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133 Cards in this Set
- Front
- Back
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What is neuroplasticity?
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The tendency of the brain to shape itself according to experience. The potential to change.
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CNS is a homeostatic balance between what 2 things?
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stability and plasticity
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In the developing brain is there more Large Scale Restructuring or Stability?
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Large Scale Restructuring
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In the adult brain is there more Large Scale Restructuring or Stability?
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Stability
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How much does the brain grow from childhood to adulthood?
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quadruples
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Increase in brain size is NOT due to what?
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addition of new neurons
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Growth of the brain is fueled by what 3 things?
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Gliogenesis
Myelination Elaboration of individual neurons (axons, dendrites, synapses, spines) |
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The number of cortical synapses peaks between what age?
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1-4 years
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Excess synapses in the brain are pruned between what age group?
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early childhood and adolescence
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Overproduction of synapses permits what?
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selection of the most useful or active connections
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Electrical activity determines what?
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which synapses are preserved
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On a cellular level plasticity refers to what?
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synaptic effectiveness
-number and strength of synapses |
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On a systems level plasticity refers to what?
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Cortical Representation
-amount of cortical representation of a certain fxn Neuronal Network Efficiency and Flexibilty -Different areas of brain working together efficiently to carry out a learned task |
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For mechanisms of plasticity, what are different changes in structure due to?
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Synapses (gain/loss of boutons and spines)
Axon branches Dendritic branches New neurons (in hippocampus and olfactory bulb) |
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What happens with synaptic effectiveness through practice?
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Synapse becomes more effective
Increase in number of effective synapses Convergence of silent synapses to active synapses |
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Cortical Reorganization is based on what?
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Use dependent plasticity
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What happens when the CNS is damaged?
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Primary cell death
Secondary cell death -Transsynaptic degeneration -Transneuronal degeneration Edema Glial Cell Reaction |
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Recovery after brain injury involves what?
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substitution of intact parallel pathways through activity-dependent mechanisms (LTP and LTP)
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What is the primary mechanism available to the brain for healing following injury?
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Use-dependent plasticity
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What are the different therapies available post CVA?
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Neuroprotection
Regeneration Neuroreorganization -Pharmacological -Rehabilitation |
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Neuroprotection involves the use of what drugs?
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NMDAr blockers
Amphetamines Antioxidants LDOPA |
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What things increase Neurogenesis?
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Running
Increased activity Dietary restriction Enriched environment Learning opportunities TBI Seizures Estrogen Growth Factors Antidepressants |
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What things decrease Neurogenesis?
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Stress
Aging Serotonin depletion Opiates Methamphetamines |
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What are the 2 main patterns of cortical reorganization?
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Focusing
Recruitment |
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What effects the potential for sparing or recovery?
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Size
Rapidity of Onset Age Gender Exogenous substances -stem cells -pharmaceuticals Experience Rehabilitation -environment -activity --intensity, CIF |
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What is the highest integrator of autonomic and endrocrine functions?
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hypothalamus
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Maintenance of homeostasis, regulates what?
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general body metabolism
body temperature blood pressure water and electrolyte balance food intake circadian rhythmicity sleep-waking cycles |
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What is the Rostral boundary of the hypothalamus?
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lamina terminalis
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What is the superior boundary of the hypothalamus?
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hypothalamic sulcus
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What is the medial boundary of the hypothalamus?
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lateral wall of the 3rd ventricle
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What is the caudal boundary of the hypothalamus?
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mamillary body is external demarcation-blends with midbrain tegmentation and PAG
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What is the inferior boundary of the hypothalamus?
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continuous with pituitary gland via infundibulum and pituitary stalk
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What are the areas involved in the anterior functional group of the hypothalamic nuclei?
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Preoptic nuclei (Preoptic Area)
Supraoptic nucleus (Medial Zone) Paraventricular nucleus (Medial Zone) |
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What are the areas involved in the middle or tuberal functional group of the hypothalamic nuclei?
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Tuberal nuclei (Lateral Zone)
Ventromedial nucleus (Medial Zone) Dorsomedial nucleus (Medial Zone) |
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What are the areas involved in the mamillary or posterior functional group of the hypothalamic nuclei?
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Mamillary nuclei (Medial Zone)
Postior hypothalamic nuclei (Medial Zone) |
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The preoptic nuclei, supraoptic nucleus, and the paraventricular nucleus are involved with what functional group of the hypothalamic nuclei?
