Term
| three forms of neuroplasticity |
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Definition
| habituation, learning and memory, cellular recovery after injury |
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Term
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Definition
| the ability to change function, chemical profile, or struture; by definition, these changes must be retained for some period of time. |
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Term
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Definition
a decrease in response to a repeated, benign stimulus. habituation has 2 phases: the irst is reversible after a few seconds of rest. the second phase causes perm. structural change and # of synaptic connections decreses. can be used therapeutically for kids who are very reactive to "normal" stim.
* opssibly glutamate may decrese in habituaiton, as well as free Ca+. |
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Term
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Definition
| persistent, long lasting changes occur in the strength of syaptic connections.At first when learning diffuse areas of the brain are activated. after many reps of learning, the activation becomes smaller and more specific. As new connex are formeed, proteins are made which alter synaptic excitability. |
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Term
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Definition
| a cellular mechanism that may contribute to learning and memory. described in the hippocampus in the temporal lobe, an area involved in menroy function. hippocampus=encodes the history of an experience. |
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Term
| long term potentiation requirements |
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Definition
1. more than one nerve fiber activated COOPERATIVELY
2. Both the CONTRIBUTING FIBERS and the POSTSYNAPTIC CELL must be activated allowing the ASSOCIATION.
3. Potentiation must be SPECIFIC to only the activated pathway. |
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Term
| mechanism of long term potentiation |
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Definition
conversion of silent synapese that lack funcitonal glutamate receptors (AMPA) to those which do.
astrocytes may be involved, sodium channels, calcium channels, and glutamate receptors |
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Term
| cellular recovery form injury |
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Definition
| some neouronal damage (e.g. severance of an axon) may be repaired. (PNS only). when cells do die, alteration in the synapesfunctinoal re-org of the CNS and activity related changes in NT release may promote recov. from an injury. |
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Term
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Definition
| the distal axon degenerates (wallerina degeneration. glial cells clean up the debris. the cell body undergoes central chromatolysis. the postsynaptic cell degenerates and may die. |
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Term
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Definition
regrowth is called sprouting.
Collateral sprouting- occurs when a denervated target is reinnervated by branches of (other) intact axons.
regenerative sprouting- occurs when an axon and its target have been damaged. the injured axon sends out side sprouts to a new target.
functional region. mostly in PNS. b/c of NGF and the scwann cells. in CNS repair of axons doesnt happen (b/c of no NGF, inhibition by oligodendrocytes, and cleanup activies of microglia. |
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Term
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Definition
| sprouting by PNS axons can innervate an inappropriate target. may innervate wrong motor units--->unintended movmts. usually control can be relearned. **also innervation of a diff. type of sensory receptor can cause confusion of sensory modalities. (i think called synaesthesia) |
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Term
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Definition
| can be inhibited by compression with edema following injury. |
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Term
| denervation hypersensitivity |
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Definition
| when the presynaptic axon terminals are destroyed, new receptor sites develop on the post synaptic memb. in response to NT released by other nearby axons. |
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Term
| synaptic hypereffectiveness |
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Definition
| when only some branches of the presynaptic axon are destroyed, the remaining axon branches receive all the NT that would usually be shared among more axonal terminals. |
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Term
| disinhibition or unmasking of silent synapses |
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Definition
| in the NS, many synapses arent used unless injury to other pathways results in increased use of previously silent synapses. |
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Term
| neuronal activity regulates NT production |
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Definition
| understim can increase cortex response/ overstim can decrease cortex response. |
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Term
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Definition
| cell death bc of realease of glutamate...likley in storke and also in "forced-use" rehab that begins too early ...there is a critical or optimal window during which certain rehab activities should take place. |
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Term
| approaches to parkinson's disease |
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Definition
deep-brain stim. of neurons in the thalumus to inhibit the firing of an overactive set of neurons by using maintained elecrical stim.
Transplantation of fetal donor dopamine producing cells into the basal ganglia.
stereotaxic surgery to destroy a small region in the globus pallidus. to treat akinesia.
thalamotomy and pallidotomy are used to destroy oveactive cells that cause tremor and akinesia. |
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Term
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Definition
| deveops into sensory organs, epidermis and the NS |
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Term
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Definition
| muscles, skeleton, and the excretory and circulatory systems. |
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Term
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Definition
| develops to form the gut liver, pancreas, and respiratory system. |
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Term
| from 8th week until birth |
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Definition
| NS develops more completely and myelination begins. |
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Term
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Definition
| up unitl this point the spinal cord segmnts are adjacent to crresponding vertebrae but then the column grows faster than the cord. as a result the adult spinal cord ends at L1 or L2. Within the adult sp. cord the neural tube persists as the central canal. |
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Term
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Definition
begins at day 28.
hindbrain=> pons, upper medulla, cerebellum, and 4th ventricle.
midbrain=> midbrain and cerebral aqueduct
forebrain=> thalamus, the hypothalamus, 3rd ventricle.
