Limbic System

Question 1

OLFACTORY SYSTEM can recognise X-Y number of different odours

Answer 1

2000-4000

Question 2

Where is the Olfactory epithelium

Answer 2

in upper part of nose

Question 3

primary neurons of the olfactory system are …

Answer 3

Bipolar olfactory neurons

Question 4

support neurons of the olfactory system are …

Answer 4

Sustentacular cells

Question 5

• Olfactory receptor cells (bipolar) project into the XX and interact with second order neurons

Answer 5

Olfactory bulb

Question 6

second order olfactory neurons, which are called project to… (along XX to YYY and then ZZ and ZZ)

Answer 6

to olfactory tract and then split into medial and lateral olfactory stria which then go to the piriform cortex of temporal lobe and orbitofrontal cortex

Question 7

the 2nd order neurons of the olfactory system are…

Answer 7

mitral cells

Question 8

Olfactory mitral cells are found in ….

Answer 8

olfactory bulb

Question 9

the 2 cortices of the olfactory system are….

Answer 9

piriform cortex of temporal lobe and orbitofrontal cortex

Question 10

ANOSMIA is…

Answer 10

Clinical deficit in response to smell

Question 11

Loss of smell is common in people developing what? (2)

Answer 11

Parkinson’s (and also Alzheimer’s)

Question 12

What is the role of the limbic system? (4)

Answer 12

 Maintenance of homeostasis vis activation of visceral effector mechanisms, modulation of pituitary hormone release and initiation of feeding and drinking
 Agonistic (defence and attack) behaviour
 Sexual and reproductive behaviour
 Memory

Question 13

Describe the Papez circuit starting with experiencing an emotional experience in the cingulate cortex:

Describe circuit
Where does emotional colouring interplay?
Where is emotional expression?

Answer 13

Emotional experience -> informs cingulate cortex -> propagates to the hippocampus via cingulum bundle -> hippocampus outputs to the hypothalamus mammillary bodies via the fornix -> hypothalamus outputs to the anterior nucleus of the thalamus via the mammillo-thalamic tract -> this projects to the cingulate cortex again

Neocortex provides emotional colouring to the cingulate cortex

Emotional expression is hypothalamic

Question 14

Hippocampus: main connections (afferent and efferent?)

What is each pathway involved in?

Answer 14

• Afferent: Perforant pathway- part of the memory encoding process
  (also from cingulate cortex)
• Efferent: Fimbria/fornix- all about memory and learning

Question 15

Hippocampus: function? (2)

Answer 15

• Memory and learning

Question 16

Hippocampus: clinical problems that can arise in the hippocampus? (2)

Answer 16

• Alzheimer’s disease (short-term memory problems), epilepsy (many epileptic foci are in the temporal lobe- where the hippocampus is embedded)

Question 17

which lobe is the hippocampus in?

Answer 17

Temporal

Question 18

Hippocampus sits on the floor of the …

Answer 18

lateral ventricle

Question 19

Fornices of the hippocampus terminate in the…

Answer 19

mammillary bodies of the hypothalamus

Question 20

Alzheimer’s pathology at the cellular level looks like X and Y

Answer 20

tangles and plaques

Question 21

Which parts of the brain are affected in the early stages of Alzheimers and what does this lead to

Answer 21

• Hippocampus and entorhinal cortex affected

- This leads to short-term memory problems

Question 22

Which parts of the brain are affected in the moderate stages of Alzheimers and what does this lead to

Answer 22

• Parietal lobe affected

- This leads to dressing apraxia (inability to dress oneself)

Question 23

Which parts of the brain are affected in the late stages of Alzheimers and what does this lead to

Answer 23

• Frontal lobe affected

- This leads to loss of executive skills

Question 24

Amygdala: main connections (afferent (5) and efferent?)

Answer 24

• Afferent Olfactory cortex, septum, temporal neocortex, hippocampus, brainstem
• Efferent Stria terminalis

Question 25

Amygdala: main functions? (4)

Answer 25

- Fear and anxiety | - Fight or flight

Question 26

Amygdala: clinical problems can arise in the Amygdala? (2)

Answer 26

- Bilateral damage to amygdala can lead to KLUVER-BUCY SYNDROME

Question 27

Amygdala: location?

Answer 27

- In the white matter of the anterior part of the temporal lobe - A medial temporal lobe structure - No ventricle should be seen on image - Anterior to hippocampus

Question 28

What is Kluver Bucy syndrome? (4)

Answer 28

- Hyperorality (putting everything in mouth) - Loss of fear - Visual agnosia (can’t recognise things) - Hypersexuality

Question 29

Structures associated with aggression? (3 and 1 can be specific)

Answer 29

- Hypothalamus (anterior parts) - Brainstem (Midbrain- grey matter around the cerebral aqueduct- periaqueductal grey) - Amygdala

Question 30

What NT and nuclei is involved in aggression?

Answer 30

is 5-HT (serotonin) in raphe nuclei (just below the PAG)

Question 31

What is the septum of the brain inbetween

Answer 31

SEPTUM (membrane between the 2 lateral ventricles anteriorly):

Question 32

Connections of the septum (afferent (4) efferent (3)

Answer 32

- Afferent Amygdala, olfactory tract, hippocampus, brainstem - Efferent Stria medularis thalami, hippocampus, hypothalamus

Question 33

Function of the septum?

Answer 33

- Reinforcement and reward

Question 34

Dopaminergic mesolimbic system neurons in the midbrain have fibres that project via the XXX

Answer 34

the median forebrain bundle

Question 35

the median forebrain bundle projects to .... (3)

Answer 35

- They go to the nucleus accumbens (area we are interested in) but also the cortex and amygdala

Question 36

Where does the mesolimbic pathway start?

Answer 36

ventral tegmental area (VTN

Question 37

What side effect of dopamine pathway potentiation in treating Parkinsons do we have to look out for?

Answer 37

pathological gambling

Question 38

A, B, C, D and E all increase DA release in the nucleus accumbens

Answer 38

Opioids, nicotine, amphetamines, ethanol and cocaine