A Baby’s Brain Development   4 comments


Infant Brain Development

Children are born with innate instincts to learn. The progression of skills, personality and intelligence are acquired and is increased 85 percent by age five. The beginning months and years of existence set the phases for lifelong learning advancement.

The extraordinary development of the human brain begins a few weeks after conception. Neurons which are brain cells that store and send information begin multiplying at 50,000 per second and this process continues throughout the development. They contain specialized structures such as synapses and chemicals called neurotransmitters. Gopnick et al. (1999) describe neurons as, “Growing telephone wires that communicate with one another.” Following birth, the brain of a newborn is flooded with information from the baby’s sense organs. This sensory information must somehow make it back to the brain where it can be processed. To do so, nerve cells must make connections with one another, transmitting the impulses to the brain. These nerve cells make up the central nervous system and reproduce before birth. The fetus brain will create approximately twice as many neurons as it will ultimately need. This is a type of protection offers newborns the greatest potential of being born into the world with healthy brains. Most of the excess neurons are discarded in utero. Every neuron has an output fiber that sends signals to other neurons. Each neuron also has many dendrites that are short hair like input fibers that receive impulses from other neurons. In this way, neurons are perfectly constructed to form connections.

Many of these recently formed neurons are programmed by a specific sequence of DNA which controls survival performance such breathing and the heartbeat, but most are not yet designated for tasks and are anticipating experiences in the environment to determine their function. Others will journey to areas in the developing brain and body where they await further instructions from the world outside of the womb. From that point forward the environment starts to contribute in the way the brain is linked for emotion, behavior and learning. Connections are created by the sensory experiences, seeing, smelling, touching, and especially tasting which stimulate the growth of neural connections. Forming and reinforcing these connections are the key tasks of early brain development.

Once in place, neurons begin developing the tools necessary to transmit the electrical language of the brain. Neurons send signals to other neurons through axons, a thin fiber that relays electrical messages that take information away from the cell body. At the time that an axon finds its intended cell, it develops dendrites which can receive a wide range of information from other brain cells. The more dendrites a nerve cell has, the better and quicker it is at learning, said Dr. Lise Eliot, a neuroscientist with Chicago Medical School.

Prior to birth, the formation of the brain has necessary elements that are built in according to genetic factors recognized in the genetic blueprint of DNA. What begins as a simple tube of embryonic tissue develops over nine months into a complex system of intellect, reflexes and emotions. The neuron population that occurs before birth comprises all that the brain will ever have.

The brain does not develop at an even pace. It tends to evolve in surges with different parts of the brain developing at different times.  J.M. Nash acknowledged, “Neuroscientists have shown that the brain is affected by environmental conditions throughout the entire process of development, even prior to birth.  This includes the type of nourishment, care, surroundings and stimulation the fetus or infant receives.”

At birth, the infant brain has few dendrites. A key ingredient in a well-formed connection is myelin, a fatty substance that coats axons like plastic insulation around an electrical wire. Myelin sheaths enable brain signals to travel 100 times faster. Arnold B. Scheibel describes these fibers as, “Serving the primary sensory (touch, vision, audition etc.) and motor areas are myelinated shortly after birth while those which are involved with more complex associative and cognitive functions myelinate later. It is generally believed that fiber systems of the prefrontal lobes (executive functions, intentions, future planning, etc.) are among the latest to myelinate, a process that may go on into young adulthood.”

Most of its 100 billion neurons are not yet connected in networks, yet begin to make connections through synapses wiring the brain for action. A connection is made depending on the stimuli or signals the brain gets from the setting. These neurons are about the same number of stars in the Milky Way. “If two neurons are synaptically coupled, and they are both electrically active at the same time, the connection between them gets stronger. Whereas, if two neurons are synaptically coupled, but they are not electrically active together, then those synapses are pruned or lost,” Eliot said.  In the Art of Changing the Brain, Zull refers to this process as the time of learning the most being correlated with losing more synapses than obtaining. This is how experience literally wires the brain. Life molds the brain’s development. Warm touches by parents and caregivers who talk positively to an infant allow the brain to take in all things around them. The brain is just waiting to send out signals to other parts connecting the wiring and forming what kind of person the infant will become. The brain defines who we are, and it is influenced by what we do. With proper stimulation, the synapses become stronger. Electrical chemicals are sent out that make the connections stronger and more permanent.

