Encyclopedia talk:Main Page

Part A

Brain development is a critical part in the physical development that children and toddlers undergo. Brain development encloses brain growth, as well as the development of auditory, visual, and language areas in the cerebral cortex. The main component of brain growth entails how the neurons, cells that transmit information, form a communication system. The neurons form synaptic connections with cells close by in order to establish their individual functions. This process is very rapid during the first two years of life. In order for neurons to continue forming connections, they must be stimulated by the environment. To ensure that the child grains the appropriate motor, cognitive, and social skills necessary, an overabundance of synapse occurs. If these neurons are not stimulated they undergo a process called synaptic pruning, in which they are returned to an unassigned state for future development. Normal brain development includes the overproduction and death of neurons, but not all brains will develop the same neural connections. According to Berk, the development can be compared to “molding a sculpture” because each individual’s brain is not only influenced by genetic programming, but also the experiences of the child (Berk, 2010). The children that aren’t exposed to certain environmental conditions may never form the necessary synapses for survival. Due to the plasticity of the brain during the first two years and the development of the cerebral cortex, there is a sensitive period crucial for proper development, and if synapses cease to be formed during that time, the neural functions may never be assigned. Brain Development is one of the most important components in childhood as well as adult development. If the brain doesn’t properly develop, the cognitive, motor, and social skills needed for survival may never be formed. Without brain development, humans wouldn’t acquire auditory and visual perception or motor skills. In order to effectively communicate and survive, these skills are needed. The development of the brain also allows people to think, control our impulses, solve problems, and have a memory. The development of the brain provides people for a life of normality and the ability to grow at the same rate as their age group. Through brain development, children mature and learn the proper skills in order to survive without a caregiver. They know when they need to sleep, eat, and basic needs that require attention. Without the development of the brain, survival would be nearly impossible.

Part B

   While the anatomy of the brain is basically developed by the time a baby is born, the majority of the maturation occurs during the first two years of life. For example, the gyri and sulci of the brain are formed by the time of birth, but there is an increase in grooves and complexity during infancy. The slow maturation of the human brain, compared to other animals, allows for learning and plasticity. Synapses, which are connections made between neurons in the brain, promote this learning. By the age of two, the synaptic density is about 150% greater than that of adults (Lenroot & Giedd, 2006). Furthermore, certain regions of the brain experience a loss of synaptic links at different times when the synapses are not being used. The visual cortex, for instance, reaches its maximum synaptic density at four months of age, while the prefrontal cortex does not climax until the child is four years old (Lenroot & Giedd, 2006). 
   PET images allow for observations of specific development in the brain by measuring glucose uptake. By the time the infant is five weeks old, the sensorimotor cortex, thalamus, brainstem, and cerebellar vermis are receiving the highest amount of glucose. This activity can be seen in the parietal, temporal and occipital cortices, basal ganglia and cerebellar cortex by three months of age. (Johnson, 2001). Also, most neurons become myelinated during infancy. Myelination speeds up communication between neurons and looks white compared to grey unmyelinated neurons. 
   Finally, while there are “windows of opportunity” for development of specific parts of the brain to develop optimally, learning and environmental exposure during infancy and early childhood is critical to brain development. The brain needs stimuli in order for neurons to be used and make synapses. However, it is possible to overstimulate and stress the connections, which could hinder learning in children (Berk, 2010).

Part C

1. Microsystem The microsystem contains the interactions that a child has directly with others. Many microsystemic factors have an effect on the development of the brain. The most prominent features of the developing brain's microsystem are the parents responsible for raising the child to whom the brain belongs. Parents provide loving care that is invaluable to the growth of the brain, including holding the child tenderly, speaking to it softly, and breastfeeding the child. The parent also exposes the child to varied visual and sensual experiences throughout childhood. This allows the child to explore environments by touching and seeing objects and listening to the surrounding language and alternate sounds. Teachers and others in direct contact with the child also add to the diversity of the child's experiences. All of these stimuli cause neurons around the brain to be used and therefore not to fall victim to programmed cell death or synaptic pruning that targets unused neurons. This allows glial cells to grow and replicate which aid in keeping the neurons healthy. It also allows myelin to coat the neurons in a process called myelination to make the already specified functions in the developing brain more efficient. This early stimulation also makes sure the brain has utilized neurons in enough of the areas of the brain to allow lateralization to proceed normally. These normal experiences that the those in direct contact with the child facilitate are examples of experience-expectant brain growth, during which the brain organizes itself and learns necessary actions and functions it will need to carry out normal tasks. More complex learning that occurs within the microsystem a little later in development is considered experience-dependent brain growth, because it is based on the things the child is taught and learns based on individual and environmental differences rather than functional necessities of the growing brain.

