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Main Sterotypes |
RELATED RESEARCH: Intact long-term potentiation but reduced connectivity between neocortical layer 5 pyramidal neurons in a mouse model of Rett syndrome. Dani VS, Nelson SB. Biology Department, Brandeis University Waltham, Massachusetts,USA. Mutations in MECP2 cause Rett syndrome and some related forms of mental retardation and autism. Mecp2-null mice exhibit symptoms reminiscent of Rett syndrome including deficits in learning. Previous reports demonstrated impaired long-term potentiation (LTP) in slices of symptomatic Mecp2-null mice, and decreased excitatory neurotransmission, but the causal relationship between these phenomena is unclear. Reduced plasticity could lead to altered transmission, or reduced excitatory transmission could alter the ability to induce LTP. To help distinguish these possibilities, we compared LTP induction and baseline synaptic transmission at synapses between layer 5 cortical pyramidal neurons in slices of wild-type and Mecp2-null mice. Paired recordings reveal that LTP induction mechanisms are intact in Mecp2-null connections, even after the onset of symptoms. However, fewer connections were found in Mecp2-null mice and individual connections were weaker. These data suggest that loss of MeCP2 function reduces excitatory synaptic connectivity and that this precedes deficits in plasticity. Getting a Read on Rett Syndrome Greg Miller, 8 December 2006 Neuroscience “Greenberg says: In his view, the emerging picture of Rett syndrome suggests a breakdown of what neuroscientists call experience-dependent plasticity. The earliest stage of brain development, in which neurons form their initial connections, proceed largely according to genetic plans. In later stages, neuronal activity triggered by (an animal's) interactions with its environment fine-tunes neuronal connections, strengthening effective synapses and weeding out ineffective ones. Early life experience literally alters the brain's wiring, and Greenberg suspects that MeCP2 plays a key role in this process by regulating genes such as BDNF.... etc.It's no coincidence, he says, that the onset of Rett syndrome happens at about 1 year of age, a time when experience-dependent plasticity is in full swing in the human brain....” |
RELATED ARTICLES: The Nervous System: The Ultimate Athlete Amy Venditta: spring 2005 ...In a newborn baby, the motor cortex area of the brain is not completely developed. This is why a newborn baby's movement is limited to sucking, swallowing, and breathing. As the motor cortex area, or motor strip, within the brain begins to develop, the baby is able to perform simple gross movements, such as lifting the head.... etc. ebsco.smartimagebase.com/imagescooked/14228W.jpg The EARLIEST RELATIONSHIP T. Berry, Brazeton M.D. Craner M.D. CHAPTER: Feeding Behavior Sucking is made possible by the thorax when the infant breathes in and by fixing the jaw between breaths. Swallowing and breathing must be coordinated, and the depth and rate of breathing are handled differently when the baby is engaged in nutritive and non-nutritive sucking (such as on fingers or a pacifier). In the latter, the chance of inhaling milk is not important. This whole process has been studied by Albrecht Peiper who argues for a hierarchical control system in which swallowing controls sucking and sucking controls breathing (Peiper, 1963). There appear to be three components of sucking: One can feel all three of these by putting a finger in the new baby's mouth. There is a brief delay before these become coordinated in an effective drinking/eating/breathing mechanism. CHAPTER: Sucking and gagging reflexes Initially, newborn babies need to rid themselves of the mucus in their airways. At this point, gagging reflexes compete with sucking. As a result, a baby's response to a nipple or finger will often be to gag and spit up before he or she can begin to suck. The sucking reflex must be gradually brought out and reinforced. Learning to suck is the baby's task. Coordination of breathing, sucking, and swallowing during bottle feedings in human infants J. S. Koenig, A. M. Davies and B. T. Thach Edward Mallinckrodt, Washington University School of Medicine, Children's Hospital St. Louis, Missouri 63110. In coordination of sucking, swallowing, and breathing might lead to the decreased ventilation that accompanies bottle feeding in infants, but the precise temporal relationship between these events has not been established. Therefore, we studied the coordination of sucks, swallows, and breaths in healthy infants (8 full-term and 5 pre-term). Respiratory movements and airflow were recorded as were sucks and swallows (intra oral and intra pharyngeal pressure). Sucks did not interrupt breathing or decrease minute ventilation during non-nutritive sucking. Minute ventilation during bottle feedings was inversely related to swallow frequency, with elimination of ventilation as the swallowing frequency approached 1.4/s. Swallows were associated with a 600-ms period of decreased respiratory initiation and with a period of airway closure lasting 530 +/- 9.8 (SE) ms. Occasional periods of prolonged airway closure were observed in all infants during feedings. Respiratory efforts during airway closure (obstructed breaths) were common. The present findings indicate that the decreased ventilation observed during bottle feedings is primarily a consequence of airway closure associated with the act of