3.13.14 29 Limbic system

Question 1

Describe the olfactory pathway

Answer 1

Olfactory receptors in epithelium cells –>
Olfactory nerve bundles –> Cribriform plate –>
Olfactory bulb (Mitral cells) –> Olfactory tract –>
1. Lateral (–> anterior perforated substance, piriform cortex, amygdala)
and 2. Medial (–> contralateral bulb via anterior commissure) olfactory stria

Question 2

What is the term describing leakage of CSF through the nasal passages? What causes this?

Answer 2

Rhinorrhea

Fractures to the floor of the anterior cranial fossa (cribriform plate, ethmoid bone)

Question 3

What is the term for the loss or impairment of smell?

Answer 3

Anosmia

Question 4

Intracranial pressure results in the compression of the temporal lobe, leading to epileptic discharges producing a “burning rubber” smell; this is referred to as…

Answer 4

Uncinate fits; irritation of the olfactory areas (piriform cortex and entorhinal areas; amygdala)

Question 5

Describe the Papez circuit

Answer 5

Entorhinal cortex (Parahippocampal gyrus) –> Dentate gyrus –>
Hippocampus –> fornix (fimbriae, crus, body, column) –>
Mammillary body –> mammillothalamic tract –>
Anterior nucleus of thalamus –>
Cingulate gyrus –>
Entorhinal cortex (Parahippocampal gyrus)

Question 6

Which specific structure of the limbic system is related to learning and memory?

Answer 6

Hippocampus

Question 7

What precedes the mammillary bodies in the Papez circuit?

Answer 7

The fornix (fimbriae –> crus –> body –> columns)

Question 8

What specific structure of the limbic system is related to pleasure?

Answer 8

Septal region/nucleus

Question 9

To what other structures is the septal nucleus connected?

Answer 9

Amygdala (via stria terminalis)
Habenular nucleus (via stria medullaris)
Olfactory lobe, hippocampus, hypothalamus

Question 10

What specific structure of the limbic system is related to emotional expression?

Answer 10

The amygdala

Question 11

What behavioral function does the hippocampus serve?

Answer 11

Learning and memory (short term –> long term)

Question 12

What behavioral function does the septal region serve?

Answer 12

Pleasure center

Question 13

What behavioral function does the habenular nucleus serve?

Answer 13

Reproduction

Question 14

What behavioral function does the amygdala serve?

Answer 14

Emotional response (sensory integration center)
Endocrine activity
Sexual behavior
Food/water intake
Modulation of hypothalamic activity

Question 15

To what structures is the cingulate gyrus connected?

Answer 15

Reciprocal connections to the thalamus (anterior nucleus)
Entorhinal cortex (parahippocampal gyrus)

Question 16

What major visceral functions does the limbic system affect through the brainstem?

Answer 16

Cardiovascular and respiratory rate

Gastric and evacuative function

Question 17

What would a bilateral lesion of the hippocampi affect?

Answer 17

Impairment of recent events (verbatim… idk, try to conceptualize)

Question 18

The limbic system an anatomic substrate for the convergence of what three functions?

Answer 18

Cognitive activities (cortical), emotional experience (amygdala), and expression (output)

Question 19

What is the cause of Korsakoff’s syndrome? What does it affect? What are the symptoms?

Answer 19

Thiamine deficiency (chronic alcoholism)
Mammillary bodies, hippocampus, dorsomedial thalamic nucleus (memory)
Inability to form new memories (pt fabricates stories to compensate)

Question 20

What is another name for Korsakoff’s syndrome?

Answer 20

Amnestic confabulatory syndrome

Question 21

What is the name for the disease that results from a thiamine deficiency?

Answer 21

Korsakoff’s syndrome or Amnestic confabulatory syndrome

Question 22

What is the name for the syndrome that results from bilateral lesions to the temporal lobe?

Answer 22

Kluver-Bucy syndrome

Question 23

What important areas are affected by Kluver-Bucy?

Answer 23

The temporal lobes, specifically the amygdala, hippocampus, and parahippocampal gyrus

Question 24

What are symptoms of Kluver-Bucy syndrome?

Answer 24

Absence of emotional response (fear, rage, aggression)
Overly attentive to sensory stimuli (orally examines objects)
Hypersexuality
Psychic blindness (inability to recognize objects)

Question 25

A patient with a history of chronic alcoholism fabricates stories due to a loss of ability to form new memories. What is this called? What is the problem?

Answer 25

Korsakoff’s Syndrome
Thiamine deficiency
Lesions to mammillary bodies, hippocampus, and dorsomedial thalamic nuclei

Question 26

A patient shows lack of emotional response, and tends to be fairly touchy-feely and places objects in his mouth; his libido is through the roof… guy can’t stop talking and thinking about sex; he also has issues visually identifying objects. What is this called? What is the problem?

Answer 26

Kluver-Bucy syndrome

Bilateral damage to the temporal lobes (amygdala, hippocampus, parahippocampal gyrus)

Question 27

5 F’s are associated with what? What are they?

Answer 27

Limbic system!
Feeding
Feeling
Fleeing
Fighting
F... sex... ;D