Limbic System

Question 1

What does the limbic system control?

Answer 1

mood

emotion

feelings

motivation

critical for memory

Question 2

What are the two reasons why the limbic system is difficult to study?

Answer 2

anatomically all the different structures are interconnected, so lesions one willa ffect function of another

physiologically hard to measure output of “feelings”

Question 3

Why is understanding the limbic system so clinically relevant?

Answer 3

50% of patients will be treated for mood disorders

Question 4

What are the 8 structures of the limbic system?

Answer 4

amygdala

hipocampus

septal nuclei

nucleus accumbens

medial prefrontal/anterior cingulate

vetnral trgmental area

anterior and dorsomedial nuclei of thalamus

mammillary nuclei

Question 5

Where does the hippocampus project to in limbis system pathways? Via what tract of fibers?

Answer 5

to the hypothalamic mamillary bodies and the septal nuclei

via the fornix thorugh a C-shaped route

Question 6

Where do the mammilary bodies project to in the limbis ystem pathways? Via what tract of biers?

Answer 6

to the anterior thalamic nuclei via the mamalothalamic tract

Question 7

Where does the amygdala project to in the limbic system pathways? Through what fibers?

Answer 7

to the septal nuclei via the stria terminalis (located lateral to the fornix)

Question 8

Where does the mibrain project to via the hypothalamis?

Answer 8

the forebrain in the medial forebrain bundle

Question 9

Through what tract does the hypothalamus project to the brain stem and spinal cord?

Answer 9

the dorsal longitudinal fasciculus

Question 10

All areas of the limbic systems are involved in circuits that somehow invove the….

Answer 10

hypothalamus - because it exerts control over the ANS, which mediates output for emotion

Question 11

What 4 neurotransmitters are particularly active in the limbic system?

Answer 11

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

Question 12

Again, where does NE come from? 5HT?

Answer 12

NE from the locus ceruleus of pons

5HT from the raphe nuclei of midbrain, pons and mdulla

Question 13

What is dopamine particularly important for the mesolimbic pathway?

Answer 13

pleasure and reward for behavior

Question 14

Where are the dopaminergic neurons of the mesolimbic system and where do they project to?

Answer 14

ventral tegmental area of the midbrain

project ot nucleus accumbens, medial prefrontal cortex, amygdala and septal nucleu via the medial forebrain bundle

Question 15

What are the affects of cocaine and amphetamine on dopamine?

Answer 15

cocaine blocks reuptake of DA

amphetamine increases DA secretion (and blocks reuptake)

Question 16

Lesions of what area and blocking of what receptors will result in a decrease in drug seeking behaivor?

Answer 16

lesion of the VTA or nucleus accumbens

blocking DA receptors

Question 17

Why is treating drug addiction so hard in terms of the mesolimbic pathway?

Answer 17

The mesolimbic pathway is also involved in the pleasure of natural rewards like food and sex

Question 18

What is the clinical importance of the nucleus basalis?

Answer 18

you lose is in AD - no ACh - memory deficits

Question 19

What is the primary role of the amygdala?

Answer 19

fear conditioning

Question 20

What is the affect of amygdala lesions?

Answer 20

1. no fear conditioning
2. prior fear conditioning goes immediatley extinct after lesion

Question 21

What symptoms would you see in a prefrontal lobe syndrome?

Answer 21

1. impariment in goal directed behavior
2. lack of emotion in decision making (lack of risk aversion)
3. Poor social judgement (antisocila behavior)
4. Poor emotional control (increased impulsivity)

NO CHANGE IN INTELLIGENCE

Question 22

What are the etiologies to prefrontal lobe syndrome, specific to the segments….

Answer 22

dorsolateral PFC involved in working memory, so damage causes the inability to “folow thorugh”/godl directed behavior

orbital frontal cortex has connections to the amygdala, so without it, you are more pront to fits of anger

ultiamatley, the prefrontal cortex is inhibitory to the amygdala, which is excitatory to the hypothalamus, so you have an uncontrolled amygdala telling the hypothalamus to alter autonomics

Question 23

What is the role of the hippocampus?

Answer 23

memory

Question 24

What were the symptoms of HM’s bilateral medial temporal lobectomy?

Answer 24

anterograde amnesia and temporally graded retrograde amnesia (loss of old memories that are more recent to the surgery)

specifically, loss of excplicit or declarative memory with conservation of implicit memory

Question 25

why was implicit memory spared in HM?

Answer 25

it doesn't require the hippocampus

Question 26

What is the disease that results in dilateral damage to the amygdala from mineral deposits?