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Anterior group
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The tuberal nuclei, ventromedial nucleus, and the dorsomedial nucleus are involved with what functional group of the hypothalamic nuclei?
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Middle or Tuberal group
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The mamillary nuclei and the posterior hypothalamic nuclei are involved with what functional group of the hypothalamic nuclei?
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Mamillary or Posterior group
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What afferent connection of the hypothalamus is the single largest input to the hypothalamus?
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Fornix
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What afferent connection of the hypothalamus conveys afferent fibers from the hippocampus to paraventricular nuclei and mammillary nuclei?
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Fornix
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What afferent connection of the hypothalamus conveys afferent fibers from olfactory areas to preoptic and other nuclei?
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Medial forebrain bundle
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What afferent connection of the hypothalamus passes through hypothalamus to the tegmentum of the midbrain and pons connecting to nuclei of CNII-XII, reticular formation and periaqueductal gray?
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Medial forebrain bundle
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What afferent connection of the hypothalamus conveys afferent fibers from the amygdala to the preoptic area and medial zone?
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Stria terminals
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What afferent connection of the hypothalamus more or less parallels the path of the fornix?
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Stria terminals
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What afferent connection of the hypothalamus also conveys afferent fibers to the septal nuclei?
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Stria terminals
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What afferent connection of the hypothalamus conveys afferent fibers from the amydala to the lateral zone, preoptic nuclei and the septal nuclei?
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Ventral amydalofugal pathway
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What afferent connection of the hypothalamus is also a reciprocal pathway back to the hypothalmus?
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Ventral amydalofugal pathway
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What afferent connection of the hypothalamus conveys afferent fibers from erogenous zones of the body to the mammillary nuclei?
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The peduncle of the mammillary body
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What afferent connection of the hypothalamus projections from retina to suprachiasmatic nucleus - presumably involved with circadian rhythms?
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Retinohypothalamic fibers
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What efferent connection of the hypothalamus arises from nuclei in the medial zone?
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longitudinal fasciculus
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What efferent connection of the hypothalamus has some neurons in the PAG relay information to solitary nucleus and dorsal motor nucleus of the vagus?
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longitudinal fasciculus
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What efferent connection of the hypothalamus has an indirect influence on autonomic nuclei of the brainstem?
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longitudinal fasciculus
Mammillotegmental tract |
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What efferent connection of the hypothalamus arises from the medial mammillary nucleus?
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Mamillothalamic tract
Mammillotegmental tract |
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What efferent connection of the hypothalamus has fibers ascend to terminate in the anterior nucleus?
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Mamillothalamic tract
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What efferent connection of the hypothalamus is part of the Papez circuit?
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Mamillothalamic tract
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What efferent connection of the hypothalamus has fibers descend to terminate in the PAG?
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Mammillotegmental tract
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What efferent connection of the hypothalamus some neurons in the PAG relay information to solitary nucleus and dorsal motor nucleus of the vagus?
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Mammillotegmental tract
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What efferent connection of the hypothalamus these fibers mediate exchange of autonomic information between the hypothalamus, cranial nerve nuclei and the spinal cord?
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Mammillotegmental tract
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What efferent connection of the hypothalamus arises primarily from the paraventricular nucleus?
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hypothalamomedullary fibers
Hypothalamospinal fibers |
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What efferent connection of the hypothalamus descends through the PAG and reticular formation of the midbrain and pons to the medulla?
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hypothalamomedullary fibers
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What efferent connection of the hypothalamus has fibers descend through the PAG and reticular formation of the midbrain and pons to the medulla continue into the spinal cord in the lateral funiculus to terminate on the preganglionic sympathetic neurons in the intermediolateral cell column (thoracolumbar outflow)?
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Hypothalamospinal fibers
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What part of the intrinsic hypothalamic pathway arises from magnocellular neurons in the supraoptic and paraventricular nuclei?
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Supraopticohypophysial (Hypothalamohypophysial) Tract
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What part of the intrinsic hypothalamic pathway transports oxytocin and antidiuretic hormone (ADH, vasopressin) to posterior pituitary – stored in ‘Herring bodies’?
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Supraopticohypophysial (Hypothalamohypophysial) Tract
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What part of the intrinsic hypothalamic pathway has hormones released in response to action potentials from cell body?
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Supraopticohypophysial (Hypothalamohypophysial) Tract
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What part of the intrinsic hypothalamic pathway is released regulated in response to appropriate stimuli?
