Psyc 2012 1st Edition Lecture 12 Outline of Last Lecture I. Learning and Longer-Term Synaptic PlasticityA. Today’s lecture goalII. Ways Our Brains ChangeA. HabituationB. In LTM we see…III. STMIV. Long Term Potentiation (LTP)A. Key pointB. Late LTPC. LTP & Long-term memoryD. LTPi. Long term depression1. Early depressionV. LTM- new synapse formation and neurogenesisA. Key pointB. 2 main ways to increase synaptic number in long-term memoryi. Synaptogenesisii. Neurogenesis1. Synaptogenesis requires extensive gene expressionC. Adult neurogenesisVI. Defects in memoryA. Amnesiai. Types of amnesia1. Retrograde amnesia2. Anterograde amnesiaii. Some causes of explicit memory amnesiaiii. Some causes of implicit memory amnesiaOutline of Current Lecture II. Brain Injury I: Tumors, Infection, Stroke & TraumaA. Today’s lecture goalIII. What is brain damage?A. Brain damageB. Key pointIV. Apoptosis vs NecrosisA. NecrosisThese 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.i. Doesn’t require signaling & gene expressionB. Apoptosisi. Requires signaling & gene expressionC. Key points regarding necrosis & apoptosisV. Causes of Brian DamageVI. Cerebrovascular disordersA. 2 types of cerebrovascular disorders that cause brain injuryi. Aneurysms & cerebral hemorrhageii. Thrombus & cerebrovascular occlusionB. Ways neurons die in cerebrovascular disordersi. Hemotomaii. HypoxiaVII. Brain TumorsA. Main types of brain tumorsi. Gliomaii. Secondary metastasesiii. Primitive neuroectodermal tumor (PNET)iv. MeningiomaB. Neural changes & brain tumorsi. Necrosisii. Necrosis & apoptosisiii. Tumor hijacking the blood supply of nutrients and oxygeniv. ApoptosisVIII. Traumatic Brain Injury (TBI)A. CausesB. Sources of injury in TBIi. Coupii. Contrecoupiii. Hematomaiv. EdemaC. How neurons die in TBIIX. InfectionsA. 2 main types of infectious organisms infecting the braini. Bacteriaii. VirusesB. Neural changes in brain infectionsX. Drugs and Neurotoxins- destruction of neural tissue by ingested toxins substancesA. Sources of common neurotoxic substancesB. Neural changes caused by neurotoxinsXI. Recovery from brain injuryCurrent LectureWeek 7- Lecture 12- 2/124Brain Injury I: Tumors, Infections, Stroke & TraumaGoal: to learn what causes damage to the brain or NS and how the NS repairs or adapts to damageWhat is brain damage?Brain damage: the damage or death of neurons due to injury or other insult/trauma. Our focus will be on what kills neurons, because we can’t regenerate them in most parts of the brain. Key point: neurons can die either by necrosis or apoptosisApoptosis vs NecrosisNecrosisAccidental cell deathDoesn’t require signaling & gene expressionCell swells, rips, lyses (like cell turning into a water balloon) and then bursts, releasing its contentsCauses inflammation due to immune cells removing debrisApoptosisCell suicideRequires signaling (for creation of proteins) & gene expressionCell shrinks, or “buds”, and fragments into apoptotic bodiesNo inflammation because the body has no debris to removeKey points regarding necrosis vs apoptosisNecrosis often represents the most immediate consequences of a brain damaging event, while apoptosis reflects the secondary consequences occurring hours & days afterward. Necrosis and apoptosis represent a continuum; some cells are so badly damaged that they die immediately be necrosis, others that are less damaged may still die later by apoptosis.Apoptosis occurs so that damaged cells not functioning normally don’t adversely affect tissue function. Causes of brain damageCerebrovascular disordersBrain tumorsPhysical traumaInfectionsDrugs and neurotoxinsNeuropsychological diseasesCerebrovascular disorders: a group of brain dysfunctions related to disorders of blood vessels supplying the brain. Neurons can’t store O2 or nutrients very well, which is why a decrease in blood to the brain is bad. Neurons will have trouble producing ATP. 2 types of cerebrovascular disorders that cause brain injuryAneurysms & cerebral hemorrhage: weakening and bursting of a blood vessel and seepage of blood into brain areas around it, caused by high blood pressure. Aneurysms happen with chronically high blood pressureHemorrhage is when the blood leaks, which can be in the brain or anywhere else in the body. Thrombus & cerebrovascular occlusion: blockage of a cerebral artery, cutting off O2 and nutrient delivery. Often caused by atherosclerosis, a disease where excess fats in the diet are deposited into blood vessels. Thrombus is something that blocks blood vesselsAtherosclerosis is when the fat collects in arteriesWays neurons die in cerebrovascular disordersCrushing and compression of neurons by bleeding and hematoma- causes death by necrosis, and occurs in cerebral hemorrhage onlyHematoma: a collection of bursted and squeezed cellsHypoxia: a lack of O2 in ‘downstream’ neurons due to lack of blood flow, which causes both necrosis and apoptosis, and occurs in both cerebral hemorrhage and cerebrovascular occlusionWhen cells are exposed to hypoxia, they release all their NT at onceHow does hypoxia cause death of neurons?Necrosis causes a(n)Energy deficit: lack of O2 disrupts ATP productionLactic acidosis: buildup of lactic acid from anaerobic metabolism, low pH kills cellsAnaerobic metabolism: cells produce energy w/o O2, this is less efficient. Lactic acid may eventually cause the cell to burst; another form of necrosis. Apoptosis causesOxidative stress: the buildup of metabolic intermediates, due to abnormal ATP production in the absence of O2, that damage DNA, proteins, and membranes.Glutamate excitotoxicity: when hypoxic neurons release excess amounts of the NT glutamate, this causes a huge Ca2+ influx into post-synaptic neurons, and triggers apoptosis. Inflammation: immune cells can also accidently damage and kill neurons by releasing substances that trigger apoptosis. However, apoptosis doesn’t cause inflammationBrain Tumors: large, excessively proliferating masses of cells in the brain or spinal cordMain types of brain tumors (for exam know if they are common in either children or adults, and how aggressive they are)Glioma: glial cell tumor, very aggressive, often found in adults.Adults can’t form tumors from neural stem cells, so tumors can form fromglial cells. Secondary metastases: tumors that form elsewhere in the body and invade into the brain from the