Synaptic growth is essential for the development and plasticity of neural circuits. Sandra Johnson and Kathleen Taylor (2006) stated, “Neural plasticity  reflects the ability of neurons to change their structure and relationships to one another in an experience-dependent manner according to environmental demands (Buonomano and Merzenenich, 1998; Trojan and Pokorny, 1999).” (p.12)33 In order to start working, the cells need to communicate with each other it a rapid pace.  B. Hart & T. Risley describes this event as, “The brain operates on a “use it or lose it” principle. Only those connections and pathways that are activated consistently are retained. Other connections that are not frequently used will be pruned or discarded so the active connections can become stronger.” As a baby starts to experience life, connections are made between cells; the more connections there are, the more the brain can do.  Forming and reinforcing these connections are the important for early brain development. Connections among neurons are formed as the growing child experiences the surrounding world and forms attachments to parents, family members and other caregivers.

Subsequent to birth, the destiny of the brain is connected to the environment. Good nutrition and a learning environment rich in sensory stimulation helps neurons grow bigger and increase the intricacy of synapses. Neurons stimulated over and over again will experience measurable structural changes that form the basis for learning.

The brain of an infant that has received stimulation, in a loving caring environment will be dense with these connections and pathways. By eight months of age the average infant, living in a stimulating, protected and affectionate environment, will have sparked 500 trillion connections. Between eight-nine months a baby can form specific memories from their experiences, such as how to push a ball to make it roll. Between ten-eighteen months, an infant’s emotions become developed. These emotions are closely connected with long-term memory.

The first year of life portrays the brain that doubles its size and works at a warp momentum. An infant’s brain can form new learning associations at a speed of 3 billion per second. The brain uses glucose twice as much for the brain’s fuel. How quickly brain signals pass through along these dendrites depends on how well their axons are coated with myelin. At the end of the first year the brain is about 55% of adult size.

By the age of two, the child will have developed around 1000 trillion connections, twice as many as adults. These connections lay the foundation for the child’s adult life. They will affect the thought process, learning abilities, interpretations and experiences that will ultimately help in understanding the world as an adult. By the end of the second year the brain is about 80% of adult size. During this year the child learns to climb, use steps, and have to capability of naming pictures or objects. They can speak in simple sentences, utilizing subject and verbs. The child will be able to sit, stand and walk showing indications that these neural pathways are functionally completely. Growth in primary sensory, motor and visual areas is significant at this stage.

Needless to say, babies have an innate learning ability at birth. Scientific research of brain development reveals that the first three years of life are extremely important for building the young child’s brain. Learning seems to peak between the ages of three-ten, but it continues throughout the lifetime.

By the age of three a child’s brain is twice as active as an adult’s brain. Throughout this time, the brain is becoming equipped for the foundation of a lifetime of learning and for future formal education.

Dr. Lise Eliot stated, “A well-connected and stimulated brain is a forest of dendrites,” They begin to branch out, forming dendrite trees with the capability of receiving signals from many other neurons. Neurons are classified by the direction that they send information. Sensory neurons send information from sensory receptors such as eyes, nose, tongue, and ears toward the central nervous system.  Motor neurons send information away from the central nervous system to muscles or glands. Interneurons send information between sensory neurons and motor neurons. Most interneurons are located in the central nervous system.

In the first decade of life, experience plays a crucial role in wiring a young child’s brain. As a baby ages, different areas of the brain become myelinated on a genetically determined timetable. These periods of mylenization are critical  periods for learning. For instance, the first axons to be in the language area of the brain are those that enable language comprehension.

