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This 7 page Class Notes was uploaded by Anahit Ghaltaghchyan on Friday August 19, 2016. The Class Notes belongs to PSY 3 at University of California Santa Barbara taught by Staff in Summer 2016. Since its upload, it has received 13 views. For similar materials see Psych 3-Biopsychology in Psychlogy at University of California Santa Barbara.
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Date Created: 08/19/16
▯ Genetic Factors Most neuropsychological diseases of genetic origin are associated with recessive genes. Why? Recessive because if it was dominant we would know that we have it, and that others have it too, and we would not reproduce with those who have it and it would die out Down syndrome o Occurs in -/15% of births, probability increases with advancing maternal age Age 20: 1 in 1667 Age 49 1 in 11 An extra chromosome 21 is created during ovulation Characteristic disfigurement, mental retardation, other health problems ▯ ▯ ▯ Programmed cell death All 6 causes of brain damage produce damage, in part, by activating apoptosis o This actually is kind of good for the brain to do! Apoptosis is the clean way to die for a neuron As the neuron dies, the debris gets packaged into vesicles No resulting inflammation or extra damage to neighboring cells ▯ Neuropsychological diseases Epilepsy Parkinson’s disease Hunington’s disease Multiple sclerosis Alzheimer’s disease ▯ ▯ Epilepsy The primary symptom to seizures, but not all who have seizures have epilepsy o Epileptics have seizures generated by their own brain dysfunction Epilepsy affects about 1% if the population It is difficult to diagnose due to the diversity and complexity of epileptic seizures Types of seizures o Convulsions: motor seizures o Some are merely subtle changes of thought, mood or behavior Causes o Brain damage o Genes: over 70 known so far o Faults at inhibitory synapses Diagnosis: o EEG electroencephalogram- electrodes on scalp o Seizures are associated with high amplitude spikes Siezures are often preceded by an aura, such as a small, hallucination or feeling o The aura’s nature suggests the epileptic focus (tells you where it could be, such as lets say a person always smells a certain scent before a seizure, then it must be near the olfactory part of the brain) o The aura warns the epileptic of an impending seizure Partial epilepsy does not involve the whole brain o Simple Symptoms are primary sensory or motor or both (Jacksonian seizures) Symptoms spread as epileptic discharge spreads o Complex Often restricted to the temporal lobes (temporal lobe epilepsy) Patients engages in compulsive and repetitive simple behaviors (automatism) More complex behaviors seem normal Generalized epilepsy: involves the entire brain o Tonic- clonic seizures Loss of consciousness and equilibrium Rigidity (tonus) Tremors (clonus) The resulting hypoxia may cause brain damage Absence seizures Not associated with convulsions Cease ongoing behavior ▯ Parkinson’s disease Parkinson’s is a movement disorder of middle and old age affecting 1 in 200 people Tremors at rest is the most common symptom of the full blown disorder o Tremors dissipate during voluntary action Dementia is not typically seen o Although cognitive deficits can occur No single cause o Parkinson’s is linked to about ten different gene mutations o Infection, stroke, injury, neurotoxins have also been implicated Associated with generation of substantia nigra ( in tegmentum of midbrain) o Responsible for releasing dopamine to the basal ganglia There is almost no dopamine in the substantia nigra of Parkinson’s patients Autopsies often reveal Lewy bodies (protein clumps) in the substantia nigra) Parkinson’s disease can be treated temporarily with L- dopa o The chemical from which the body synthesizes dopamine o Effects lessen over time Deep brain stimulation of subthalamic nucleaus reduces symptoms, but its effectiveness slowly declines over months or years o Also produces side effects such as cognitive, speech, and gait problems ▯ Hunington’s disease H disease is rare, progressive motor disorder of middle and old age with a strong genetic basis o Huntingtin gene Single, dominant gene First symptoms are usually not seen until age 40, too late since you’ll already have kids Hunington’s disease begins with fidgetiness and progresses to jerky movements of entire limbs and severe dementia Death usually occurs within 15 years ▯ Multiple sclerosis MS is a progressive disease that attacks CSN myelin, leaving areas of hard scar tissue (sclerosis) The nature and severity of deficits vary with the nature, size and position of sclerotic lesions Periods of remission are common Symptoms include visual disturbances, muscle weakness, numbness, tremor and loss of motor coordination (ataxia) Autoimmune disorder o The immune system attacks the myelin Epidemiological studies finds that MS likelihood is increased in those who spend childhood in a cool climate MS is rare amongst Africans and Asians Only a small genetic predisposition has been found Hard to find the main cause because of all those random facts Alzheimer’s disease The most common cause of dementia: ones likelihood of developing it increases with age AD is progressive, Symptomsà confusion and memory loss Definitive diagnosis is only possible at autopsy, one must obverse o Neurofibrillary tangles (tangles of protein in cytoplasm) o Amyloid plaques ( scar tissues made of dead neurons and amyloid protein) Several genes associated with early onset AD synthesize amyloid or tau, a protein fond in the tangles Which comes first, amyloid plaques or neurofibrillary tangles? o Genetic research on early onset AD supports the amyloid hypothesis (amyloid first) Effective treatments are not yet available ▯ Animal models of human neuropsychological diseases Experiments regarding neuropathology are not usually possible with human subjects Animal models are often utilized ▯ ▯ Kindling model of epilepsy A series of periodic brain stimulations eventually elicits convulsions: the kindling phenomenon o Produced by stimulation distribution over time Stimulations must be separated by a few hours Typically 1 stimulation per day o Neural changes are permanent. Start happening spontaneously after doing it for a very long time Similar to those seen in human epilepsy Kindling phenomenon is comparable to the development of epilepsy (epileptogenic) seen following a head injury Transgenic mouse model of AD Only humans and a few related primates develop amyloid plaques Transgenic animal o Genes of another species have been introduced into DNA Genes accelerating human amyloid synthesis are introduced into mice o Plaque distribution comparable to that in AD o Unlike humans, no neurofibrillary tangles Can inject mutations now that promote tau accumulation ▯ MTPT Model for Parkinson’s disease The case of the frozen addicts o Synthetic heroin produced the symptoms of Parkinson’s o Contained MPTP MPTP(molecule)causes cell loss in the substantia nigra like that seen in PD Animal studies provide the means to identify potentially useful treatments for PD ▯ Neuroplastic Responses to nervous system damage Swann cells promote regeneration, oligodendroglia inhibit regeneration Neural reorganization Reorganization of primary sensory and motor systems has been observed in laboratory animals following damage to sensory receptors Ex lesion part of the retina o V1 neurons that originally respond to the lesioned area respond to adjacent area instead. Ramapping occurs within minutes ▯ Phantom Limbs: Neuroplastic phenomena Phantom libs syndrome is caused by reorganization of the somato sensory cortex following amputation The amputee feels a touch on his face and also on his phantom limb (due to their proximity on somatosensory cortex) Effects of sensory maniplations on sensory cortex maps o Cross modal rewriting experiments demonstrate the plasticity of sensory cortexes With visual input, the auditory cortex becomes organized retinotopiclaly o Change the input, and you can change the cortical Skill training also leads to reorganization of motor cortex Cant grow neurons. Gives every neuron something to do.