Social and Cultural Foundations of American Education/Knowing/Brain Research

Brain research is an important field dedicated to helping us learn how our brains function. This knowledge will help us better understand how we learn and some important differences between the brains of children and adults. As educators it is crucial that we have an understanding of the biology that is affecting how our students learn.

CAT Scans
Computerized axial tomography (CAT) scans are one imaging technique that is used to create an image of the brain. It consists of multiple X-ray exposures which are combined by a computer to create image slices of the brain. This is particularly useful when looking at interior parts of the brain. CAT scans however pose the same radiation risks as other forms of X-ray and therefore are used less regularly in brain research than for personal diagnoses of abnormal anatomy (Barlow & Durand, 2005).

PET Scans
To measure brain function a positron emission tomography (PET) scan can be used. A tracer substance attached to radioactive isotopes is injected into the blood where it interacts. When parts of the brain become active blood is sent to deliver oxygen which creates spots which are picked up by detectors and used to create a video image of the brain during a particular task (Barlow & Durand, 2005). PET scans are costly and invasive, making their usage limited.

MRI and fMRI
Magnetic resonance imaging (MRI) and functional magnetic resonance imagining (fMRI) are commonly used brain imaging techniques which use echo waves to discriminate between grey, white and cerebral spinal fluid (Giedd, Blumenthal, Jeffries, Castellanos, Liu, Zijdenbos, Paus, Evans & Rapoport, 1999). MRI is noninvasive, poses little health risk and can be used on infants and in utero providing a consistent mode of imaging across the development spectrum (Lenroot & Giedd, 2007). MRI is used to create an image of the brain structure and fMRI, which is really a series of MRIs, measures the functioning of the brain through computer adaptation of many images (Barlow & Durand, 2005).

Structure of the Brain
The brain is composed of over 140 billion nerve cells, called neurons, by the time we reach adulthood. Unique live experiences and biological processing means that individual brains contain the potential to become drastically different. However, the brain is generally organized into several lobes that control categorical parts of life. The brain stem handles most of the essential automatic functions including sleeping, breathing, pumping of the heart and digestion. Parts of the brain stem, the hippocampus, thalamus, hypothalamus and limbic system are largely involved with controlling behavior and emotions; especially stress responses (Barlow & Durand, 2005).

The cerebral cortex is distinctly human and houses two hemispheres which are responsible for all our cognitive functions. Each hemisphere consists of four separate lobes: temporal, parietal, occipital and frontal. The temporal lobe recognizes various sights and sounds and is responsible for long-term memory storage. The parietal lobe recognizes touch sensations. The occipital integrates and understands visual inputs. The frontal lobe is responsible for our thinking and reasoning abilities as well as memory and is the most interesting for educators because it continues to grow well into adulthood. The hemispheres are connected through a structure called the corpus collasum which allows collaboration between different brain regions housed in opposite brain hemispheres (Barlow & Durand, 2005).

Early Childhood
Although the brain is well organized into lobes there is a great deal of plasticity available. Depending on the person and their environment different parts of the brain may be more or less developed (Slavkin, 2004). Proper development of all brain sections begins in early childhood with an enriched environment composed of proper nutrition and interaction with attentive caregivers. Development of the brain occurs through sensitive periods where exposure is necessary for proper growth. If young children are not adequately exposed to visual, auditory and tactile stimulus they risk underdevelopment. Some of these critical periods include visual development between the 2nd and 8th month of life, motor development between the 5th and 12th month of life, and the limbic system development from birth to the 3rd month of life. The frontal lobe and language skills also have a critical period which is much longer and spans most of early and middle childhood. (Murray, 2007).

Middle Childhood
As development continues into middle childhood there is an increasing amount of specialization in the brain and integration between brain regions. This process is accomplished through the pruning of unnecessary neurons. Specialization is essential for the development of language, reading, numerical computations and higher level reasoning. For example, the development of reading is characterized by orthographic processing in the occipital lobe, phonological and semantic processing in the temporal lobe, syntactic processing in the frontal lobe and integration in the parietal lobe (Booth, 2007). While each part of the brain is responsible for individual functions involved in reading the whole brain must function together to create the result of a child who can read. It is important for educators to realize that young minds are in the process of growing, pruning and strengthening connections.

Adolescence
The adolescent brain continues to build upon the specialization which occurred during childhood. It is focused on increasing myelination of neurons, a process that allows information to travel faster and integrate better in the brain. Analyses of brain images from adolescents indicate that the process begins at the back of the brain in the occipital lobe and moves toward the front, ending in the frontal lobe (Balkemore & Choudhury, 2006). The increasing of myelination is the reason adolescents more closely resemble adults in their cognitive abilities. The frontal lobe, which is the last to receive this myelination processes is responsible for higher level reasoning and impulse control and the immaturity of this region in adolescence contributes to the reputation of reckless behavior during the teen years (Durston, Pol, Casey, Giedd, Buitelaar & Engeland, 2001).

There is also a lateral change in the brain during adolescence. The right and left hemispheres become more connected and are better able to communicate across the corpus callosum. This development means the hemispheres can work more quickly together to process language, math, and spatial problems. This interconnection is also related to increases in long term memory as memories are better coded across different regions and more easily retrieved into a cohesive entity (Durston et al. 2001). One study has found that this maturation of the brain may continue well into a person’s 20s or 30s and that full brain maturity may not be reached until well after puberty (Balkemore & Choudhury, 2006).

The Influence of Stress on Brain Development
In today’s schools children are constantly dealing with outside stressors, influences that affect their ability to pay attention and learn. Stress has been shown to have a profoundly negative effect on the developing brain which results in a lower level of learning. Stress can affect neurophysiology before the child is even born. Monk found that stress hormones crossed the placenta in unborn children and caused a rise in fetal heart rate and cortisol, a stress neurohormone, levels (Monk, Fifer, Myers, Sloan, Trien & Hurtado, 2000). Increased levels of cortisol in infancy, childhood or adolescence have been correlated to a later inability to deal with stress and stunted cognitive development. This is because chronic stress leading to chronic secretion of cortisol may cause neuron death in the hippocampus, which leads to cognitive deficients (Barlow & Durand, 2005). The hippocampus is located in the brain stem, which indicates that children who are using their hippocampus area to regulate stress may not be spending valuable time developing other regions of their brains, those necessary for higher level reasoning and social skills development. These children quickly find themselves falling behind in school which perpetuates the stress cycle.

Conclusion
As educators the more we know about our students the better able we are to adjust our classrooms and create an environment that helps all students to excell. Children through out development are experiencing changes and learning how to use their brains to store and retrieve information. It is important to present information in such a way as to maximize a student's effort. Stress can also affect the amount of information a student can process. By creating classrooms that are safe and secure we can help to improve the brain power of our students. When teachers understand the child's brain better we can be more effective educators.

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