Before children are able to talk, emotional expressions are the language of interaction. Research exhibits that an infant’s positive and negative emotions, and parents receptive responsiveness to them, can help early brain progression. For example, common positive emotion between a caregiver and an infant, such as laughter and smiling, will engage brain activity in good ways and encourages feelings of safekeeping. Also, when communication is accompanied by emotion, they are more readily to be remembered and recalled.

An infant’s external experiences develop the brain. Sensory experiences such as hearing, seeing, touching, feeling and tasting teach the brain cells their task. It has been scientifically proven that listening to Mozart and other classical music early in life exercises the same neurons used for mathematics and spatial reasoning. Babies who have increased sensory experiences are able to expand their brain power. This entails that an infant’s social, emotional, cognitive and physical as well as language advancements are stimulated during multi-sensory experiences. Infants and toddlers need the opportunity to participate in a world filled with stimulating sights, sounds and people.

The sensory motor stage occurs in infancy from birth to about 12 months. This is when infants learn about the world through their senses, looking around continually, gazing at faces of parents or caregivers and reacting to happy emotions such as smiling faces. Their eyes focus on bright colors while responding to sounds by looking in the direction towards the noise. During this time of sensory learning, infants will demonstrate interest in light and movement, such as a mobile above the crib.

Infants learn through communication. One of the early communications is through an expression of grief which is a common cry to bring awareness to their needs. Later, the emotional cry is modified and becomes distinctive in identifying what the baby needs or wants. The cry develops into gestures of the body and progresses into the beginning stages of language such as babbling at five months old. At this stage an infant will begin the process of learning to speak. Between five-seven months babies can now differentiate and even create the sounds of their own language and making one and two syllable words such as ba and da-da and no longer pay attention to the sounds of languages that are foreign. At this time, a child begins to recognize their own name and begins to associate certain familiar words with their meanings.

Infants also communicate through their motor actions as they grow, kicking and utilizing their arms to reach for people and things that are attractive to them. They respond to voices and seek to be picked up by reaching out. Infants make very important learning discoveries through their actions of reaching, making sounds, or crying, that cause others to respond in certain ways. It is crucial that parents and caregivers nurture and react to the infant’s actions; to hold, carry, sing, play, and meet the child’s needs in other responsive and nurturing ways.

As infants consistently interact with their environment, making sense out of their world, they also learn about themselves and their own bodies. Their hands, fingers and toes become body objects of interest. They begin to suck on their hands and toes and may appear to be captivated with their own hands. During this stage of sensory learning, infants hit and grasp objects that are within their reach such as long hair and dangling jewelry. Babies also enjoy toys that catch their attention with sound for example, something that rattles and squeaks. They are so curious about the external world that they will put any and all things in their mouth. These are all sensory ways that the infant learns.

As infants master new developments in the motor sequence such as creeping and crawling, they learn that they have more control over their world. A baby is no longer totally dependent on an adult to meet some of their needs. For example, if an infant sees a toy, or their bottle within reach, they have the motor capacity to move toward it, reach and grab it. The infant’s increased freedom and self determination to move towards toys and objects within reach is crucial for the learning phase of a baby.

Understanding the characteristics of cognitive development in an infant gives insight to the knowledge of how they are developing, thinking, and learning. Principles of cognitive development provide the basis of how to encourage exploration and the thought process. As a parent or caregiver it is important  to be supportive by providing a variety of appropriate and stimulating materials and activities that encourage learning cycle process.

Each part of the brain partakes in the learning cycle of an infant, starting with the cerebral cortex which is the thin layer on the brain’s surface that includes the lobes. They are described as the occipital lobe which processes vision located near base of back of head; the temporal lobe provides the connection for hearing, speech and language development; the parietal lobe controls the sensory stimuli and the prefrontal lobe allows the planning of future actions. This is connected to the limbic area to help regulate emotions and last, there is the frontal lobe where critical thinking and problem solving occur. The limbic system controls emotions and long-term memory and the cerebellum controls automatic movements and balance. All of these areas complete the brain and help an infant start its life long learning progression beginning with sensory and motor skills.