2.Mesosystem The mesosytem is the interaction of a child's various microsystems. The amalgamation of the experiences from all of child's microsystems aids greatly in experience-dependent brain growth. The wide variety of direct contacts that the individual child increases the variety or visual, sensory, and auditory information that it receives. The infinite combination of ways that an individuals mesosystem can affect their brain growth is a demonstration of experience-dependent brain growth and also stimulates neurons to make the brain more efficient.

3. Exosystem The exosystem is the variety of factors that affect an individual's social setting but do not interact with the individual directly. Similar to the mesosytem, the exosystem's effects are to broaden the individual's exposure to more distinct objects and sensory events by influencing people and things the individual does have contact with, for example, educating a parent on proper stimulation, or donating a teaching tool to the school which the individual child attends. This improvement in education can decrease the frequency of overstimulation in which a child receives too many new factors to gain any benefit, subsequently improving the quality of microsystem interactions. The exosystem is mostly and extension of experience-dependent brain growth.

4. Macrosystem The macrosystem is made up of culture, societal laws, customs, values, and resources. The macrosystem affects brain development in a variety of ways. The macrosystem has a huge influence on the recources available to all of the lesser systems. For example, in certain macrosystems, access to early educational opportunities may be severely limited. As well, public care for orphaned children varies in quality everywhere. Some orphanage environments limit adult contact and stimulation, which severely impairs development! Also a societies customs and values can affect the diversity of experiences and environments that children experience. For example a community in which most of the inhabitants work in the field might put far less focus on general education, instead focusing solely on specific job training, This type of learning environment cuts down on experience-dependent brain growth and ultimately can hinder ideal development.

5. Chronosystem The chronosystem encompasses the changes in an individuals' environment that stem from the individuals themselves. Both experience-expectant brain growth and experience-dependent brain growth affect the outcome of an individuals' life selections and modifications. Every system's effect on brain development factors into an individuals chronosystem, and it is infinitely variable between individuals.

Part D

   While brain development is a physiological process that occurs most rapidly in the first few years of life, there are some factors that can promote this growth along the way. Nutrition and and sleep are important aspects to consider in this process. As discussed in part B, the brain needs glucose to develop properly. Therefore, nutrition is essential to growth. The average newborn sleeps between 16 and 18 hours a day, whereas a two-year-old only requires 12 to 13 hours. This being said, it is important for parents to recognize that melatonin, a hormone within in the brain that associates nighttime/darkness with drowsiness, is not produced until around 6 months of age (Berk, 2010). Therefore, an infant’s sleep will occur at any point throughout the day, and should not be forced by parents at night by overfeeding.

Works Cited

Berk, L. (2010). Development Through the Lifespan (5th edition). Boston: Allyn & Bacon

Gogtay, Nitin, Jay N. Giedd, Leslie Lusk, et al. "Dynamic Mapping of Human Cortical Development during Childhood through Early Adulthood." Proceedings of the National Academy of Sciences of the United States of America. 2004. http://www.pnas.org/content/101/21/8174.full.

Johnson, Mark. “Functional brain development in humans.” Nature Reviews Neuroscience. 475-483. July 2001. http://www.nature.com/nrn/journal/v2/n7/full/nrn0701_475a.html

Lenroot, Rhoshel K., Giedd, Jay N. “Brain development in children and adolescents: Insights from anatomical magnetic resonance imaging.” Neuroscience & Biobehavioral Reviews 30(6). Pages 718-726. 2006. http://www.wisspd.org/html/training/ProgMaterials/CH980-09/BDCA.pdf