Neuroanatomy Practice Questions

Q: Which of the following is not a component of the medial reticular column?

Raphe nuclei. The reticular formation is organized into three longitudinal columns: the **Median (Raphe) column**, the **Medial (Magnocellular) column**, and the **Lateral (Parvocellular) column**. ### 1. Why Raphe Nuclei is the Correct Answer The **Raphe nuclei** constitute the **Median column**, which is located in the mid-sagittal plane of the brainstem. While it is centrally located, it is distinct from the **Medial column**. The Raphe nuclei are primarily serotonergic and are involved in pain modulation and sleep-wake cycles. ### 2. Analysis of Incorrect Options (Components of the Medial Column) The Medial column is also known as the **Magnocellular column** because it contains large neurons. It serves as the primary "effector" area, giving rise to the long ascending and descending tracts (like the reticulospinal tract) [1]. * **Magnocellular nucleus (B):** This is the hallmark nucleus of the medial column, particularly prominent in the medulla and pons. * **Cuneiform and Subcuneiform nuclei (C & D):** These are located in the medial column of the **midbrain** reticular formation. They play a role in motor control and the initiation of locomotion. ### 3. High-Yield Facts for NEET-PG * **Lateral Column (Parvocellular):** Small-celled; primarily "sensory" in function, receiving afferents from cranial nerves and the spinothalamic tract. * **Median Column (Raphe):** The main source of **Serotonin** in the CNS. * **Medial Column:** The main source of the **Reticulospinal tracts**, which regulate muscle tone and posture [1]. * **Clinical Pearl:** The Ascending Reticular Activating System (ARAS), responsible for consciousness, primarily passes through the medial column. Lesions here can lead to irreversible coma.

Q: The vestibulocerebellar tract terminates in which part of the cerebellum?

All of the above. The **vestibulocerebellar tract** is the primary afferent pathway of the **vestibulocerebellum** (archicerebellum), which is the oldest part of the cerebellum phylogenetically. Its primary role is the maintenance of equilibrium, posture, and coordination of eye movements [2]. ### **Explanation of the Correct Answer** The vestibulocerebellar fibers originate from the vestibular nuclei (secondary fibers) and the vestibular ganglion (primary fibers). These fibers enter the cerebellum through the **inferior cerebellar peduncle** and terminate in the **flocculonodular lobe** [1]. This lobe is anatomically composed of: 1. **The Flocculus:** Paired lateral structures. 2. **The Nodulus:** The most inferior part of the vermis. 3. **The Uvula:** While often grouped with the paleocerebellum, the uvula (specifically the ventral part) receives significant direct vestibular input. Therefore, since the tract projects to the flocculus, nodulus, and the uvula, **Option D (All of the above)** is the correct answer. ### **Why Other Options are Incomplete** * **Options A & B:** While both the Flocculus and Nodulus are major termination sites [2], selecting either one individually would be incomplete. * **Option C:** The Uvula is frequently tested as a

Q: Cyclosporine is an:

Immunosuppressant. **Explanation:** **Cyclosporine** is a potent **calcineurin inhibitor** primarily used as an **immunosuppressant**. Its mechanism of action involves binding to an intracellular protein called cyclophilin [1]. This complex inhibits calcineurin, a phosphatase required for the activation of the transcription factor NFAT (Nuclear Factor of Activated T-cells) [1]. Consequently, the transcription of **Interleukin-2 (IL-2)** is blocked, preventing the proliferation and activation of T-lymphocytes [1]. **Analysis of Options:** * **Option D (Correct):** As a calcineurin inhibitor, Cyclosporine suppresses cell-mediated immunity, making it a cornerstone therapy in preventing organ transplant rejection (e.g., kidney, liver, heart) and treating autoimmune conditions like psoriasis and rheumatoid arthritis [1]. * **Option A:** While some drugs have antioxidant properties to reduce oxidative stress, Cyclosporine does not function via this pathway. * **Option B:** Cyclosporine does the opposite of a booster; it suppresses the immune system, which actually increases the risk of opportunistic infections. * **Option C:** Although it was originally isolated from a fungus (*Tolypocladium inflatum*), it lacks significant antibacterial activity and is classified strictly by its immunomodulatory effects [2]. **NEET-PG High-Yield Pearls:** * **Side Effects (The "6 Gs"):** **G**ingival hyperplasia, **G**lucose intolerance (Hyperglycemia), **G**out (Hyperuricemia), **G**rowth of hair (Hirsutism), **G**astrointestinal upset, and **G**enotoxicity (though Nephrotoxicity is the most significant dose-limiting side effect) [2]. * **Metabolism:** It is metabolized by the **CYP3A4** enzyme system; therefore, grapefruit juice increases its toxicity. * **Comparison:** Unlike Tacrolimus (another calcineurin inhibitor), Cyclosporine is more frequently associated with hirsutism and gingival hyperplasia [2].

