Exam #3: Limbic System Flashcards Preview

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Flashcards in Exam #3: Limbic System Deck (52):
1

What are the general functions of the limbic structures?

- Memory
- Defense
- Reproduction

2

What are the major structures of the limbic system? What are the two major structures of the limbic system?

- Cingulate gyrus
- Subcallosal gyrus--located below the corpus callosum
- Parahippocampal gyrus
- Hippocampus
- Amygdala
- Septal area/ nuclei of the thalamus & hypothalamus

****Hippocampus (memory) & amygdala (emotions) are the main regions

3

What is the gyrus that lies above the corpus callosum?

Cingulate gyrus

4

Describe the shape of the amygdala.

Almond-shaped

5

Where are the septal nuclei?

Located on either side of the septum pellucidum in the lateral ventricle

6

What is the major input into the limbic system that we covered in class?

Olfaction via the olfactory tracts

*****Specifically, the lateral olfactory stria (division of the olfactory tracts) synapse with the
1) amygdala
2) primary olfactory cortex i.e. piriform lobe & uncus

7

What commissure carries olfactory information that crosses over?

Anterior commissure (specifically the medial olfactory stria crossover)

****Note that the anterior commissure carries sensory information from the MEDIAL olfactory stria

8

What is the primary portion of the olfactory cortex?

Piriform lobe

9

What is the entorhinal cortex?

Association cortex for olfactory information

10

In regards to olfaction, where does the thalamus project? What is the function of this area?

Orbitofrontal cortex--taste

11

What is the commissure that connects the two parts of the hippocampus?

Commissure of the fornix

12

What are the different parts of the hippocampus? What is an alternative name for the hippocampus?

- Pes hippocampus
- Hippoampus proper-- CA 1, 2, 3
- Fornix
- Dentate Gyrus
- Subiculum

****The hippocampus is also known as the "Cornu ammonis"

13

Draw the path of flow through the hippocampus.

N/A

14

What are the different types of memory?

Working
Short-term
Long-term
Declarative

15

What is working memory?

Transient holding and processing of new and already stored information e.g. a phone number

16

What is short term memory?

This refers to a small amount of information in mind in an active, readily available state for a short period of time e.g. facts retained for min or hours with some with reinforcement

17

What is long-term memory?

Memories stored for decades or life via cerebral association areas

18

What is declarative memory?

Declarative memory refers to memories that can be consciously recalled such as facts and knowledge; it falls into two main categories
- Semantics i.e. words/ facts
- Episodic memory i.e. what you did throughout the day

19

What is the function of the amygdala?

Attaching emotional significance to sensory stimuli

20

Where do the medial stria of the olfactory tracts project?

Septal nuclei of the limbic system

21

Where do the amygdala and olfactory cortex project?

Entorhinal complex or "olfactory association cortex"

22

Where does the entorhinal cortex project?

Hippocampus

23

What is unusual about the olfactory pathway?

Does not project directly to the thalamus

24

What tract connects the amygdala to the hippocampus? What tract connects the hippocampus to the hypothalamus?

Amygdala= stria terminalis
Hippocampus= fornix

25

What is the recurrent pathway of the hippocampus? What is the proposed function of this pathway?

Subiculum-->entorhinal cortex

*****Possibly implicated in long term memory consolidation

26

What are the three main groups of nuclei in the amygdala?

1) Corticomedial
2) Basolateral
3) Central nuclei

27

What nuclei of the amygdala the "input gateway?"

Corticomedial
Basolateral

28

What nucleus of the amygdala is the "output gateway?"

Central

29

What are the four major inputs into the amygdala?

- Olfactory tracts
- Orbitofrontal cortex
- Cingulate cortex
- Somatosensory cortex

30

What are the two major output pathways from the amygdala?

1) Stria terminalis (hippocampus)
2) Ventral amygdalofugal (ventral striatum i.e. nucleus accumbens)

31

What areas have reciprocal connections with the septal area?

1) Amygdala
2) Hippocampus
3) Brainstem
4) Hypothalamus
5) Cingulate gyrus

32

What is the function of the septal area?

Pleasure/ reward

33

What is the function of olfactory input to the hippocampus that connects to the hypothalamus?

Visceral responses to odors

34

What is the function of the olfactory input on the orbitofrontal cortex?

Awareness of odors

35

What structure helps to fine-tune olfactory sensitivity?

Anterior commissure

36

What is the input gate to the hippocampus?

Dentate gyrus

37

What is the output gate of the hippocampus?

Subiculum

38

What region of the hippocampus is most vulnerable to anoxia & ischemia?

Internal fields of cells i.e. CA1, CA2, CA3

39

What region of the brain is believed to be the trigger zone for temporal epilepsy?

Internal fields of cells i.e. CA1, CA2, CA3

40

What is the function of the stria terminalis?

Reciprocal connection between the central nucleus of the amygdala with septal area and hypothalamus that modulates visceral responses

41

What does the ventroamygdalofugal pathway connect to?

Brainstem
Ventral striatum or nucleus accumbens

42

What is the function of the ventroamygdalofugal pathway?

Allows emotions to influence movements

43

What does damage to the amygdala result in?

- Inability to express appropriate behavioral & visceral responses to known stimuli
- Inability to learn these responses to new stimuli
- Loss of the ability to read facial expressions

44

What are the major inputs to the septal area?

Hippocampus via the forix
Amygdala via the stria terminalis

45

What is the major output of the septal area?

Medial forebrain bundle to:
- Hypothalamus
- Brainstem nuclei

46

What is the function of the septal area?

"Pleasure & reward"

Also, relation of emotions to respiratory, cardiovascular, and salivatory centers/ nuclei

47

What was the major problem with the Papez Circuit?

It did NOT include the amygdala as part of the limbic system

48

What part of the brain is the target for benzodiasepines?

Limbic System

49

What is an alternative name for Korsakoff Syndrome?

Anmestic Confabulatory Syndrome

50

What is the typical cause of Korsakoff Syndrome?

Thiamin (B1) deficiency seen in chronic alcoholism

51

What are the symptoms of Korsakoff Syndrome?

- Loss of recent memory compensated for by making up fictitious information to fill the gaps

52

What part of the brain has the most damage in Korsakoff Syndrome?

Medial dorsal nucleus of the thalamus