This session is a quick developmental review and discussion of how problems or differences in stages of development can provide challenges for the

Transcription

1 This session is a quick developmental review and discussion of how problems or differences in stages of development can provide challenges for the developing child and adolescent. 1

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3 The prenatal, perinatal, and postnatal environments have a great deal to do with later function. Maternal health and habits during pregnancy can impact the fetus, with concerns often expressed about smoking, alcohol consumption, prescription or recreational drug use, lack of sleep, and nutrition being prime aspects. The mother s general health is also a factor, with chronic issues like diabetes, lung problems, or any circulatory conditions being of concern. With every new sensory experience, a child s brain changes. New smells, tastes, sounds, movements, and sights expand the landscape of the child. With the addition of language from those in the environment, the archive of experiences from which the child will draw for future learning will grow. The issue of neural plasticity has led to an expanded notion of ability to learn languages and music. Although individuals who learn languages and music in the first decade of life tend to have better natural accents and an easier time of managing instruments, tone and pitch, the brain s plasticity extends well into adulthood. 3

4 The circuitry involved in processing the information environment develops into a smoothly operating system. The brain develops its systems simultaneously, with integration of functions resulting. When we listen, our vision doesn t shut off. When we remember, we can still speak. The limbic region, deep in the brain houses those components that allow us to feel as we process the information environment. If you have ever read something that made you cry, or heard something that made you laugh out loud, or saw something that made you angry, each of those experiences contributes to the archive of learning mentioned earlier. Because the brain is a chemical factory, balance of those transmissions is essential. Otherwise, our behaviors that reflect our mood and the overall balance of our personality can be affected. 4

5 The major sites for processing the world are in the four lobes pictured here. The brain develops back to front, with the executive functions of organization, planning, self-regulation, impulse control, and higher order thinking emerging to maturity well past the years we are in school. The frontal lobes mature when we are approximately 32 years of age, give or take two years on either side. The temporal region houses language, ambient sound recognition, and part of our memory. The parietal lobes at the crown of the head assist with motor skills, calculation and our ability to connect what we process immediately to our memory, such as facial recognition. Finally, at the notch just above the neck is the occipital lobes, which are essential for processing what we see. The optic nerve, when stimulated, sends the signal from the eye to the occipital region. It is one of the reasons that when someone is hit on the back of the head, they sometimes say Everything went black. 5

6 As we delve to the core of the brain, we encounter the regions that serve more primal functions sensation, emotion, and distribution. The deepest parts of the brain connect us more to other animals it is the cortex, with its gray and white matter, that distinguishes the human animal as having higher order capacities. The thalamus allows the processing of all sensory input with the exception of smell, which occurs in the olfactory receptors located in both the cilia and synapses of the olfactory sensory neurons and in the epithelium of the human airway. Once the input is perceived, the message system directs or distributes the data the regions of the brain for action. The filing system is the business of the hippocampus which takes the limited amount of information we can retain immediately and converts into the long term memory. Loss of memory in late adulthood may relate to hippocampal atrophy. A good deal of study of this is being done as the population ages and conditions such as Alzeimer s become a concern. Hippocampus means seahorse due to its shape. The amygdala, the word meaning almond due to its shape, is the emotional expression center. Here lies rage, fear and pleasure centers. Head injuries that impact this area often result in significant personality changes in the patients. 6

7 The connector of the hemispheres, the corpus callosum, thickens with development into adolescence and the role of myelination. Females tend to have thicker connectors. Signals move across this connector to allow both hemispheres to function and communicate. As mentioned a bit earlier, the frontal region of the cortex allows our maturing brain to engage in higher order thought on more abstract, creative and critical levels. The development of this area with puzzles, word games, and picture clues assists children in using this region in early learning. Just at the spot where the vertebrae of the spine move down the cervical path, is the little brain the cerebellum. Our equilibrium, coordination, and motor skills are impacted by this region. Because it is located where the signaling from the brain to the nerves of the spine occurs, any damage to this area can impact movement. It also has some connection to our ability to attend and remember. 7

8 As mentioned before, the brain is a chemical factory with transmission of chemicals being done in the synaptic cleft between the axon and dendrite in every neuron. When in balance, we move, speak, control our bodies, handle large and small objects, feel pleasure or anger or fear. The transmission goes from electrical to chemical to electrical at each synapse millions of times per minute. The synaptic network grows with the individual as we mature into adulthood. 8

9 You are probably familiar with these neurotransmitters and their functions. The amines have more general functions. Peptides are more specific in purpose. 9

10 In the temporal region, language processes are activated. The left temporal region handles the sound system and motor processes for speech either processing and comprehending messages given by others (Wernicke) or drawing upon the fund of words accumulated to create a verbal reply. This area is assisted by the parietal region in connecting meaning to the message. Damage to one area does not impact the function of another area. One can lose the ability to speak and still comprehend what is said by others. If damage occurs in the comprehension area, the verbal output will be nonsensical. 10

11 Our earliest moments are learning opportunities. Infants process sensory experiences within the first hour of life. The one area of child development that is impacted for future learning is language acquisition. Hearing language and the multiple sounds of the human voice, music, environmental sounds, and household noises, gives the growing child much to process and imitate. It is from this imitation that language emerges. As many models of sustained language as possible help children learn to speak and communicate needs and thoughts. 11

