S14 Neuro Limbic System

Question 1

Limbic system overal functions

Answer 1

survival instincts (innate behavior)

memory (making new memories)

behavioral and emotional expression

Question 2

limbic system pathologically linked to

Answer 2

encephalopathy

epilepsy

cognitive deficity

psychotic symptoms (schizophrenia)

Question 3

Major components of the limbic system

Answer 3

Medial and basal forebrain
- septal area and ventral stratum

Hippocampal formation:
- hippocampus proper, dentate gyrus and subiculum

limbic lobe:
- parahippocampus gyrus and the amygdala

amygdala
hippocampus (indexer)
fornix
hypothalamus
thalamus (anterior)
cingulate gyrus
olfcatory cortex
entorhinal cortex

Question 4

cingulate gyrus

Answer 4

three layered cortex

communicates with thalamus and hippocampus

Part of the Paper circuit (memory)

involved with sensory input concerning emotions

regulation of aggressive behavior

anterior part size is smaller in people with schizophrenia

Question 5

Amygdala

Answer 5

Large, almond shape, nuclear mass
- anterior and medial temporal lobe

substantia innominata (basilar nucleus of meynert)

• origin of primary cholinergic system of the basilar forebrain
• affected in Alzheimer’s disease

Emotional responses

Memory
- Fear conditioning (associative learning process by which we learn to fear some thing)

fear and threat detection

• stimulus 1+ stimulus 2
• adoptive behavioral relationship
• re-enforcement

processing positive stimuli

emotional, more vivid memory

implicit (unconscious) kind of memory

Question 6

Hippocampus

Answer 6

2 layered allocortex

• dentate gyrus
• Ammon’s horn
• subiculum

memory index

sends memory for remote storage

decides the site of storage

retrieve the memory when necessary

Question 7

Fornix

Answer 7

band that connects hippocampus to the thalamus

Question 8

Mammillary bodies (corpus mamillare)

Answer 8

part of diencephalon

2 rounded small bodies

located at the end of the anterior arch of fornix

Important for recollective memory

Damaged with Thiamine (B1) deficiency

Question 9

Hypothalamus nuclei

Answer 9

Anterior nuclei
- Preoptic & supraoptic
Posterior nuclei
- Mammillary nuclei

Middle group
- Medial and lateral
+Orexin (hypocretin) releasing neurons (lateral)
=Regulates wakefulness and appetite

Question 10

Hypothalamus parasympathetic control

Answer 10

anterior and medial nuclear groups

Question 11

hypothalamus sympathetic control

Answer 11

posterior and lateral nuclear groups

Question 12

hypothalamus portion of the diencephalon

Answer 12

wakeful

emotional center

• angry
• unhappy

behavior
motivation

Question 13

Lateral hypothalamus

Answer 13

stimulation
- excessive eating

destruction (lesion)
- anorexia and emaciation

Question 14

Ventromedial hypothalamus nucleus

Answer 14

• destruction (lesion)

+ hyperphagia (excessive eating) asa nearly symptom

Question 15

Mating driving- humans

Answer 15

Originate in deep frontal lobe structures of the anterior cingulate gyrus and the septal nuclei

Significantly modified by inhibitory input from the temporal lobe limbic structures

Learned social behavioral patterns that develops in the cortex
- Forms another controlling influence of sexual behavior in humans

Question 16

Libido

Answer 16

deep midline limbic structures

midline limbic structures

• cingulate gyrus
• septal nuclei
• hypothalamus
• limbic midbrain structures
• possibly anterior thalamus

Prefrontral lobectomy
- uninhibited sexual interest and behavior

removal of temporal lobes (Kluver-Buccy Syndrome)
- inappropriate and exaggerated sexual activity

chronic, subclinical, stimulation of the temporal lobes
- global hypo sexuality

Question 17

Fighting and fleeing

Answer 17

Function of limbic system
- temporal lobe
\+ amygdala
\+ hippocampus
- hypothalamus (modulator)

stimulation of the amygdala or hippocampus-> violent attack behavior in Monkeys
- similar behavior seen in
+ temporal lobe epilepsy
+ destructive lesions to ventromedial hypothalamus

Question 18

memory network/areas

Answer 18

medial temporal lobes

• hippocampus
• amygdala

basal forebrain

diencephalone

• dorsomedial and paramedian thalamic nuclei
• maxillary bodies

Question 19

Memory and limbic system

Answer 19

mamillothalamic tract

Question 20

mamilllothalamic tract

Answer 20

mammillary bodies-> anterior nucleus of the thalamus-> cingulate gyrus

Question 21

Papez circuit

Answer 21

mammillary bodies-(mamillothalamic)-> anterior thalami -(internal capsule)-> cingulate- (cingulum)-> amygdala hippocampus -(fornix)->

Question 22

amnesia

Answer 22

inability to learn new information:

• disorder of recent memory
• involves the medial temporal lobes, diencephalon and basal forebrain
• amygdala may assign emotional significance to signals prior to processing in hippocampus

Question 23

limbic dysfunction and Amnesia possible causes

Answer 23

limbic encephalitis
- infectious:
+ herpes simplex virus

• immune/inflammatory + paraneoplastic
  + autoimmune

Amnesia:

• transient global amnesia
• anoxic encephalopathy
• traumatic brain injury
• stroke (PCA stroke)
• Diencephalic tumors
• Alzheimer’s disease
• Korsakoff’s psychosis

Question 24

Wernicke’s encephalopathy

Answer 24

• triad of:
  + acute mental confusion (encephalopathy)
  + Ataxia (cerebellar involvement)
  + ophthalmoplegia (diplopia)
• Korsakoff Amnestic syndrome is a late neuropsychiatric manifestation
  + retrograde and anterograde amnesia
  + confabulation
• thiamine (B1) deficiency
  + works as coenzyme in metabolism of glucose and lipid
  + LA and failure of energy-> cellular death
• early recognition and treatment
  + resolution of symptoms within hours
• alcoholics
  + alcohol affects B1 uptake and utilization

-none alcoholics
\+ hyperemesis gravidarum
\+ bariatric surgery (bariatric beriberi)
\+ prolonged starvation
\+ HIV/ AIDS
\+ infants fed thiamine deficient formula
\+ iatrogenic exacerbation
= prolonged glucose or carbohydrate loading in a person with marginal deficiency

Question 25

Kluver-Bucy syndrome

Answer 25

areas involved:

• bilateral lesions of the medial temporal lobes
• including the amygdaloid nucleus

symptoms:
- amnesia (retrograde and anterograde)
- hyperplasia and hyperorality
- hyper sexuality
- diminished fear responses (placidity)
- visual agnosia
+ inability to recognize familiar objects or people

Question 26

Kluver-bucy syndrome- damage to the bilateral medial temporal lobes

Answer 26

temporal lobectomy

meningoencephalitis (herpes encephalitis)

traumatic brain injury

brain tumors

ischemic/anoxic (stroke)

Question 27

conscious appreciation of an emotion: positive feelings

Answer 27

frontal cortex/ septal nuclei/ cingulate gyrus

Question 28

conscious appreciation of an emotion: negative feelings

Answer 28

temporal lobe cortex/ amygdala/hippocampus

Question 29

conscious appreciation of an emotion cortical phenomena

Answer 29

• cingulate and phylogenetically order limbic cortex

- entire cortex will participate in fully emotional experience