Limbic System I

Question 1

What does the limbic system control?

Answer 1

Mood, emotion, feelings, motivation and memory

Question 2

Why is the limbic sytem difficult to study?

Answer 2

1. anatomically interconnected
2. physiological it’s hard to measure limbic system output

Question 3

What are the 5 pathwways of the limbic system?

Answer 3

1. Fornix
2. MMT
3. Stria terminalis
4. Medial forebrain bundle
5. Dorsal longitudinal fasiculus

Question 4

Fornix pathway

Answer 4

Hippocampus to mammilary bodies and septal nuclei

Question 5

MMT

Answer 5

Mammilary bodies to anterior nucleus of the thalamus

Question 6

Stria terminalis

Answer 6

Amydala to the septal nuclei

Fornix and stria terminalis lie close together

Question 7

Medial forebrain bundle

Answer 7

Midbrain through the hypothalmus to the forebrain

Question 8

Dorsal longitudinal fasiculus

Answer 8

Hypothalmus to the brainstem and spinal cord

Question 9

The limbic system receives innervation from what types of axons?

Answer 9

Monaminergic and cholinergic

Question 10

Where is NE stored?

Answer 10

NE is stored in the locus ceruleus in the dorsal pons

Question 11

Where is 5HT stored?

Answer 11

In the Raphe nuclei in the midbrain, pons and medulla

Question 12

NE and 5HT are important for what basal funcitons?

Answer 12

sleep and wake cycles

attention and arousal

Question 13

Where is dopamine made and stored?

Answer 13

The VTA in the MIDBRAIN.

DA travels through themedial forebrain bundle to reach the nucleus acccumbens, medial prefrontal cortex, amygdala and septal nuceli

Question 14

What causes drug addiction?

Answer 14

Cocaine and amphetamines both increase DA in the synaptic cleft leading to a HIGH.

Question 15

A lesion of the VTA/nucleus accumbens/septal nuclei would do what?

Answer 15

It would DECREASE drug seeking behaviors because there would be LESS dopamine.

Blocking DA receptors is a way of decreasing drug seeking behaviors….this also makes you feel naseous and sick.

Question 16

Where is ACh made?

Answer 16

Nucleus bassilus and the septal nucleus

Both project to the forebrain and hippocampus

Question 17

What nucleus is commonly lost in Alzheimers?

Answer 17

The nucleus basalis. This leads to memory defects.

Question 18

What is the role of the amydala?

Answer 18

Processes memory and emotional responses.

Plays a role in fear conditioning.

Question 19

A lesion of the amygdala causes what deficits?

Answer 19

Leads to decreased conditioning–don’t associate a connection between “shock” and “tone”.

If there is a conditioned fear resonse it is lost!

Question 20

How are the prefrontal cortex and the amygdala connected?

Answer 20

The prefrontal cortex inhibits the amygdala which activates the hypothalamus and leads to an emotional response.

Question 21

What is prefrontal lobe syndrome?

Answer 21

Discovered becasue of Phinneus Gage!

He was a nice man but then suffered damage to his prefrontal lobe and became a weiner face. He had no emotional conrol, poor social judegmeent and impaired goal directed behavior.

Question 22

What are hte DLPFC and the OFC?

Answer 22

Dorsolateral PFC is responsible for working memory.

The orbitofrontal cortex connects to the amygdala.

Question 23

The hippocampus plays a role in what type of memory?

Answer 23

Explicit or declarative moemroy!

Semantic- memory of words/facts

episodic- memory of events, experiences

Question 24

What type of memory is the hippocmampus NOT involved in?

Answer 24

Implicit memory (procedural/nondeclarative)

NOT needed for motor skills.

Question 25

What is anterograde amnesia?

Answer 25

No NEW memories

Question 26

What is temporally graded amnesia?

Answer 26

Childhood memories- strongest

Memories before surgery- weakest