidos Grasos/sangre , Trastornos del Sueño-Vigilia/etiología , Adulto , Análisis de Varianza , Trastorno Depresivo/complicaciones , Ácidos Grasos Monoinsaturados/sangre , Ácidos Grasos Insaturados/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos del Sueño-Vigilia/metabolismoRESUMEN
Motor hyperactivity is one of the most outstanding symptoms of attention deficit hyperactivity disorder (ADHD) which might be caused by a disturbed inhibitory motor control. Using focal transcranial magnetic stimulation (TMS) we tested the cortico-callosal inhibition (duration and latency of the ipsilateral Silent Period, iSP) in 23 children with ADHD (mean age 11+/-2.6 years) before and on treatment with methylphenidate (MPH). iSP latency was age correlated, whereas iSP duration as well as Conners scores were age independent. Analyses of mean differences revealed a significant prolongation of iSP duration (p=0.001), shortening of iSP latency (p=0.027) and reduction of Conners score (p=0.001) under medication. Increase of iSP duration and reduction of Conners score under medication were significantly correlated (t=-9.87, p=0.016). Reduced iSP duration and prolonged iSP latency in ADHD children could be the result of a disturbed transcallosally mediated inhibition, most probable due to a combination of maturation deficits of callosal fiber tracts as well as neuronal synaptical transmission within the neuronal network between ipsilaterally stimulated cortex layer III--the origin of transcallosal motor-cortical fibers--and contralateral layer V, the origin of the pyramidal tract. MPH may indirectly improve the dysbalance between excitatory and inhibitory interneuronal activities of this neuronal network via dopaminergic modulatory effects of the striato-thalamo-cortical loop.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Cuerpo Calloso/fisiopatología , Agonistas de Dopamina/uso terapéutico , Metilfenidato/uso terapéutico , Actividad Motora/efectos de los fármacos , Adolescente , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Niño , Potenciales Evocados Motores , Femenino , Humanos , Masculino , Estimulación Magnética TranscranealRESUMEN
In the present study inquiries have been made about the changes EEG cross-correlation in mental activities is subject to. The EEG recordings were made at rest, in visual and acoustical response, when reading and in the solution of an acoustical differentiation problem. In conjunction with plain reflex processes a decline in the intrahemispherical correlation was observed. During complex-structured psycho-request situations dissimilar changes in the EEG correlation have occurred on the scalp. Between the cerebral regions functionally essential for the solution of the problems, an increase in the bio-electric correlation and between other cerebral areas a decline were registered. The findings in conclusion come to realize that the topographic EEG cross-correlation analysis is appropriate to give an insight into the present situation of cerebral functional organization.
Asunto(s)
Nivel de Alerta/fisiología , Atención/fisiología , Corteza Cerebral/fisiología , Electroencefalografía , Solución de Problemas/fisiología , Niño , Dominancia Cerebral/fisiología , Potenciales Evocados , Humanos , Procesamiento de Señales Asistido por ComputadorRESUMEN
Average negative (N) and positive (P) latent deflection of the optically elicited orbicularis oculi reflex in 9 to 11 year old boys of normal intelligence was 68 +/- 11 and 182 +/- 34 ms. This was no different to results obtained from a group parallel in respect of age, sex, and intelligence but with brain damage sustained in early childhood.
Asunto(s)
Parpadeo , Daño Encefálico Crónico/fisiopatología , Tiempo de Reacción/fisiología , Reflejo Anormal/fisiopatología , Tronco Encefálico/fisiopatología , Niño , Humanos , Masculino , Estimulación LuminosaRESUMEN
EEG correlation analyses were conducted with children with and without specific learning weaknesses. Reduced left parietal correlation was found in children with dyslectic problems, and in children with adjustment and concentration problems, reduced bioelectric correlation. The frequent evidence of brain injury criteria suggests a link with general affectations of correlation but not specifically with cerebral correlation affections. It would appear to be appropriate to employ computer-assisted EEG correlation analysis, together with frequency analysis and the examination of evoked potentials in objective neurometric diagnosis where children with learning weaknesses are involved.
Asunto(s)
Electroencefalografía , Discapacidades para el Aprendizaje/fisiopatología , Trastornos Neurocognitivos/fisiopatología , Corteza Cerebral/fisiopatología , Niño , Potenciales Evocados , Humanos , Procesamiento de Señales Asistido por ComputadorRESUMEN
Changes of the pattern reversal EP and heart rate (HR) during calculating were studied on 32 boys with minimal brain damage and a control group (n 27) matched in age, sex and intelligence. The introduction of a reference period and repetition of the calculation period should improve the value of all results and should give simultaneously a first insight in the course of the parameters investigated, during mental loading. Both groups reached the same results in calculating, yet only the brain damaged boys simultaneously showed significant longer latencies of the EP. This result was interpreted as an effect of the higher loading of the damaged subjects. The task-depended increase of the HR was significant in both groups. The HR-level was getting lower with the increasing number of brain damage criteria. The results of intercorrelation between in physiologic parameters and datas of subjective feeling and results of calculating was negative in all cases. These findings were interpreted on the basis of several difficulties to find out clear cut patterns of reaction for different clinical groups.
