FSHD 3232/11/14Brain DevelopmentI. Brain development in contextA. Brain development underlies cognitive (including language), social and emotional development 1. integratedB. Relationships influence brain development, especially early in life development1. learning and environmental experiences occur within relationships2. provide secure foundation for exploration and stimulationII. Brain Development in PerspectiveA. Development that begins prenatally continues into early childhood .begins prenatally and continues into childhoodB. Reaches adult size earlier than any other organC. Size weight1. Birth: the brain weighs approximately 25% of the adult brain2. 6 months it weighs .50%3. 2 years it weighs 70%4. 6 years: 90%III. Neurons – 100-200 billion A. Structure1. Soma – cell body that contains the basic biological material2. Dendrites – fibers that receive input from other cells and conduct this inputtowards the soma; more dendrites = more connections3. Axon – fiber that conducts electrical signals away from the soma to the connected neuronsB. Synapse – tiny gaps between neurons (where the axon of one cell meets the dendrite of another neuron) through which neurotransmitters = chemical messages are sentIV. Key ProcessesA. Myelination – process of laying down a fatty sheath of myelin on the neurons1. Allows for more efficient transfer of information 2. Begins prenatally and continues to at least until adolescence 3. Infants need specialized fats in their dietsB. Neuron Proliferation (neurogenesis) – rapid appearance of neurons in the developing brain .development of neurons1. Begins during embryonic period and is nearly complete by 18 weeks2. Rapid rate of development : nearly 250,000 new neurons a minute3. By birth: 100-200 billion neurons – most of what we need as adults: weightincrease represents the establishment of connections and myelination we are born with the most of the brain cells we are going to haveWEIGHT INCREASE REPRESENTS THE ESTABLISHED OF CONNECTIONS AND MYELINATIONFSHD 3232/11/14C. Neuronal Migration – movement of neurons within the brain that ensures that all brain areas have a sufficient number of neural connections1. GUIDED by neurochemicals2. Failure to migrate to proper places can result in disorders D. Programmed Cell Death (Neuronal Death) – elimination of some neurons that surround newly formed synapses around neighboring neurons – as manyas 20-80% depending on the regionE. Synaptogenesis – development of new synapsesa. begins early in pre-natal period (embryonic) but explodes in infancyb. synapses form more rapidly than neurons: i. ex: by age 2 in visual cortex there are 15,000 synapses for each neuronii. by adulthood – 1 quadrillion synapsesE. Synaptic Pruning – deterioration and disappearance of synapses that are not used .1. elimination of axons and dendrites of a neuron that are not stimulated often (”you don’t use it, you lose it”)2. can form new synapses later 3. about 40% of all synapses during childhood and adolescenceSynaptic and programmed cells death processes to serve:F. These 2 elimination processes (neuronal death & pruning) serve to:G. .development (growth) 1. Increase the speed, efficiency and complexity of transmissions among neurons. 2. Allow space for new connections to form based on G. Brain development is a dynamic process as the formation of some synapses may enhance or facilitate the development of other synapses.1. Trace synaptic growth and myelination in specific brain areas to the development of specific abilities and skills2. Cross-domain patternsMusic lessons tied to improved spatial temporal reasoningV. Brain Plasticity - .(the idea that our brains are moldable) capacity of the brain to change in form and function in response to input from the external environment.ex: mr potato headA. Sensitive periods – optimal times for certain capacities to emerge and in which the individual is especially responsive to environmental influence0-3 years of age is brain developmentFSHD 3232/11/14B. Brain size (.mean weight post prenatally) and function can be altered by the environmentC. Two types of brain development – co-occurring1. Experience expectant brain development – occurs when we encounter experiences that our brain expects as normal events - Seeing and touching objects moving around and exploring the environment- Necessary but not sufficient- universal2. Experience dependent brain development –occurs in response to specific learning experiences that vary widely across individuals and cultures- .Ex: playing music- Not-over stimulation http://vimeo.com/28024661D. In rats, more enriched environments (greater cognitive and social stimulation) was associated with:1. heavier brains, primarily because of increased dendrites and synapses2. greater biochemical activity 3. better retention and information processing abilitiesE. Lack of Stimulation in Humans1. Abused and neglected children – limbic system (brain centers involved in emotions) are 20-30% smaller and have fewer synapses so less active2. Infants raised in Romanian orphanages exhibit decreased brain activity (lower metabolic rates) and fewer synapses, but by middle childhood those who were adopted into supportive environments before 3 developednormal brain function- by middle childhood those who were adopted into supportive environments before age 3 developed normal brain functionF. Stress and brain development 1. High levels of stress set the body on alert2. Impairs or interferes with cognitive and emotional development3. Diminishes capacity for learning and formation of synapses4. Young children need caring and low-stress environmentsNeed caring and low stress environment Nurturing environment and care promote effective stress