Thalamus

Question 1

What is the main purpose of the thalamus?

Answer 1

Relay and integration station for information en route to the cortex

Question 2

What are the major derivatives in the adult brain of the telencephalon?

What are the associated cavities in the mature brain?

Answer 2

• Cerebral hemispheres, including corpus striatum
• Lateral ventricle

Question 3

What are the major derivatives in the adult brain of the diencephalon?

What are the associated cavities in the mature brain?

Answer 3

• Thalamus
• Hypothalamus
• Third ventricle

Question 4

What are the major derivatives in the adult brain of the mesencephalon?

What are the associated cavities in the mature brain?

Answer 4

• Midbrain
• Cerebral aqueduct

Question 5

What are the major derivatives in the adult brain of the metencephalon?

What are the associated cavities in the mature brain?

Answer 5

• Pons
• Cerebellum
• Upper portion of fourth ventricle

Question 6

What are the major derivatives in the adult brain of the myelencephalon?

What are the associated cavities in the mature brain?

Answer 6

• Medulla oblongata
• Lower portion of the fourth ventricle

Question 7

Identify the structure indicated by the arrow

Answer 7

Pinneal gland

Question 8

Identify the structure indicated by the arrow

Answer 8

Posterior commissure

Question 9

Identify the structures indicated by the arrows

Answer 9

This section is too far anterior to include the thalamus

Question 10

Identify the structure indicated by the arrow

Answer 10

This section is so far posterior that only a small part of the thalamus is present

Question 11

Identify the structures indicated by the arrows

Answer 11

Question 12

All nuclei of the thalamus send fibres to the cerebral cortex except one. Which nucleus is the exception?

What is its function?

Answer 12

Reticular nucleus

Inhibits other thalamuc nuclei - possible role in suppressing sensory input to the cortex in sleep.

Question 13

Describe the reticular nucleus of the thalamus

Answer 13

• Thin sheet of grey matter on the lateral surface of the thalamus.
• Sends inhibitory fibres to all of the nuclei of the thalamus.

Question 14

Identify the structure indicated by the arrow

Answer 14

Ventral anterior nucleus of the thalamus

Question 15

Identify the structure indicated by the arrow

Answer 15

Lateral dorsal nucleus of the thalamus

Question 16

Identify the structure indicated by the arrow

Answer 16

Ventral lateral nucleus of the thalamus

Question 17

Identify the structure indicated by the arrow

Answer 17

Lateral posterior nucleus of the thalamus

Question 18

Identify the structure indicated by the arrow

Answer 18

Ventral posterior nucleus of the thalamus

Question 19

Identify the structure indicated by the arrow

Answer 19

Pulvinar of the thalamus

Question 20

Identify the structure indicated by the arrow

Answer 20

Medial geniculate body of the thalamus

Question 21

Identify the structure indicated by the arrow

Answer 21

Lateral geniculate body of the thalamus

Question 22

Identify the structure indicated by the arrow

Answer 22

Internal medullary lamina of the thalamus

Question 23

Identify the structure indicated by the arrow

Answer 23

Mediodorsal nucleus of the thalamus

Question 24

Identify the structure indicated by the arrow

Answer 24

Massa intermedia of the thalamus (also known as interthalamic adhesion)

Question 25

Identify the structure indicated by the arrow

Answer 25

Anterior nucleus of the thalamus

Question 26

Identify the structure indicated by the arrow

Answer 26

Centromedian nucleus of the thalamus

Question 27

Identify the structure indicated by the arrow

Answer 27

Ventral posterior nucleus of the thalamus

Question 28

Identify the structure indicated by the arrow

Answer 28

Parafasicular nucleus of the thalamus

Question 29

Identify the structure indicated by the arrow

Answer 29

Mediodorsal nucleus of the thalamus

Question 30

Which thalamic nuclei are included in the intralaminar group? ## Footnote **What is this group responsible for?**

Answer 30

* Centromedian nucleus * Parafasicular nucleus * **Arousal from sleep** * **Sensation of pain** Extensive connections to the cortex

Question 31

Which thalamic nuclei are included in the ventral group? ## Footnote **What is this group responsible for?**

Answer 31

* Ventral posterior nucleus - **relay centre for somatosensation.** * Ventral lateral nucleus - **relay in cerebellar and basal ganglia circuits to the motor and premotor cortex.** * Ventral anterior nucleus - **same as ventral lateral ^** * Lateral geniculate body - **relay for vision** * Medial geniculate body - **relay for audition**

Question 32

Which thalamic nuclei are included in the lateral group? ## Footnote **What is this group responsible for?**

Answer 32

* Pulvinar * Lateral dorsal nucleus * Lateral posterior nucleus * **Extensive connections to the cortex. May be important for i****Interpretation of visual stimuli, among other functions**

Question 33

Which thalamic nuclei are included in the medial group? ## Footnote **What is this group responsible for?**

Answer 33

* Anterior nucleus - **input to cingulate gyrus, part of circuit of papez and important in memory.** * Mediodorsal nucleus - **input to prefrontal cortex, involved in decisions based on predictions and memory.**

Question 34

Which input does the ventroposteromedial nucleus of the thalamus send to the somatosensory cortex?

Answer 34

Sensory input from the head

Question 35

Which input does the ventroposterolateral nucleus of the thalamus send to the somatosensory cortex?

Answer 35

Sensory input from the body

Question 36

Which input does the lateral geniculate body have and to where?

Answer 36

Input from the optic nerves to the primary visual cortex

Question 37

Which input does the medial geniculate body have and to where?

Answer 37

Input from auditory system to the auditory cortex

Question 38

Which input goes from the thalamic nuclei to the motor cortex?

Answer 38

* Ventrolateral nucleus sends input to the motor cortex from the cerebellum. * Ventroanterior nucleus sends input to the motor cortex from the basal ganglia.

Question 39

What is the mediodorsal nucleus of the thalamus responsible for?

Answer 39

* Emotion and subjective responses * Integration with sensory information * Connects to: * Prefrontal gyrus * Hypothalamus * Other thalamic nuclei * Also receives output from these same regions

Question 40

What is the anterior nucles of the thalamus responsible for?

Answer 40

* Memory * Instinctive behaviour * Connects with the limbic system - mainly via the cingulate gyrus and hypothalamus. * Also receives input from these regions

Question 41

What are the intralaminar nuclei of the thalamus responsible for?

Answer 41

* Influences level of consciousness and alertness * Connects with several other thalamic nuclei and so projects widely to the cortex. * Receives input from the reticular formation and spinal sensory systems.

Question 42

What is the reticular nucleus of the thalamus?

Answer 42

Thin covering over the lateral part of the thalamus