Brain development
Structure of the Brain
The brain is divided down the middle into two halves, or hemispheres. Some parts of the brain are the same on both sides, and some are different. The two sides of the brain communicate with each other through the structure that joins them, called the corpus callosum. Both halves of our brains are involved in complex ways in almost everything we do.
Developmental Processes
Neurons and Synaptic Connections
The brain is made of 100 billion nerve cells, called neurons. Each nerve cell sends messages via special chemicals called neurotransmitters to other nerve cells through extensions of the cell called axons. Each cell receives messages through receptors called dendrites. The place where the axon from one neuron meets the dendrite of another neuron is called the synapse. Just about everything we do depends on communication between nerve cells. Neurotransmitters are released from one cell and bring their "message" to the second cell. Infants are born with almost all the neurons they will ever have; however, they have relatively few synapses or connections between them. As a result, babies have fewer inborn behavior patterns than other animals, and they are more open to learning from their environment. The experiences they have actually shape the development of synaptic connections and the formation of their brains.
Plasticity of the Brain
The ability of the infant brain to change in form and function is referred to as plasticity. Until about age 4 or 5, children who have had one hemisphere of their brain removed to treat an otherwise untreatable condition can recover almost full function. This occurs because the brain at this young age has enough plasticity that brain cells that were originally intended to serve one function can turn into cells that control another function instead. At various times within the first years of life, babies' brains produce so many new synaptic connections that the density of connections is greater than that found in the adult brain. However, many of these connections do not survive. In a process called pruning, synaptic connections that are used remain and those that are not used deteriorate and disappear.This process strengthens the brain and produces a brain that is much more efficient.
Myelination of Neurons in the Brain
For messages to be sent successfully, another necessary process in the development of the nervous system is myelination. For neurons to work efficiently, they need to be coated with a fatty substance known as myelin. When babies are born, just as the synaptic connections are not complete, so too the myelin sheath does not yet cover all of the nerves in the nervous system. The process of producing synaptic connections, pruning away those that are not being used, and myelinating the connections that are left will continue throughout childhood and adolescence. There is evidence that myelination is affected by our experiences. Connections between the centers for reasoning and the centers for emotions are still developing during adolescence, so emotional responses in adolescents are less tempered by reasoning than will be the case in adults.
The brain is divided down the middle into two halves, or hemispheres. Some parts of the brain are the same on both sides, and some are different. The two sides of the brain communicate with each other through the structure that joins them, called the corpus callosum. Both halves of our brains are involved in complex ways in almost everything we do.
Developmental Processes
Neurons and Synaptic Connections
The brain is made of 100 billion nerve cells, called neurons. Each nerve cell sends messages via special chemicals called neurotransmitters to other nerve cells through extensions of the cell called axons. Each cell receives messages through receptors called dendrites. The place where the axon from one neuron meets the dendrite of another neuron is called the synapse. Just about everything we do depends on communication between nerve cells. Neurotransmitters are released from one cell and bring their "message" to the second cell. Infants are born with almost all the neurons they will ever have; however, they have relatively few synapses or connections between them. As a result, babies have fewer inborn behavior patterns than other animals, and they are more open to learning from their environment. The experiences they have actually shape the development of synaptic connections and the formation of their brains.
Plasticity of the Brain
The ability of the infant brain to change in form and function is referred to as plasticity. Until about age 4 or 5, children who have had one hemisphere of their brain removed to treat an otherwise untreatable condition can recover almost full function. This occurs because the brain at this young age has enough plasticity that brain cells that were originally intended to serve one function can turn into cells that control another function instead. At various times within the first years of life, babies' brains produce so many new synaptic connections that the density of connections is greater than that found in the adult brain. However, many of these connections do not survive. In a process called pruning, synaptic connections that are used remain and those that are not used deteriorate and disappear.This process strengthens the brain and produces a brain that is much more efficient.
Myelination of Neurons in the Brain
For messages to be sent successfully, another necessary process in the development of the nervous system is myelination. For neurons to work efficiently, they need to be coated with a fatty substance known as myelin. When babies are born, just as the synaptic connections are not complete, so too the myelin sheath does not yet cover all of the nerves in the nervous system. The process of producing synaptic connections, pruning away those that are not being used, and myelinating the connections that are left will continue throughout childhood and adolescence. There is evidence that myelination is affected by our experiences. Connections between the centers for reasoning and the centers for emotions are still developing during adolescence, so emotional responses in adolescents are less tempered by reasoning than will be the case in adults.
