The limbic system

Question 1

What is the limbic system involved in

Answer 1

Pleasure
Pain
Learning
Memory

Question 2

Where are the nuclei of the limbic system located

Answer 2

Medial aspect of frontal, parietal and temporal lobes

Question 3

In simple organisms, what systems is the limbic system connected to

Answer 3

Olfactory and memory

Question 4

What makes up the limbic system in the frontal and parietal lobes

Answer 4

Orbito-frontal cortex

Cingulate cortex

Question 5

What makes up the limbic system in the medial temporal lobe

Answer 5

Parahippocampal cortex

Question 6

What is the main blood supply to the limbic system

Answer 6

Anterior and posterior cerebral artery

Question 7

What blood vessel supplies the tip of temporal lobe and orbital cortex in some people

Answer 7

Middle cerebral artery

Question 8

When is the anterior cingulate cortex activated

Answer 8

Pain and depression

Question 9

What does the caudal anterior cingulate register

Answer 9

The quality of pain (how bad on scale of 1-10)

Question 10

What does the rostral anterior cingulate register

Answer 10

What actions to take to deal with the pain

Question 11

Where does nociceptive information travel up

Answer 11

Lateral spinothalamic tract

Question 12

Where does nociceptive information go once travelled up lateral spinothalamic tract

Answer 12

Parabrachial nucleus
Amygdala
Anterior thalamic nucleus
Anterior cingulate cortex and insula

Question 13

What area of the brain is responsible for processing the unpleasantness of the pain and its emotional consequences

Answer 13

Anterior cingulate cortex and insula

Question 14

What area of the brain is activated to ‘do something’ about the pain

Answer 14

Prefrontal cortex

Question 15

What is a cingulotomy

Answer 15

Procedure of cutting the cingulate fibres to disrupt the fibres passing rostro-caudally reducing the emotional distress of pain

Question 16

What % of people report improvement post cingulotomoy?

What % didn’t need painkillers anymore

Answer 16

72% report improvement

50% report reduction for need of painkillers

Question 17

What is the orbitofrontal cortex involved in

Answer 17

Reacted to an anticipated threat (eg actions to avoid more pain)

Question 18

How does the behaviours associated with orbitofrontal cortex differ in people with OCD

Answer 18

• In a difficult decision, person may be unable to respond to threat and ‘freeze’
• Prolonged pressure to make these choices00> OCD

Question 19

When does the posterior cingulate cortex show activity

Answer 19

When recalling memories with emotional significance

Question 20

Where do the parahippocampal gyrus lie

Answer 20

Medially and inferiorly on temporal lobe

Question 21

What is the parahippocampal gyrus involved in primarily

Answer 21

Acquisition of new memories

Question 22

What 2 structures are the subcortical parts of the limbic system

Answer 22

Hippocampus and amygdala

Question 23

Where are the hippocampus and amygdala located

Answer 23

Walls of the inferior horn of lateral ventricles

Question 24

What do the output fibres from the hippocampus form

Answer 24

The fornix

Question 25

What shape does the fornix follow

Answer 25

Curves upwards and round and over the top of the third ventricle

Question 26

Where does the fornix end up lying

Answer 26

Under the corpus collosum

Question 27

How are the fornices attached to the corpus collosum

Answer 27

By the septum pullucidum

Question 28

Where do the fornix axons end

Answer 28

In the septal nuclei and the mammillary body of the hypothalamus

Question 29

Papez's circuit is required for the formation of what

Answer 29

Memories

Question 30

Describe the passage of information in the loop between the hippocampus and the limbic cortex

Answer 30

1) From cingulate cortex to parahippocampal gyrus 2) From parahippocampal gyrus to hippocampus 3) Along fornix to mamillary bodies of the hypothalamus 4) From hypothalamus to anterior thalamus 5) From anterior thalamus back to cingulate cortex

Question 31

What is observed if there is damage to any structure in Papez's loop

Answer 31

Deficits in recall from memory (recollective memory)

Question 32

What are the mammilliary bodies important in

Answer 32

Include olfactory clues in memory of places

Question 33

Is memory stored in the hippocampus

Answer 33

No

Question 34

What are the current views of the hippocampus' role in memory storage

Answer 34

- Labels new experiences with time and place they occured - Transferring new memories to long term memories - Learning new motor skills

Question 35

What is anterograde amnesia

Answer 35

Loss of ability to store new experiences

Question 36

What is Kluver-Bacy due to?

Answer 36

Bilateral removal of amygdala

Question 37

What are the features of Kluver-Bacy syndrome?

Answer 37

``` Psychic blindness Oral tendencies Hypermetamorphosis Altered sexual behaviour Emotional changes ```

Question 38

Where is the amygdala embedded?

Answer 38

In the anterior medial temporal lobe

Question 39

What does electrical stimulation of the amygdala produce

Answer 39

Panic, fear and terror responses

Question 40

What was the loss of fear seen in Kluver-Bacy monkeys attributed to

Answer 40

Removal of amygdala

Question 41

What could be regarded as the command centre for the autonomic nervous system

Answer 41

Amygdala

Question 42

2 main functions of the amygdala

Answer 42

Monitors and analyses sensory input | Activates fight/ flight response

Question 43

Describe the steps that begin with the amygdala and end with sympathetic activation

Answer 43

Amydala--- Hypothalamus--- Reticular formation-- (via reticulospinal tract)-- Preganglionic sympathetic neurones-- Sympathetic activation

Question 44

What is seen if there is local bilatereal damage to the amygdala

Answer 44

Unable to identify fearful expression

Question 45

What is seen if there is complete bilateral damage to the amygdala

Answer 45

Unable if face was sad or extremly sad (eg)

Question 46

What brain structure is hypothesised to be damaged in autism?

Answer 46

Amygdala

Question 47

Inputs from which lobe enable to amygdad to detect if stimulus is associated with pleasure or pain

Answer 47

Temporal

Question 48

What makes up the ventral striatum

Answer 48

Accumbens nuclei Septal nuclei Basal nuclei

Question 49

Where do septal nuclei lie

Answer 49

At the bottom of septum pellucidum | Merges into basal nuclei of meynert

Question 50

What is the accumbens nuclei part of a) anatomically b) functionally

Answer 50

a) basal ganglia | b) limbic system

Question 51

What does the accumbens nuclei receive fibres as part of?

Answer 51

The mesolimbic dopamine pathway

Question 52

Where do fibres in the mesolimbic pathway project from and to

Answer 52

from the brainstem regions next to substantia nigra to the accumbens nuclei

Question 53

What are the mesocortical and mesolimbic pathways

Answer 53

Part of a single diffuse system of dopamine neurones projectedd from VTA to limbic structures and to prefrontal limbic cerebral cortex

Question 54

What happens if you block dopamine pathways in accumbens

Answer 54

Stops pleasure

Question 55

What is the accumbens involved in

Answer 55

Initiation and termination of behaviours that trigger reward pathways