Adolescence to adulthood Rats Loss of neurons between puberty and adulthood in medial prefrontal cortex and in amygdala Rats and humans synapses are lost in pfc myelination increases adult humans through the fourth decade Adult brain changes both rats and humans proliferation in 2 brain areas only increase glia no long axon growth grow and prune dendrites add and subtract synapses Damage to the nervous system Retrograde degeneration unless there is an axon collateral side branch with synapse to sustain the neuron Anterograde degeneration axon terminals cut of Can axons regrow Peripheral Yes CNS NOPE Myelin Oligodendroglia vs Shwann cells Nogo Collateral axon sprouting happens a lot when young but still happens a little when youre old Denervation supersensitivity Loss of synapses increase in neurotransmitter Parkinson s disease loss of dopamine in axons from substantia nigra to striatum caudate putamen Increased dopamine receptors response to L DOPA o Parkinson s disease symptoms Tremor Trouble initiating movements Eventual cognitive decrements TBI Difficult to treat Often not seen in MRI Second injury more destructive Repeats eventually lead to dementia Rest the brain stabilize blood pressure Epilepsy Recurrent seizures Seizure imbalance between excitation and inhibition Too much excitatory transmitter or their receptors Ion channel changes may get worse with time Treatment increases inhibitory transmitters usually works o May make people drowsy because it increases all inhibitory transmitters not just at the site of the seizure Tumors Mostly from glia division gliomas Fast vs slow growing Encapsulated removable vs invasive Can come from other body cancers Treatment stop blood vesicle growth Multiple Sclerosis MS Immune system attacks CNS myelin Late 30s early 40s more common in women Axons can become dysfunctional Variable symptoms remissions Treat symptoms Fragile X Most common type of developmental disability DNA for fragile C protein is silenced More common in males Behavior autism symptoms hyperactivity short term memory deficits Brain dendritic spines are immature in the cortex Dendritic spines spines excitatory synapses Fetal Alcohol Syndrome Prenatal exposure to alcohol Variable severity Intellectual disabilities poor muscle tone Alcohol increases apoptosis and kills proliferating cells Interferes with CAMs and other cell signals No safe dose
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