Motor development
Infant Reflexes
Newborns can't move around on their own, and they don't have much control over their limbs, but from the time they are born they have a set of involuntary, patterned motor responses called reflexes that are controlled by the lower brain centers and that help them respond to some of the stimuli in the environment. Infants begin moving even before birth, exercising their developing muscles, and giving feedback to the motor cortex of the brain that helps develop voluntary movements after birth.
Development of Motor Skills
Two basic forms of motor skills are gross motor and fine motor. Gross motor skills involve the large muscle groups of the body. Fine motor skills involve small movements, mostly of the hands and fingers, but also of the lips and tongue.
Variability in Motor Milestones
Although brain development is necessary for motor skill development, it is not the only factor involved. The sequence of motor milestones happens in the same way for most babies around the world. However, there is some variation in the timing of motor milestones. Development may be uneven with some areas forging ahead while others are slower to develop. Parents can promote normal development of motor skills by providing a safe, "baby-proofed" space that is large enough for infants and toddlers to explore and by enthusiastically encouraging the development of each motor milestone in its turn.
The Importance of Physical Activity
Physical activity is important for children and teens at all ages. As schools cut back on recess time, it becomes even more important for families to ensure that their children are running, biking, and playing actively for their long-term health and the development of their muscles. Physical activity is related not only to optimal functioning of your muscles but also to optimal functioning of your brain.
Newborns can't move around on their own, and they don't have much control over their limbs, but from the time they are born they have a set of involuntary, patterned motor responses called reflexes that are controlled by the lower brain centers and that help them respond to some of the stimuli in the environment. Infants begin moving even before birth, exercising their developing muscles, and giving feedback to the motor cortex of the brain that helps develop voluntary movements after birth.
Development of Motor Skills
Two basic forms of motor skills are gross motor and fine motor. Gross motor skills involve the large muscle groups of the body. Fine motor skills involve small movements, mostly of the hands and fingers, but also of the lips and tongue.
Variability in Motor Milestones
Although brain development is necessary for motor skill development, it is not the only factor involved. The sequence of motor milestones happens in the same way for most babies around the world. However, there is some variation in the timing of motor milestones. Development may be uneven with some areas forging ahead while others are slower to develop. Parents can promote normal development of motor skills by providing a safe, "baby-proofed" space that is large enough for infants and toddlers to explore and by enthusiastically encouraging the development of each motor milestone in its turn.
The Importance of Physical Activity
Physical activity is important for children and teens at all ages. As schools cut back on recess time, it becomes even more important for families to ensure that their children are running, biking, and playing actively for their long-term health and the development of their muscles. Physical activity is related not only to optimal functioning of your muscles but also to optimal functioning of your brain.
Sensation and perception
Sensations are referred to as the information from the environment that is picked up by our sense organs. The brain puts together the sensory information that it receives so it can attach meaning to that information and interpret what is happening in the world. This is the process of perception.
Mirror Neurons
Newborn babies are capable of imitating adults' simple facial expressions. Results from brain imaging studies indicate that for humans the same regions are activated for both experienced and observed motor movement and emotional expression. For newborns, this built-in system may activate an automatic imitative response.
Development of the Five Senses
Vision
Although newborns are capable of focusing their eyes, their vision is much worse than normal adult vision. The visual acuity of young infants is about 20/400, which means that an infant can clearly see at 20 feet what an adult with normal vision can see at 400 feet. They will not develop adult levels of visual acuity until sometime between 6 months and 3 years. Infants can see faces, and from birth they are attracted to looking at the faces of people around them, especially their mother. In addition, they tend to concentrate on areas of high contrast-- that is, where darkest dark meets lightest light.
Hearing
Hearing becomes functional while the fetus is still in the womb, and one sound fetuses hear loudly is their mother's voice. Subsequently, babies show a preference for their mother's voice within the first three days of life. They even remember specifically what the mother said, if she repeats it regularly.
Smell
Babies know their mother's smell from very early in their lives. Within the first 6 days of life, they will turn toward their mother's smell more often than toward another mother's scent, and research has shown that babies who are being breastfed recognize their mother's scent within the first 2 weeks of life. This may be linked to a similarity between the smell of the amniotic fluid and the smell of the mother's breast milk.
