Clinical Correlation With The Limbic System

Question 1

What are the 5 primary limbic system?

Answer 1

Limbic channel

Hippocampal formation

Amygdala

Septal area

Hypothalamus

Question 2

HOME

Answer 2

Acronym for the 4 catagories of functions the limbic system helps regulate

Homeostasis
Olfaction
Memory
Emotion

Question 3

What is the general relay of information associated with the limbic system?

Answer 3

Cerebral cortex -> limbic system -> hypothalamus -> brain stem -> autonomic nervous system responses

not always this pathway though, just generally

Question 4

Temporal lobe seizures

Answer 4

Have been known to directly affect the limbic system

Symptoms/signs

• uncontrolled outburst or sustained behavior (sustained only severe)
• urinary incontinence
• olfactory hallucinations
• fear/panic episodes
• extreme night terrors
• autonomic changes (can become chronic)

Question 5

Limbic channel

Answer 5

Makes up all the connections of the cerebral cortex includes

• medial and frontal cortex
• anterior cingulate
• precentral gyrus (motor cortex)
• prefrontal cortex

Helps regulate motivational drives and emotions

Question 6

Hippocampal formation

Answer 6

Part of the limbic system that is predominant in learning and emotional processing

Takes information rom the perforant pathway and the fornix

Damage affected short-term -> long term memory formation as well as recalling declarative/explicit memories

Question 7

Long term memory types

Answer 7

1) Declarative/explicit
- conscious memory that takes work to store it.
- hippocampus formation is primarily this

Subdivisions of declarative is:

• semantic (facts/concepts)
• episodic (events/experiences)

2) nondeclerative memory
- unconscious memory (i.e typing)
- not encoded in the hippocampus formation so not working with his

Question 8

Wernickes encephalopathy

Answer 8

Caused by thiamine deficiency which results. In a triad of symptoms

1) opthalmoparesis/nystagmus (ocular movement dysfunction)
2) ataxia
3) acute altered mental status w/ global confusion

Treatment:
- intravenous thiamine

• if not treated leads to korsakoff syndrome*

Question 9

Korsakoff syndrome

Answer 9

Prolonged/untreated wernickes encephalopathy

Symptoms/signs:
- same as wernickes encephalopathy

• short and long term memory defects
• confabulation (combines bits and pieces of short term memories to form false short/long term memories)

Treatment:
- irreversible but requires oral thiamine tablets thou to try and lower the symptoms

Question 10

Alzheimer’s disease

Answer 10

Body builds inappropriate protein bundles that are deposited into he limbic structures (especially hippocampal formation)

Destroys memories and behavior (although behavior is later on)

Question 11

Amygdala functions

Answer 11

Receives sensory information and projects it to the hypothalamus after it attaches emotional information to the sensory information

Stimulation of the amygdala results in fear/aversion to particular sensory stimuli

Lesions lead to Kluver-bucy syndrome

Question 12

Nucleus accumbens functions

Answer 12

Gratification center

Coordinates joy/pleasure with stimulation

Lesion causes the following

• addiction
• impulsive behavior

Combats with the amygdala

Question 13

Kluver-Bucy syndrome

Answer 13

Lesions in the amygdala (or bilateral temporal lobes) causes the following
- placidity (no fear to normal fear stimuli)
- hypermetamorphosis
- hyperplagia
- hypersexuality
(essentially the nucleus accumbens runs unchecked)

Question 14

Septal area

Answer 14

Relays information from amygdala and hippocampus to the hypothalamus

Damage looks similar to damage to the hippocampal formation