swallowing, whereas the decreased ventilatory efforts result from respiratory inhibition during swallows. ARTICLE: Normal breathing Inspiration is the process of taking in a breath, while expiration is the process of breathing the air out. Inspiration involves three groups of muscles: Expiration mostly occurs passively (the chest that has expanded during inspiration gradually falls back to the starting point before inspiration), but forceful expiration involves the use of abdominal muscles. For example, a cough is a forceful expiration and requires contraction of the abdominal muscles. The diaphragm is supplied by nerves that come from the spinal cord at the levels C3, C4, and C5. The external intercostal muscles are supplied by nerves T1 through T11. For example, the T1 nerve supplies the intercostal muscles between the ribs T1 and T2. The T10 nerve supplies the intercostal muscles between the ribs T10 and T11. Some of the accessory muscles such as the trapezes are supplied by cranial nerves that come from the brain stem. The abdominal muscles are supplied by nerves from T6 through L1. Ventilation is the mechanics of breathing in and out. When you inhale, muscles in the chest wall contract, lifting the ribs and pulling them, outward. The diaphragm at this time moves downward enlarging the chest cavity. Reduced air pressure in the lungs causes air to enter the lungs. Exhaling reverses theses steps. ARTICLE: Vagus nerve Source: www.neurologychannel.com/vagus/ Vagus nerve stimulation involves the implantation of a generator that stimulates the vagus nerve and thus reduces seizure activity. The vagus nerve is one of 12 pairs of cranial nerves (i.e. nerves that originate in the brain). It has motor functions in the larynx (voice box), diaphragm, stomach, and heart, and sensory functions in the ears and tongue. It has both motor and sensory functions in the pharynx (sinuses) and esophagus. Stimulation of the vagus nerve is thought to affect some of its connections to areas in the brain that are prone to seizure activity. |
RELATED RESEARCH: Repetitive behaviors in autistic disorder Militerni Roberto. Bravaccio Carmela, Fico Cinzia, Palermo Mark T. The Department of Child Neuropsychiatry, II University of Naples, Naples, ITALIE A recurrent suggestion for the developmental origins of aberrant stereotyped behaviors among persons with mental retardation proposes that such behaviors emerge or evolve from repetitive motor behaviors typical during infant development. This behavioral pattern resembled that of typical repetitive movements in infant development to such an extent that it was suggested that they have a similar etiology, neuro maturation, and share adaptive significance as discharge or displacement activities. Younger autistic children displayed more motor and sensory repetitive behaviours. Older children had more complex behaviours. Children with higher IQ scores, likewise, demonstrated more complex repetitive behaviours..... RELATED BOOKS about the normal development: Understanding Motor Development Gallahue, D.L. & Ozmun, J.C.. McGraw-Hill This book covers the entire lifespan. It focuses on the phases of motor development and provides a solid introduction to the biological, affective, cognitive, and behavioral aspects within each developmental stage. The reader is presented with the most up-to-date research and theory, while the Hourglass Model is used as a consistent conceptual framework that brings clarity to understanding infant, childhood, adolescent, and adult motor development. Important is Chapter 2: NORMAL Infant Reflexes and Rhythmical Stereotypes The study of infant reflexes and stereotypical patterns of behavior yields useful information for better understanding the process of motor development and designing therapies. Key Concept of this chapter are Rhythmical stereotypes. They are repetitive rhythmical movements normal in infants from 4 weeks – 1 year. Some of them include: These early rhytmical movements are an important precursor to motor skill development. But they were also found to persist in children with disabilities (Down syndrome, Tourette's syndrome, psychomotor retardation, blindness, deafness etc) |
Developmental Stage & Approximate Age |
Characteristic Behavior |
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Reflexive Stage |
Simple reflex activity such as grasping, sucking. ( SINGLE reflexes) |
Primary Circular Reactions |
Reflexive behaviors occur in stereotyped repetition such as opening and closing fingers repetitively. |
Secondary Circular Reactions |
Repetition of change actions to reproduce interesting consequences such as kicking one's feet to more a mobile suspended over the crib. |
Coordination of Secondary Reactions |
Responses become coordinated into more complex sequences. Actions take on an intentional character: the infant reaches behind a screen to find a hidden object. |
Tertiary Circular Reactions |
Discovery of new ways to produce the same consequence or obtain the same goal such as the infant may pull a pillow toward him in an attempt to get a toy resting on it. |
Invention of New Means Through Mental Combination |
Evidence of an internal representational system. Symbolizing the problem-solving sequence before actually responding. Deferred imitation. |
Spine curvature, without rotation, can be caused by following problems: "slipped" disc perhaps |
Congenital form develops (in utero) before birth. Acquired form develops after birth and includes: |