Taste
Infants prefer sweet taste and react negatively to salty, sour, and bitter tastes. Mother's milk is sweet, so this draws the baby to the food and to the mother. In addition, mother's milk, as well as amniotic fluid, takes on some of the flavor of the foods the mother eats. Therefore, babies are introduced to the tastes of their local foods even before birth, and there is evidence that early experience with particular tastes becomes acceptance or preference for such tastes later in life.
Touch
Touch is very soothing. Studies have found that infant massage improves growth and effectively soothes babies of all ages, even premature babies. Many adults who have had a massage know how relaxing it can be. Massage with children can be helpful in improving conditions that range from anxiety to HIV. It can also raise the level of your body's ability to fight off the effects of disease.
Mirror Neurons
Newborn babies are capable of imitating adults' simple facial expressions. Results from brain imaging studies indicate that for humans the same regions are activated for both experienced and observed motor movement and emotional expression. For newborns, this built-in system may activate an automatic imitative response.
Development of the Five Senses
Vision
Although newborns are capable of focusing their eyes, their vision is much worse than normal adult vision. The visual acuity of young infants is about 20/400, which means that an infant can clearly see at 20 feet what an adult with normal vision can see at 400 feet. They will not develop adult levels of visual acuity until sometime between 6 months and 3 years. Infants can see faces, and from birth they are attracted to looking at the faces of people around them, especially their mother. In addition, they tend to concentrate on areas of high contrast-- that is, where darkest dark meets lightest light.
Hearing
Hearing becomes functional while the fetus is still in the womb, and one sound fetuses hear loudly is their mother's voice. Subsequently, babies show a preference for their mother's voice within the first three days of life. They even remember specifically what the mother said, if she repeats it regularly.
Smell
Babies know their mother's smell from very early in their lives. Within the first 6 days of life, they will turn toward their mother's smell more often than toward another mother's scent, and research has shown that babies who are being breastfed recognize their mother's scent within the first 2 weeks of life. This may be linked to a similarity between the smell of the amniotic fluid and the smell of the mother's breast milk.
Taste
Infants prefer sweet taste and react negatively to salty, sour, and bitter tastes. Mother's milk is sweet, so this draws the baby to the food and to the mother. In addition, mother's milk, as well as amniotic fluid, takes on some of the flavor of the foods the mother eats. Therefore, babies are introduced to the tastes of their local foods even before birth, and there is evidence that early experience with particular tastes becomes acceptance or preference for such tastes later in life.
Touch
Touch is very soothing. Studies have found that infant massage improves growth and effectively soothes babies of all ages, even premature babies. Many adults who have had a massage know how relaxing it can be. Massage with children can be helpful in improving conditions that range from anxiety to HIV. It can also raise the level of your body's ability to fight off the effects of disease.
Body Growth and changes
Infant Proportions and Changing Bodily Proportions
A baby's head is very large in comparison to his small, helpless-looking body. In addition to their large head, infants also have large eyes, a small nose and mouth, and relatively fat cheeks. Growth during infancy and until age 2 is very rapid. The average infant doubles her birth weight by about 5 months of age, and triples it by her first birthday. Children slow down into a steady growth rate in middle childhood, adding on average a little over two inches in height each year, and gaining about 6.5 pounds. Bones continue to grow until sometime, usually during adolescence, when the soft spongy ends of the bone harden off and growth is complete. As children approach adolescence, growth hormones work together with sex hormones to produce the rapid increase in height in both girls and boys that is known as the adolescent growth spurt.
A baby's head is very large in comparison to his small, helpless-looking body. In addition to their large head, infants also have large eyes, a small nose and mouth, and relatively fat cheeks. Growth during infancy and until age 2 is very rapid. The average infant doubles her birth weight by about 5 months of age, and triples it by her first birthday. Children slow down into a steady growth rate in middle childhood, adding on average a little over two inches in height each year, and gaining about 6.5 pounds. Bones continue to grow until sometime, usually during adolescence, when the soft spongy ends of the bone harden off and growth is complete. As children approach adolescence, growth hormones work together with sex hormones to produce the rapid increase in height in both girls and boys that is known as the adolescent growth spurt.
Nutrition
Children who get off to a good start with a diet that contains a variety of healthy foods benefit not only in childhood but throughout adolescence. We are interested in the amount, quality, and diversity of the food that a child or an adolescent eats. In addition to the foods that are included in a healthy diet, there are some foods that should be avoided because they pose a type of risk for young children. Unpasteurized milk or food juices can contain harmful bacteria. When children are malnourished they do not receive the right amount or mix of nutrients necessary to sustain their growth and good health.