Q: The anterior inferior cerebellar artery is a branch of which artery?

Basilar artery. **Explanation:** The **Anterior Inferior Cerebellar Artery (AICA)** is a major branch of the **Basilar artery**. The basilar artery is formed by the union of the two vertebral arteries at the lower border of the pons. It gives off several branches before bifurcating into the posterior cerebral arteries. The AICA typically arises from the lower third of the basilar artery and supplies the anterior part of the inferior surface of the cerebellum, the lower pons, and often gives rise to the labyrinthine artery. **Analysis of Options:** * **Subclavian artery (A):** This is the parent vessel of the vertebral artery, but it does not directly supply the brain or cerebellum. * **Vertebral artery (B):** While the vertebral artery gives rise to the **Posterior Inferior Cerebellar Artery (PICA)**, it does not give off the AICA. This is a common point of confusion for students. * **Middle cerebral artery (D):** This is a branch of the internal carotid artery and is part of the anterior circulation, supplying the lateral surface of the cerebral hemispheres, not the cerebellum. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of "S":** The **S**uperior Cerebellar Artery (SCA) and **A**ICA arise from the **Basilar** artery, while **P**ICA arises from the **Vertebral** artery. * **AICA Syndrome:** Occlusion can lead to lateral pontine syndrome, characterized by ipsilateral facial paralysis, deafness (labyrinthine artery involvement), and vestibular symptoms. * **Relationship to Nerves:** The AICA is closely related to the **CN VI (Abducens)**, **CN VII (Facial)**, and **CN VIII (Vestibulocochlear)** nerves. It often loops around the nerves in the cerebellopontine angle.

Q: The cranial nerve nucleus supplying the marked muscle lies at the level of:

Superior colliculus. ***Superior colliculus*** - The **oculomotor nucleus (CN III)** is located at the level of the **superior colliculus** in the midbrain, supplying most extraocular muscles including **medial rectus**, **inferior rectus**, **superior rectus**, **inferior oblique**, and **levator palpebrae superioris**. - This anatomical relationship is a key landmark for identifying the **rostral midbrain** level in neuroanatomy. *Inferior colliculus* - The **trochlear nucleus (CN IV)** is located at the level of the **inferior colliculus** in the caudal midbrain, not CN III. - CN IV supplies only the **superior oblique muscle**, which is not the muscle referenced in this question. *Facial colliculus* - The **facial colliculus** is formed by **CN VII fibers** looping around the **abducens nucleus (CN VI)** in the **rostral pons**. - CN VI supplies the **lateral rectus muscle**, while CN VII supplies **facial muscles**, neither being CN III-innervated extraocular muscles. *Olive* - The **olive** is located in the **rostral medulla**, where the **hypoglossal nucleus (CN XII)** is found. - CN XII supplies **tongue muscles**, not extraocular muscles, and is anatomically distant from the midbrain CN III nucleus.

Q: In which nucleus does the dorsal column relay occur?

