Neuroscience Chapter: The Thalamus

Questions and Answers

Which artery supplies the ventrolateral region of the thalamus and is known to be very pliable?

Tuberothalamic arteries

Thalamic-subthalamic arteries

Thalamogeniculate arteries (correct)

Posterior choroidal arteries

What is the function of the internal medullary lamina in the thalamus?

It divides the thalamus into medial and lateral halves. (correct)

It separates the thalamus into anterior and posterior parts.

It forms the outer layer of the thalamus.

It provides a cover to the superior surface of the thalamus.

Which artery is also referred to as the polar artery?

Thalamic-subthalamic arteries

Posterior choroidal arteries

Tuberothalamic arteries (correct)

Thalamogeniculate arteries

Which of the following statements about thalamogeniculate arteries is correct?

They are known for being thin like hair and prone to rupture. Signup and view all the answers

Which white matter layer is difficult to identify in MRI due to its thin structure?

Stratum zonale Signup and view all the answers

What type of pain is commonly reported by patients suffering from thalamic pain syndrome?

Constant pain with needle sensation Signup and view all the answers

What is a potential symptom related to temperature sensations in patients with thalamic pain syndrome?

Significant discomfort with temperature changes Signup and view all the answers

What causes the misinterpretation of sensory signals seen in thalamic pain syndrome?

Destruction of the pathways in the brain Signup and view all the answers

What might be an unusual occurrence in patients with an anterior infarction affecting the thalamus?

Thalamic aphasia Signup and view all the answers

Why are thalamic nuclei artery and polar artery considered prone to infarction or hemorrhage?

They are difficult to identify in angiograms due to their small size Signup and view all the answers

Which of the following sensations is typically NOT associated with thalamic pain syndrome?

Sharp pressure Signup and view all the answers

What type of sensory issue is often observed in patients with disruptions in pathways affecting temperature sensation due to stroke?

Misinterpretation of temperature signals Signup and view all the answers

What is a common reporting time for the onset of thalamic pain following a stroke?

Years after the stroke Signup and view all the answers

What anatomical feature does the posterior end of the thalamus predominantly form?

Pulvinar Signup and view all the answers

Which artery supplies mainly the pulvinar region of the thalamus?

Artery of Percheron Signup and view all the answers

In what proportion of the population is the tuberothalamic artery typically absent?

1/3 Signup and view all the answers

What structure is continuous with the inferior surface of the thalamus?

Tegmentum of the midbrain Signup and view all the answers

What is the result of occlusion in the area supplied by the thalamic-subthalamic artery?

Bilateral paramedian thalamic infarction Signup and view all the answers

What anatomical variant involves supplying bilateral paramedian thalami from a single artery?

Artery of Percheron Signup and view all the answers

What is the role of the interthalamic adhesion?

Connecting the left and right thalami Signup and view all the answers

Which of the following best describes the relationship between the pulvinar and the anterior region of the thalamus?

The pulvinar and anterior region are interconnected through blood supply Signup and view all the answers

What autoimmune response can potentially lead to damage of the myelin following infection or vaccination?

Dorsal infarction Signup and view all the answers

Which condition is characterized by loss of myelin due to rapid correction of hyponatremia?

Osmotic demyelinating syndrome Signup and view all the answers

What is the hallmark neuroimaging finding in Fabry disease?

Pulvinar sign with T1 hyperintensity Signup and view all the answers

Which location is NOT commonly associated with extrapontine myelinolysis?

Occipital lobe Signup and view all the answers

What type of brain tumor is Glioblastoma multiforme classified as?

WHO Grade IV Signup and view all the answers

What neurological deficits are commonly observed with dorsal infarction?

Amnesia and hearing loss Signup and view all the answers

Which condition is specifically associated with a mutation in the alpha-galactosidase A gene?

Fabry disease Signup and view all the answers

What is the typical presentation of dorsal hemorrhages or posterior choroidal artery infarcts?

