Lecture 37 Outline of Last Lecture I. Neural migrations begins at the subventricular zone and radiates outward to form layers of the cortexa. Neuroblast soma follows path of radial glial cellsb. Growth cones aid advancement outwardII. Cell adhesion molecules provide a surface to which growth cones can attach a. Tropic molecules are produced by target cells and increase axon affinityIII. Chemoaffinity hypothesis there are guidance cue gradients that attract axons to their targetsa. Increased tropic molecule concentration closest to the target cellIV. Dendritic growth occurs at a slower rate than axonal growth V. Apoptotic signals are induced by genetic mechanisms, whereas synaptic pruning is induced by loss of functionality in a neural networka. Loss of synapses and less dendritic arborizationsb. Cortex becomes thinnerOutline of Current Lecture I. Behaviors emerge as the adequate neural circuitry developsa. Epigenetic factors affect the rate of behavioral development among individualsb. Example: grasping behaviors in infantsII. Language development is associated with increased dendritic complexity and increase myelination in speech areas of the brainIII. Jean Piaget proposed four primary stages of knowledge developmenta. Sensorimotorb. Preoperationalc. Concrete operationald. Formal operationalIV. Stimulating environments promote maximum brain developmenta. Individuals raised in enriched environments exhibit larger synapses and more astrocytesb. Exercise dramatically increases neurogenesisCurrent Lecture- Kallmann Syndrome: neurons never migrate to the olfactory bulbo Results in anosmia, sense of smell is not recoverable - Hypogonadism low sex steroidso Individuals do not undergo puberty- Behaviors don’t emerge until the requisite neural machinery has developedo Develop through subsequent stages and are shaped by epigenetic factorsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. NSCI 110 1st Editiono i.e. motor behaviors grasping in infants Right handedness arises around 10 months oldo Axons of motor cortex are myelinated at the time that reaching and grasping developo Gray matter thins with increasing pincer grasp ability Hand region of left motor cortex in right-handers- Language developmento Language onset occurs at about 1-3 years of age, is mostly complete by age 12o Neural changes during this time: Increased dendritic complexity and interconnections Increased myelination of speech areas- Jean Piageto Development psychologist interested in the process of developing knowledgeo Stages Sensorimotor (0-2) stranger anxiety Preoperational (2-7) playing, pretending, beliefs symbolic representations Concrete operational (7-11) logic and conservation, classification skills Formal operational stage (11-16) abstract thinking, metacognition- People raised in different environments/cultures acquire differences in brain structure that effect behavioro Donald Hebb (student of Lashley) discovered that stimulating environments maximize intellectual development Compared with rats raised in standard lab cages, those raised in “enrichedenvironments” have larger and more synapses and astrocytes Evolutionary, we need more stimulating and enriching environmentso Hippocampus BrDU used to label new neurons Rats who exercised (versus sedentary) showed more neurogenesis Enrichment (no exercise in either) did not significantly improve neurogenesis Exercise has a more influential effect on neuronal
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