Motor development in infants usually progress in three month intervals, with most babies following the same general pattern of growth and development. Motor advancement leads to muscle control, coordination, the capability to raise the head, sit, stand, and walk. Motor progression is also dependent on cognitive ability, since the infant needs to be able to process the complex series of events needed to make the movements happen, the necessary brain development must have occurred to put all this together. The infant must also be motivated to use its motor abilities, and for this the senses of vision and hearing must be advanced adequately for the infant to see or hear things that will in turn create motivation to turn towards, swing at, grab, and crawl to reach them. Each of these interacting systems needs to be at the right stage of development for motor development to take place. A particular motor skill cannot develop unless all these systems are acting in harmony. As new motor skills develop, old ones are discarded. There is a gradual progression of movement from clumsiness and awkwardness to a more refined controlled movement.

Many theorists believe that human infants are biologically programmed to be responsive to language. Newborns are hardwired to learn any language which means they can detect the most subtle distinctions of sound and pitch. Bukatko and Daehler note, “That from birth an infant is sensitive to sounds made by other human beings while showing a preference for human voices over other sounds, and showing a partiality for the voice of their mother over those of a stranger. More than this, infants respond in specific ways to small changes in the vibrations human’s make, especially those changes in that signify how one word or part of a word is distinguished from another. “ As early as two days of age, infants show that they are responsive to phonemes from many of the world’s languages and show a clear preference for speech from their own language rather than another. Between the ages of two-four months, the infant’s brain responds to every sound produced in all the languages of the world.

Playing is another aspect of the learning cycle which teaches an infant how to behave, incorporates learning about social cooperation and conflict. From infancy through childhood, there is a long period in which learning through playing and experiences helps in absorbing information from external memories and the accumulation of information from external resources. This processes of learning by experience and gaining knowledge continues throughout a lifetime. Each new experience adds to an infants knowledge and plays a part in shaping their views of the world in which they live.

In conclusion, the power of the brain is complex and interconnected. In early years, children learn symbols to comprehend meanings. For example, outstretched arms may mean a toddler wants “up,” or hugs may be a symbol of love and security. But over time, these elements found in the emotional centers of the brain begin to categorize reactions to things that happen. Over time, life experiences merge to form the understanding of abstract concepts, such as justice, integrity, pride, forgiveness, anger, and safety. Adults play a significant role in the lives of children. Helping children arrange their world takes time, patience, and tenderness. These efforts form the building blocks to positive, human interactions and a healthy brain of an infant.

 

References

Gopnic, A., & Meltzoff, A., & Kuhl, P. (1999). The Scientist in the Crib: What Early Learning Tells Us About the Mind. New York, NY: HarperCollins Publisher.

Goswami, U. (2004). A Quick Primer on Brain Development. Retrieved July 3, 2007 from Web site: www.oecd.org

Johnson, S. & Taylor, K.(2006). The Neuroscience of Adult Learning. (p.12)

Hart, B. & Risley, T. (1995). Meaningful Differences in the Everyday

Experience of Young American Children. Baltimore, MD: Brookes Publishing.

Murray, B. Understanding Brain Development and Early Learning.  Retrieved July 1, 2007 from Web site: www.zerotothree.org/brainwonders.html

Nash J. M. (1997 February 3). Fertile Minds. Time. 48-51.

Scheibel, A. Embryological Development of the Human Brain. Retrieved July 3, 2007 from Web site: http://www.newhorizons.org/neuro/scheibel.htm

Zull, J. (2002) The Art Of Changing The Brain. Stylus Publishing.

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4 responses to “A Baby’s Brain Development

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