Gracile nucleus. **Explanation:** The **Dorsal Column-Medial Lemniscus (DCML) pathway** is responsible for transmitting fine touch, conscious proprioception, and vibration sense. The first-order neurons (pseudounipolar neurons in the dorsal root ganglion) ascend ipsilaterally in the spinal cord via the **Fasciculus Gracilis** (medial; carrying fibers from lower limbs/T6 and below) and **Fasciculus Cuneatus** (lateral; carrying fibers from upper limbs/above T6). These fibers reach the lower medulla, where they relay (synapse) in the **Gracile nucleus** and **Cuneate nucleus**, respectively [1]. Therefore, the Gracile nucleus is a primary relay station for this pathway. **Analysis of Incorrect Options:** * **Substantia gelatinosa (Rexed Lamina II):** Located in the dorsal horn of the spinal cord, it primarily processes pain and temperature (Lateral Spinothalamic tract) [1]. * **Nucleus proprius (Rexed Lamina III & IV):** Located in the dorsal horn, it serves as a relay for crude touch and pressure (Anterior Spinothalamic tract). * **Accessory cuneate nucleus:** This nucleus receives unconscious proprioceptive fibers from the upper limbs and relays them to the cerebellum via the **Cuneocerebellar tract**, not the conscious DCML pathway. **High-Yield Facts for NEET-PG:** * **Decussation:** Second-order neurons from the Gracile/Cuneate nuclei cross as **Internal Arcuate Fibers** to form the Medial Lemniscus [1]. * **Somatotopy:** In the Medial Lemniscus (Medulla), the "little man" stands upright (sacral fibers are ventral), but in the Pons/Midbrain, he "lies down" (sacral fibers move lateral) [1]. * **Clinical Correlation:** Lesions of the dorsal columns result in **Tabes Dorsalis** (syphilis) or Subacute Combined Degeneration (B12 deficiency), leading to sensory ataxia and a positive Romberg’s sign.

Q: All of the following cranial nerves contain somatic efferents except?

7th nerve. To answer this question, it is essential to distinguish between **General Somatic Efferent (GSE)** and **Special Visceral Efferent (SVE)** functional columns. ### **1. Why the 7th Nerve (Facial Nerve) is the Correct Answer** The 7th cranial nerve does **not** contain General Somatic Efferent (GSE) fibers. Instead, the motor fibers that supply the muscles of facial expression are classified as **Special Visceral Efferent (SVE)** (also known as Branchial Efferent). This is because these muscles are derived from the **2nd pharyngeal arch**, not from somites. ### **2. Why the Other Options are Incorrect** The GSE column supplies muscles derived from **embryonic somites** (specifically the pre-otic and occipital somites). * **12th Nerve (Hypoglossal):** Contains GSE fibers to supply the intrinsic and extrinsic muscles of the tongue (except palatoglossus). * **4th Nerve (Trochlear):** Contains GSE fibers to supply the Superior Oblique extraocular muscle. * **6th Nerve (Abducent):** Contains GSE fibers to supply the Lateral Rectus extraocular muscle. *(Note: The 3rd nerve also contains GSE fibers for the remaining extraocular muscles). ### **3. High-Yield Clinical Pearls for NEET-PG** * **GSE Mnemonic:** Remember **3, 4, 6, and 12**. These nerves supply "pure" skeletal muscles (extraocular and tongue) and are located near the midline of the brainstem. * **SVE (Branchial Efferents):** These supply muscles derived from pharyngeal arches. The nerves are **5 (1st arch), 7 (2nd arch), 9 (3rd arch), and 10 (4th/6th arches)**. * **Nucleus of 7th Nerve:** The motor nucleus of the facial nerve is located in the pons; its fibers loop around the 6th nerve nucleus (forming the facial colliculus) before exiting the brainstem.

Q: Which artery is involved in Wallenberg syndrome?

Artery D. ***Artery D*** - **Posterior Inferior Cerebellar Artery (PICA)** occlusion causes **Wallenberg syndrome** (lateral medullary syndrome). - Results in characteristic symptoms including **ipsilateral facial numbness**, **contralateral body numbness**, **dysphagia**, and **ataxia**. *Artery A* - Does not supply the **lateral medulla** where Wallenberg syndrome pathology occurs. - Occlusion would cause different neurological deficits not consistent with **lateral medullary syndrome**. *Artery B* - Not the primary vessel responsible for **lateral medullary** blood supply. - Involvement would produce alternative stroke syndromes without the classic **PICA territory** features. *Artery C* - Does not correspond to the **PICA distribution** necessary for Wallenberg syndrome. - Occlusion would result in different anatomical areas affected, lacking the **dorsolateral medullary** involvement.

