DEVELOPMENT OF BRAIN AND BEHAVIOR GENETICS

DEVELOPMENT OF BRAIN AND BEHAVIOR GENETICS 

BRAIN DEVELOPMENT 

The most noticeable changes in the brain is the size. At birth, a baby's brain is only about 400 grams or 25 percent of the average weight of the adult brain, which weighs about 1400 grams. Like many other aspects of development, brain growth is not smooth and continuous, but occurred at a push. (Segalowitz, 1995)
 

BRAIN STRUCTURE 

brain consists of two hemispheres, known as the brain or cerebrum. Various parts are connected by a set of nerve fibers known as the corpus callosum. The left and right parts of the brain have functions and different anatomy. Big brain or cerebrum is protected by a layer called the cerebral cortex known. Cerebral cortex accounts for about 90 percent of the brain cells. The most important part of the brain, is the brain supports complex functions such as language, vision, and motor skills. Cerebral cortex is divided into four main areas called lobes and two other areas known as association areas. Contained four different lobes of the brain is the frontal lobe, temporal lobe, parietal lobe and occipital lobe. Anterior association area (located on the front of the brain) and the posterior association area (located near the back of the brain) is involved in linking information from different parts of the brain

BRAIN STRUCTURE

DEVELOPMENT NEURONAL 

The brain consists of several types of cells vary. Neurons are nerve cells that send and receive nerve impulses throughout the brain and nervous system. The average human brain consists of nerve over from 100 million each nerve consists of 15,000 connections to other nerves. The second type of cells that build the brain are glial cells. These cells provide structural support for neurons, regulate the concentration of nutrients delivered to the nerve, and provide direction on myelination, in which nerves are covered by an insulating layer of myelin that makes nerves effectively transmits electrical information. 

Nerve itself is made from the dendrites, cell bodies, axons, and connections knob (terminal buttons). Dendrites receive signals from the nerves to function and transmit other information to the cell body. The information collected is then radiated along the axon to the knob where the connection information is crossing the synapse and then glued into other nerves. What is meant by the transmission of information across the synapse is a specialized chemical signals known as neurotransmitters.Nerves often move to another place in the brain, is protected by a set of complex neurochemical processes, known as neuronal migration (immigration neural).

SPECIALTY HEMISPHER 

Hemisphere specialization refers to the different functions performed by the two hemispheres. Hemispheric specialization began to appear at birth and differences between the two hemispheres is largely remain the same until adulthood. However, if there is a change, things will change is what a child can do with the information processed by the two parts of the brain. 

Movement or something that feels each (sensation) is controlled by the respective hemispheres. In this case, the left side of the brain controls movement and sensation perceived by the body to the right. While the right brain controls movement and sensation perceived by the body to the left.
The two parts of the brain that is believed to be a difference in the emotional process. According to Davidson, the left hemisphere is responsible for the expression of the emotions associated with the approach of the external environment. emotions such as anxiety, anger, and feelings of happiness. Instead the right part of the brain responsible for emotional processes being associated with the withdrawal from the environment, such as fear, stress, and a feeling of disgust.
Lateralization (laterarization) is the part that is used to describe the process by the two parts of the brain are specialized to perform specific functions. There is evidence that may indicate a child who suffered a brain injury can be cured from his illness. It can occur in children because their brains are still developing and lateralization process is not perfect. 

Although children who suffered brain damage can improve their language skills, they will often show a considerable lack in their later work. Children who have difficulty reading as dyslexia characterized by difficulty in reading disorders often show lateralization. Children who do not have dyslexia generally process the information on the spatial nature of the right hemisphere, but children who have dyslexia memperoses the same information in the right hemisphere and left at random.
MATURITY AND DEVELOPMENT CHANGES IN THE BRAIN 

Brain experiencing some growth impetus to the development of his net itself. Many psychologists and developmental neuropsychologist who has described / explained the relationship between brain development and cognitive development itself. Greenough is a writer who has shown how neural thread associated with the event. Some neural circuits require input from the environment to begin to grow, one of the processes mentioned as Greenough and his development experience. Another type of neural circuit is greatly affected by the type of environment that they receive.
GENES AND ENVIRONMENT 

Modern psychologists acknowledge that both genes and environment affect the shape of a series of developments. We also know now that genes can shape the environment. Based on the work of Sandra Scarr, a gene can affect the environment at least three ways: first, genes have a passive effect as submitted Scarr. Second, the gene will lead to a close relationship with the environment. Finally, the gene will affect the environment in a way that is active.
Environment can also have profound effects on genetic factors. One way in which this relationship has been conceptualized is through the concept of the various reactions (Gottesman). According to Gottesman, the gene does not improve behavior in a rigid manner but rather to build a variety of possibilities that are highly dependent on environmental conditions.
But the concept of this reaction has been criticized by Gilbert Gottlieb. He said that genes play a deterministic role far less than what has been said by various concepts reaction.
BEHAVIOR GENETICSThe study was able to determine the importance of genetic factors relative to environmental factors caused by specific properties, namely how much variance in a given trait is caused by genetic factors and how much is caused by environmental factors. The area of ​​this investigation closely examine the relationship between genetic and environmental factors are often referred to as behavioral genetics. 

We know that genetic factors play an important role in human growth. Behavioural genetics have shown that genetically also plays an important role in the development of psychological traits such as cognitive ability, school achievement, personality, self-esteem and drug use.
HERITABILITY 

Genetic behavior using a concept known as the heritability to measure the influence of genetic factors on a trait. Basically, the heritability was estimated relative influence of genetic factors against environmental factors.  

According Plominet heritability can be defined as the proportion of phenotypic variance that can be explained by genetic differences between individuals. By examining correlations between relatives for certain properties and is commonly expressed as the intraclass correlation relationships can be straightforwardly interpreted as a percentage. In other words, intraclass correlation of 80 for IQ between identical twins would show that 80 percent of the variance in IQ scores between the twins due to genetic factors.
DESIGN RESEARCH IN BEHAVIORAL GENETICS 

A large number of behavioral genetic studies have been conducted to examine the heritability of intelligence. Many researchers have recognized or approved those findings. while the substantial role of genetic factors showed a large role in the development of general intelligence, it also shows the importance of environmental factors in determining intelligence. 

Now we will briefly consider the genetic effects on personality. behavioral genetic research in the field of personality has been said that as many as 50 percent of the personality differences between people due to genetic factors (Bouchard). Loehlin reported evidence of significant genetic effects on two aspects of personality are usually measured neuroticism (emotional instability) and extraversion (hospitality). 

Recent research has sought to better understand the interaction between genes and environment. These relationships tend to be more complex than a simple formula explanation percentage.