Minimal transient hemiparesis Signup and view all the answers

Which lesion is responsible for contralateral homonymous hemianopia?

Result of LGN lesion Signup and view all the answers

What group of nerve cells is adjacent to the third ventricle?

Midline Nuclei Signup and view all the answers

Which condition is commonly seen in immunocompromised patients, such as those with HIV?

Primary CNS Lymphoma Signup and view all the answers

Which statement describes hemineglect?

Patient does not attend to the side of space contralateral to the lesion. Signup and view all the answers

Which histological feature distinguishes gliomatosis cerebri from other brain lesions?

Homogeneous T2/FLAIR hyperintense signals Signup and view all the answers

What imaging feature is least likely to be seen in glioblastoma multiforme compared to gliomatosis cerebri?

Homogeneous contrast enhancement Signup and view all the answers

In which brain region is lymphoma most commonly found?

Thalamus Signup and view all the answers

What characteristic is most definitive in distinguishing different brain lesions through biopsies?

Presence of necrosis Signup and view all the answers

Study Notes

Posterior End of Thalamus

Expanded to form the pulvinar, characterized as the bumpy end of the thalamus.
Overhangs the superior colliculus, indicating its anatomical position.

Blood Supply to the Thalamus

Supplies posterior thalamus and pulvinar; primarily from the posterior cerebral artery (PCA).
Continuous with the midbrain's tegmentum, facilitating anatomical connections.
Artery of Percheron: a variant where a single unpaired artery from PCA supplies bilateral thalami, affecting rostral areas and propensity for occlusions.
Tuberothalamic artery often missing in roughly one-third of the population; its region supplied by thalamic-subthalamic artery.

Arteries Contributing to Blood Supply

Thalamogeniculate arteries: Originate from P2 PCA or basilar artery, supplying ventrolateral thalamus; susceptible to rupture under high blood pressure.
Tuberothalamic arteries: Also called polar arteries, arise from the Posterior Communicating Artery, supplying anteromedial and anterolateral regions.
Thalamic-subthalamic arteries: Known as paramedian thalamic arteries, arising from P1 PCA, supplying medial thalamus.
Posterior choroidal arteries: These originate from P2 PCA and impact thalamic blood supply.

Internal Organization of the Thalamus

Stratum zonale: A thin white matter layer covering the superior surface, challenging to identify in MRI.
External medullary lamina: Another thin white matter layer on the lateral surface.
Internal medullary lamina: A Y-shaped vertical sheet dividing thalamus into medial and lateral halves.

Thalamic Infarctions and Clinical Conditions

Thalamic pain syndrome: Resulting from disruptions in sensory pathways, causes constant pain, burning sensations, and discomfort with temperature changes.
Anterior infarction typically involves anterior nucleus deficiency, which can lead to thalamic aphasia.
Dorsal infarction from posterior choroidal artery occlusions can cause homonymous quadrantinopia, memory impairments, and other deficits.

Hemorrhage and Associated Conditions

Hemorrhages may cross anatomical boundaries, causing widespread damage, including into the ventricular system.
Fabry Disease: An X-linked lysosomal storage disorder characterized by a "pulvinar sign" on imaging due to calcification.
Osmotic Demyelinating Syndrome (ODS): Results from rapid sodium correction leading to myelin loss, previously known as central pontine myelinolysis.

Glioblastoma Multiforme

A common primary brain tumor, classified as WHO Grade IV, frequently seen in the thalamus and aggressive in nature.

Thalamic Lesions and Conditions

Lesions in various thalamic regions (MGN, LGN, anterior nucleus, dorsothalamic) can lead to contralateral homonymous hemianopia.
Hemineglect syndrome leads to the inability to attend to contralateral space side relative to the lesion's location.

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Description

This quiz focuses on the anatomical features of the thalamus, particularly its posterior end and its relation to nearby structures such as the superior colliculus. It will cover the pulvinar region and explore its significance within the thalamus. Prepare to deepen your understanding of brain anatomy.