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Supraopticohypophysial (Hypothalamohypophysial) Tract
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What part of the intrinsic hypothalamic pathway has hormones enter capillary plexus in pituitary then enter general circulation via hypophysial veins?
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Supraopticohypophysial (Hypothalamohypophysial) Tract
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What part of the intrinsic hypothalamic pathway arises from parvicellular neurons in the arcuate nucleus and periventricular zone and the paraventricular, suprachiasmatic, tuberal and medial preoptic nuclei?
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Tuberoinfundibular Tract
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What part of the intrinsic hypothalamic pathway conveys releasing hormones to a plexus of capillary sinusoids in the median eminence and infundibulum of the pituitary?
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Tuberoinfundibular Tract
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What part of the intrinsic hypothalamic pathway has a second plexus of sinusoids in the anterior pituitary where they regulate the production of several hormones by adenohypophysial cells?
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Tuberoinfundibular Tract
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Oxytocin is increased in response to what factors?
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increased levels of estrogen
labor and postpartum suckling results in increased smooth muscle contraction |
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ADH is increased in response to increased osmolarity of blood (NaCl >300 milliosmoles) resulting in what?
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increased H2O absorption in kidney tubules
increased blood volume decreased osmolarity increased concentration of urine (darker) |
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ADH is increased in response to hypotension from decreased blood volume resulting in what?
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increased contraction of arterial smooth muscle
increased blood pressure |
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Stimulation of the suprachiasmatic nucleus results in what?
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adjustment of circadian clock
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Stimulation of the supraoptic/paraventricular nucleus results in what?
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increased blood volume, blood pressure and metabolism
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Stimulation of the lateral hypothalamic nucleus results in what?
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increased feeding
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Stimulation of the ventromedial nucleus results in what?
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decreased feeding
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Stimulation of the dorsomedial nucleus results in what?
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sham rage
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A lesion of the suprachiasmatic nucleus results in what?
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abolishes circadian rhythms
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A lesion of the supraoptic/paraventricular nucleus results in what?
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diabetes insipidus
-increased urination (polyuria) -increased drinking (polydipsia) |
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A lesion of the lateral hypothalamic nucleus results in what?
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decreased feeding
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A lesion of the ventromedial nucleus results in what?
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increased feeding
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A lesion of the dorsomedial nucleus results in what?
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decreased aggression and feeding
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A lesion of the mamillary body results in what?
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short term memory not processed into long term memory
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What is adaptation?
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a decrease in action potential frequency despite constant stimulus energy
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What are the 5 characteristics of generator potentials?
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1. graded
2. additive 3. variable duration (up to 15 msec) 4. no refractory period 5. decrements with time and distance |
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How is an action potential "re-started" in a second neuron?
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postsynaptic potential, which is very similar to a generator potential
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What is the site where postsynaptic potentials are converted to action potentials?
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axon hillock
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What are the characteristics of action potentials?
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graded
capable of being added of longer duration without refractory periods decrement with time and distance can be inhibitory |
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What is latency?
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the time between stimulus and the response, and thus is an indirect measure of conduction velocity (i.e. a longer latency time means slower nerves).
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What does "Distal" latency mean?
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the measurement is taken at the distal portion of the nerve, not at the roots or spinal cord
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How do demyelinating diseases or entrapments affect action potentials?
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affect velocity because the neurons are still alive but slowed
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What is the affect of axonopathy on action potentials?
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affects the amplitude
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What is the major benefit of synapses?
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integration of information
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What does orthodromic mean?
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describes a signal traveling in the usual direction
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What does antidromic mean?
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when the signal travels in reverse
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Synaptic delay is mostly caused by the biochemical events at what site?
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the presynaptic side
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End Plate Potentials (EPP) are created where?
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at the neuromuscular junction
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Postsynaptic Potentials (PSP) are created where?
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at a nerve-nerve synapse
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What is the receptive field for a first-order neuron?
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the area of skin served by the receptor endings of a given axon, the area over which an appropriate stimulus will generate a response in the axon
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What is the receptive field for a second-order neuron?
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the area of receptors in the periphery that causes a change in the firing rate of that second-order neuron
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Fibers to thoracic viscera are what type of fibers when they leave the sympathetic chain ganglia?
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postganglionic
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Fibers to the viscera below the thorax are what type of fibers when they leave the sympathetic chain ganglia?
