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Flashcards in Limbic System Deck (52):
1

Generally describe the limbic system:

The limbic system is a term used for a number of interconnected cortical regions and subcortical structures that function to serve a number of survival mechanisms.

2

List 5 cortical structures that are included in the Limbic lobe:

1. septal area
2. cingulate area
3. parahippocampal gyrus
4. hippocampus
5. other related cortical areas (orbitofrontal cortex and prefrontal cortex)

3

Describe the septal area:

area surrounding end of rostrum of corpus callosum

4

What are the associated subcortical nuclei of the limbic system?

1. amygdala
2. hypothalamus
3. septal nuclei
4. anterior thalamic group

5

where is the amygdala located?

located deep to the uncus

6

Where is the septal nuclei located?

deep to septal cortical region; near the fornix and anterior commisure

7

List the 4 nerve fiber pathways of the limbic system:

1. mamilothalamic tract
2. fornix
3. stria terminalis
4. medial forebrain bundle

8

The limbic lobe connections are organized as a complex loop. The mamillary bodies connect to the ______________________ via the mamillothalamic tract.

anterior thalamic group

9

The anterior thalamic group connects to the __________________.

cingulate gyrus

10

the cingulate gyrus connects to the __________________________.

parahippocampal gyrus

11

the parahippocampal gyrus connects to the ________________________.

hippocamus

12

the hippocamus connects to the _______________________ and _______________________ via the ____________.

mamillary bodies
and septal region
via the fornix

13

Describe the route of the limbic lobe:

mamillary bodies --> anterior thalamic group (via mamilothalamic tract) --> cingulate gyrus --> cingulate gyrus --> parahippocampal gyrus --> hippocampus --> mamillary bodies AND sepatal region (via fornix)

14

How is the amygdala connected to the limbic circuit?

by way of the connections to the septal region and the hypothalamus via stria terminalis

15

What are the two afferents of the limbic system?

1. cortex
2. reticular formation

16

In the limbic system, the afferent cortex projects:

to all parts of limbic lobe, amygdala and hypothalamus

17

In the limbic system, the afferent reticular formation projects:

to all parts of limbic lobe, amygdala and hypothalamus

18

In the limbic system list two of the efferent locations:

1. limbic lobe
2. amygdala

19

In the limbic system the limbic lobe is efferent and projects to:

all parts of the cortex by way of thalamic gating

and to the hypothalamus and reticular formation

20

In the limbic system the amygdala is efferent and projects to:

dorsomedial thalamic nucleus, which in turn projects to prefrontal cortex (medial forebrain bundle)

21

in the limbic system the amygdala is efferent and projects to the brainstem reticular formation nuclei both directly and indirectly via the:

hypothalamus (medial forebrain bundle)

22

The limbic system generates behaviors necessary for:

preservation of the individual and the species (e.g., motivation, emotion, learning and memory).

23

In the limbic system, the relationship of anatomy to function is only partially known, but suffice it to say that the influence this system has on the hypothalamus and the autonomic nervous system is very powerful. Lesions of the hippocampus and amygdala must be ____________ to result in major deficits of normal behavior.

bilateral

24

In the limbic system, unilateral stimulation, however, may result in ____________ behavior.

abnormal

25

The limbic system has been labeled the 3-F, 1-R system:

(fighting, fleeing, feeding and sexual behavior).

or 4 F's

26

(Hippocampus) Attention: What does unilateral or bilateral stimulation produce?

alertness and searching behavior.

27

What my the proposed circuitry be?

(Hippocampus_Attention: unilateral or bilateral stimulation produces alertness and searching behavior)

???

(remember that alertness and awareness are cycled through the reticular formation as the reticular activating system)

28

(Hippocampus) Memory: loss of recent memory and the inability to form new memories is the result of a ___________ lesion.

bilateral

29

What type of memories is the hippocampus responsible for, declarative or procedural?

declarative (explicit, facts)

NOT procedural (implicit, motor memory)

30

The process of consolidation is the transfer of short-term memories into:

long lasting memories

31

Patient H.M. had ______________ and D.B. had ______________.

epilepsy

limbic encephalitis

32

(hippocampus) Spatial orientation; there is a "cognitive mapping system" which makes what possible?

possible to compare present spatial situations with those already experienced

33

(hippocampus) stress projections go to the ________________ hippocampus.

anterior

34

Stress causes the pathway to the anterior hippocampus to release _____________________________ that then acts at the ______________.

corticotropin releasing factor (CRF)

pituitary.

35

What does the pituitary release?

adrenocorticotropic hormone (ACTH)

36

What does ACTH act on? What does this structure then secrete?
What else is released at this time?

the adrenal gland

cortisol

vasopressin

** this is the stress the body senses when there is an injury, not stress related to fear

37

(septal nuclei) pleasure: What does stimulation of septal nuclei and surrounding hypothalamus (part of anterior division) result in?

sexual arousal; pleasure/ euphoria from drug activation

38

(septal nuclei) rage: what do bilateral lesions to the septal region result in?

hyperexcitability (exaggerate jumping when startled), rage (unprovoked attacks)

** these symptoms are identified in the experimental situation

39

(Amygdala) sensory- affective interactions: What is the amygdala important for?

instinctive reactions to sensory stimuli

40

The amygdala is important for instinctive reactions to sensory stimuli including the:

motivational and emotional significance of sensations

41

What do lesions to the amygdala result in?

inappropriate emotional responses to sensory stimuli

42

(amygdala) emotion: the emotional component to:

learning

43

The amygdala (emotional part) is important for what?

developing emotional reactions to new experiences, which if repeated become instinctive emotional reactions.

44

What set of nuclei are implicated in the learned memory of fear?

amygdala

45

(amygdala) modulator or controller of hypothalamic activities: what does stimulation or lesion of the amygdala produce?

autonomic effects, arousal, sexual activity, motor activity related to eating, aggressive behavior.

46

What does stimulation of the lateral amygdala produce?

a gradual build up of aggressive behavior (anger), hyperphagia (overeating - lateral hyopthalamus), pleasure reactions, and tameness.

This may sound contradictory, but it is based on the normal social behaviors of an individual

47

What does stimulation of the medial amygdala produce?

decreases aggressive behavior, aphagia (trouble swallowing/ eating -medial hypothalamus), sadness, and fear associated defensive behavior

48

There is a connectional relationship of the limbic system with the hypothalamus. This is generally thought to be displayed as the:

autonomic component of aggressive or defensive behaviors.

49

The medial parts of the amygdala have a preferential connection with medial hypothalamus and are more attuned to behaviors generated out of:

defense of self.

50

The lateral parts of the amygdala receive powerful sensory association cortical input and are connected more with the lateral divisions of the hypothalamus. This region is more associated with:

predatory or feeding behaviors.

51

What is the anterior septal region more attuned to?

acting in satisfaction or pleasure

52

What is the anterior septal region thought to function in?

the euphoria associated with the onset of addictions: cocaine, methamphetamines