Answer 26

Urbach-Wiethe Disease

Question 27

What are the symptoms of Urbach-Wiethe Disease?

Answer 27

1. impaired reocgition of emotion - especially anger and fear 2. inability to differentiate between similar emotions (like anger and fear) 3. Memory loss especially for information with emotional content

Question 28

What's the triad of symptoms in PTSD?

Answer 28

1. re-experiencing phenomena - flashbacks 2. avoidance of situational triggers 3. hyperarousal - increased anxiety of what;s to happen

Question 29

What is the etiology of PTSD found through fMRI studies?

Answer 29

decreased medial prefrontal, so disinhibtion of the amygdala and subsequent increase in amygdala activity

Question 30

WHat are the general symptoms of schizophrenia?

Answer 30

fregmentation of thought, action and mood positive symptoms - delusions and hallusinations negative symptoms - social withdrawal

Question 31

What is the US incidence of schizophrenia?

Answer 31

1%

Question 32

What are the two "hypotheses" in schizophrenia?

Answer 32

1. that dopamine receptor activity is too high 2. That glutamine NMDA activity is too low

Question 33

What ttreatments do we do we utilized if we take the dopamine hypothesis as true?

Answer 33

Block dopamine receptors haloperidol - DA2 receptor blocker closapine - CA2 receptor blocker, 5HT receptor blocker, blocks glue receptor to increase glutamate concentration

Question 34

What proof do we have that glutamine is related to psychotic symptoms?

Answer 34

phencyclidine (PCP) blocks the nDMA receptor and causes psychotic symptoms

Question 35

How how do you treat schizophrenia thorugh the glutamate arm?

Answer 35

increase glutamate receptor activity

Question 36

What are the 3 general symptoms of depression?

Answer 36

1. anhydnia 2. sleep wake disturbance 3. social withdrawal

Question 37

What is th eincidence of depression in women compared to men?

Answer 37

20% women, 13% men

Question 38

What NTs are implicated ind epression?

Answer 38

monoamines: NE and 5HT thought to be low

Question 39

What are the three general kinds of anti-depressants?

Answer 39

MAO inhibition to block NE and 5HT degradation Tricclics: block reuptake of NE and 5HT by blocking the transporter SSRIS (fluoxetine): block reuptake of serotonin only

Question 40

Why is there a long latency for depression treatments to take?

Answer 40

it may depend on affecting neural plasticity

Question 41

What is the triad of symptoms in Korsakoff's syndrome?

Answer 41

1. disorder of immediate memory - no new memory 2. disorientation in space and time 3. Confabulation - complete fabrications of info

Question 42

What is the cause of korsakoff's syndrome?

Answer 42

chronic alcoholism and related nutritional deficits specifically, B1 thiamine deficiency

Question 43

What is Kluver-Bucy Syndrome?

Answer 43

When you have bilateral medial temporal lobe damage (originally described in monkeys after bilateral surgical removal of amygdala, hippocampus, and temporal cortex)

Question 44

What two issues are likel to have bilateral medial temporal lobe damage?

Answer 44

stroke or encephalitis

Question 45

What are the 4 symptoms of Kluver-Bucy?

Answer 45

1. oral tendencies 2. changes in emotions - neutral affect 3. hypersexuality 4. Visual agnosia (inability to discriminate visual stimuli)

Question 46

WHat are the 4 symptoms of AD?

Answer 46

1. memory loss 2. mood change: depanx 3. motor dysfunction 4. complete loss of ocgnitive funciton

Question 47

What is th eincidence of AD in 85+

Answer 47

50%

Question 48

What is the etiology of AD?

Answer 48

1. loss of cholinergic input to hippocampus form the nucleus basalis 2. loss of neuron sin multiple brain areas 3. presence of neurofibrillary tangles of taue proteins and beta-amyloid plaques

Question 49

Why do we treat AD patients with Donepezil (aricept)?

Answer 49

it's an anticholinesterase, so increases concentraiton of ACh

Question 50

What is chronic traumatic encephlalopathy?

Answer 50

it's a progressive neurodegenerative disease cause by repeated head trauma

Question 51

What are the symptoms of CTE?

Answer 51

memory impairment - anterograde amnesia executive dysfunction depression apathy decreased impulse control increased aggressiveness

Question 52

What is the etiology of CTE?

Answer 52

generalized brain atrophy - esp prefrontal corte, temporal lobes, and parietal lboes neurofibrillaty tau protein tangles present