Thalamus Flashcards

Examine thalamic anatomy, including its nuclei, sensory and motor relay pathways, cortical connections, blood supply, and clinical significance.

Card 1 of 30Question

What is the thalamus?

A paired mass of gray matter in the diencephalon that relays and processes information between subcortical structures and the cerebral cortex.

In This Section

1. What is the thalamus?

A paired mass of gray matter in the diencephalon that relays and processes information between subcortical structures and the cerebral cortex.

2. Where is the thalamus located?

On either side of the third ventricle, superior to the hypothalamus and medial to the internal capsule.

3. Which ventricular cavity is bordered laterally by the medial surfaces of the thalami?

The third ventricle.

4. Which sulcus separates the thalamus from the hypothalamus?

The hypothalamic sulcus.

5. What is the interthalamic adhesion?

A variable bridge of gray matter connecting the medial surfaces of the two thalami across the third ventricle.

6. What is the internal medullary lamina of the thalamus?

A Y-shaped sheet of myelinated fibers dividing the thalamus into major nuclear groups.

7. What are the three major nuclear groups separated by the internal medullary lamina?

The anterior, medial, and lateral nuclear groups.

8. Which thalamic nuclei lie within the internal medullary lamina?

The intralaminar nuclei, including the centromedian and parafascicular nuclei.

9. Which thalamic nucleus forms a thin shell around much of the lateral surface of the thalamus?

The thalamic reticular nucleus.

10. What is the principal neurotransmitter released by neurons of the thalamic reticular nucleus?

Gamma-aminobutyric acid (GABA), which inhibits other thalamic neurons.

11. Which thalamic nucleus receives somatosensory information from the body?

The ventral posterolateral nucleus (VPL).

12. Which ascending pathways terminate primarily in the ventral posterolateral nucleus?

The medial lemniscus and spinothalamic pathways.

13. Which thalamic nucleus relays somatosensory information from the face?

The ventral posteromedial nucleus (VPM).

14. Which thalamic structure relays visual information to the primary visual cortex?

The lateral geniculate nucleus.

15. Which thalamic structure relays auditory information to the primary auditory cortex?

The medial geniculate nucleus.

16. Which thalamic nucleus relays major motor-related signals from the cerebellum?

The ventral lateral nucleus (VL).

17. Which thalamic nucleus receives major input from the globus pallidus internus and substantia nigra pars reticulata?

The ventral anterior nucleus (VA), with related input also reaching motor territories of VL.

18. Which thalamic nucleus receives input from the mammillary bodies through the mammillothalamic tract?

The anterior thalamic nucleus.

19. What is the principal functional significance of the anterior thalamic nuclei?

They participate in limbic circuits involved in memory and spatial navigation.

20. Which thalamic nucleus has extensive reciprocal connections with the prefrontal cortex?

The mediodorsal nucleus, also called the dorsomedial nucleus.

21. What functions are associated with the mediodorsal thalamic nucleus?

Executive processing, motivation, memory, and emotional regulation.

22. Which thalamic nuclear complex is associated with attention and integration of sensory information?

The pulvinar complex.

23. What is the pulvinar of the thalamus?

The enlarged posterior portion of the thalamus containing higher-order association nuclei.

24. Which sensory modality reaches its primary cerebral cortex without an obligatory initial thalamic relay?

Olfaction.

25. What are thalamocortical radiations?

Bundles of projection fibers connecting thalamic nuclei with the cerebral cortex.

26. Through which major white matter structure do many thalamocortical fibers travel?

The internal capsule.

27. Which major arterial systems supply the thalamus?

Branches of the posterior cerebral and posterior communicating arteries.

28. What is the artery of Percheron?

An arterial variant in which a single perforating vessel supplies portions of both paramedian thalami.

29. What sensory deficit commonly follows a unilateral lesion of the ventral posterior thalamic nuclei?

Contralateral hemisensory loss involving the face, arm, and leg.

30. What is thalamic pain syndrome?

A central neuropathic pain syndrome that may develop after a thalamic lesion, particularly a stroke affecting sensory pathways.