Asunto(s)
Nivel de Alerta , Trastorno por Déficit de Atención con Hiperactividad/psicología , Solución de Problemas , Atención , Niño , Potenciales Evocados Visuales , Frecuencia Cardíaca , Humanos , Masculino , Matemática , Tiempo de ReacciónRESUMEN
The cross-correlation method was used to measure interhemisphere phase differences over four areas of the brain in 22 healthy children aged between 7 and 10 years. Apart from defining normal values, the authors describe age-dependent characteristics and changes that take place as a result of mental stress.
Asunto(s)
Corteza Cerebral/fisiología , Desarrollo Infantil , Dominancia Cerebral/fisiología , Electroencefalografía , Niño , Sincronización Cortical , Potenciales Evocados , Humanos , MasculinoRESUMEN
The occurrence of the P3 component of the acoustic vertex ERP after an appropriate stimulus was recorded for 27 male children (including 6 with early brain damage) with normal and 37 (including 33 with early brain damage) with below-normal concentration. Both groups had the same mean age and intelligence. A P3 component was found in the case of 18 subjects with normal and 9 with below-normal concentration. The rearrangement of the subjects to give one group with, and one without, brain damage yielded smaller differences. The significant difference (p less than 1%) in the frequencies with which the P3 component occurred, taking the mean concentration into account, leads to the assumption that the internal processing of the stimulus is disturbed in boys with poor concentration.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Potenciales Evocados Auditivos , Nivel de Alerta , Atención , Daño Encefálico Crónico/diagnóstico , Niño , Humanos , Inteligencia , MasculinoRESUMEN
Frequent stimulation induces a state of permanent evoked activity, i.e. the Steady State Response (SSR). An attempt was undertaken to assess the effects of various parameters on the SSR-configuration. 23 boys with normal brains and normal intelligence were studied under constant conditions. Light flashes were delivered in trains of 1 s at a flash repetition rate of 8 c/s. 60 trains were averaged. Three intensities of stimulation (1,2; 0,6; 0,3 Joule) were used. SSR could be observed in 87% of all volunteers (using intensity 1,2 Joule). Independently of the intensities of the stimulation a well-shaped SSR was found after the 3rd or 4th stimulus of the train. Considering the number of deflections four different types of SSR were detectable. There was a slight coherence between the types of SSR and the dominant alpha-frequency. Continuous enhancement of amplitude with increasing stimulus intensity was found only in 50%. Furthermore changing of the SSR-type was found in 5 cases. Taking into account the variability of SSR in healthy probands using of this method for clinical applications on a larger scale remains to be seen.
Asunto(s)
Corteza Cerebral/fisiología , Electroencefalografía/métodos , Percepción Visual/fisiología , Niño , Potenciales Evocados Visuales , Humanos , Masculino , Tiempo de Reacción/fisiologíaRESUMEN
The latency and amplitude data of optically evoked potentials (unipolar from the vertex) were measured during the 50-200 ms interval in a group of normal boys (n = 26) and a group of boys with brain damage sustained during early childhood (n = 38). The latency periods were sometimes significantly longer and the amplitudes larger (flash stimulus) and smaller (pattern stimulus) respectively in the brain damaged than in the normal subjects. In view of the results of clinical, neurological and psychological examinations, these phenomena must be attributed to delayed maturation of the central nervous functional system.
Asunto(s)
Daño Encefálico Crónico/diagnóstico , Electroencefalografía/métodos , Tiempo de Reacción/fisiología , Daño Encefálico Crónico/fisiopatología , Corteza Cerebral/fisiopatología , Niño , Potenciales Evocados Visuales , Femenino , Humanos , MasculinoRESUMEN
The behaviour of normally intelligent children experiencing difficulties in reading and writing and with poor concentration was assessed by means of the Meyer-Probst questionnaire which was answered by the mothers, fathers and teachers. The results were compared with those for a parallel control group composed of normal children. The assessments given by parents and teachers were in good agreement in the case of the control group, but those given by the different persons involved differed in education and upbringing regarding certain psychological aspects in the case of the children with poor performance at school.
Asunto(s)
Trastornos de la Conducta Infantil/diagnóstico , Discapacidades para el Aprendizaje/diagnóstico , Relaciones Padres-Hijo , Medio Social , Atención , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Niño , Trastornos de la Conducta Infantil/psicología , Femenino , Humanos , Inteligencia , Discapacidades para el Aprendizaje/psicología , MasculinoRESUMEN
In 21 boys with normal brains and 34 boys who had sustained brain lesions during early childhood the time course of habituation of the vertex response was studied. All boys showed normal intelligence and were aged between 9 and 11. Boys were tested under different experimental conditions using periodic and aperiodic flash-stimuli at constant intensities (1.2 J). The peak-to-peak amplitudes of the prominent N1-P1 and P1-N2 component were measured. A gradual decrease of the amplitude was observed as a function of the stimulus program and the duration of the experiment. A significant, more rapid habituation was observed in boys with early brain damage. These results suggest that the capacity of tonic activation is disturbed in children with brain-organically impaired performance.
Asunto(s)
Daño Encefálico Crónico/fisiopatología , Potenciales Evocados Visuales , Habituación Psicofisiológica/fisiología , Niño , Humanos , MasculinoRESUMEN
Berger effect behavior was tested in a group of 15 boys with early brain damage and a control group of 15 boys without an anamnesis of brain damage, with a view to development, conditioning ability and habituation. In the group of brain-damaged test persons the proportion of BE-positive subjects was markedly less in all trials. Habituation occurred earlier and in a larger percentage. The conditioning capacity was worse in each series. The phenomena observed suggest that subjects with early brain damage suffer from a disturbance in the general reticular action system.