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Mesolimbic
- Dopaminergic neurons originating in the ventral tegmental area (VTA) and terminating in the nucleus accumbens, amygdala, and hippocampus
- Influences limbic and cognitive function, and behavior
- Hyperactivity in this pathway is associated with positive symptoms of schizophrenia
- Associated with BEHAVIOR
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Mesocortical
- Dopaminergic neurons originating in the ventral tegmental area (VTA) and terminating in the prefrontal cortex (PFC)
- Influences formation of cognitive processing short-term memories,planning, preparing strategies for problem solving, and psychomotor stimulation
- Associated with BEHAVIOR
- Hyperactivity
may cause psychomotor agitation - Hypoactivity may cause slowed thinking in Parkinson’s disease, reduced concentration in patients with ADHD, and negative symptoms of schizophreniaProvides negative feedback to the mesolimbic pathway to the nucleus accumbens -Diminished activity may cause overactivity of limbic system,causing or exacerbating the positive symptoms of schizophrenia
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Nigostriatal
- Dopamine neurons originating in substantia nigra and terminating in corpus striatum (basal ganglia)
- Part of extrapyramidal motor system that controls motor function
- Deficiency of dopamine associated with MOVEMENT Disruptions
- D2 receptor antagonists cause side effects of extrapyramidal reactions (EPS)
- -Produces a movement disorder similar to Parkinson’s disease(pseudoparkinsonism)
- -Muscle spasms or dystonias
- -Hyperkinetic movements seen as akathisia and tardive dyskinesia
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Tuberinfundibular
- Short neurons running from the arcuate nucleus of the hypothalamus to the median eminence and pituitary
- Dopamine regulates hormone secretion from pituitary
- -Inhibits prolactin secretion [PIF]
- -Stimulates growth hormone secretion
- Blockade of D2 receptors (as seen with the use of antipsychotic medications) increases prolactin secretion and may cause
- -Females: Galactorrhea (breast engorgement), lactation (inappropriate milk production), amenorrhea, and infertility
- -Males: Gynecomastia and impotence
- Prolactinomas: Most Common Hyperfunctioning Pituitary Adenoma
- -Hypersecretion
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Pyramidal System
- Pathway for voluntary movement
- Most fibers originate in motor cortex and cross to contralateral side in the medulla to affect voluntary movement
- -Corticospinal tract
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Extrapyramidal System
- Pathways for postural control / certain reflex movements
- Originates in brainstem
- Fibers do not cross
- Cortex can influence this system via inputs to brain stem
- Descend to spinal cord, but do NOT pass through pyramids
- -Axial muscles responsible for balance and posture
- -Muscles controlling movements of proximal portions of limbs
- -Head, neck and eye movements
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Thioridazine
- Mellaril
- 1st generation Refractory Schizophrenia
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Stelazine
- Trifluoperazine
- 1st generation
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