Diencephalon

Question 1

Where is the Thalamus located?

Answer 1

In the middle of the brain just under the posterior half of the Corpus Callosum

Question 2

What are the parts of the diencephalon?

Answer 2

Thalamus

Subthalamus

Hypothalamus

Question 3

What is the structure present within the Thalamus?

Answer 3

The 3rd Ventricle - Divides thalamus in two

Question 4

What are Neuroanatomical Nuclei?

Answer 4

Clusters of neurones with similar functions and connections

Question 5

What is contained in the Thalamus?

Answer 5

Collection fo individual nuclei with separate but interconnected functions

They have Ipsilateral connections with the forebrain

(Also 3rd ventricle)

(Note picture is the Left Thalamus)

Question 6

What is the function of the Thalamus?

Answer 6

Relay Centre between the cerebral cortex and the rest of the CNS
Two-way reciprocal connection

There is Integration and Modification of information that passes through

It contains a nucleus for virtually every functional system within the CNS
(Except Olfaction)

Question 7

How are Thalamic nuclei classified?

Answer 7

Based on the connection of the nuclei with the cortex: SARI

Specific: Connected to primary cortical areas

Association: Connected to association cortex

Reticular: Not connected to the cortex

Intralaminar: Connected to all cortical areas

Question 8

What ar ethe Thalamic Nuclei connected to the Motor Cortices?

(Primary, premotor and supplementary Cortices)

Answer 8

Ventral Lateral Nucleus

Ventral Anterior Nucleus

Question 9

What are the two nuclei that relay Somatosensory information?

Answer 9

Ventral Posterolateral (Body)

Ventral Posteromedial (Head)

Question 10

What do the Lateral geniculate and Medial Geniculate nuclei connect to?

Answer 10

Lateral Geniculate - Visual cortex

Medial Geniculate - Auditory cortex

Question 11

Label the Functional Cortical Areas

Answer 11

Question 12

What is the name given to the non-functional cortical areas?

What is it split into?

Answer 12

Association Cortex

Prefrontal Cortex

Parieto-tempero-occipital Cortex

Cingulate cortex

Question 13

Where is the cingulate cortex?

Answer 13

It sits posteriorly to the corpus callosum and ‘follows it round’

(Can be viewed when looking at the medial surface of the cerebral hemisphere)

Question 14

What are the thalamic nuclei connected to the areas of the association cortex?

Answer 14

Cingulate + Prefrontal cortices: Anterior, Lateral Dorsal, Dorsomedial

Parieto-temporo-occipital + Prefrontal Cortices: Lateral Posterior, Pulvinar

Question 15

What is the Reticular Nucleus?
Where is?
What does?
What Neurotransmitter?

Answer 15

Extends over the whole lateral surface of the Thalamus
Has no cortical connections, but connects to nearly all Thalamic Nuclei

GABAergic neurones (inhibitory) that can modulate thalamic activity via negative feedback

Part of the Reticular activating system

Question 16

Where do the Intralaminar Nuclei project?

What do these structures do?

Answer 16

Amygdala: emotions, fear, anxiety

Hippocampus: memory

Basal Ganglia: movement

Question 17

What type of neurones are in the Intralaminar Nuclei?

What is associated with their loss?

Answer 17

Glutamatergic neurones (i.e. excitatory)

Progressive supranuclear palsy
Parkinson’s Disease

Question 18

What is the reticular formation?

What does it do?

Answer 18

Set of interconnected pathways in the brainstem

Send ascending projections to forebrain nuclei:
- Ascending reticular activating system (ARAS)

Involved in consciousness and arousal

Degrees of wakefulness depend on ARAS activity (increased activity = increased wakefulness)

Both intralaminar and reticular nucleus receive inputs from ARAS

Question 19

Where is the Hypothalamus?

What is in proximity to it?
What divides it?

Answer 19

Lies below the Thalamus

Optic chiasm and pituitary stalk are seen just anteriorly to it

It is divided by the third ventricle

Question 20

What are the main functions of the Hypothalamus?

Answer 20

Homeostasis via:
ANS
Endocrine system

Behaviour control

(involved in 4 F’s; Fighting, Fleeing, Feeding, Mating)

Question 21

Which forebrain structures are associated with the Hypothalamus?

Answer 21

Olfactory System

Limbic System (Hippocampus, Amygdala, Cingulate cortex, Septal Nuclei)

Question 22

Which behaviours are controlled by the Hypothalamus?

Answer 22

Eating and Drinking

Expression of emotion

Sexual behaviour

Circadian Rhythm

Memory

Question 23

How does the hypothalamus modulate hunger?

Answer 23

The Arcuate nucleus becomes more active when hungry and communicates with the Paraventricular nucleus to reduce levels of satiety peptides/hormones making you go and eat

Question 24

On what side do Hypothalamic nuclei connect to other nuclei?

Answer 24

Ipsilateral - unlike most nuclei

Question 25

What are the two cell types in the Paraventricular nuclei?

What do they do?

Answer 25

Magnocellular - Stimulates release of hormones from the pituitary

Parvocellular - Controls autonomic outflow

Question 26

Label this diagram of the Hypothalamus:

Answer 26

Question 27

What is the main function of the Suprachiasmatic Nucleus?

Answer 27

Controlling Circadian rhythm

Receives signals about light levels from the eye and connects to the Pineal gland to regulate the production of Melatonin