Well, we reached the end of year celebrations and I think today is a good day to raise the Blog this week. This time I'll upload an entry written by Martha Beatriz Moreno-related brain differences between children and adults to pay attention.
"CHILDREN AND ADULTS USING THE SAME PAY ATTENTION TO BRAIN REGIONS?
Apparently yes, but with different intensity and specificity. Childhood and adult brain is different in form and function in some aspects. For example, children have more gray matter (neuron bodies) and less white matter (neuronal axons) than adults. As we grow the white matter increases as the axons of myelinated neurons, ie, fat covering that allows for better conduction of nerve signals. But he also noted that to solve the childhood and adult brain functions differently. To explore such differences Konrad and colleagues (2005) conducted an MRI study which involved 32 subjects (16 adults from 20 to 34 years and 16 children from 8 to 12 years). Each participant had to attend to visual stimuli presented on a screen inside the scanner magnet. In children and adults presented the same set of images composed of different visual stimuli: fixing (a cross), warning (asterisk) and target images (5 arrows) presented as a column. Each participant had to be vigilant in identifying when the image appeared of 5 arrows. Main focus should be put in the direction of the arrow in the middle to press the left button of a keypad near your hand when that arrow pointing to the left or the right button when pointing to the right. (See Figure 1)
Figure 1. Visual stimuli presented to subjects (in Konrad et al., 2005:431)
The results showed that all participants selected the same region, but children and adults had different patterns of activación. Al estar alerta, se activó principalmente una región de la corteza frontal llamado giro del cíngulo frontal derecho (figura 2A) y una estructura subcortical denominada tallo cerebral (figura 2B), el cual es la continuación de las fibras que conforman la médula espinal. Las discrepancias en el tamaño de las barras corresponden a diferencias en la intensidad de señal provocada por los diferentes cambios metabólicos (oxigenación) neuronales de niños y adultos al resolver la tarea. Las barras rojas corresponden a la activación neuronal al estar alertas a las imágenes sin pista y las barras verdes a las imágenes de alerta con pista (doble asterisco). Los autores sugieren que las observed differences are due to different processing mechanisms in children and adults.
Figure 2. Brain activation to the task of alerting images with or without tracks (asterisk).
Seeing the stimulus and to identify if all the column arrows point to the same direction (congruent) or not (mismatch), adults had greater activation in superior parietal cortex and the inferior frontal gyrus than boys (Figure 3A and B) and greater activation in the superior temporal gyrus and superior frontal gyrus in children than in adults (Figure 3C and D). The authors believe that these results give evidence of immaturity of neural networks (parietofrontales) on cognitive tasks. Conclude that the results provide evidence that the attentional system is functional but immature children compared to adults, children showed a more diffuse activation pattern that covers more areas of brain regions than adults. This nature reflects immaturity of the system during childhood, which gets more focus and specialize in the development and experience.
Figure 3. Differences in brain activation between children and adults to address visual stimuli
Research Konrad and colleagues is respectable given the complexity of doing fMRI with children because of the difficulty of having the cooperation, following instructions and stillness that the child should have during the study of resonance magnetic and the importance of their results as they provide evidence of differences in cognitive processing reflected in neural activation differences. This work allows a better understanding of brain functioning children with cognitive tasks. The authors say their figures represent not only a characteristic neural functioning of children, but also the use of different strategies but functional as they enable the child to interact with their environment and their cognitive development continue to develop more efficient cognitive strategies without requiring major neural substrate (Konrad et al, 2005).
Cognition, Brain and Consciousness, Academic Press,
Konrad, K., Neufang, S., Thiel, CM et al . (2005). Development of attentional networks an fMRI study with Children and adults. Neuroima433ge, 28 (2), 429-439
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