Session 5

Question 1

What are the main roles of the limbic system

Answer 1

Learning

Regulation/translation of our emotional state into appropriate behaviour

Memory

Question 2

What connects the main parts of the limbic system

Answer 2

The papez circuit

Question 3

Where do the olfactory cells in the nasal epithelium project to

Answer 3

• The olfactory bulb to form the olfactory tract

Question 4

What are association fibres

Answer 4

• Axons interconnecting different areas of the cerebral cortex of one hemisphere
• Largest bundle is the superior longitudinal fasciculus

Question 5

What forms the:

• Roof and anterior wall of the lateral ventricle
• The medial wall of the lateral ventricle

Answer 5

• The body and the genu of the corpus callosum

- Fornix and septum pellucidum

Question 6

What is the stria terminalis

Answer 6

• Bundle of white fibres accompanying the curve of the caudate around into the temporal horn of the ventricle
• Connects the amygdala with septal nuclei of hypothalamus

Question 7

What is the Fimbria

Answer 7

• Efferent fibres from hippocampus to fornix

Question 8

What is the caudate nucleus important for

Answer 8

voluntary movement

Question 9

What is the amygdala important for

Answer 9

fear responses

Question 10

Pes hippocampi

Answer 10

The shallow grooves at the anterior end of the hippocampus

Question 11

What do efferents from the hippocampus form

Answer 11

The fimbria, which thickens to form the fornix

Question 12

What is the hippocampus important for

Answer 12

Processes long-term memory and emotional responses

Question 13

What structure shrinks during Alzheimer’s

Answer 13

The hippocampus

Question 14

What can limbic system lesions result in

Answer 14

• Anterograde amnesia
• Generation of emotions and emotional responses in the absence of external stimulation
• Production of inappropriate emotional responses to particular stimuli
• Inability to detect the emotional state of others and inability to regulate our own emotional responses

Question 15

Describe hydrocephalus

Answer 15

• Blockage of CSF flow in ventricles or SAS
• Rise in fluid pressure causing ventricles to swell
• Symptoms and signs include RICP, headache, unsteadiness and mental impairment
• pressure can be relieved by insertion of a shunt connecting the ventricular system to the peritoneum or jugular vein

Question 16

What are the basal ganglia

Answer 16

A collection of subcortical structures important for controlling movement

Question 17

What structures make up the basal ganglia

Answer 17

Caudate nucleus + Putamen = Striatum
Globus pallidus + putamen = lentiform nucleus
subthalamic nuclei
substantia nigra

Question 18

What is the BG course of action

Answer 18

Receive information from the cortex, process it, and transmit it back to the cortex via the thalamus

Question 19

What is the function of the BG

Answer 19

• Permit a selection of desired movements and inhibition of competing movements
• permit smooth and fluid movements
• non-motor functions (cognition and emotion)

Question 20

What is the output of the hippocampus

Answer 20

The fornix, which separates to form columns that descend into mammilary bodies

Question 21

What lies between the striatum and the thalamus

Answer 21

The internal capsule

Question 22

Describe the arrangement of the BG structures from outside to medial

Answer 22

• Extreme capsule
• Claustrum
• External capsule
• Lentiform nucleus (putamen and GP)
• Putamen and GP separated by lateral medullary lamina
• External segment of GP
• Medial medullary lamina
• Internal segment of GP

Question 23

Nucleus Accumbens

Answer 23

• Where the caudate and putamen meet
• Receives dopaminergic input from the VTA in the midbrain
• Reward and addiction behaviour

Question 24

Describe the corpus callosum

Answer 24

• Anterior curve = forceps minor (passes through genu)

- Posterior curve = forceps major (passes through splenium)

Question 25

Parkinson's disease

Answer 25

- Degeneration of dopaminergic neurons of the substantia nigra - Depletion of striatal dopamine levels - Treatment with Levadopa can minimise symptoms - Symptoms include: cog-wheel rigidity, pill-rolling tremor at rest, shuffling, festinant gait (difficulty starting and stopping), bradykinseia (slowing of movements), loss of facial expressions

Question 26

Huntington's disease

Answer 26

- Autosomal dominantly inherited genetic disorder - Symptoms: chorea (overshooting, unintentional movements), personality change, depression, progressive dementia (due to degeneration of striatum and cerebral cortex)

Question 27

Luncar stroke

Answer 27

- The most common type of ischaemic stroke - From occlusion of small penetrating arteries that provide blood to deeper brain structures - Commonly occur in lenticulostriate arteries (a branch of the MCA), which supply parts of the internal capsule

Question 28

What can a stroke affecting the internal capsule cause

Answer 28

- Hemiparesis typically of half the face (ipsilateral), one arm or leg (contralateral) - Ataxic hemiparesis (combination of cerebellar and motor symptoms) most commonly affecting the leg - Mixed sensorimotor stroke of the thalamus is also affected, causing hemiparesis with contralateral sensory impairment

Question 29

Projection fibres

Answer 29

Connect cortical and subcortical regions e.g. the internal capsule

Question 30

What does the olfactory tract divide into?

Answer 30

The medial and lateral olfactory straie

Question 31

Where does the lateral olfactory straie project to?

Answer 31

- The uncus, where the primary olfactory cortex is situated - To the hippocampus and orbitofrontal cortex via the thalamus - Important for the recognition and perception of smells

Question 32

Where does the medial olfactory straie project to?

Answer 32

- The septal nuclei in the hypothalamus | - Olfactory centres connected via the anterior commissure

Question 33

What do connections between the olfactory centres on either side of the brain allow

Answer 33

- Ability to perceive odourant radients (turn our head to the source of the smell)