Q: Wallenberg's syndrome does not involve which cranial nerve?

Cranial Nerve XII. Explanation: Wallenberg’s Syndrome, also known as **Lateral Medullary Syndrome**, results from the occlusion of the **Posterior Inferior Cerebellar Artery (PICA)** or the vertebral artery. The syndrome affects the lateral portion of the medulla oblongata. **Why Option D is Correct:** The **Hypoglossal nerve (CN XII)** nucleus and its exiting fibers are located in the **medial medulla**. Therefore, CN XII is involved in Medial Medullary Syndrome (Dejerine syndrome), presenting with ipsilateral tongue deviation. Because Wallenberg’s syndrome is strictly a lateral medullary event, the medial structures—including the hypoglossal nucleus, the medial lemniscus, and the corticospinal tract—are characteristically **spared**. **Why Incorrect Options are Wrong:** * **Options A & B (CN IX and X):** The **Nucleus Ambiguus** is located in the lateral medulla. Damage to this nucleus affects the glossopharyngeal (IX) and vagus (X) nerves, leading to dysphagia, dysarthria, and loss of the gag reflex. * **Option C (CN XI):** While the spinal portion of CN XI arises from the cervical cord, the cranial accessory fibers (which join the vagus) originate from the nucleus ambiguus in the lateral medulla. In the context of NEET-PG, CN IX and X are the primary clinical markers, but CN XII is the definitive "outlier" due to its medial location. **High-Yield Clinical Pearls for NEET-PG:** * **PICA occlusion** is the classic cause. * **Key Features:** Ipsilateral Horner’s syndrome, ipsilateral ataxia (inferior cerebellar peduncle), and loss of pain/temperature on the **ipsilateral face** (Trigeminal spinal nucleus) but **contralateral body** (Lateral spinothalamic tract). * **Mnemonic:** "Lateral is Lower (CN IX, X) and Medial is Midline (CN XII)."

Question 1

Which of the following is not a component of the medial reticular column?

Accepted Answer

Raphe nuclei

Answer

Magnocellular nucleus

Answer

Subcuneiform nucleus

Answer

Cuneiform nucleus

Question 2

The vestibulocerebellar tract terminates in which part of the cerebellum?

Accepted Answer

All of the above

Answer

Flocculus

Answer

Nodulus

Answer

Uvula

Question 3

Cyclosporine is an:

Accepted Answer

Immunosuppressant

Answer

Antioxidant

Answer

Immunity booster

Answer

Antibiotic

Question 4

The anterior inferior cerebellar artery is a branch of which artery?

Accepted Answer

Basilar artery

Answer

Subclavian artery

Answer

Vertebral artery

Answer

Middle cerebral artery

Question 5

The cranial nerve nucleus supplying the marked muscle lies at the level of:

Accepted Answer

Superior colliculus

Answer

Inferior colliculus

Answer

Facial colliculus

Answer

Olive

Question 6

Transection of the anterolateral spinothalamic tract results in what kind of sensory deficit?

Accepted Answer

Loss of pain and temperature sensation

Answer

Areflexia

Answer

Cerebellar incoordination

Answer

Complete flaccid paralysis

Question 7

In which nucleus does the dorsal column relay occur?

Accepted Answer

Gracile nucleus

Answer

Substantia gelatinosa

Answer

Nucleus proprius

Answer

Accessory cuneate nucleus

Question 8

All of the following cranial nerves contain somatic efferents except?

Accepted Answer

7th nerve

Answer

12th nerve

Answer

4th nerve

Answer

6th nerve

Question 9

Which artery is involved in Wallenberg syndrome?

Accepted Answer

Artery D

Answer

Artery A

Answer

Artery B

Answer

Artery C

Question 10

Wallenberg's syndrome does not involve which cranial nerve?

Accepted Answer

Cranial Nerve XII

Answer

Cranial Nerve IX

Answer

Cranial Nerve X

Answer

Cranial Nerve XI

Neuroanatomy — MCQs

Neuroanatomy — MCQs

On this page

Practice by Chapter

Want unlimited practice?