Limbic System Flashcards
What does the limbic system control?
mood
emotion
feelings
motivation
critical for memory
What are the two reasons why the limbic system is difficult to study?
anatomically all the different structures are interconnected, so lesions one willa ffect function of another
physiologically hard to measure output of “feelings”
Why is understanding the limbic system so clinically relevant?
50% of patients will be treated for mood disorders
What are the 8 structures of the limbic system?
amygdala
hipocampus
septal nuclei
nucleus accumbens
medial prefrontal/anterior cingulate
vetnral trgmental area
anterior and dorsomedial nuclei of thalamus
mammillary nuclei
Where does the hippocampus project to in limbis system pathways? Via what tract of fibers?
to the hypothalamic mamillary bodies and the septal nuclei
via the fornix thorugh a C-shaped route
Where do the mammilary bodies project to in the limbis ystem pathways? Via what tract of biers?
to the anterior thalamic nuclei via the mamalothalamic tract
Where does the amygdala project to in the limbic system pathways? Through what fibers?
to the septal nuclei via the stria terminalis (located lateral to the fornix)
Where does the mibrain project to via the hypothalamis?
the forebrain in the medial forebrain bundle
Through what tract does the hypothalamus project to the brain stem and spinal cord?
the dorsal longitudinal fasciculus
All areas of the limbic systems are involved in circuits that somehow invove the….
hypothalamus - because it exerts control over the ANS, which mediates output for emotion
What 4 neurotransmitters are particularly active in the limbic system?
norepinephrine from the locus ceruleous (pons0
serotonin from raphe nucleus of the midbrain, pons and medulla
dopamine in the mesolimbic system
acetylcholine from the nucleus basilis and septal nuclei
Again, where does NE come from? 5HT?
NE from the locus ceruleus of pons
5HT from the raphe nuclei of midbrain, pons and mdulla
What is dopamine particularly important for the mesolimbic pathway?
pleasure and reward for behavior
Where are the dopaminergic neurons of the mesolimbic system and where do they project to?
ventral tegmental area of the midbrain
project ot nucleus accumbens, medial prefrontal cortex, amygdala and septal nucleu via the medial forebrain bundle
What are the affects of cocaine and amphetamine on dopamine?
cocaine blocks reuptake of DA
amphetamine increases DA secretion (and blocks reuptake)
Lesions of what area and blocking of what receptors will result in a decrease in drug seeking behaivor?
lesion of the VTA or nucleus accumbens
blocking DA receptors
Why is treating drug addiction so hard in terms of the mesolimbic pathway?
The mesolimbic pathway is also involved in the pleasure of natural rewards like food and sex
What is the clinical importance of the nucleus basalis?
you lose is in AD - no ACh - memory deficits
What is the primary role of the amygdala?
fear conditioning
What is the affect of amygdala lesions?
- no fear conditioning
- prior fear conditioning goes immediatley extinct after lesion
What symptoms would you see in a prefrontal lobe syndrome?
- impariment in goal directed behavior
- lack of emotion in decision making (lack of risk aversion)
- Poor social judgement (antisocila behavior)
- Poor emotional control (increased impulsivity)
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