Thalamus and Hypothalamus

Question 1

Where is the thalamus found within the brain?

Answer 1

The middle of the brain just under the posterior half of the corpus callosum + ventral to the lateral ventricles

Question 2

What separates the 2 halves of the thalamus?

Answer 2

3rd ventricle

Some people have a bridge connecting the 2 halves

Question 3

Describe the connections of the thalamus with the forebrain.

Answer 3

Each half of the thalamus has ipsilateral connections with the forebrain

Question 4

What is the main function of the thalamus?

Answer 4

Key relay centre to cortical sensory areas

Enhances or restricts signals

Question 5

What is the only sensory system not represented within the thalamus?

Answer 5

Olfaction

Question 6

Describe how thalamic nuclei are named.

Answer 6

Named based on their location within the thalamus

Question 7

Which nuclei connect with the motor cortex (primary, premotor and supplementary)?

Answer 7

Ventral lateral

Ventral anterior

Question 8

Which nuclei relay sensory information from different parts of the body?

Answer 8

Head: Ventral posteromedial

Below the neck: Ventral posterolateral

Question 9

To what medial temporal lobe structures do the intralaminar nuclei project too?

Answer 9

Amygdala (emotions, fear, anxiety)
Hippocampus (memory)
Basal ganglia (motor initiation/ movement)

Question 10

Describe the main type of neurones found in the intralaminar nucleus

Answer 10

Glutamatergic

excitatory

Question 11

What is loss of neurones in the intralaminar nuclei region associated with?

Answer 11

Progressive supranuclear palsy

Parkinson’s disease

Question 12

What does the reticular nucleus form?

Answer 12

Outer covering of the thalamus

Question 13

Describe the main type of neurones found in the reticular nucleus

Answer 13

GABAergic

Inhibitory

Question 14

What important system are the intralaminar and reticular nuclei a part of?

Answer 14

Ascending Reticular activating system (ARAS)– involved in maintaining consciousness

Question 15

Describe how the reticular nuclei affect cortical activity.

Answer 15

They have no direct connections with the cortex, but they do have widespread intrathalamic connections with all other thalamic nuclei so it can influence the flow of information from the other nuclei to the cortex

Question 16

What is the set of interconnected pathways in the brainstem involved in the reticular activating system?

Answer 16

Reticular formation

Question 17

Describe the location and structure of the hypothalamus.

Answer 17

Just below the thalamus
Divided in 2 by the 3rd ventricle
Collections of individual nuclei with distinct functions
Largely ipsilateral connections with other nuclei

Question 18

What are the 4 F’s the hypothalamus is involved in?

Answer 18

Fighting
Fleeing
Feeding
Mating

Question 19

State 2 forebrain structures that the hypothalamus has very close connections with

Answer 19

Olfactory system

Limbic system

Question 20

List 4 structures of the limbic system.

Answer 20

Hippocampus
Amygdala
Cingulate Cortex
Septal Nuclei

Question 21

How is the hypothalamus involved in maintaining homeostasis?

Answer 21

It coordinates these different mechanisms to maintain homeostasis:
Autonomic nervous system
Endocrine system
Behaviour

Question 22

Which nucleus is involved in the circadian rhythm?

Answer 22

Suprachiasmatic nucleus

Question 23

How is our behaviour directed towards homeostatic goals?

Answer 23

There is a pleasure centre within the limbic system, which, whenever you’ve achieved homeostasis (e.g. eating food when you’re hungry), the activity of the pleasure centre increases

Question 24

What does the diencephalon consist of?

Answer 24

Thalamus
Hypothalamus
Subthalamic nucleus

Question 25

What is a collection of cell bodies called in the CNS + PNS? What is the exception to this?

Answer 25

CNS: Nuclei
PNS: Ganglia
Exception: Basal ganglia in CNS

Question 26

How do reticula nuclei differ to other thalamic nuclei?

Answer 26

They don’t connect with distal regions

They connect with other thalamic nuclei

Question 27

Where does the reticular nucleus receive inputs from?

Answer 27

Collaterals of axons from other thalamic nuclei

Therefore, acts to modulate thalamic activity (negative feedback)

Question 28

Where does the Paraventricular nucleus send projections to?

Answer 28

Autonomic nervous system (Vasculature, Heart, Kidney)

Posterior pituitary gland (Vasopressin and Oxytocin)

Question 29

What does the suprachiasmatic nucleus control?

Answer 29

Sleep-wake cycles

has connections to Pineal gland which secretes melatonin

Question 30

What may a lesion in the paraventricular nucleus cause?

Answer 30

Loss of inhibitory neurones

Hyperphagia + weight gain

Question 31

What may a lesion in the suprachiasmatic nucleus cause?

Answer 31

A disrupted sleep cycle