Limbic System

Question 1

the limbic lobe is also called ____

Answer 1

paul broca

Question 2

components of the limbic lobe

Answer 2

• septal area
• cingulate gyrus
• parahippocampal gyrus with hippocampus & amygdala
• uncus

Question 3

what is the limbic system defined as?

Answer 3

the limbic lobe and all its subcortical and cortical connections (papez ciruit)
- hypothalamus
- thalamus
- brainstem reticular formation
- epithalamus
- olfactory cortex
- prefrontal cortex

Question 4

components of hippocampal formation

Answer 4

• part of parahippocampal gyrus
• hippocampus
• dentate gyrus
• subiculum

Question 5

afferents of hippocampal formation

Answer 5

• entorhinal area of parahippocampal gyrus
• contra hippocampus via hippocampal commissure
• amygdala
• thalamus
• locus coeruleus
• raphe nuclei
• ventral tegmental area

Question 6

efferents of hippocampal formation

Answer 6

fornix -> septal area & mammillary bodies of hypothalamus
(mamm. bodies -> ant. nucleus of thalamus (mammillothalamic tract) -> cingulate gyrus)

Question 7

function of hippocampal formation

Answer 7

holds map of spatial memory, implicated in learning & memory, especially short term -> long term explicit memory

Question 8

lesion of hippocampal formation & surrounding areas

Answer 8

defects in explicit memory and spatial orientation

Question 9

what were Patient H.M.’s symptoms after having bilateral removal of temporal lobe portions for his intractable epilepsy?

Answer 9

• anterograde amnesia
• profound difficulty with spatial orientation
• unaffected ability to learn, retain, & improve performance in new motor skills, but no recollection of previous attempts

Question 10

what is explicit/declarative memory and what area of the brain is responsible?

Answer 10

• episodic (events)
• semantic (facts)

medial temporal lobe

Question 11

what is implicit/non-declarative memory and what areas of the brain are responsible?

Answer 11

• priming (neocortex)
• procedural (skills & habits// striatum)
• emotional responses to associative learning (amygdala)
• MSK responses to associative learning (cerebellum)

Question 12

what is retrograde amnesia?

Answer 12

don’t remember past

Question 13

what is anterograde amnesia?

Answer 13

unable to form memories after event

Question 14

what is global amnesia?

Answer 14

unable to remember anything

Question 15

what is modality specific amnesia?

Answer 15

unable to form memories via a specific sensory channel (hearing, sight, touch, etc)

Question 16

afferents of amygdala

Answer 16

autonomic, sensory, auditory & visual info converges in amygdala

Question 17

efferents of amygdala

Answer 17

via stria terminalis -> septal nuclei & hypothalamus, brainstem & cortex

Question 18

function of amygdala

Answer 18

affective perception of sensory stimuli:
stimulation results in intense feeling of fear and maybe accompanied by disagreeable olfactory hallucinations

Question 19

lesion of amygdala

Answer 19

diminished capacity for fear conditioning

Question 20

what is Kluver Bucy syndrome?

Answer 20

bilateral experimental lesion of monkey temporal lobes including the amygdala & hippocampal formation

Question 21

symptoms of Kluver Bucy syndrome

Answer 21

• visual agnosia (psychic blindness)
• hyperorality (put things in mouth)
• hypersexuality
• docility
• apathy
• bulimia
• memory deficit

Question 22

what is Korsakoff’s psychosis?

Answer 22

thiamine deficiency seen sometimes in severe alcoholism that results in anterograde and progressively retrograde amnesia

Question 23

what is temporal lobe epilepsy?

Answer 23

• olfactory (uncinate fits), visual (deja vu), gustatory, and auditory hallucinations
• lip smacking
• motor acts
• amnesia that can last for several hours
• sometimes aggressive behaviour

Question 24

what causes schizophrenia?

Answer 24

abnormal temporal lobe differentiation

Question 25

what causes Alzheimer’s?

Answer 25

senile plaques containing an amyloid protein in the temporal frontal and parietal cortices

Question 26

afferents/efferents of septal area

Answer 26

• hippocampus via the fornix
• amygdala via stria terminalis
• hypothalamus, midbrain, habenula via stria medullaris thalami
• thalamus
• cingulate gyrus

Question 27

function of septal area

Answer 27

emotional behaviour:
stimulation results in transient rage and increased water consumption, and a reward reaction