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preganglionic
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The superior salivatory nucleus deals with what cranial nerve?
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CN 7
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The inferior salivatory nucleus deals with what cranial nerve?
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CN 9
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The Edwinger-Westphal nucleus deals with what cranial nerve?
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CN 3
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The Nucleus Ambigus deals with what cranial nerve?
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CN 9 and 10
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What are the cell groups of the Reticular Formation?
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vasopressor center
respiration center micturition center vomiting center |
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What is the limbic lobe comprised of?
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cingulate gyrus and isthmus
parahippocampal gyrus and uncus subcallosal area hippocampal formation |
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Where does the primary afferent come from for the fornix?
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primarily from the hippocampus and subiculum
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Where does the primary afferent come from for the stria terminalis and the ventral amygdalofugal pathway?
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primarily from the amygdaloid complex
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Where does the primary afferent come from for the mammillothalamic tract?
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from the mammillary nuclei by way of the anterior thalamic nucleus
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How many layers does the neocortex have?
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6 layers
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How many layers does the paleocortex have?
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3-5 layers
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How many layers does the archicortex have?
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3 layers
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What are the functions of the hippocampus?
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Consolidation of long term memory from immediate and short term memory
Regulation of the hypothalamus, e.g. inhibition of the release of corticotropin-releasing hormone (CRH) by the hypothalamus in response to stress |
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What are 2 of the first areas to show signs of Alzheimer's disease?
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The subiculum and the entorhinal cortex
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How does Alzheimer's disease affect the hippocampus?
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Relay of information through the hippocampus is impeded thus probably explaining the memory problems associated with this disease
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What is the cause of Korsakoff Syndrome?
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results from long term thiamine deficiency often associated with chronic alcoholism
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What does Korsakoff Syndrome cause?
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causes degeneration in the mammillary bodies, the dorsomedial thalamus and fornix and loss of neurons in the hippocampus
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What are the results of Korsakoff Syndrome?
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victims are unable to form short term memory and thus long term memory of events since the onset of the disease.
victims may appear to be demented and will piece together parts of old memories to make up for their lack of recent memory (confabulation) These made up memories will be different every time |
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What brain disease is associated with confabulation?
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Korsakoff Syndrome
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What causes Bilateral Temporal Ischemia?
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can result from a heart attack or near drowning
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What is the results of Bilateral Temporal Ischemia?
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Victims retain old memories but have difficulty forming new short term memory
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What is the results of Cingulate Damage?
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bilateral damage can result in a diminution of emotional response to stimuli. It can also result in an inability to remember the proper order of previous events
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What are the functions of the amygdala?
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Higher order regulation of the hypothalamus
Modification of drive-related behaviors and the subjective feelings that accompany these behaviors |
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What causes Klüver-Bucy Syndrome?
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results from bilateral temporal lobe lesions affecting both amygdaloid complexes and other areas of the temporal lobe.
largely based on animal experimentation but has been seen in humans as a result of trauma |
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What are the signs of Klüver-Bucy Syndrome?
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victims display an inability to identify objects by sight (visual agnosia).
victims may display tactile and auditory agnosia victims may display excessive oral examination of objects (hyperorality victims display a tendency to excessively explore their immediate surroundings (hypermetamorphosis). victims show an overreaction to visual stimuli. victims display placidity - no display of fear or anger even if appropriate. victims display an excessive eating drive even when not hungry (hyperphagia). victims display hypersexuality and inappropriate sexual behavior. |
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What is the function of the Septal Nuclei?
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The septal nuclei project to the habenula which in turn projects to the midbrain reticular formation.
This pathway along with the stria medullaris provides a pathway for the limbic system to influence the respiratory, cardiovascular and salivary centers in the brainstem. |
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What is the role of the Nucleus Acumbens?
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a role in addiction and related behavior.
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What is the result of a lesion in the Septal Nuclei?
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a little is known from humans with infarcts in the area with the primary symptom being inappropriate rage
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Postsynaptic membranes use only what 2 mechanisms?
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ligand-gated channels
G-protein-coupled membrane proteins |
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When does Presynaptic autoregulation occur?
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occurs when the presynaptic membrane possesses receptors for the neurotransmitter, which act to diminish the amount of further release
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When does Postsynaptic neuromodulation occur?
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occurs when the postsynaptic membrane sends a different molecule in the retrograde direction to the presynaptic membrane
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