12 The first two trimesters are the period when a lot of brain development is done. Like fingerprints, the folds of the brain are unique as we develop. 12

13 As the cells grow, the glia, which means glue guides the pathways that form the neural connections. These transmissions build the fiber or network that continues to grow, with most of the cell development proceeding normally. 13

14 The developing child reacts to his or her environment during this developmental stage of the last trimester. The fetus can hear and uses the forming motor skills to move about. This is showing the synaptic transmissions are growing the neural network is allowing the stimulus-response pattern to emerge. 14

15 In the first year, much of the network changes. Unused or deficient transmission causes the ineffective neurons to die. The other phenomenon that occurs is that neurons unite into webs or systems that strengthen development in all area. Pruning has a good function. It eliminates that which is not use or is functioning at a less than desired rate or in an inefficient manner. 15

16 Myelin is an outgrowth of a glial cell and it insulates the axon of a neuron. This insulation is needed for the connections in the brain to work. It forms the myelin sheath for all neuronal transmissions. In earliest development, prior to birth, the value of the myelination process is the development of motor and sensory connections. As the infant develops after birth the motor skills and ability to process the environment as a sensory experience allows higher order skills to develop speak, fine motor, walking, running, etc. This process extends into the adolescent developmental stages. 16

17 In the first three years a constantly expanding development of networking is going on in the brain with the result that skills not used dissipate. The principle known as Hebb s Law comes into play. Cells that fire together, wire together. This is the use it or lose it statement. As mentioned earlier, if experiences such as multiple language usage or musical skill development don t emerge in the earliest years, the individual strives harder to attain these skills. They may gain the skills eventually, the ease with which this happens will be diminished. In the first chapters of the Aamodt and Wang text, the sensitive periods of development are discussed. 17

18 Entering the toddler and preschool years, the activity in the brain has to do with the expansion of the connections, not the growth of new cells. The synaptic connections and the resulting neurotransmission is primary at this period. The battle of proliferation and pruning is apparent at this stage as the activity in the brain is at a fever pitch, and if proliferation wins..look out. This time is often called the terrible twos, but it is really a period of blooming. The building of any new structure makes noise and causes confusion, but the result is usually worth the wait. 18

19 Sorry, guys. From earliest development, the male of the species lingers a bit in development. Maybe the females are just pushy. Until puberty, girls develop neurologically at a faster rate. There is much discussion in the education community about having single sex preschool and kindergarten classes so that boys can gain skills in an environment where are not challenged by the faster development in language and motor skills of girls. Without the competition for approval and acknowledgement by teachers and others, boys might develop skill sets with more confidence. With the current emphasis on meeting assessment standards, this places a burden on boys that girls do not share to the same degree. 19

20 As children enter preschool (if they are fortunate enough to go to preschool), most of the activities involve following structured processes. This is often in the form of a regular schedule of entry rituals like going to a cubby and putting belongings away, going to a specific table for a snack, sitting in a circle for a ritual of activities such as greetings, noting the date and weather, singing a routine number of songs, napping, engaging in activities that require fine and gross motor skills, and learning socialization habits such as greetings, turn taking, sharing, etc. This procedural learning is helpful because the young child doesn't have a lot of memory to draw upon and the repetition of the learning activities start a collection of memories for processes that are used as the more academic demands of school start. As experiences increase, memory for prior learning increases, and is directed and distributed by the hippocampus. As the cortex develops, children expand their repertoire of skills by calling upon prior learning experiences and connecting them to new learning. 20

21 The growth of intuitive, creative and imaginative thought is often described as right brain in characteristic, while the left brain characteristics are those requiring logic, analysis, and verbal reasoning. Children are great at play with fantasy and imagination a big part of what they are good at. School, however, is a regimented set of activities that initiate the child into social, linguistic, and cognitive activities in large groups of peers. In these years that account for the elementary grades, myelination is at work, extending neural pathways so that more and more diversity of information is presented for storage and retrieval for comprehension, application, analysis, synthesis, evaluation and reasoning. Bloom s work, and that of Sperry give a well rounded view of the left brain/right brain demands of the young scholar. A balance of academics with humanities can assist children in expanding their cognitive growth, since both hemispheres communicate and work together for all learning experiences. 21

22 As children move toward middle school, puberty engages them in a real developmental battle. Another chemical upheaval occurs and the hormonal changes in the body, combined with the increased myelination of the connectors between the hemispheres and the continuing to grow frontal lobes, can cause explosive change. Just as the blooming, buzzing confusion around age two occurred with the resulting difficult period in the child, the adolescent period of hormonal growth and myelination can also cause the emotional and physical unpredictability that can impact mood, personality, and activity level. Impulsivity in a two year old can be physically managed by an adult. Teen agers often engage in risk taking activities as they explore their changing world and exhibit emotional imbalance as the center of emotion, the amygdala grows. This difficult period may extend for a longer period than the original two year old period lasted. It is a difficult time for the developing child and for those around him or her as well. 22