telencephalon=> cerebral hemis, including the basal ganglia, cerebral corte, and the lateral ventricles. |
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Term
| cellular level development |
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Definition
| the processes of development (including cell proliferation, migration, and growth, extension of axons to target cells, formation of synapses, and mylelination of axons) are balanced by the regressie processses the remodel the NS during development. |
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Term
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Definition
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Term
| myelination is complete when? |
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Definition
| third year of life. the process occurs at different rates for each system |
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Term
| the motor roots of the spinal cord are myelinated when? |
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Definition
| one month of age. however, the tracts sending info from the cortex to activate motor neurons are not complete and fully functional until the child is approx 2 years old. so a deficit that happened beofre or around the time of bith might not be recognized until the child matures to the point where systems damages would normally become functional. |
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Term
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Definition
| is the formation of a rudimentary brain stem without the cerebral and cerebellar hemis. occurs when the cranial end of the tube remeains oopen and the forebrain does not develop.the skull does not form over the incomplete brain leaving the brain stem and meninges exposed. this defect can be detected by blood or amniotic fluid test and ultrasound imaging. causes: chromosomal abnormalities , maternal nutritional deficiency, and maternal hyperthermia. if the fetus survives and is born it dies within a week. |
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Term
| Arnold-Chiari malformation |
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Definition
| this is a developmental deformity of hte hind brain. malformation of the pons, medulla, and inferiorcerebellum. the medulla and the infereior cerebellum protude into the foramen magnum. symptoms begin in early adolescence/adulthood. symptoms include headache, initiated by coughin straining and sneezing, loss of pain ansd temp on houlders, may hae restriction of CSF=>hydrocephalus. mvmt and coordination may be affcted becouase of malformation of lower cranial nerves and of the cerebellum. |
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Term
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Definition
| the result of a neural tube defect in which the neuropore does not close. deeloping vertebrae do not close around an incomplete neural tube, resulting in a bony defect at the distal end of the tube. amternal mutritional devficits are assoc with a higher incidence of the disroder (folic aci). meningiocele is a more severe malformation where the spinal cord protudes outside the the body. spinal cord function may be impaired. this more severe form alomst alway s results in abnormal growth of the sp cord with some degree of lower extremity dysfunction. probably lose bowel and bladder control. |
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Term
| forebrain malformation (holoprosencephaly). |
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Definition
| genentic factors may be implicated, the prosencephalon does not normally divide into 2 cerebral hemispheres=> a single eye or no eye may develop. a deformed nose and cleft lip or palate may result. |
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Term
| alcohol exposure in utero |
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Definition
| impairment of the CNS; growth deficiency abnormally small head, eyes set abnormally far apart, and aberrant neurobehavioral development are common |
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Term
| cocaine exposure in utero |
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Definition
| disturbance of neuronal proliferation is the most common, the effects of cocaine are dependent upon the time period in which the developing embryo or fetus had exposure and the degree of exposure. |
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Term
| abnormal location of cells |
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Definition
| during cell migration cellscan fail to reach their normal destination. abnormal gyri can result, with abnormal number of cells in the cortex, the displacement of gray matter, commonly into the deep cerebral whhite matter. |
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Term
| severe mental retardation |
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Definition
| assoc with major defects in the morphology of dendrites and their spines.as dendritic spines are involved in synapses, these changes have functional consequences. |
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Term
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Definition
| is a mvmt and postural disorder caused by permanent, non-progressive damage of a developing brain. it was once believed that it sprung from a difficult birth/labor, but now we find that most cases arise from events before the onset of labor or after the deliv. Cognitive, somatosensory, visual, auditory, and speech defictis are freq. assoc. with CP. As it is nonprogr. porlems appear as the child reaches eaxh age for normal developmental milestones. |
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Term
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Definition
| the damaged neurons are adjacent to the ventricles. muscle shortening often results in toe walking and a scissor gait where one leg swings in front of the other so that legs criss-cross during walking |
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Term
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Definition
| the neuronal damage is found in the basal ganglia. slow writhing mvmts of the extremities or trunk are seen |
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Term
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Definition
the damage is in the cerebellum
lack of coordination, weakness, and shaking during voluntary mvmts are features of this type. |
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Term
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Definition
| when more than one type of abnormal mvmt coexist, the disorder is classified as mixed. |
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Term
| sensory deprivation of the infant NS. |
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Definition
| studies have identified the presence of citical periods during which sensory input plays a major role i the funcitonal and morphological development of nervous tissue. |
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Term
| neural substrate for behavior |
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Definition
| synapse. there is competition for synaptic sites. when sensory input is depried those connections that were supposed to be made lose out in the competition. |
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Term
| suturing eyelid in baby monkeys |
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Definition
| they sutured the eyelid during thecritical period for vision and then removed it after. the retinal cells responded but th emonkeys were blind bc the cortex did not respond to the input. this does not happen in adult monkeys |
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Term
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Definition
| interruption of devel. during a critical period may explain some of the difference s in outcomes b/n perinatal and adult brain injury. damage to fibers descending from the cerebrum to the spinal cord may eliminate some competition for synaptic sites during a critical period, resulting in persistence of INAPPROPRIATE CONNECTIONS, in addtion to the dec\ficiency of descending control seen in adult and child brain injury=> result in the abnormal mvmts seen in CP |
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Term
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Definition
| interruption of devel. during a critical period may explain some of the difference s in outcomes b/n perinatal and adult brain injury. damage to fibers descending from the cerebrum to the spinal cord may eliminate some competition for synaptic sites during a critical period, resulting in persistence of INAPPROPRIATE CONNECTIONS, in addtion to the dec\ficiency of descending control seen in adult and child brain injury=> result in the abnormal mvmts seen in CP |
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Term
| important point about brain damage in babies vs. adults. |
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Definition
| the adult with brain damage loses descending control, but because development is complete, dysfunction is not compunded by inappropriate connections. |
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